vendor: update buildkit to opentelemetry support

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/go.opentelemetry.io/otel/.gitattributes

@@ -0,0 +1,3 @@
+* text=auto eol=lf
+*.{cmd,[cC][mM][dD]} text eol=crlf
+*.{bat,[bB][aA][tT]} text eol=crlf

vendor/go.opentelemetry.io/otel/.gitignore

@@ -0,0 +1,20 @@
+.DS_Store
+Thumbs.db
+
+.tools/
+.idea/
+.vscode/
+*.iml
+*.so
+coverage.*
+
+gen/
+
+/example/jaeger/jaeger
+/example/namedtracer/namedtracer
+/example/opencensus/opencensus
+/example/passthrough/passthrough
+/example/prometheus/prometheus
+/example/prom-collector/prom-collector
+/example/zipkin/zipkin
+/example/otel-collector/otel-collector

vendor/go.opentelemetry.io/otel/.gitmodules

@@ -0,0 +1,3 @@
+[submodule "opentelemetry-proto"]
+	path = exporters/otlp/internal/opentelemetry-proto
+	url = https://github.com/open-telemetry/opentelemetry-proto

vendor/go.opentelemetry.io/otel/.golangci.yml

@@ -0,0 +1,32 @@
+# See https://github.com/golangci/golangci-lint#config-file
+run:
+  issues-exit-code: 1 #Default
+  tests: true #Default
+
+linters:
+  enable:
+    - misspell
+    - goimports
+    - revive
+    - gofmt
+
+issues:
+  exclude-rules:
+    # helpers in tests often (rightfully) pass a *testing.T as their first argument
+    - path: _test\.go
+      text: "context.Context should be the first parameter of a function"
+      linters:
+        - revive
+    # Yes, they are, but it's okay in a test
+    - path: _test\.go
+      text: "exported func.*returns unexported type.*which can be annoying to use"
+      linters:
+        - revive
+
+linters-settings:
+  misspell:
+    locale: US
+    ignore-words:
+      - cancelled
+  goimports:
+    local-prefixes: go.opentelemetry.io

vendor/go.opentelemetry.io/otel/.markdown-link.json

@@ -0,0 +1,16 @@
+{
+    "ignorePatterns": [
+        {
+            "pattern": "^http(s)?://localhost"
+        }
+    ],
+    "replacementPatterns": [
+        {
+            "pattern": "^/registry",
+            "replacement": "https://opentelemetry.io/registry"
+        }
+    ],
+    "retryOn429": true,
+    "retryCount": 5,
+    "fallbackRetryDelay": "30s"
+}

vendor/go.opentelemetry.io/otel/.markdownlint.yaml

@@ -0,0 +1,29 @@
+# Default state for all rules
+default: true
+
+# ul-style
+MD004: false
+
+# hard-tabs
+MD010: false
+
+# line-length
+MD013: false
+
+# no-duplicate-header
+MD024:
+  siblings_only: true
+
+#single-title
+MD025: false
+
+# ol-prefix
+MD029:
+  style: ordered
+
+# no-inline-html
+MD033: false
+
+# fenced-code-language
+MD040: false
+

vendor/go.opentelemetry.io/otel/CODEOWNERS

@@ -0,0 +1,17 @@
+#####################################################
+#
+# List of approvers for this repository
+#
+#####################################################
+#
+# Learn about membership in OpenTelemetry community:
+#  https://github.com/open-telemetry/community/blob/main/community-membership.md
+#
+#
+# Learn about CODEOWNERS file format:
+#  https://help.github.com/en/articles/about-code-owners
+#
+
+* @jmacd @MrAlias @Aneurysm9 @evantorrie @XSAM @dashpole @paivagustavo @MadVikingGod
+
+CODEOWNERS @MrAlias @Aneurysm9

vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

@@ -0,0 +1,473 @@
+# Contributing to opentelemetry-go
+
+The Go special interest group (SIG) meets regularly. See the
+OpenTelemetry
+[community](https://github.com/open-telemetry/community#golang-sdk)
+repo for information on this and other language SIGs.
+
+See the [public meeting
+notes](https://docs.google.com/document/d/1A63zSWX0x2CyCK_LoNhmQC4rqhLpYXJzXbEPDUQ2n6w/edit#heading=h.9tngw7jdwd6b)
+for a summary description of past meetings. To request edit access,
+join the meeting or get in touch on
+[Slack](https://cloud-native.slack.com/archives/C01NPAXACKT).
+
+## Development
+
+You can view and edit the source code by cloning this repository:
+
+```sh
+git clone https://github.com/open-telemetry/opentelemetry-go.git
+```
+
+Run `make test` to run the tests instead of `go test`.
+
+There are some generated files checked into the repo. To make sure
+that the generated files are up-to-date, run `make` (or `make
+precommit` - the `precommit` target is the default).
+
+The `precommit` target also fixes the formatting of the code and
+checks the status of the go module files.
+
+If after running `make precommit` the output of `git status` contains
+`nothing to commit, working tree clean` then it means that everything
+is up-to-date and properly formatted.
+
+## Pull Requests
+
+### How to Send Pull Requests
+
+Everyone is welcome to contribute code to `opentelemetry-go` via
+GitHub pull requests (PRs).
+
+To create a new PR, fork the project in GitHub and clone the upstream
+repo:
+
+```sh
+go get -d go.opentelemetry.io/otel
+```
+
+(This may print some warning about "build constraints exclude all Go
+files", just ignore it.)
+
+This will put the project in `${GOPATH}/src/go.opentelemetry.io/otel`. You
+can alternatively use `git` directly with:
+
+```sh
+git clone https://github.com/open-telemetry/opentelemetry-go
+```
+
+(Note that `git clone` is *not* using the `go.opentelemetry.io/otel` name -
+that name is a kind of a redirector to GitHub that `go get` can
+understand, but `git` does not.)
+
+This would put the project in the `opentelemetry-go` directory in
+current working directory.
+
+Enter the newly created directory and add your fork as a new remote:
+
+```sh
+git remote add <YOUR_FORK> git@github.com:<YOUR_GITHUB_USERNAME>/opentelemetry-go
+```
+
+Check out a new branch, make modifications, run linters and tests, update
+`CHANGELOG.md`, and push the branch to your fork:
+
+```sh
+git checkout -b <YOUR_BRANCH_NAME>
+# edit files
+# update changelog
+make precommit
+git add -p
+git commit
+git push <YOUR_FORK> <YOUR_BRANCH_NAME>
+```
+
+Open a pull request against the main `opentelemetry-go` repo. Be sure to add the pull
+request ID to the entry you added to `CHANGELOG.md`.
+
+### How to Receive Comments
+
+* If the PR is not ready for review, please put `[WIP]` in the title,
+  tag it as `work-in-progress`, or mark it as
+  [`draft`](https://github.blog/2019-02-14-introducing-draft-pull-requests/).
+* Make sure CLA is signed and CI is clear.
+
+### How to Get PRs Merged
+
+A PR is considered to be **ready to merge** when:
+
+* It has received two approvals from Collaborators/Maintainers (at
+  different companies). This is not enforced through technical means
+  and a PR may be **ready to merge** with a single approval if the change
+  and its approach have been discussed and consensus reached.
+* Feedback has been addressed.
+* Any substantive changes to your PR will require that you clear any prior
+  Approval reviews, this includes changes resulting from other feedback. Unless
+  the approver explicitly stated that their approval will persist across
+  changes it should be assumed that the PR needs their review again. Other
+  project members (e.g. approvers, maintainers) can help with this if there are
+  any questions or if you forget to clear reviews.
+* It has been open for review for at least one working day. This gives
+  people reasonable time to review.
+* Trivial changes (typo, cosmetic, doc, etc.) do not have to wait for
+  one day and may be merged with a single Maintainer's approval.
+* `CHANGELOG.md` has been updated to reflect what has been
+  added, changed, removed, or fixed.
+* Urgent fix can take exception as long as it has been actively
+  communicated.
+
+Any Maintainer can merge the PR once it is **ready to merge**.
+
+## Design Choices
+
+As with other OpenTelemetry clients, opentelemetry-go follows the
+[opentelemetry-specification](https://github.com/open-telemetry/opentelemetry-specification).
+
+It's especially valuable to read through the [library
+guidelines](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/library-guidelines.md).
+
+### Focus on Capabilities, Not Structure Compliance
+
+OpenTelemetry is an evolving specification, one where the desires and
+use cases are clear, but the method to satisfy those uses cases are
+not.
+
+As such, Contributions should provide functionality and behavior that
+conforms to the specification, but the interface and structure is
+flexible.
+
+It is preferable to have contributions follow the idioms of the
+language rather than conform to specific API names or argument
+patterns in the spec.
+
+For a deeper discussion, see
+[this](https://github.com/open-telemetry/opentelemetry-specification/issues/165).
+
+## Style Guide
+
+One of the primary goals of this project is that it is actually used by
+developers. With this goal in mind the project strives to build
+user-friendly and idiomatic Go code adhering to the Go community's best
+practices.
+
+For a non-comprehensive but foundational overview of these best practices
+the [Effective Go](https://golang.org/doc/effective_go.html) documentation
+is an excellent starting place.
+
+As a convenience for developers building this project the `make precommit`
+will format, lint, validate, and in some cases fix the changes you plan to
+submit. This check will need to pass for your changes to be able to be
+merged.
+
+In addition to idiomatic Go, the project has adopted certain standards for
+implementations of common patterns. These standards should be followed as a
+default, and if they are not followed documentation needs to be included as
+to the reasons why.
+
+### Configuration
+
+When creating an instantiation function for a complex `type T struct`, it is
+useful to allow variable number of options to be applied. However, the strong
+type system of Go restricts the function design options. There are a few ways
+to solve this problem, but we have landed on the following design.
+
+#### `config`
+
+Configuration should be held in a `struct` named `config`, or prefixed with
+specific type name this Configuration applies to if there are multiple
+`config` in the package. This type must contain configuration options.
+
+```go
+// config contains configuration options for a thing.
+type config struct {
+	// options ...
+}
+```
+
+In general the `config` type will not need to be used externally to the
+package and should be unexported. If, however, it is expected that the user
+will likely want to build custom options for the configuration, the `config`
+should be exported. Please, include in the documentation for the `config`
+how the user can extend the configuration.
+
+It is important that internal `config` are not shared across package boundaries.
+Meaning a `config` from one package should not be directly used by another. The
+one exception is the API packages.  The configs from the base API, eg.
+`go.opentelemetry.io/otel/trace.TracerConfig` and
+`go.opentelemetry.io/otel/metric.InstrumentConfig`, are intended to be consumed
+by the SDK therefor it is expected that these are exported.
+
+When a config is exported we want to maintain forward and backward
+compatibility, to achieve this no fields should be exported but should
+instead be accessed by methods.
+
+Optionally, it is common to include a `newConfig` function (with the same
+naming scheme). This function wraps any defaults setting and looping over
+all options to create a configured `config`.
+
+```go
+// newConfig returns an appropriately configured config.
+func newConfig([]Option) config {
+	// Set default values for config.
+	config := config{/* […] */}
+	for _, option := range options {
+		option.apply(&config)
+	}
+	// Preform any validation here.
+	return config
+}
+```
+
+If validation of the `config` options is also preformed this can return an
+error as well that is expected to be handled by the instantiation function
+or propagated to the user.
+
+Given the design goal of not having the user need to work with the `config`,
+the `newConfig` function should also be unexported.
+
+#### `Option`
+
+To set the value of the options a `config` contains, a corresponding
+`Option` interface type should be used.
+
+```go
+type Option interface {
+	apply(*config)
+}
+```
+
+Having `apply` unexported makes sure that it will not be used externally.
+Moreover, the interface becomes sealed so the user cannot easily implement
+the interface on its own.
+
+The name of the interface should be prefixed in the same way the
+corresponding `config` is (if at all).
+
+#### Options
+
+All user configurable options for a `config` must have a related unexported
+implementation of the `Option` interface and an exported configuration
+function that wraps this implementation.
+
+The wrapping function name should be prefixed with `With*` (or in the
+special case of a boolean options `Without*`) and should have the following
+function signature.
+
+```go
+func With*(…) Option { … }
+```
+
+##### `bool` Options
+
+```go
+type defaultFalseOption bool
+
+func (o defaultFalseOption) apply(c *config) {
+	c.Bool = bool(o)
+}
+
+// WithOption sets a T to have an option included.
+func WithOption() Option {
+	return defaultFalseOption(true)
+}
+```
+
+```go
+type defaultTrueOption bool
+
+func (o defaultTrueOption) apply(c *config) {
+	c.Bool = bool(o)
+}
+
+// WithoutOption sets a T to have Bool option excluded.
+func WithoutOption() Option {
+	return defaultTrueOption(false)
+}
+```
+
+##### Declared Type Options
+
+```go
+type myTypeOption struct {
+	MyType MyType
+}
+
+func (o myTypeOption) apply(c *config) {
+	c.MyType = o.MyType
+}
+
+// WithMyType sets T to have include MyType.
+func WithMyType(t MyType) Option {
+	return myTypeOption{t}
+}
+```
+
+##### Functional Options
+
+```go
+type optionFunc func(*config)
+
+func (fn optionFunc) apply(c *config) {
+	fn(c)
+}
+
+// WithMyType sets t as MyType.
+func WithMyType(t MyType) Option {
+	return optionFunc(func(c *config) {
+		c.MyType = t
+	})
+}
+```
+
+#### Instantiation
+
+Using this configuration pattern to configure instantiation with a `NewT`
+function.
+
+```go
+func NewT(options ...Option) T {…}
+```
+
+Any required parameters can be declared before the variadic `options`.
+
+#### Dealing with Overlap
+
+Sometimes there are multiple complex `struct` that share common
+configuration and also have distinct configuration. To avoid repeated
+portions of `config`s, a common `config` can be used with the union of
+options being handled with the `Option` interface.
+
+For example.
+
+```go
+// config holds options for all animals.
+type config struct {
+	Weight      float64
+	Color       string
+	MaxAltitude float64
+}
+
+// DogOption apply Dog specific options.
+type DogOption interface {
+	applyDog(*config)
+}
+
+// BirdOption apply Bird specific options.
+type BirdOption interface {
+	applyBird(*config)
+}
+
+// Option apply options for all animals.
+type Option interface {
+	BirdOption
+	DogOption
+}
+
+type weightOption float64
+func (o weightOption) applyDog(c *config)  { c.Weight = float64(o) }
+func (o weightOption) applyBird(c *config) { c.Weight = float64(o) }
+func WithWeight(w float64) Option          { return weightOption(w) }
+
+type furColorOption string
+func (o furColorOption) applyDog(c *config) { c.Color = string(o) }
+func WithFurColor(c string) DogOption       { return furColorOption(c) }
+
+type maxAltitudeOption float64
+func (o maxAltitudeOption) applyBird(c *config) { c.MaxAltitude = float64(o) }
+func WithMaxAltitude(a float64) BirdOption      { return maxAltitudeOption(a) }
+
+func NewDog(name string, o ...DogOption) Dog    {…}
+func NewBird(name string, o ...BirdOption) Bird {…}
+```
+
+### Interfaces
+
+To allow other developers to better comprehend the code, it is important
+to ensure it is sufficiently documented. One simple measure that contributes
+to this aim is self-documenting by naming method parameters. Therefore,
+where appropriate, methods of every exported interface type should have
+their parameters appropriately named.
+
+#### Interface Stability
+
+All exported stable interfaces that include the following warning in their
+doumentation are allowed to be extended with additional methods.
+
+> Warning: methods may be added to this interface in minor releases.
+
+Otherwise, stable interfaces MUST NOT be modified.
+
+If new functionality is needed for an interface that cannot be changed it MUST
+be added by including an additional interface. That added interface can be a
+simple interface for the specific functionality that you want to add or it can
+be a super-set of the original interface. For example, if you wanted to a
+`Close` method to the `Exporter` interface:
+
+```go
+type Exporter interface {
+	Export()
+}
+```
+
+A new interface, `Closer`, can be added:
+
+```go
+type Closer interface {
+	Close()
+}
+```
+
+Code that is passed the `Exporter` interface can now check to see if the passed
+value also satisfies the new interface. E.g.
+
+```go
+func caller(e Exporter) {
+	/* ... */
+	if c, ok := e.(Closer); ok {
+		c.Close()
+	}
+	/* ... */
+}
+```
+
+Alternatively, a new type that is the super-set of an `Exporter` can be created.
+
+```go
+type ClosingExporter struct {
+	Exporter
+	Close()
+}
+```
+
+This new type can be used similar to the simple interface above in that a
+passed `Exporter` type can be asserted to satisfy the `ClosingExporter` type
+and the `Close` method called.
+
+This super-set approach can be useful if there is explicit behavior that needs
+to be coupled with the original type and passed as a unified type to a new
+function, but, because of this coupling, it also limits the applicability of
+the added functionality. If there exist other interfaces where this
+functionality should be added, each one will need their own super-set
+interfaces and will duplicate the pattern. For this reason, the simple targeted
+interface that defines the specific functionality should be preferred.
+
+## Approvers and Maintainers
+
+Approvers:
+
+- [Evan Torrie](https://github.com/evantorrie), Verizon Media
+- [Josh MacDonald](https://github.com/jmacd), LightStep
+- [Sam Xie](https://github.com/XSAM)
+- [David Ashpole](https://github.com/dashpole), Google
+- [Gustavo Silva Paiva](https://github.com/paivagustavo), LightStep
+- [Aaron Clawson](https://github.com/MadVikingGod)
+
+Maintainers:
+
+- [Anthony Mirabella](https://github.com/Aneurysm9), AWS
+- [Tyler Yahn](https://github.com/MrAlias), Splunk
+
+### Become an Approver or a Maintainer
+
+See the [community membership document in OpenTelemetry community
+repo](https://github.com/open-telemetry/community/blob/main/community-membership.md).

vendor/go.opentelemetry.io/otel/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
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+
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+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/Makefile

@@ -0,0 +1,183 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+EXAMPLES := $(shell ./get_main_pkgs.sh ./example)
+TOOLS_MOD_DIR := ./internal/tools
+
+# All source code and documents. Used in spell check.
+ALL_DOCS := $(shell find . -name '*.md' -type f | sort)
+# All directories with go.mod files related to opentelemetry library. Used for building, testing and linting.
+ALL_GO_MOD_DIRS := $(filter-out $(TOOLS_MOD_DIR), $(shell find . -type f -name 'go.mod' -exec dirname {} \; | egrep -v '^./example' | sort)) $(shell find ./example -type f -name 'go.mod' -exec dirname {} \; | sort)
+ALL_COVERAGE_MOD_DIRS := $(shell find . -type f -name 'go.mod' -exec dirname {} \; | egrep -v '^./example|^$(TOOLS_MOD_DIR)' | sort)
+
+GO = go
+TIMEOUT = 60
+
+.DEFAULT_GOAL := precommit
+
+.PHONY: precommit ci
+precommit: dependabot-check license-check lint build examples test-default
+ci: precommit check-clean-work-tree test-coverage
+
+# Tools
+
+TOOLS = $(CURDIR)/.tools
+
+$(TOOLS):
+	@mkdir -p $@
+$(TOOLS)/%: | $(TOOLS)
+	cd $(TOOLS_MOD_DIR) && \
+	$(GO) build -o $@ $(PACKAGE)
+
+SEMCONVGEN = $(TOOLS)/semconv-gen
+$(TOOLS)/semconv-gen: PACKAGE=go.opentelemetry.io/otel/$(TOOLS_MOD_DIR)/semconv-gen
+
+CROSSLINK = $(TOOLS)/crosslink
+$(TOOLS)/crosslink: PACKAGE=go.opentelemetry.io/otel/$(TOOLS_MOD_DIR)/crosslink
+
+GOLANGCI_LINT = $(TOOLS)/golangci-lint
+$(TOOLS)/golangci-lint: PACKAGE=github.com/golangci/golangci-lint/cmd/golangci-lint
+
+MISSPELL = $(TOOLS)/misspell
+$(TOOLS)/misspell: PACKAGE= github.com/client9/misspell/cmd/misspell
+
+STRINGER = $(TOOLS)/stringer
+$(TOOLS)/stringer: PACKAGE=golang.org/x/tools/cmd/stringer
+
+$(TOOLS)/gojq: PACKAGE=github.com/itchyny/gojq/cmd/gojq
+
+.PHONY: tools
+tools: $(CROSSLINK) $(GOLANGCI_LINT) $(MISSPELL) $(STRINGER) $(TOOLS)/gojq $(SEMCONVGEN)
+
+
+# Build
+
+.PHONY: examples generate build
+examples:
+	@set -e; for dir in $(EXAMPLES); do \
+	  echo "$(GO) build $${dir}/..."; \
+	  (cd "$${dir}" && \
+	   $(GO) build .); \
+	done
+
+generate: $(STRINGER)
+	set -e; for dir in $(ALL_GO_MOD_DIRS); do \
+	  echo "$(GO) generate $${dir}/..."; \
+	  (cd "$${dir}" && \
+	    PATH="$(TOOLS):$${PATH}" $(GO) generate ./...); \
+	done
+
+build: generate
+	# Build all package code including testing code.
+	set -e; for dir in $(ALL_GO_MOD_DIRS); do \
+	  echo "$(GO) build $${dir}/..."; \
+	  (cd "$${dir}" && \
+	    $(GO) build ./... && \
+		$(GO) list ./... \
+		  | grep -v third_party \
+		  | xargs $(GO) test -vet=off -run xxxxxMatchNothingxxxxx >/dev/null); \
+	done
+
+# Tests
+
+TEST_TARGETS := test-default test-bench test-short test-verbose test-race
+.PHONY: $(TEST_TARGETS) test
+test-default: ARGS=-v -race
+test-bench:   ARGS=-run=xxxxxMatchNothingxxxxx -test.benchtime=1ms -bench=.
+test-short:   ARGS=-short
+test-verbose: ARGS=-v
+test-race:    ARGS=-race
+$(TEST_TARGETS): test
+test:
+	@set -e; for dir in $(ALL_GO_MOD_DIRS); do \
+	  echo "$(GO) test -timeout $(TIMEOUT)s $(ARGS) $${dir}/..."; \
+	  (cd "$${dir}" && \
+	    $(GO) list ./... \
+		  | grep -v third_party \
+		  | xargs $(GO) test -timeout $(TIMEOUT)s $(ARGS)); \
+	done
+
+COVERAGE_MODE    = atomic
+COVERAGE_PROFILE = coverage.out
+.PHONY: test-coverage
+test-coverage:
+	@set -e; \
+	printf "" > coverage.txt; \
+	for dir in $(ALL_COVERAGE_MOD_DIRS); do \
+	  echo "$(GO) test -coverpkg=./... -covermode=$(COVERAGE_MODE) -coverprofile="$(COVERAGE_PROFILE)" $${dir}/..."; \
+	  (cd "$${dir}" && \
+	    $(GO) list ./... \
+	    | grep -v third_party \
+	    | xargs $(GO) test -coverpkg=./... -covermode=$(COVERAGE_MODE) -coverprofile="$(COVERAGE_PROFILE)" && \
+	  $(GO) tool cover -html=coverage.out -o coverage.html); \
+	  [ -f "$${dir}/coverage.out" ] && cat "$${dir}/coverage.out" >> coverage.txt; \
+	done; \
+	sed -i.bak -e '2,$$ { /^mode: /d; }' coverage.txt
+
+.PHONY: lint
+lint: misspell lint-modules | $(GOLANGCI_LINT)
+	set -e; for dir in $(ALL_GO_MOD_DIRS); do \
+	  echo "golangci-lint in $${dir}"; \
+	  (cd "$${dir}" && \
+	    $(GOLANGCI_LINT) run --fix && \
+	    $(GOLANGCI_LINT) run); \
+	done
+
+.PHONY: misspell
+misspell: | $(MISSPELL)
+	$(MISSPELL) -w $(ALL_DOCS)
+
+.PHONY: lint-modules
+lint-modules: | $(CROSSLINK)
+	set -e; for dir in $(ALL_GO_MOD_DIRS) $(TOOLS_MOD_DIR); do \
+	  echo "$(GO) mod tidy in $${dir}"; \
+	  (cd "$${dir}" && \
+	    $(GO) mod tidy); \
+	done
+	echo "cross-linking all go modules"
+	$(CROSSLINK)
+
+.PHONY: license-check
+license-check:
+	@licRes=$$(for f in $$(find . -type f \( -iname '*.go' -o -iname '*.sh' \) ! -path '**/third_party/*') ; do \
+	           awk '/Copyright The OpenTelemetry Authors|generated|GENERATED/ && NR<=3 { found=1; next } END { if (!found) print FILENAME }' $$f; \
+	   done); \
+	   if [ -n "$${licRes}" ]; then \
+	           echo "license header checking failed:"; echo "$${licRes}"; \
+	           exit 1; \
+	   fi
+
+.PHONY: dependabot-check
+dependabot-check:
+	@result=$$( \
+		for f in $$( find . -type f -name go.mod -exec dirname {} \; | sed 's/^.//' ); \
+			do grep -q "directory: \+$$f" .github/dependabot.yml \
+			|| echo "$$f"; \
+		done; \
+	); \
+	if [ -n "$$result" ]; then \
+		echo "missing go.mod dependabot check:"; echo "$$result"; \
+		echo "new modules need to be added to the .github/dependabot.yml file"; \
+		exit 1; \
+	fi
+
+.PHONY: check-clean-work-tree
+check-clean-work-tree:
+	@if ! git diff --quiet; then \
+	  echo; \
+	  echo 'Working tree is not clean, did you forget to run "make precommit"?'; \
+	  echo; \
+	  git status; \
+	  exit 1; \
+	fi

vendor/go.opentelemetry.io/otel/README.md

@@ -0,0 +1,106 @@
+# OpenTelemetry-Go
+
+[![CI](https://github.com/open-telemetry/opentelemetry-go/workflows/ci/badge.svg)](https://github.com/open-telemetry/opentelemetry-go/actions?query=workflow%3Aci+branch%3Amain)
+[![codecov.io](https://codecov.io/gh/open-telemetry/opentelemetry-go/coverage.svg?branch=main)](https://app.codecov.io/gh/open-telemetry/opentelemetry-go?branch=main)
+[![PkgGoDev](https://pkg.go.dev/badge/go.opentelemetry.io/otel)](https://pkg.go.dev/go.opentelemetry.io/otel)
+[![Go Report Card](https://goreportcard.com/badge/go.opentelemetry.io/otel)](https://goreportcard.com/report/go.opentelemetry.io/otel)
+[![Slack](https://img.shields.io/badge/slack-@cncf/otel--go-brightgreen.svg?logo=slack)](https://cloud-native.slack.com/archives/C01NPAXACKT)
+
+OpenTelemetry-Go is the [Go](https://golang.org/) implementation of [OpenTelemetry](https://opentelemetry.io/).
+It provides a set of APIs to directly measure performance and behavior of your software and send this data to observability platforms.
+
+## Project Status
+
+**Warning**: this project is currently in a pre-GA phase. Backwards
+incompatible changes may be introduced in subsequent minor version releases as
+we work to track the evolving OpenTelemetry specification and user feedback.
+
+Our progress towards a GA release candidate is tracked in [this project
+board](https://github.com/orgs/open-telemetry/projects/5). This release
+candidate will follow semantic versioning and will be released with a major
+version greater than zero.
+
+Progress and status specific to this repository is tracked in our local
+[project boards](https://github.com/open-telemetry/opentelemetry-go/projects)
+and
+[milestones](https://github.com/open-telemetry/opentelemetry-go/milestones).
+
+Project versioning information and stability guarantees can be found in the
+[versioning documentation](./VERSIONING.md).
+
+| Signal | Status |
+| --- | --- |
+| Traces | Stable [release](https://github.com/orgs/open-telemetry/projects/5) is primary focus |
+| Metrics | Development paused [1] |
+| Logs | Frozen [2] |
+
+- [1]: The development of the metrics API and SDK has paused due to limited development resources, prioritization of a stable Traces release, and instability of the official overall design from the OpenTelemetry specification.
+   Pull Requests for metrics related issues are not being accepted currently outside of security vulnerability mitigations.
+- [2]: The Logs signal development is halted for this project while we develop both Traces and Metrics.
+   No Logs Pull Requests are currently being accepted.
+
+### Compatibility
+
+This project is tested on the following systems.
+
+| OS      | Go Version | Architecture |
+| ------- | ---------- | ------------ |
+| Ubuntu  | 1.16       | amd64        |
+| Ubuntu  | 1.15       | amd64        |
+| Ubuntu  | 1.16       | 386          |
+| Ubuntu  | 1.15       | 386          |
+| MacOS   | 1.16       | amd64        |
+| MacOS   | 1.15       | amd64        |
+| Windows | 1.16       | amd64        |
+| Windows | 1.15       | amd64        |
+| Windows | 1.16       | 386          |
+| Windows | 1.15       | 386          |
+
+While this project should work for other systems, no compatibility guarantees
+are made for those systems currently.
+
+## Getting Started
+
+You can find a getting started guide on [opentelemetry.io](https://opentelemetry.io/docs/go/getting-started/).
+
+OpenTelemetry's goal is to provide a single set of APIs to capture distributed
+traces and metrics from your application and send them to an observability
+platform. This project allows you to do just that for applications written in
+Go. There are two steps to this process: instrument your application, and
+configure an exporter.
+
+### Instrumentation
+
+To start capturing distributed traces and metric events from your application
+it first needs to be instrumented. The easiest way to do this is by using an
+instrumentation library for your code. Be sure to check out [the officially
+supported instrumentation
+libraries](https://github.com/open-telemetry/opentelemetry-go-contrib/tree/main/instrumentation).
+
+If you need to extend the telemetry an instrumentation library provides or want
+to build your own instrumentation for your application directly you will need
+to use the
+[go.opentelemetry.io/otel/api](https://pkg.go.dev/go.opentelemetry.io/otel/api)
+package. The included [examples](./example/) are a good way to see some
+practical uses of this process.
+
+### Export
+
+Now that your application is instrumented to collect telemetry, it needs an
+export pipeline to send that telemetry to an observability platform.
+
+All officially supported exporters for the OpenTelemetry project are contained in the [exporters directory](./exporters).
+
+| Exporter                              | Metrics | Traces |
+| :-----------------------------------: | :-----: | :----: |
+| [Jaeger](./exporters/jaeger/)         |         | ✓      |
+| [OTLP](./exporters/otlp/)             | ✓       | ✓      |
+| [Prometheus](./exporters/prometheus/) | ✓       |        |
+| [stdout](./exporters/stdout/)         | ✓       | ✓      |
+| [Zipkin](./exporters/zipkin/)         |         | ✓      |
+
+Additionally, OpenTelemetry community supported exporters can be found in the [contrib repository](https://github.com/open-telemetry/opentelemetry-go-contrib/tree/main/exporters).
+
+## Contributing
+
+See the [contributing documentation](CONTRIBUTING.md).

vendor/go.opentelemetry.io/otel/RELEASING.md

@@ -0,0 +1,120 @@
+# Release Process
+
+## Semantic Convention Generation
+
+If a new version of the OpenTelemetry Specification has been released it will be necessary to generate a new
+semantic convention package from the YAML definitions in the specification repository. There is a utility in
+`internal/tools/semconv-gen` that can be used to generate the a package with the name matching the specification
+version number under the `semconv` package. This will ideally be done soon after the specification release is
+tagged. Make sure that the specification repo contains a checkout of the the latest tagged release so that the
+generated files match the released semantic conventions.
+
+There are currently two categories of semantic conventions that must be generated, `resource` and `trace`.
+
+```
+cd internal/tools/semconv-gen
+go run generator.go -i /path/to/specification/repo/semantic_conventions/resource
+go run generator.go -i /path/to/specification/repo/semantic_conventions/trace
+```
+
+Using default values for all options other than `input` will result in using the `template.j2` template to
+generate `resource.go` and `trace.go` in `/path/to/otelgo/repo/semconv/<version>`.
+
+There are several ancillary files that are not generated and should be copied into the new package from the
+prior package, with updates made as appropriate to canonical import path statements and constant values.
+These files include:
+
+* doc.go
+* exception.go
+* http(_test)?.go
+* schema.go
+
+Uses of the previous schema version in this repository should be updated to use the newly generated version.
+No tooling for this exists at present, so use find/replace in your editor of choice or craft a `grep | sed`
+pipeline if you like living on the edge.
+
+## Pre-Release
+
+Update go.mod for submodules to depend on the new release which will happen in the next step.
+
+1. Run the pre-release script. It creates a branch `pre_release_<new tag>` that will contain all release changes.
+
+    ```
+    ./pre_release.sh -t <new tag>
+    ```
+
+2. Verify the changes.
+
+    ```
+    git diff main
+    ```
+
+    This should have changed the version for all modules to be `<new tag>`.
+
+3. Update the [Changelog](./CHANGELOG.md).
+   - Make sure all relevant changes for this release are included and are in language that non-contributors to the project can understand.
+       To verify this, you can look directly at the commits since the `<last tag>`.
+
+       ```
+       git --no-pager log --pretty=oneline "<last tag>..HEAD"
+       ```
+
+   - Move all the `Unreleased` changes into a new section following the title scheme (`[<new tag>] - <date of release>`).
+   - Update all the appropriate links at the bottom.
+
+4. Push the changes to upstream and create a Pull Request on GitHub.
+    Be sure to include the curated changes from the [Changelog](./CHANGELOG.md) in the description.
+
+## Tag
+
+Once the Pull Request with all the version changes has been approved and merged it is time to tag the merged commit.
+
+***IMPORTANT***: It is critical you use the same tag that you used in the Pre-Release step!
+Failure to do so will leave things in a broken state.
+
+***IMPORTANT***: [There is currently no way to remove an incorrectly tagged version of a Go module](https://github.com/golang/go/issues/34189).
+It is critical you make sure the version you push upstream is correct.
+[Failure to do so will lead to minor emergencies and tough to work around](https://github.com/open-telemetry/opentelemetry-go/issues/331).
+
+1. Run the tag.sh script using the `<commit-hash>` of the commit on the main branch for the merged Pull Request.
+
+    ```
+    ./tag.sh <new tag> <commit-hash>
+    ```
+
+2. Push tags to the upstream remote (not your fork: `github.com/open-telemetry/opentelemetry-go.git`).
+    Make sure you push all sub-modules as well.
+
+    ```
+    git push upstream <new tag>
+    git push upstream <submodules-path/new tag>
+    ...
+    ```
+
+## Release
+
+Finally create a Release for the new `<new tag>` on GitHub.
+The release body should include all the release notes from the Changelog for this release.
+Additionally, the `tag.sh` script generates commit logs since last release which can be used to supplement the release notes.
+
+## Verify Examples
+
+After releasing verify that examples build outside of the repository.
+
+```
+./verify_examples.sh
+```
+
+The script copies examples into a different directory removes any `replace` declarations in `go.mod` and builds them.
+This ensures they build with the published release, not the local copy.
+
+## Post-Release
+
+### Contrib Repository
+
+Once verified be sure to [make a release for the `contrib` repository](https://github.com/open-telemetry/opentelemetry-go-contrib/blob/main/RELEASING.md) that uses this release.
+
+### Website Documentation
+
+Update [the documentation](./website_docs) for [the OpenTelemetry website](https://opentelemetry.io/docs/go/).
+Importantly, bump any package versions referenced to be the latest one you just released and ensure all code examples still compile and are accurate.

vendor/go.opentelemetry.io/otel/VERSIONING.md

@@ -0,0 +1,224 @@
+# Versioning
+
+This document describes the versioning policy for this repository. This policy
+is designed so the following goals can be achieved.
+
+**Users are provided a codebase of value that is stable and secure.**
+
+## Policy
+
+* Versioning of this project will be idiomatic of a Go project using [Go
+  modules](https://github.com/golang/go/wiki/Modules).
+  * [Semantic import
+    versioning](https://github.com/golang/go/wiki/Modules#semantic-import-versioning)
+    will be used.
+    * Versions will comply with [semver
+      2.0](https://semver.org/spec/v2.0.0.html) with the following exceptions.
+      * New methods may be added to exported API interfaces. All exported
+        interfaces that fall within this exception will include the following
+        paragraph in their public documentation.
+
+        > Warning: methods may be added to this interface in minor releases.
+
+    * If a module is version `v2` or higher, the major version of the module
+      must be included as a `/vN` at the end of the module paths used in
+      `go.mod` files (e.g., `module go.opentelemetry.io/otel/v2`, `require
+      go.opentelemetry.io/otel/v2 v2.0.1`) and in the package import path
+      (e.g., `import "go.opentelemetry.io/otel/v2/trace"`). This includes the
+      paths used in `go get` commands (e.g., `go get
+      go.opentelemetry.io/otel/v2@v2.0.1`.  Note there is both a `/v2` and a
+      `@v2.0.1` in that example. One way to think about it is that the module
+      name now includes the `/v2`, so include `/v2` whenever you are using the
+      module name).
+    * If a module is version `v0` or `v1`, do not include the major version in
+      either the module path or the import path.
+  * Modules will be used to encapsulate signals and components.
+    * Experimental modules still under active development will be versioned at
+      `v0` to imply the stability guarantee defined by
+      [semver](https://semver.org/spec/v2.0.0.html#spec-item-4).
+
+      > Major version zero (0.y.z) is for initial development. Anything MAY
+      > change at any time. The public API SHOULD NOT be considered stable.
+
+    * Mature modules for which we guarantee a stable public API will be versioned
+      with a major version greater than `v0`.
+      * The decision to make a module stable will be made on a case-by-case
+        basis by the maintainers of this project.
+    * Experimental modules will start their versioning at `v0.0.0` and will
+      increment their minor version when backwards incompatible changes are
+      released and increment their patch version when backwards compatible
+      changes are released.
+    * All stable modules that use the same major version number will use the
+      same entire version number.
+      * Stable modules may be released with an incremented minor or patch
+        version even though that module has not been changed, but rather so
+        that it will remain at the same version as other stable modules that
+        did undergo change.
+      * When an experimental module becomes stable a new stable module version
+        will be released and will include this now stable module. The new
+        stable module version will be an increment of the minor version number
+        and will be applied to all existing stable modules as well as the newly
+        stable module being released.
+* Versioning of the associated [contrib
+  repository](https://github.com/open-telemetry/opentelemetry-go-contrib) of
+  this project will be idiomatic of a Go project using [Go
+  modules](https://github.com/golang/go/wiki/Modules).
+  * [Semantic import
+    versioning](https://github.com/golang/go/wiki/Modules#semantic-import-versioning)
+    will be used.
+    * Versions will comply with [semver 2.0](https://semver.org/spec/v2.0.0.html).
+    * If a module is version `v2` or higher, the
+      major version of the module must be included as a `/vN` at the end of the
+      module paths used in `go.mod` files (e.g., `module
+      go.opentelemetry.io/contrib/instrumentation/host/v2`, `require
+      go.opentelemetry.io/contrib/instrumentation/host/v2 v2.0.1`) and in the
+      package import path (e.g., `import
+      "go.opentelemetry.io/contrib/instrumentation/host/v2"`). This includes
+      the paths used in `go get` commands (e.g., `go get
+      go.opentelemetry.io/contrib/instrumentation/host/v2@v2.0.1`.  Note there
+      is both a `/v2` and a `@v2.0.1` in that example. One way to think about
+      it is that the module name now includes the `/v2`, so include `/v2`
+      whenever you are using the module name).
+    * If a module is version `v0` or `v1`, do not include the major version
+      in either the module path or the import path.
+  * In addition to public APIs, telemetry produced by stable instrumentation
+    will remain stable and backwards compatible. This is to avoid breaking
+    alerts and dashboard.
+  * Modules will be used to encapsulate instrumentation, detectors, exporters,
+    propagators, and any other independent sets of related components.
+    * Experimental modules still under active development will be versioned at
+      `v0` to imply the stability guarantee defined by
+      [semver](https://semver.org/spec/v2.0.0.html#spec-item-4).
+
+      > Major version zero (0.y.z) is for initial development. Anything MAY
+      > change at any time. The public API SHOULD NOT be considered stable.
+
+    * Mature modules for which we guarantee a stable public API and telemetry will
+      be versioned with a major version greater than `v0`.
+    * Experimental modules will start their versioning at `v0.0.0` and will
+      increment their minor version when backwards incompatible changes are
+      released and increment their patch version when backwards compatible
+      changes are released.
+    * Stable contrib modules cannot depend on experimental modules from this
+      project.
+    * All stable contrib modules of the same major version with this project
+      will use the same entire version as this project.
+      * Stable modules may be released with an incremented minor or patch
+        version even though that module's code has not been changed. Instead
+        the only change that will have been included is to have updated that
+        modules dependency on this project's stable APIs.
+      * When an experimental module in contrib becomes stable a new stable
+        module version will be released and will include this now stable
+        module. The new stable module version will be an increment of the minor
+        version number and will be applied to all existing stable contrib
+        modules, this project's modules, and the newly stable module being
+        released.
+  * Contrib modules will be kept up to date with this project's releases.
+    * Due to the dependency contrib modules will implicitly have on this
+      project's modules the release of stable contrib modules to match the
+      released version number will be staggered after this project's release.
+      There is no explicit time guarantee for how long after this projects
+      release the contrib release will be. Effort should be made to keep them
+      as close in time as possible.
+    * No additional stable release in this project can be made until the
+      contrib repository has a matching stable release.
+    * No release can be made in the contrib repository after this project's
+      stable release except for a stable release of the contrib repository.
+* GitHub releases will be made for all releases.
+* Go modules will be made available at Go package mirrors.
+
+## Example Versioning Lifecycle
+
+To better understand the implementation of the above policy the following
+example is provided. This project is simplified to include only the following
+modules and their versions:
+
+* `otel`: `v0.14.0`
+* `otel/trace`: `v0.14.0`
+* `otel/metric`: `v0.14.0`
+* `otel/baggage`: `v0.14.0`
+* `otel/sdk/trace`: `v0.14.0`
+* `otel/sdk/metric`: `v0.14.0`
+
+These modules have been developed to a point where the `otel/trace`,
+`otel/baggage`, and `otel/sdk/trace` modules have reached a point that they
+should be considered for a stable release. The `otel/metric` and
+`otel/sdk/metric` are still under active development and the `otel` module
+depends on both `otel/trace` and `otel/metric`.
+
+The `otel` package is refactored to remove its dependencies on `otel/metric` so
+it can be released as stable as well. With that done the following release
+candidates are made:
+
+* `otel`: `v1.0.0-rc.1`
+* `otel/trace`: `v1.0.0-rc.1`
+* `otel/baggage`: `v1.0.0-rc.1`
+* `otel/sdk/trace`: `v1.0.0-rc.1`
+
+The `otel/metric` and `otel/sdk/metric` modules remain at `v0.14.0`.
+
+A few minor issues are discovered in the `otel/trace` package. These issues are
+resolved with some minor, but backwards incompatible, changes and are released
+as a second release candidate:
+
+* `otel`: `v1.0.0-rc.2`
+* `otel/trace`: `v1.0.0-rc.2`
+* `otel/baggage`: `v1.0.0-rc.2`
+* `otel/sdk/trace`: `v1.0.0-rc.2`
+
+Notice that all module version numbers are incremented to adhere to our
+versioning policy.
+
+After these release candidates have been evaluated to satisfaction, they are
+released as version `v1.0.0`.
+
+* `otel`: `v1.0.0`
+* `otel/trace`: `v1.0.0`
+* `otel/baggage`: `v1.0.0`
+* `otel/sdk/trace`: `v1.0.0`
+
+Since both the `go` utility and the Go module system support [the semantic
+versioning definition of
+precedence](https://semver.org/spec/v2.0.0.html#spec-item-11), this release
+will correctly be interpreted as the successor to the previous release
+candidates.
+
+Active development of this project continues. The `otel/metric` module now has
+backwards incompatible changes to its API that need to be released and the
+`otel/baggage` module has a minor bug fix that needs to be released. The
+following release is made:
+
+* `otel`: `v1.0.1`
+* `otel/trace`: `v1.0.1`
+* `otel/metric`: `v0.15.0`
+* `otel/baggage`: `v1.0.1`
+* `otel/sdk/trace`: `v1.0.1`
+* `otel/sdk/metric`: `v0.15.0`
+
+Notice that, again, all stable module versions are incremented in unison and
+the `otel/sdk/metric` package, which depends on the `otel/metric` package, also
+bumped its version. This bump of the `otel/sdk/metric` package makes sense
+given their coupling, though it is not explicitly required by our versioning
+policy.
+
+As we progress, the `otel/metric` and `otel/sdk/metric` packages have reached a
+point where they should be evaluated for stability. The `otel` module is
+reintegrated with the `otel/metric` package and the following release is made:
+
+* `otel`: `v1.1.0-rc.1`
+* `otel/trace`: `v1.1.0-rc.1`
+* `otel/metric`: `v1.1.0-rc.1`
+* `otel/baggage`: `v1.1.0-rc.1`
+* `otel/sdk/trace`: `v1.1.0-rc.1`
+* `otel/sdk/metric`: `v1.1.0-rc.1`
+
+All the modules are evaluated and determined to a viable stable release. They
+are then released as version `v1.1.0` (the minor version is incremented to
+indicate the addition of new signal).
+
+* `otel`: `v1.1.0`
+* `otel/trace`: `v1.1.0`
+* `otel/metric`: `v1.1.0`
+* `otel/baggage`: `v1.1.0`
+* `otel/sdk/trace`: `v1.1.0`
+* `otel/sdk/metric`: `v1.1.0`

vendor/go.opentelemetry.io/otel/attribute/doc.go

@@ -0,0 +1,19 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// package attribute provides key and value attributes.
+//
+// This package is currently in a Release Candidate phase. Backwards incompatible changes
+// may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+package attribute // import "go.opentelemetry.io/otel/attribute"

vendor/go.opentelemetry.io/otel/attribute/encoder.go

@@ -0,0 +1,150 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+import (
+	"bytes"
+	"sync"
+	"sync/atomic"
+)
+
+type (
+	// Encoder is a mechanism for serializing a label set into a
+	// specific string representation that supports caching, to
+	// avoid repeated serialization. An example could be an
+	// exporter encoding the label set into a wire representation.
+	Encoder interface {
+		// Encode returns the serialized encoding of the label
+		// set using its Iterator.  This result may be cached
+		// by a attribute.Set.
+		Encode(iterator Iterator) string
+
+		// ID returns a value that is unique for each class of
+		// label encoder.  Label encoders allocate these using
+		// `NewEncoderID`.
+		ID() EncoderID
+	}
+
+	// EncoderID is used to identify distinct Encoder
+	// implementations, for caching encoded results.
+	EncoderID struct {
+		value uint64
+	}
+
+	// defaultLabelEncoder uses a sync.Pool of buffers to reduce
+	// the number of allocations used in encoding labels.  This
+	// implementation encodes a comma-separated list of key=value,
+	// with '/'-escaping of '=', ',', and '\'.
+	defaultLabelEncoder struct {
+		// pool is a pool of labelset builders.  The buffers in this
+		// pool grow to a size that most label encodings will not
+		// allocate new memory.
+		pool sync.Pool // *bytes.Buffer
+	}
+)
+
+// escapeChar is used to ensure uniqueness of the label encoding where
+// keys or values contain either '=' or ','.  Since there is no parser
+// needed for this encoding and its only requirement is to be unique,
+// this choice is arbitrary.  Users will see these in some exporters
+// (e.g., stdout), so the backslash ('\') is used as a conventional choice.
+const escapeChar = '\\'
+
+var (
+	_ Encoder = &defaultLabelEncoder{}
+
+	// encoderIDCounter is for generating IDs for other label
+	// encoders.
+	encoderIDCounter uint64
+
+	defaultEncoderOnce     sync.Once
+	defaultEncoderID       = NewEncoderID()
+	defaultEncoderInstance *defaultLabelEncoder
+)
+
+// NewEncoderID returns a unique label encoder ID. It should be
+// called once per each type of label encoder. Preferably in init() or
+// in var definition.
+func NewEncoderID() EncoderID {
+	return EncoderID{value: atomic.AddUint64(&encoderIDCounter, 1)}
+}
+
+// DefaultEncoder returns a label encoder that encodes labels
+// in such a way that each escaped label's key is followed by an equal
+// sign and then by an escaped label's value. All key-value pairs are
+// separated by a comma.
+//
+// Escaping is done by prepending a backslash before either a
+// backslash, equal sign or a comma.
+func DefaultEncoder() Encoder {
+	defaultEncoderOnce.Do(func() {
+		defaultEncoderInstance = &defaultLabelEncoder{
+			pool: sync.Pool{
+				New: func() interface{} {
+					return &bytes.Buffer{}
+				},
+			},
+		}
+	})
+	return defaultEncoderInstance
+}
+
+// Encode is a part of an implementation of the LabelEncoder
+// interface.
+func (d *defaultLabelEncoder) Encode(iter Iterator) string {
+	buf := d.pool.Get().(*bytes.Buffer)
+	defer d.pool.Put(buf)
+	buf.Reset()
+
+	for iter.Next() {
+		i, keyValue := iter.IndexedLabel()
+		if i > 0 {
+			_, _ = buf.WriteRune(',')
+		}
+		copyAndEscape(buf, string(keyValue.Key))
+
+		_, _ = buf.WriteRune('=')
+
+		if keyValue.Value.Type() == STRING {
+			copyAndEscape(buf, keyValue.Value.AsString())
+		} else {
+			_, _ = buf.WriteString(keyValue.Value.Emit())
+		}
+	}
+	return buf.String()
+}
+
+// ID is a part of an implementation of the LabelEncoder interface.
+func (*defaultLabelEncoder) ID() EncoderID {
+	return defaultEncoderID
+}
+
+// copyAndEscape escapes `=`, `,` and its own escape character (`\`),
+// making the default encoding unique.
+func copyAndEscape(buf *bytes.Buffer, val string) {
+	for _, ch := range val {
+		switch ch {
+		case '=', ',', escapeChar:
+			buf.WriteRune(escapeChar)
+		}
+		buf.WriteRune(ch)
+	}
+}
+
+// Valid returns true if this encoder ID was allocated by
+// `NewEncoderID`.  Invalid encoder IDs will not be cached.
+func (id EncoderID) Valid() bool {
+	return id.value != 0
+}

vendor/go.opentelemetry.io/otel/attribute/iterator.go

@@ -0,0 +1,143 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+// Iterator allows iterating over the set of labels in order,
+// sorted by key.
+type Iterator struct {
+	storage *Set
+	idx     int
+}
+
+// MergeIterator supports iterating over two sets of labels while
+// eliminating duplicate values from the combined set.  The first
+// iterator value takes precedence.
+type MergeIterator struct {
+	one     oneIterator
+	two     oneIterator
+	current KeyValue
+}
+
+type oneIterator struct {
+	iter  Iterator
+	done  bool
+	label KeyValue
+}
+
+// Next moves the iterator to the next position. Returns false if there
+// are no more labels.
+func (i *Iterator) Next() bool {
+	i.idx++
+	return i.idx < i.Len()
+}
+
+// Label returns current KeyValue. Must be called only after Next returns
+// true.
+func (i *Iterator) Label() KeyValue {
+	kv, _ := i.storage.Get(i.idx)
+	return kv
+}
+
+// Attribute is a synonym for Label().
+func (i *Iterator) Attribute() KeyValue {
+	return i.Label()
+}
+
+// IndexedLabel returns current index and attribute. Must be called only
+// after Next returns true.
+func (i *Iterator) IndexedLabel() (int, KeyValue) {
+	return i.idx, i.Label()
+}
+
+// Len returns a number of labels in the iterator's `*Set`.
+func (i *Iterator) Len() int {
+	return i.storage.Len()
+}
+
+// ToSlice is a convenience function that creates a slice of labels
+// from the passed iterator. The iterator is set up to start from the
+// beginning before creating the slice.
+func (i *Iterator) ToSlice() []KeyValue {
+	l := i.Len()
+	if l == 0 {
+		return nil
+	}
+	i.idx = -1
+	slice := make([]KeyValue, 0, l)
+	for i.Next() {
+		slice = append(slice, i.Label())
+	}
+	return slice
+}
+
+// NewMergeIterator returns a MergeIterator for merging two label sets
+// Duplicates are resolved by taking the value from the first set.
+func NewMergeIterator(s1, s2 *Set) MergeIterator {
+	mi := MergeIterator{
+		one: makeOne(s1.Iter()),
+		two: makeOne(s2.Iter()),
+	}
+	return mi
+}
+
+func makeOne(iter Iterator) oneIterator {
+	oi := oneIterator{
+		iter: iter,
+	}
+	oi.advance()
+	return oi
+}
+
+func (oi *oneIterator) advance() {
+	if oi.done = !oi.iter.Next(); !oi.done {
+		oi.label = oi.iter.Label()
+	}
+}
+
+// Next returns true if there is another label available.
+func (m *MergeIterator) Next() bool {
+	if m.one.done && m.two.done {
+		return false
+	}
+	if m.one.done {
+		m.current = m.two.label
+		m.two.advance()
+		return true
+	}
+	if m.two.done {
+		m.current = m.one.label
+		m.one.advance()
+		return true
+	}
+	if m.one.label.Key == m.two.label.Key {
+		m.current = m.one.label // first iterator label value wins
+		m.one.advance()
+		m.two.advance()
+		return true
+	}
+	if m.one.label.Key < m.two.label.Key {
+		m.current = m.one.label
+		m.one.advance()
+		return true
+	}
+	m.current = m.two.label
+	m.two.advance()
+	return true
+}
+
+// Label returns the current value after Next() returns true.
+func (m *MergeIterator) Label() KeyValue {
+	return m.current
+}

vendor/go.opentelemetry.io/otel/attribute/key.go

@@ -0,0 +1,102 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+// Key represents the key part in key-value pairs. It's a string. The
+// allowed character set in the key depends on the use of the key.
+type Key string
+
+// Bool creates a KeyValue instance with a BOOL Value.
+//
+// If creating both key and a bool value at the same time, then
+// instead of calling Key(name).Bool(value) consider using a
+// convenience function provided by the api/key package -
+// key.Bool(name, value).
+func (k Key) Bool(v bool) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: BoolValue(v),
+	}
+}
+
+// Int64 creates a KeyValue instance with an INT64 Value.
+//
+// If creating both key and an int64 value at the same time, then
+// instead of calling Key(name).Int64(value) consider using a
+// convenience function provided by the api/key package -
+// key.Int64(name, value).
+func (k Key) Int64(v int64) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: Int64Value(v),
+	}
+}
+
+// Float64 creates a KeyValue instance with a FLOAT64 Value.
+//
+// If creating both key and a float64 value at the same time, then
+// instead of calling Key(name).Float64(value) consider using a
+// convenience function provided by the api/key package -
+// key.Float64(name, value).
+func (k Key) Float64(v float64) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: Float64Value(v),
+	}
+}
+
+// String creates a KeyValue instance with a STRING Value.
+//
+// If creating both key and a string value at the same time, then
+// instead of calling Key(name).String(value) consider using a
+// convenience function provided by the api/key package -
+// key.String(name, value).
+func (k Key) String(v string) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: StringValue(v),
+	}
+}
+
+// Int creates a KeyValue instance with an INT64 Value.
+//
+// If creating both key and an int value at the same time, then
+// instead of calling Key(name).Int(value) consider using a
+// convenience function provided by the api/key package -
+// key.Int(name, value).
+func (k Key) Int(v int) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: IntValue(v),
+	}
+}
+
+// Defined returns true for non-empty keys.
+func (k Key) Defined() bool {
+	return len(k) != 0
+}
+
+// Array creates a KeyValue instance with a ARRAY Value.
+//
+// If creating both key and a array value at the same time, then
+// instead of calling Key(name).String(value) consider using a
+// convenience function provided by the api/key package -
+// key.Array(name, value).
+func (k Key) Array(v interface{}) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: ArrayValue(v),
+	}
+}

vendor/go.opentelemetry.io/otel/attribute/kv.go

@@ -0,0 +1,108 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+)
+
+// KeyValue holds a key and value pair.
+type KeyValue struct {
+	Key   Key
+	Value Value
+}
+
+// Valid returns if kv is a valid OpenTelemetry attribute.
+func (kv KeyValue) Valid() bool {
+	return kv.Key != "" && kv.Value.Type() != INVALID
+}
+
+// Bool creates a new key-value pair with a passed name and a bool
+// value.
+func Bool(k string, v bool) KeyValue {
+	return Key(k).Bool(v)
+}
+
+// Int64 creates a new key-value pair with a passed name and an int64
+// value.
+func Int64(k string, v int64) KeyValue {
+	return Key(k).Int64(v)
+}
+
+// Float64 creates a new key-value pair with a passed name and a float64
+// value.
+func Float64(k string, v float64) KeyValue {
+	return Key(k).Float64(v)
+}
+
+// String creates a new key-value pair with a passed name and a string
+// value.
+func String(k, v string) KeyValue {
+	return Key(k).String(v)
+}
+
+// Stringer creates a new key-value pair with a passed name and a string
+// value generated by the passed Stringer interface.
+func Stringer(k string, v fmt.Stringer) KeyValue {
+	return Key(k).String(v.String())
+}
+
+// Int creates a new key-value pair instance with a passed name and
+// either an int32 or an int64 value, depending on whether the int
+// type is 32 or 64 bits wide.
+func Int(k string, v int) KeyValue {
+	return Key(k).Int(v)
+}
+
+// Array creates a new key-value pair with a passed name and a array.
+// Only arrays of primitive type are supported.
+func Array(k string, v interface{}) KeyValue {
+	return Key(k).Array(v)
+}
+
+// Any creates a new key-value pair instance with a passed name and
+// automatic type inference. This is slower, and not type-safe.
+func Any(k string, value interface{}) KeyValue {
+	if value == nil {
+		return String(k, "<nil>")
+	}
+
+	if stringer, ok := value.(fmt.Stringer); ok {
+		return String(k, stringer.String())
+	}
+
+	rv := reflect.ValueOf(value)
+
+	switch rv.Kind() {
+	case reflect.Array, reflect.Slice:
+		return Array(k, value)
+	case reflect.Bool:
+		return Bool(k, rv.Bool())
+	case reflect.Int, reflect.Int8, reflect.Int16:
+		return Int(k, int(rv.Int()))
+	case reflect.Int64:
+		return Int64(k, rv.Int())
+	case reflect.Float64:
+		return Float64(k, rv.Float())
+	case reflect.String:
+		return String(k, rv.String())
+	}
+	if b, err := json.Marshal(value); b != nil && err == nil {
+		return String(k, string(b))
+	}
+	return String(k, fmt.Sprint(value))
+}

vendor/go.opentelemetry.io/otel/attribute/set.go

@@ -0,0 +1,426 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+import (
+	"encoding/json"
+	"reflect"
+	"sort"
+)
+
+type (
+	// Set is the representation for a distinct label set.  It
+	// manages an immutable set of labels, with an internal cache
+	// for storing label encodings.
+	//
+	// This type supports the `Equivalent` method of comparison
+	// using values of type `Distinct`.
+	//
+	// This type is used to implement:
+	// 1. Metric labels
+	// 2. Resource sets
+	// 3. Correlation map (TODO)
+	Set struct {
+		equivalent Distinct
+	}
+
+	// Distinct wraps a variable-size array of `KeyValue`,
+	// constructed with keys in sorted order.  This can be used as
+	// a map key or for equality checking between Sets.
+	Distinct struct {
+		iface interface{}
+	}
+
+	// Filter supports removing certain labels from label sets.
+	// When the filter returns true, the label will be kept in
+	// the filtered label set.  When the filter returns false, the
+	// label is excluded from the filtered label set, and the
+	// label instead appears in the `removed` list of excluded labels.
+	Filter func(KeyValue) bool
+
+	// Sortable implements `sort.Interface`, used for sorting
+	// `KeyValue`.  This is an exported type to support a
+	// memory optimization.  A pointer to one of these is needed
+	// for the call to `sort.Stable()`, which the caller may
+	// provide in order to avoid an allocation.  See
+	// `NewSetWithSortable()`.
+	Sortable []KeyValue
+)
+
+var (
+	// keyValueType is used in `computeDistinctReflect`.
+	keyValueType = reflect.TypeOf(KeyValue{})
+
+	// emptySet is returned for empty label sets.
+	emptySet = &Set{
+		equivalent: Distinct{
+			iface: [0]KeyValue{},
+		},
+	}
+)
+
+// EmptySet returns a reference to a Set with no elements.
+//
+// This is a convenience provided for optimized calling utility.
+func EmptySet() *Set {
+	return emptySet
+}
+
+// reflect abbreviates `reflect.ValueOf`.
+func (d Distinct) reflect() reflect.Value {
+	return reflect.ValueOf(d.iface)
+}
+
+// Valid returns true if this value refers to a valid `*Set`.
+func (d Distinct) Valid() bool {
+	return d.iface != nil
+}
+
+// Len returns the number of labels in this set.
+func (l *Set) Len() int {
+	if l == nil || !l.equivalent.Valid() {
+		return 0
+	}
+	return l.equivalent.reflect().Len()
+}
+
+// Get returns the KeyValue at ordered position `idx` in this set.
+func (l *Set) Get(idx int) (KeyValue, bool) {
+	if l == nil {
+		return KeyValue{}, false
+	}
+	value := l.equivalent.reflect()
+
+	if idx >= 0 && idx < value.Len() {
+		// Note: The Go compiler successfully avoids an allocation for
+		// the interface{} conversion here:
+		return value.Index(idx).Interface().(KeyValue), true
+	}
+
+	return KeyValue{}, false
+}
+
+// Value returns the value of a specified key in this set.
+func (l *Set) Value(k Key) (Value, bool) {
+	if l == nil {
+		return Value{}, false
+	}
+	rValue := l.equivalent.reflect()
+	vlen := rValue.Len()
+
+	idx := sort.Search(vlen, func(idx int) bool {
+		return rValue.Index(idx).Interface().(KeyValue).Key >= k
+	})
+	if idx >= vlen {
+		return Value{}, false
+	}
+	keyValue := rValue.Index(idx).Interface().(KeyValue)
+	if k == keyValue.Key {
+		return keyValue.Value, true
+	}
+	return Value{}, false
+}
+
+// HasValue tests whether a key is defined in this set.
+func (l *Set) HasValue(k Key) bool {
+	if l == nil {
+		return false
+	}
+	_, ok := l.Value(k)
+	return ok
+}
+
+// Iter returns an iterator for visiting the labels in this set.
+func (l *Set) Iter() Iterator {
+	return Iterator{
+		storage: l,
+		idx:     -1,
+	}
+}
+
+// ToSlice returns the set of labels belonging to this set, sorted,
+// where keys appear no more than once.
+func (l *Set) ToSlice() []KeyValue {
+	iter := l.Iter()
+	return iter.ToSlice()
+}
+
+// Equivalent returns a value that may be used as a map key.  The
+// Distinct type guarantees that the result will equal the equivalent
+// Distinct value of any label set with the same elements as this,
+// where sets are made unique by choosing the last value in the input
+// for any given key.
+func (l *Set) Equivalent() Distinct {
+	if l == nil || !l.equivalent.Valid() {
+		return emptySet.equivalent
+	}
+	return l.equivalent
+}
+
+// Equals returns true if the argument set is equivalent to this set.
+func (l *Set) Equals(o *Set) bool {
+	return l.Equivalent() == o.Equivalent()
+}
+
+// Encoded returns the encoded form of this set, according to
+// `encoder`.
+func (l *Set) Encoded(encoder Encoder) string {
+	if l == nil || encoder == nil {
+		return ""
+	}
+
+	return encoder.Encode(l.Iter())
+}
+
+func empty() Set {
+	return Set{
+		equivalent: emptySet.equivalent,
+	}
+}
+
+// NewSet returns a new `Set`.  See the documentation for
+// `NewSetWithSortableFiltered` for more details.
+//
+// Except for empty sets, this method adds an additional allocation
+// compared with calls that include a `*Sortable`.
+func NewSet(kvs ...KeyValue) Set {
+	// Check for empty set.
+	if len(kvs) == 0 {
+		return empty()
+	}
+	s, _ := NewSetWithSortableFiltered(kvs, new(Sortable), nil)
+	return s
+}
+
+// NewSetWithSortable returns a new `Set`.  See the documentation for
+// `NewSetWithSortableFiltered` for more details.
+//
+// This call includes a `*Sortable` option as a memory optimization.
+func NewSetWithSortable(kvs []KeyValue, tmp *Sortable) Set {
+	// Check for empty set.
+	if len(kvs) == 0 {
+		return empty()
+	}
+	s, _ := NewSetWithSortableFiltered(kvs, tmp, nil)
+	return s
+}
+
+// NewSetWithFiltered returns a new `Set`.  See the documentation for
+// `NewSetWithSortableFiltered` for more details.
+//
+// This call includes a `Filter` to include/exclude label keys from
+// the return value.  Excluded keys are returned as a slice of label
+// values.
+func NewSetWithFiltered(kvs []KeyValue, filter Filter) (Set, []KeyValue) {
+	// Check for empty set.
+	if len(kvs) == 0 {
+		return empty(), nil
+	}
+	return NewSetWithSortableFiltered(kvs, new(Sortable), filter)
+}
+
+// NewSetWithSortableFiltered returns a new `Set`.
+//
+// Duplicate keys are eliminated by taking the last value.  This
+// re-orders the input slice so that unique last-values are contiguous
+// at the end of the slice.
+//
+// This ensures the following:
+//
+// - Last-value-wins semantics
+// - Caller sees the reordering, but doesn't lose values
+// - Repeated call preserve last-value wins.
+//
+// Note that methods are defined on `*Set`, although this returns `Set`.
+// Callers can avoid memory allocations by:
+//
+// - allocating a `Sortable` for use as a temporary in this method
+// - allocating a `Set` for storing the return value of this
+//   constructor.
+//
+// The result maintains a cache of encoded labels, by attribute.EncoderID.
+// This value should not be copied after its first use.
+//
+// The second `[]KeyValue` return value is a list of labels that were
+// excluded by the Filter (if non-nil).
+func NewSetWithSortableFiltered(kvs []KeyValue, tmp *Sortable, filter Filter) (Set, []KeyValue) {
+	// Check for empty set.
+	if len(kvs) == 0 {
+		return empty(), nil
+	}
+
+	*tmp = kvs
+
+	// Stable sort so the following de-duplication can implement
+	// last-value-wins semantics.
+	sort.Stable(tmp)
+
+	*tmp = nil
+
+	position := len(kvs) - 1
+	offset := position - 1
+
+	// The requirements stated above require that the stable
+	// result be placed in the end of the input slice, while
+	// overwritten values are swapped to the beginning.
+	//
+	// De-duplicate with last-value-wins semantics.  Preserve
+	// duplicate values at the beginning of the input slice.
+	for ; offset >= 0; offset-- {
+		if kvs[offset].Key == kvs[position].Key {
+			continue
+		}
+		position--
+		kvs[offset], kvs[position] = kvs[position], kvs[offset]
+	}
+	if filter != nil {
+		return filterSet(kvs[position:], filter)
+	}
+	return Set{
+		equivalent: computeDistinct(kvs[position:]),
+	}, nil
+}
+
+// filterSet reorders `kvs` so that included keys are contiguous at
+// the end of the slice, while excluded keys precede the included keys.
+func filterSet(kvs []KeyValue, filter Filter) (Set, []KeyValue) {
+	var excluded []KeyValue
+
+	// Move labels that do not match the filter so
+	// they're adjacent before calling computeDistinct().
+	distinctPosition := len(kvs)
+
+	// Swap indistinct keys forward and distinct keys toward the
+	// end of the slice.
+	offset := len(kvs) - 1
+	for ; offset >= 0; offset-- {
+		if filter(kvs[offset]) {
+			distinctPosition--
+			kvs[offset], kvs[distinctPosition] = kvs[distinctPosition], kvs[offset]
+			continue
+		}
+	}
+	excluded = kvs[:distinctPosition]
+
+	return Set{
+		equivalent: computeDistinct(kvs[distinctPosition:]),
+	}, excluded
+}
+
+// Filter returns a filtered copy of this `Set`.  See the
+// documentation for `NewSetWithSortableFiltered` for more details.
+func (l *Set) Filter(re Filter) (Set, []KeyValue) {
+	if re == nil {
+		return Set{
+			equivalent: l.equivalent,
+		}, nil
+	}
+
+	// Note: This could be refactored to avoid the temporary slice
+	// allocation, if it proves to be expensive.
+	return filterSet(l.ToSlice(), re)
+}
+
+// computeDistinct returns a `Distinct` using either the fixed- or
+// reflect-oriented code path, depending on the size of the input.
+// The input slice is assumed to already be sorted and de-duplicated.
+func computeDistinct(kvs []KeyValue) Distinct {
+	iface := computeDistinctFixed(kvs)
+	if iface == nil {
+		iface = computeDistinctReflect(kvs)
+	}
+	return Distinct{
+		iface: iface,
+	}
+}
+
+// computeDistinctFixed computes a `Distinct` for small slices.  It
+// returns nil if the input is too large for this code path.
+func computeDistinctFixed(kvs []KeyValue) interface{} {
+	switch len(kvs) {
+	case 1:
+		ptr := new([1]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 2:
+		ptr := new([2]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 3:
+		ptr := new([3]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 4:
+		ptr := new([4]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 5:
+		ptr := new([5]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 6:
+		ptr := new([6]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 7:
+		ptr := new([7]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 8:
+		ptr := new([8]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 9:
+		ptr := new([9]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	case 10:
+		ptr := new([10]KeyValue)
+		copy((*ptr)[:], kvs)
+		return *ptr
+	default:
+		return nil
+	}
+}
+
+// computeDistinctReflect computes a `Distinct` using reflection,
+// works for any size input.
+func computeDistinctReflect(kvs []KeyValue) interface{} {
+	at := reflect.New(reflect.ArrayOf(len(kvs), keyValueType)).Elem()
+	for i, keyValue := range kvs {
+		*(at.Index(i).Addr().Interface().(*KeyValue)) = keyValue
+	}
+	return at.Interface()
+}
+
+// MarshalJSON returns the JSON encoding of the `*Set`.
+func (l *Set) MarshalJSON() ([]byte, error) {
+	return json.Marshal(l.equivalent.iface)
+}
+
+// Len implements `sort.Interface`.
+func (l *Sortable) Len() int {
+	return len(*l)
+}
+
+// Swap implements `sort.Interface`.
+func (l *Sortable) Swap(i, j int) {
+	(*l)[i], (*l)[j] = (*l)[j], (*l)[i]
+}
+
+// Less implements `sort.Interface`.
+func (l *Sortable) Less(i, j int) bool {
+	return (*l)[i].Key < (*l)[j].Key
+}

vendor/go.opentelemetry.io/otel/attribute/type_string.go

@@ -0,0 +1,28 @@
+// Code generated by "stringer -type=Type"; DO NOT EDIT.
+
+package attribute
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[INVALID-0]
+	_ = x[BOOL-1]
+	_ = x[INT64-2]
+	_ = x[FLOAT64-3]
+	_ = x[STRING-4]
+	_ = x[ARRAY-5]
+}
+
+const _Type_name = "INVALIDBOOLINT64FLOAT64STRINGARRAY"
+
+var _Type_index = [...]uint8{0, 7, 11, 16, 23, 29, 34}
+
+func (i Type) String() string {
+	if i < 0 || i >= Type(len(_Type_index)-1) {
+		return "Type(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _Type_name[_Type_index[i]:_Type_index[i+1]]
+}

vendor/go.opentelemetry.io/otel/attribute/value.go

@@ -0,0 +1,204 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package attribute // import "go.opentelemetry.io/otel/attribute"
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strconv"
+
+	"go.opentelemetry.io/otel/internal"
+)
+
+//go:generate stringer -type=Type
+
+// Type describes the type of the data Value holds.
+type Type int
+
+// Value represents the value part in key-value pairs.
+type Value struct {
+	vtype    Type
+	numeric  uint64
+	stringly string
+	// TODO Lazy value type?
+
+	array interface{}
+}
+
+const (
+	// INVALID is used for a Value with no value set.
+	INVALID Type = iota
+	// BOOL is a boolean Type Value.
+	BOOL
+	// INT64 is a 64-bit signed integral Type Value.
+	INT64
+	// FLOAT64 is a 64-bit floating point Type Value.
+	FLOAT64
+	// STRING is a string Type Value.
+	STRING
+	// ARRAY is an array Type Value used to store 1-dimensional slices or
+	// arrays of bool, int, int32, int64, uint, uint32, uint64, float,
+	// float32, float64, or string types.
+	ARRAY
+)
+
+// BoolValue creates a BOOL Value.
+func BoolValue(v bool) Value {
+	return Value{
+		vtype:   BOOL,
+		numeric: internal.BoolToRaw(v),
+	}
+}
+
+// Int64Value creates an INT64 Value.
+func Int64Value(v int64) Value {
+	return Value{
+		vtype:   INT64,
+		numeric: internal.Int64ToRaw(v),
+	}
+}
+
+// Float64Value creates a FLOAT64 Value.
+func Float64Value(v float64) Value {
+	return Value{
+		vtype:   FLOAT64,
+		numeric: internal.Float64ToRaw(v),
+	}
+}
+
+// StringValue creates a STRING Value.
+func StringValue(v string) Value {
+	return Value{
+		vtype:    STRING,
+		stringly: v,
+	}
+}
+
+// IntValue creates an INT64 Value.
+func IntValue(v int) Value {
+	return Int64Value(int64(v))
+}
+
+// ArrayValue creates an ARRAY value from an array or slice.
+// Only arrays or slices of bool, int, int64, float, float64, or string types are allowed.
+// Specifically, arrays  and slices can not contain other arrays, slices, structs, or non-standard
+// types. If the passed value is not an array or slice of these types an
+// INVALID value is returned.
+func ArrayValue(v interface{}) Value {
+	switch reflect.TypeOf(v).Kind() {
+	case reflect.Array, reflect.Slice:
+		// get array type regardless of dimensions
+		typ := reflect.TypeOf(v).Elem()
+		kind := typ.Kind()
+		switch kind {
+		case reflect.Bool, reflect.Int, reflect.Int64,
+			reflect.Float64, reflect.String:
+			val := reflect.ValueOf(v)
+			length := val.Len()
+			frozen := reflect.Indirect(reflect.New(reflect.ArrayOf(length, typ)))
+			reflect.Copy(frozen, val)
+			return Value{
+				vtype: ARRAY,
+				array: frozen.Interface(),
+			}
+		default:
+			return Value{vtype: INVALID}
+		}
+	}
+	return Value{vtype: INVALID}
+}
+
+// Type returns a type of the Value.
+func (v Value) Type() Type {
+	return v.vtype
+}
+
+// AsBool returns the bool value. Make sure that the Value's type is
+// BOOL.
+func (v Value) AsBool() bool {
+	return internal.RawToBool(v.numeric)
+}
+
+// AsInt64 returns the int64 value. Make sure that the Value's type is
+// INT64.
+func (v Value) AsInt64() int64 {
+	return internal.RawToInt64(v.numeric)
+}
+
+// AsFloat64 returns the float64 value. Make sure that the Value's
+// type is FLOAT64.
+func (v Value) AsFloat64() float64 {
+	return internal.RawToFloat64(v.numeric)
+}
+
+// AsString returns the string value. Make sure that the Value's type
+// is STRING.
+func (v Value) AsString() string {
+	return v.stringly
+}
+
+// AsArray returns the array Value as an interface{}.
+func (v Value) AsArray() interface{} {
+	return v.array
+}
+
+type unknownValueType struct{}
+
+// AsInterface returns Value's data as interface{}.
+func (v Value) AsInterface() interface{} {
+	switch v.Type() {
+	case ARRAY:
+		return v.AsArray()
+	case BOOL:
+		return v.AsBool()
+	case INT64:
+		return v.AsInt64()
+	case FLOAT64:
+		return v.AsFloat64()
+	case STRING:
+		return v.stringly
+	}
+	return unknownValueType{}
+}
+
+// Emit returns a string representation of Value's data.
+func (v Value) Emit() string {
+	switch v.Type() {
+	case ARRAY:
+		return fmt.Sprint(v.array)
+	case BOOL:
+		return strconv.FormatBool(v.AsBool())
+	case INT64:
+		return strconv.FormatInt(v.AsInt64(), 10)
+	case FLOAT64:
+		return fmt.Sprint(v.AsFloat64())
+	case STRING:
+		return v.stringly
+	default:
+		return "unknown"
+	}
+}
+
+// MarshalJSON returns the JSON encoding of the Value.
+func (v Value) MarshalJSON() ([]byte, error) {
+	var jsonVal struct {
+		Type  string
+		Value interface{}
+	}
+	jsonVal.Type = v.Type().String()
+	jsonVal.Value = v.AsInterface()
+	return json.Marshal(jsonVal)
+}

vendor/go.opentelemetry.io/otel/baggage/baggage.go

@@ -0,0 +1,509 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package baggage
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+	"regexp"
+	"strings"
+
+	"go.opentelemetry.io/otel/internal/baggage"
+)
+
+const (
+	maxMembers               = 180
+	maxBytesPerMembers       = 4096
+	maxBytesPerBaggageString = 8192
+
+	listDelimiter     = ","
+	keyValueDelimiter = "="
+	propertyDelimiter = ";"
+
+	keyDef      = `([\x21\x23-\x27\x2A\x2B\x2D\x2E\x30-\x39\x41-\x5a\x5e-\x7a\x7c\x7e]+)`
+	valueDef    = `([\x21\x23-\x2b\x2d-\x3a\x3c-\x5B\x5D-\x7e]*)`
+	keyValueDef = `\s*` + keyDef + `\s*` + keyValueDelimiter + `\s*` + valueDef + `\s*`
+)
+
+var (
+	keyRe      = regexp.MustCompile(`^` + keyDef + `$`)
+	valueRe    = regexp.MustCompile(`^` + valueDef + `$`)
+	propertyRe = regexp.MustCompile(`^(?:\s*` + keyDef + `\s*|` + keyValueDef + `)$`)
+)
+
+var (
+	errInvalidKey      = errors.New("invalid key")
+	errInvalidValue    = errors.New("invalid value")
+	errInvalidProperty = errors.New("invalid baggage list-member property")
+	errInvalidMember   = errors.New("invalid baggage list-member")
+	errMemberNumber    = errors.New("too many list-members in baggage-string")
+	errMemberBytes     = errors.New("list-member too large")
+	errBaggageBytes    = errors.New("baggage-string too large")
+)
+
+// Property is an additional metadata entry for a baggage list-member.
+type Property struct {
+	key, value string
+
+	// hasValue indicates if a zero-value value means the property does not
+	// have a value or if it was the zero-value.
+	hasValue bool
+}
+
+func NewKeyProperty(key string) (Property, error) {
+	p := Property{}
+	if !keyRe.MatchString(key) {
+		return p, fmt.Errorf("%w: %q", errInvalidKey, key)
+	}
+	p.key = key
+	return p, nil
+}
+
+func NewKeyValueProperty(key, value string) (Property, error) {
+	p := Property{}
+	if !keyRe.MatchString(key) {
+		return p, fmt.Errorf("%w: %q", errInvalidKey, key)
+	}
+	if !valueRe.MatchString(value) {
+		return p, fmt.Errorf("%w: %q", errInvalidValue, value)
+	}
+	p.key = key
+	p.value = value
+	p.hasValue = true
+	return p, nil
+}
+
+// parseProperty attempts to decode a Property from the passed string. It
+// returns an error if the input is invalid according to the W3C Baggage
+// specification.
+func parseProperty(property string) (Property, error) {
+	p := Property{}
+	if property == "" {
+		return p, nil
+	}
+
+	match := propertyRe.FindStringSubmatch(property)
+	if len(match) != 4 {
+		return p, fmt.Errorf("%w: %q", errInvalidProperty, property)
+	}
+
+	if match[1] != "" {
+		p.key = match[1]
+	} else {
+		p.key = match[2]
+		p.value = match[3]
+		p.hasValue = true
+	}
+	return p, nil
+}
+
+// validate ensures p conforms to the W3C Baggage specification, returning an
+// error otherwise.
+func (p Property) validate() error {
+	errFunc := func(err error) error {
+		return fmt.Errorf("invalid property: %w", err)
+	}
+
+	if !keyRe.MatchString(p.key) {
+		return errFunc(fmt.Errorf("%w: %q", errInvalidKey, p.key))
+	}
+	if p.hasValue && !valueRe.MatchString(p.value) {
+		return errFunc(fmt.Errorf("%w: %q", errInvalidValue, p.value))
+	}
+	if !p.hasValue && p.value != "" {
+		return errFunc(errors.New("inconsistent value"))
+	}
+	return nil
+}
+
+// Key returns the Property key.
+func (p Property) Key() string {
+	return p.key
+}
+
+// Value returns the Property value. Additionally a boolean value is returned
+// indicating if the returned value is the empty if the Property has a value
+// that is empty or if the value is not set.
+func (p Property) Value() (string, bool) {
+	return p.value, p.hasValue
+}
+
+// String encodes Property into a string compliant with the W3C Baggage
+// specification.
+func (p Property) String() string {
+	if p.hasValue {
+		return fmt.Sprintf("%s%s%v", p.key, keyValueDelimiter, p.value)
+	}
+	return p.key
+}
+
+type properties []Property
+
+func fromInternalProperties(iProps []baggage.Property) properties {
+	if len(iProps) == 0 {
+		return nil
+	}
+
+	props := make(properties, len(iProps))
+	for i, p := range iProps {
+		props[i] = Property{
+			key:      p.Key,
+			value:    p.Value,
+			hasValue: p.HasValue,
+		}
+	}
+	return props
+}
+
+func (p properties) asInternal() []baggage.Property {
+	if len(p) == 0 {
+		return nil
+	}
+
+	iProps := make([]baggage.Property, len(p))
+	for i, prop := range p {
+		iProps[i] = baggage.Property{
+			Key:      prop.key,
+			Value:    prop.value,
+			HasValue: prop.hasValue,
+		}
+	}
+	return iProps
+}
+
+func (p properties) Copy() properties {
+	if len(p) == 0 {
+		return nil
+	}
+
+	props := make(properties, len(p))
+	copy(props, p)
+	return props
+}
+
+// validate ensures each Property in p conforms to the W3C Baggage
+// specification, returning an error otherwise.
+func (p properties) validate() error {
+	for _, prop := range p {
+		if err := prop.validate(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// String encodes properties into a string compliant with the W3C Baggage
+// specification.
+func (p properties) String() string {
+	props := make([]string, len(p))
+	for i, prop := range p {
+		props[i] = prop.String()
+	}
+	return strings.Join(props, propertyDelimiter)
+}
+
+// Member is a list-member of a baggage-string as defined by the W3C Baggage
+// specification.
+type Member struct {
+	key, value string
+	properties properties
+}
+
+// NewMember returns a new Member from the passed arguments. An error is
+// returned if the created Member would be invalid according to the W3C
+// Baggage specification.
+func NewMember(key, value string, props ...Property) (Member, error) {
+	m := Member{key: key, value: value, properties: properties(props).Copy()}
+	if err := m.validate(); err != nil {
+		return Member{}, err
+	}
+
+	return m, nil
+}
+
+// parseMember attempts to decode a Member from the passed string. It returns
+// an error if the input is invalid according to the W3C Baggage
+// specification.
+func parseMember(member string) (Member, error) {
+	if n := len(member); n > maxBytesPerMembers {
+		return Member{}, fmt.Errorf("%w: %d", errMemberBytes, n)
+	}
+
+	var (
+		key, value string
+		props      properties
+	)
+
+	parts := strings.SplitN(member, propertyDelimiter, 2)
+	switch len(parts) {
+	case 2:
+		// Parse the member properties.
+		for _, pStr := range strings.Split(parts[1], propertyDelimiter) {
+			p, err := parseProperty(pStr)
+			if err != nil {
+				return Member{}, err
+			}
+			props = append(props, p)
+		}
+		fallthrough
+	case 1:
+		// Parse the member key/value pair.
+
+		// Take into account a value can contain equal signs (=).
+		kv := strings.SplitN(parts[0], keyValueDelimiter, 2)
+		if len(kv) != 2 {
+			return Member{}, fmt.Errorf("%w: %q", errInvalidMember, member)
+		}
+		// "Leading and trailing whitespaces are allowed but MUST be trimmed
+		// when converting the header into a data structure."
+		key, value = strings.TrimSpace(kv[0]), strings.TrimSpace(kv[1])
+		if !keyRe.MatchString(key) {
+			return Member{}, fmt.Errorf("%w: %q", errInvalidKey, key)
+		}
+		if !valueRe.MatchString(value) {
+			return Member{}, fmt.Errorf("%w: %q", errInvalidValue, value)
+		}
+	default:
+		// This should never happen unless a developer has changed the string
+		// splitting somehow. Panic instead of failing silently and allowing
+		// the bug to slip past the CI checks.
+		panic("failed to parse baggage member")
+	}
+
+	return Member{key: key, value: value, properties: props}, nil
+}
+
+// validate ensures m conforms to the W3C Baggage specification, returning an
+// error otherwise.
+func (m Member) validate() error {
+	if !keyRe.MatchString(m.key) {
+		return fmt.Errorf("%w: %q", errInvalidKey, m.key)
+	}
+	if !valueRe.MatchString(m.value) {
+		return fmt.Errorf("%w: %q", errInvalidValue, m.value)
+	}
+	return m.properties.validate()
+}
+
+// Key returns the Member key.
+func (m Member) Key() string { return m.key }
+
+// Value returns the Member value.
+func (m Member) Value() string { return m.value }
+
+// Properties returns a copy of the Member properties.
+func (m Member) Properties() []Property { return m.properties.Copy() }
+
+// String encodes Member into a string compliant with the W3C Baggage
+// specification.
+func (m Member) String() string {
+	// A key is just an ASCII string, but a value is URL encoded UTF-8.
+	s := fmt.Sprintf("%s%s%s", m.key, keyValueDelimiter, url.QueryEscape(m.value))
+	if len(m.properties) > 0 {
+		s = fmt.Sprintf("%s%s%s", s, propertyDelimiter, m.properties.String())
+	}
+	return s
+}
+
+// Baggage is a list of baggage members representing the baggage-string as
+// defined by the W3C Baggage specification.
+type Baggage struct { //nolint:golint
+	list baggage.List
+}
+
+// New returns a new valid Baggage. It returns an error if the passed members
+// are invalid according to the W3C Baggage specification or if it results in
+// a Baggage exceeding limits set in that specification.
+func New(members ...Member) (Baggage, error) {
+	if len(members) == 0 {
+		return Baggage{}, nil
+	}
+
+	b := make(baggage.List)
+	for _, m := range members {
+		if err := m.validate(); err != nil {
+			return Baggage{}, err
+		}
+		// OpenTelemetry resolves duplicates by last-one-wins.
+		b[m.key] = baggage.Item{
+			Value:      m.value,
+			Properties: m.properties.asInternal(),
+		}
+	}
+
+	// Check member numbers after deduplicating.
+	if len(b) > maxMembers {
+		return Baggage{}, errMemberNumber
+	}
+
+	bag := Baggage{b}
+	if n := len(bag.String()); n > maxBytesPerBaggageString {
+		return Baggage{}, fmt.Errorf("%w: %d", errBaggageBytes, n)
+	}
+
+	return bag, nil
+}
+
+// Parse attempts to decode a baggage-string from the passed string. It
+// returns an error if the input is invalid according to the W3C Baggage
+// specification.
+//
+// If there are duplicate list-members contained in baggage, the last one
+// defined (reading left-to-right) will be the only one kept. This diverges
+// from the W3C Baggage specification which allows duplicate list-members, but
+// conforms to the OpenTelemetry Baggage specification.
+func Parse(bStr string) (Baggage, error) {
+	if bStr == "" {
+		return Baggage{}, nil
+	}
+
+	if n := len(bStr); n > maxBytesPerBaggageString {
+		return Baggage{}, fmt.Errorf("%w: %d", errBaggageBytes, n)
+	}
+
+	b := make(baggage.List)
+	for _, memberStr := range strings.Split(bStr, listDelimiter) {
+		m, err := parseMember(memberStr)
+		if err != nil {
+			return Baggage{}, err
+		}
+		// OpenTelemetry resolves duplicates by last-one-wins.
+		b[m.key] = baggage.Item{
+			Value:      m.value,
+			Properties: m.properties.asInternal(),
+		}
+	}
+
+	// OpenTelemetry does not allow for duplicate list-members, but the W3C
+	// specification does. Now that we have deduplicated, ensure the baggage
+	// does not exceed list-member limits.
+	if len(b) > maxMembers {
+		return Baggage{}, errMemberNumber
+	}
+
+	return Baggage{b}, nil
+}
+
+// Member returns the baggage list-member identified by key.
+//
+// If there is no list-member matching the passed key the returned Member will
+// be a zero-value Member.
+func (b Baggage) Member(key string) Member {
+	v, ok := b.list[key]
+	if !ok {
+		// We do not need to worry about distiguising between the situation
+		// where a zero-valued Member is included in the Baggage because a
+		// zero-valued Member is invalid according to the W3C Baggage
+		// specification (it has an empty key).
+		return Member{}
+	}
+
+	return Member{
+		key:        key,
+		value:      v.Value,
+		properties: fromInternalProperties(v.Properties),
+	}
+}
+
+// Members returns all the baggage list-members.
+// The order of the returned list-members does not have significance.
+func (b Baggage) Members() []Member {
+	if len(b.list) == 0 {
+		return nil
+	}
+
+	members := make([]Member, 0, len(b.list))
+	for k, v := range b.list {
+		members = append(members, Member{
+			key:        k,
+			value:      v.Value,
+			properties: fromInternalProperties(v.Properties),
+		})
+	}
+	return members
+}
+
+// SetMember returns a copy the Baggage with the member included. If the
+// baggage contains a Member with the same key the existing Member is
+// replaced.
+//
+// If member is invalid according to the W3C Baggage specification, an error
+// is returned with the original Baggage.
+func (b Baggage) SetMember(member Member) (Baggage, error) {
+	if err := member.validate(); err != nil {
+		return b, fmt.Errorf("%w: %s", errInvalidMember, err)
+	}
+
+	n := len(b.list)
+	if _, ok := b.list[member.key]; !ok {
+		n++
+	}
+	list := make(baggage.List, n)
+
+	for k, v := range b.list {
+		// Do not copy if we are just going to overwrite.
+		if k == member.key {
+			continue
+		}
+		list[k] = v
+	}
+
+	list[member.key] = baggage.Item{
+		Value:      member.value,
+		Properties: member.properties.asInternal(),
+	}
+
+	return Baggage{list: list}, nil
+}
+
+// DeleteMember returns a copy of the Baggage with the list-member identified
+// by key removed.
+func (b Baggage) DeleteMember(key string) Baggage {
+	n := len(b.list)
+	if _, ok := b.list[key]; ok {
+		n--
+	}
+	list := make(baggage.List, n)
+
+	for k, v := range b.list {
+		if k == key {
+			continue
+		}
+		list[k] = v
+	}
+
+	return Baggage{list: list}
+}
+
+// Len returns the number of list-members in the Baggage.
+func (b Baggage) Len() int {
+	return len(b.list)
+}
+
+// String encodes Baggage into a string compliant with the W3C Baggage
+// specification. The returned string will be invalid if the Baggage contains
+// any invalid list-members.
+func (b Baggage) String() string {
+	members := make([]string, 0, len(b.list))
+	for k, v := range b.list {
+		members = append(members, Member{
+			key:        k,
+			value:      v.Value,
+			properties: fromInternalProperties(v.Properties),
+		}.String())
+	}
+	return strings.Join(members, listDelimiter)
+}

vendor/go.opentelemetry.io/otel/baggage/context.go

@@ -0,0 +1,39 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package baggage // import "go.opentelemetry.io/otel/baggage"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/internal/baggage"
+)
+
+// ContextWithBaggage returns a copy of parent with baggage.
+func ContextWithBaggage(parent context.Context, b Baggage) context.Context {
+	// Delegate so any hooks for the OpenTracing bridge are handled.
+	return baggage.ContextWithList(parent, b.list)
+}
+
+// ContextWithoutBaggage returns a copy of parent with no baggage.
+func ContextWithoutBaggage(parent context.Context) context.Context {
+	// Delegate so any hooks for the OpenTracing bridge are handled.
+	return baggage.ContextWithList(parent, nil)
+}
+
+// FromContext returns the baggage contained in ctx.
+func FromContext(ctx context.Context) Baggage {
+	// Delegate so any hooks for the OpenTracing bridge are handled.
+	return Baggage{list: baggage.ListFromContext(ctx)}
+}

vendor/go.opentelemetry.io/otel/baggage/doc.go

@@ -0,0 +1,23 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package baggage provides functionality for storing and retrieving
+baggage items in Go context. For propagating the baggage, see the
+go.opentelemetry.io/otel/propagation package.
+
+This package is currently in a Release Candidate phase. Backwards incompatible changes
+may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+*/
+package baggage // import "go.opentelemetry.io/otel/baggage"

vendor/go.opentelemetry.io/otel/codes/codes.go

@@ -0,0 +1,106 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package codes // import "go.opentelemetry.io/otel/codes"
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+)
+
+const (
+	// Unset is the default status code.
+	Unset Code = 0
+	// Error indicates the operation contains an error.
+	Error Code = 1
+	// Ok indicates operation has been validated by an Application developers
+	// or Operator to have completed successfully, or contain no error.
+	Ok Code = 2
+
+	maxCode = 3
+)
+
+// Code is an 32-bit representation of a status state.
+type Code uint32
+
+var codeToStr = map[Code]string{
+	Unset: "Unset",
+	Error: "Error",
+	Ok:    "Ok",
+}
+
+var strToCode = map[string]Code{
+	`"Unset"`: Unset,
+	`"Error"`: Error,
+	`"Ok"`:    Ok,
+}
+
+// String returns the Code as a string.
+func (c Code) String() string {
+	return codeToStr[c]
+}
+
+// UnmarshalJSON unmarshals b into the Code.
+//
+// This is based on the functionality in the gRPC codes package:
+// https://github.com/grpc/grpc-go/blob/bb64fee312b46ebee26be43364a7a966033521b1/codes/codes.go#L218-L244
+func (c *Code) UnmarshalJSON(b []byte) error {
+	// From json.Unmarshaler: By convention, to approximate the behavior of
+	// Unmarshal itself, Unmarshalers implement UnmarshalJSON([]byte("null")) as
+	// a no-op.
+	if string(b) == "null" {
+		return nil
+	}
+	if c == nil {
+		return fmt.Errorf("nil receiver passed to UnmarshalJSON")
+	}
+
+	var x interface{}
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	switch x.(type) {
+	case string:
+		if jc, ok := strToCode[string(b)]; ok {
+			*c = jc
+			return nil
+		}
+		return fmt.Errorf("invalid code: %q", string(b))
+	case float64:
+		if ci, err := strconv.ParseUint(string(b), 10, 32); err == nil {
+			if ci >= maxCode {
+				return fmt.Errorf("invalid code: %q", ci)
+			}
+
+			*c = Code(ci)
+			return nil
+		}
+		return fmt.Errorf("invalid code: %q", string(b))
+	default:
+		return fmt.Errorf("invalid code: %q", string(b))
+	}
+}
+
+// MarshalJSON returns c as the JSON encoding of c.
+func (c *Code) MarshalJSON() ([]byte, error) {
+	if c == nil {
+		return []byte("null"), nil
+	}
+	str, ok := codeToStr[*c]
+	if !ok {
+		return nil, fmt.Errorf("invalid code: %d", *c)
+	}
+	return []byte(fmt.Sprintf("%q", str)), nil
+}

vendor/go.opentelemetry.io/otel/codes/doc.go

@@ -0,0 +1,24 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package codes defines the canonical error codes used by OpenTelemetry.
+
+This package is currently in a Release Candidate phase. Backwards incompatible changes
+may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+
+It conforms to [the OpenTelemetry
+specification](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#statuscanonicalcode).
+*/
+package codes // import "go.opentelemetry.io/otel/codes"

vendor/go.opentelemetry.io/otel/doc.go

@@ -0,0 +1,37 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package otel provides global access to the OpenTelemetry API. The subpackages of
+the otel package provide an implementation of the OpenTelemetry API.
+
+This package is currently in a Release Candidate phase. Backwards incompatible changes
+may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+
+The provided API is used to instrument code and measure data about that code's
+performance and operation. The measured data, by default, is not processed or
+transmitted anywhere. An implementation of the OpenTelemetry SDK, like the
+default SDK implementation (go.opentelemetry.io/otel/sdk), and associated
+exporters are used to process and transport this data.
+
+To read the getting started guide, see https://opentelemetry.io/docs/go/getting-started/.
+
+To read more about tracing, see go.opentelemetry.io/otel/trace.
+
+To read more about metrics, see go.opentelemetry.io/otel/metric.
+
+To read more about propagation, see go.opentelemetry.io/otel/propagation and
+go.opentelemetry.io/otel/baggage.
+*/
+package otel // import "go.opentelemetry.io/otel"

vendor/go.opentelemetry.io/otel/error_handler.go

@@ -0,0 +1,27 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otel // import "go.opentelemetry.io/otel"
+
+// ErrorHandler handles irremediable events.
+type ErrorHandler interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Handle handles any error deemed irremediable by an OpenTelemetry
+	// component.
+	Handle(error)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
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+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
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+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
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+      (an example is provided in the Appendix below).
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+      form, that is based on (or derived from) the Work and for which the
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+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
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+      "Contribution" shall mean any work of authorship, including
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+          notices within Derivative Works that You distribute, alongside
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+          that such additional attribution notices cannot be construed
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+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
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+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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+      risks associated with Your exercise of permissions under this License.
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+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
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+      on Your own behalf and on Your sole responsibility, not on behalf
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+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
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+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/clients.go

@@ -0,0 +1,54 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptrace // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+
+import (
+	"context"
+
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
+)
+
+// Client manages connections to the collector, handles the
+// transformation of data into wire format, and the transmission of that
+// data to the collector.
+type Client interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Start should establish connection(s) to endpoint(s). It is
+	// called just once by the exporter, so the implementation
+	// does not need to worry about idempotence and locking.
+	Start(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Stop should close the connections. The function is called
+	// only once by the exporter, so the implementation does not
+	// need to worry about idempotence, but it may be called
+	// concurrently with UploadTraces, so proper
+	// locking is required. The function serves as a
+	// synchronization point - after the function returns, the
+	// process of closing connections is assumed to be finished.
+	Stop(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// UploadTraces should transform the passed traces to the wire
+	// format and send it to the collector. May be called
+	// concurrently.
+	UploadTraces(ctx context.Context, protoSpans []*tracepb.ResourceSpans) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/exporter.go

@@ -0,0 +1,103 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptrace // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+
+import (
+	"context"
+	"errors"
+	"sync"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/tracetransform"
+
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+)
+
+var (
+	errAlreadyStarted = errors.New("already started")
+)
+
+// Exporter exports trace data in the OTLP wire format.
+type Exporter struct {
+	client Client
+
+	mu      sync.RWMutex
+	started bool
+
+	startOnce sync.Once
+	stopOnce  sync.Once
+}
+
+// ExportSpans exports a batch of spans.
+func (e *Exporter) ExportSpans(ctx context.Context, ss []tracesdk.ReadOnlySpan) error {
+	protoSpans := tracetransform.Spans(ss)
+	if len(protoSpans) == 0 {
+		return nil
+	}
+
+	return e.client.UploadTraces(ctx, protoSpans)
+}
+
+// Start establishes a connection to the receiving endpoint.
+func (e *Exporter) Start(ctx context.Context) error {
+	var err = errAlreadyStarted
+	e.startOnce.Do(func() {
+		e.mu.Lock()
+		e.started = true
+		e.mu.Unlock()
+		err = e.client.Start(ctx)
+	})
+
+	return err
+}
+
+// Shutdown flushes all exports and closes all connections to the receiving endpoint.
+func (e *Exporter) Shutdown(ctx context.Context) error {
+	e.mu.RLock()
+	started := e.started
+	e.mu.RUnlock()
+
+	if !started {
+		return nil
+	}
+
+	var err error
+
+	e.stopOnce.Do(func() {
+		err = e.client.Stop(ctx)
+		e.mu.Lock()
+		e.started = false
+		e.mu.Unlock()
+	})
+
+	return err
+}
+
+var _ tracesdk.SpanExporter = (*Exporter)(nil)
+
+// New constructs a new Exporter and starts it.
+func New(ctx context.Context, client Client) (*Exporter, error) {
+	exp := NewUnstarted(client)
+	if err := exp.Start(ctx); err != nil {
+		return nil, err
+	}
+	return exp, nil
+}
+
+// NewUnstarted constructs a new Exporter and does not start it.
+func NewUnstarted(client Client) *Exporter {
+	return &Exporter{
+		client: client,
+	}
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/go.mod

@@ -0,0 +1,81 @@
+module go.opentelemetry.io/otel/exporters/otlp/otlptrace
+
+go 1.15
+
+require (
+	github.com/cenkalti/backoff/v4 v4.1.1
+	github.com/google/go-cmp v0.5.6
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/otel v1.0.0-RC1
+	go.opentelemetry.io/otel/oteltest v1.0.0-RC1
+	go.opentelemetry.io/otel/sdk v1.0.0-RC1
+	go.opentelemetry.io/otel/trace v1.0.0-RC1
+	go.opentelemetry.io/proto/otlp v0.9.0
+	google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013
+	google.golang.org/grpc v1.38.0
+	google.golang.org/protobuf v1.26.0
+)
+
+replace go.opentelemetry.io/otel => ../../..
+
+replace go.opentelemetry.io/otel/sdk => ../../../sdk
+
+replace go.opentelemetry.io/otel/metric => ../../../metric
+
+replace go.opentelemetry.io/otel/oteltest => ../../../oteltest
+
+replace go.opentelemetry.io/otel/trace => ../../../trace
+
+replace go.opentelemetry.io/otel/bridge/opencensus => ../../../bridge/opencensus
+
+replace go.opentelemetry.io/otel/bridge/opentracing => ../../../bridge/opentracing
+
+replace go.opentelemetry.io/otel/example/jaeger => ../../../example/jaeger
+
+replace go.opentelemetry.io/otel/example/namedtracer => ../../../example/namedtracer
+
+replace go.opentelemetry.io/otel/example/opencensus => ../../../example/opencensus
+
+replace go.opentelemetry.io/otel/example/otel-collector => ../../../example/otel-collector
+
+replace go.opentelemetry.io/otel/example/prom-collector => ../../../example/prom-collector
+
+replace go.opentelemetry.io/otel/example/prometheus => ../../../example/prometheus
+
+replace go.opentelemetry.io/otel/example/zipkin => ../../../example/zipkin
+
+replace go.opentelemetry.io/otel/exporters/prometheus => ../../prometheus
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ./
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ./otlptracegrpc
+
+replace go.opentelemetry.io/otel/exporters/jaeger => ../../jaeger
+
+replace go.opentelemetry.io/otel/exporters/zipkin => ../../zipkin
+
+replace go.opentelemetry.io/otel/internal/tools => ../../../internal/tools
+
+replace go.opentelemetry.io/otel/sdk/export/metric => ../../../sdk/export/metric
+
+replace go.opentelemetry.io/otel/sdk/metric => ../../../sdk/metric
+
+replace go.opentelemetry.io/otel/example/passthrough => ../../../example/passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp => ./otlptracehttp
+
+replace go.opentelemetry.io/otel/internal/metric => ../../../internal/metric
+
+replace go.opentelemetry.io/otel/exporters/metric/prometheus => ../../metric/prometheus
+
+replace go.opentelemetry.io/otel/exporters/trace/jaeger => ../../trace/jaeger
+
+replace go.opentelemetry.io/otel/exporters/trace/zipkin => ../../trace/zipkin
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric => ../otlpmetric
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc => ../otlpmetric/otlpmetricgrpc
+
+replace go.opentelemetry.io/otel/exporters/stdout/stdoutmetric => ../../stdout/stdoutmetric
+
+replace go.opentelemetry.io/otel/exporters/stdout/stdouttrace => ../../stdout/stdouttrace

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/go.sum

@@ -0,0 +1,123 @@
+cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
+github.com/cenkalti/backoff/v4 v4.1.1 h1:G2HAfAmvm/GcKan2oOQpBXOd2tT2G57ZnZGWa1PxPBQ=
+github.com/cenkalti/backoff/v4 v4.1.1/go.mod h1:scbssz8iZGpm3xbr14ovlUdkxfGXNInqkPWOWmG2CLw=
+github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
+github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
+github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
+github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
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vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/connection/connection.go

@@ -0,0 +1,429 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package connection
+
+import (
+	"context"
+	"fmt"
+	"math/rand"
+	"sync"
+	"sync/atomic"
+	"time"
+	"unsafe"
+
+	"github.com/cenkalti/backoff/v4"
+	"google.golang.org/genproto/googleapis/rpc/errdetails"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	"google.golang.org/grpc/encoding/gzip"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+)
+
+type Connection struct {
+	// Ensure pointer is 64-bit aligned for atomic operations on both 32 and 64 bit machines.
+	lastConnectErrPtr unsafe.Pointer
+
+	// mu protects the Connection as it is accessed by the
+	// exporter goroutines and background Connection goroutine
+	mu sync.Mutex
+	cc *grpc.ClientConn
+
+	// these fields are read-only after constructor is finished
+	cfg                  otlpconfig.Config
+	SCfg                 otlpconfig.SignalConfig
+	metadata             metadata.MD
+	newConnectionHandler func(cc *grpc.ClientConn)
+
+	// these channels are created once
+	disconnectedCh             chan bool
+	backgroundConnectionDoneCh chan struct{}
+	stopCh                     chan struct{}
+
+	// this is for tests, so they can replace the closing
+	// routine without a worry of modifying some global variable
+	// or changing it back to original after the test is done
+	closeBackgroundConnectionDoneCh func(ch chan struct{})
+}
+
+func NewConnection(cfg otlpconfig.Config, sCfg otlpconfig.SignalConfig, handler func(cc *grpc.ClientConn)) *Connection {
+	c := new(Connection)
+	c.newConnectionHandler = handler
+	c.cfg = cfg
+	c.SCfg = sCfg
+	if len(c.SCfg.Headers) > 0 {
+		c.metadata = metadata.New(c.SCfg.Headers)
+	}
+	c.closeBackgroundConnectionDoneCh = func(ch chan struct{}) {
+		close(ch)
+	}
+	return c
+}
+
+func (c *Connection) StartConnection(ctx context.Context) error {
+	c.stopCh = make(chan struct{})
+	c.disconnectedCh = make(chan bool, 1)
+	c.backgroundConnectionDoneCh = make(chan struct{})
+
+	if err := c.connect(ctx); err == nil {
+		c.setStateConnected()
+	} else {
+		c.SetStateDisconnected(err)
+	}
+	go c.indefiniteBackgroundConnection()
+
+	// TODO: proper error handling when initializing connections.
+	// We can report permanent errors, e.g., invalid settings.
+	return nil
+}
+
+func (c *Connection) LastConnectError() error {
+	errPtr := (*error)(atomic.LoadPointer(&c.lastConnectErrPtr))
+	if errPtr == nil {
+		return nil
+	}
+	return *errPtr
+}
+
+func (c *Connection) saveLastConnectError(err error) {
+	var errPtr *error
+	if err != nil {
+		errPtr = &err
+	}
+	atomic.StorePointer(&c.lastConnectErrPtr, unsafe.Pointer(errPtr))
+}
+
+func (c *Connection) SetStateDisconnected(err error) {
+	c.saveLastConnectError(err)
+	select {
+	case c.disconnectedCh <- true:
+	default:
+	}
+	c.newConnectionHandler(nil)
+}
+
+func (c *Connection) setStateConnected() {
+	c.saveLastConnectError(nil)
+}
+
+func (c *Connection) Connected() bool {
+	return c.LastConnectError() == nil
+}
+
+const defaultConnReattemptPeriod = 10 * time.Second
+
+func (c *Connection) indefiniteBackgroundConnection() {
+	defer func() {
+		c.closeBackgroundConnectionDoneCh(c.backgroundConnectionDoneCh)
+	}()
+
+	connReattemptPeriod := c.cfg.ReconnectionPeriod
+	if connReattemptPeriod <= 0 {
+		connReattemptPeriod = defaultConnReattemptPeriod
+	}
+
+	// No strong seeding required, nano time can
+	// already help with pseudo uniqueness.
+	rng := rand.New(rand.NewSource(time.Now().UnixNano() + rand.Int63n(1024)))
+
+	// maxJitterNanos: 70% of the connectionReattemptPeriod
+	maxJitterNanos := int64(0.7 * float64(connReattemptPeriod))
+
+	for {
+		// Otherwise these will be the normal scenarios to enable
+		// reconnection if we trip out.
+		// 1. If we've stopped, return entirely
+		// 2. Otherwise block until we are disconnected, and
+		//    then retry connecting
+		select {
+		case <-c.stopCh:
+			return
+
+		case <-c.disconnectedCh:
+			// Quickly check if we haven't stopped at the
+			// same time.
+			select {
+			case <-c.stopCh:
+				return
+
+			default:
+			}
+
+			// Normal scenario that we'll wait for
+		}
+
+		if err := c.connect(context.Background()); err == nil {
+			c.setStateConnected()
+		} else {
+			// this code is unreachable in most cases
+			// c.connect does not establish Connection
+			c.SetStateDisconnected(err)
+		}
+
+		// Apply some jitter to avoid lockstep retrials of other
+		// collector-exporters. Lockstep retrials could result in an
+		// innocent DDOS, by clogging the machine's resources and network.
+		jitter := time.Duration(rng.Int63n(maxJitterNanos))
+		select {
+		case <-c.stopCh:
+			return
+		case <-time.After(connReattemptPeriod + jitter):
+		}
+	}
+}
+
+func (c *Connection) connect(ctx context.Context) error {
+	cc, err := c.dialToCollector(ctx)
+	if err != nil {
+		return err
+	}
+	c.setConnection(cc)
+	c.newConnectionHandler(cc)
+	return nil
+}
+
+// setConnection sets cc as the client Connection and returns true if
+// the Connection state changed.
+func (c *Connection) setConnection(cc *grpc.ClientConn) bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	// If previous clientConn is same as the current then just return.
+	// This doesn't happen right now as this func is only called with new ClientConn.
+	// It is more about future-proofing.
+	if c.cc == cc {
+		return false
+	}
+
+	// If the previous clientConn was non-nil, close it
+	if c.cc != nil {
+		_ = c.cc.Close()
+	}
+	c.cc = cc
+	return true
+}
+
+func (c *Connection) dialToCollector(ctx context.Context) (*grpc.ClientConn, error) {
+	dialOpts := []grpc.DialOption{}
+	if c.cfg.ServiceConfig != "" {
+		dialOpts = append(dialOpts, grpc.WithDefaultServiceConfig(c.cfg.ServiceConfig))
+	}
+	if c.SCfg.GRPCCredentials != nil {
+		dialOpts = append(dialOpts, grpc.WithTransportCredentials(c.SCfg.GRPCCredentials))
+	} else if c.SCfg.Insecure {
+		dialOpts = append(dialOpts, grpc.WithInsecure())
+	}
+	if c.SCfg.Compression == otlpconfig.GzipCompression {
+		dialOpts = append(dialOpts, grpc.WithDefaultCallOptions(grpc.UseCompressor(gzip.Name)))
+	}
+	if len(c.cfg.DialOptions) != 0 {
+		dialOpts = append(dialOpts, c.cfg.DialOptions...)
+	}
+
+	ctx, cancel := c.ContextWithStop(ctx)
+	defer cancel()
+	ctx = c.ContextWithMetadata(ctx)
+	return grpc.DialContext(ctx, c.SCfg.Endpoint, dialOpts...)
+}
+
+func (c *Connection) ContextWithMetadata(ctx context.Context) context.Context {
+	if c.metadata.Len() > 0 {
+		return metadata.NewOutgoingContext(ctx, c.metadata)
+	}
+	return ctx
+}
+
+func (c *Connection) Shutdown(ctx context.Context) error {
+	close(c.stopCh)
+	// Ensure that the backgroundConnector returns
+	select {
+	case <-c.backgroundConnectionDoneCh:
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+
+	c.mu.Lock()
+	cc := c.cc
+	c.cc = nil
+	c.mu.Unlock()
+
+	if cc != nil {
+		return cc.Close()
+	}
+
+	return nil
+}
+
+func (c *Connection) ContextWithStop(ctx context.Context) (context.Context, context.CancelFunc) {
+	// Unify the parent context Done signal with the Connection's
+	// stop channel.
+	ctx, cancel := context.WithCancel(ctx)
+	go func(ctx context.Context, cancel context.CancelFunc) {
+		select {
+		case <-ctx.Done():
+			// Nothing to do, either cancelled or deadline
+			// happened.
+		case <-c.stopCh:
+			cancel()
+		}
+	}(ctx, cancel)
+	return ctx, cancel
+}
+
+func (c *Connection) DoRequest(ctx context.Context, fn func(context.Context) error) error {
+	expBackoff := newExponentialBackoff(c.cfg.RetrySettings)
+
+	for {
+		err := fn(ctx)
+		if err == nil {
+			// request succeeded.
+			return nil
+		}
+
+		if !c.cfg.RetrySettings.Enabled {
+			return err
+		}
+
+		// We have an error, check gRPC status code.
+		st := status.Convert(err)
+		if st.Code() == codes.OK {
+			// Not really an error, still success.
+			return nil
+		}
+
+		// Now, this is this a real error.
+
+		if !shouldRetry(st.Code()) {
+			// It is not a retryable error, we should not retry.
+			return err
+		}
+
+		// Need to retry.
+
+		throttle := getThrottleDuration(st)
+
+		backoffDelay := expBackoff.NextBackOff()
+		if backoffDelay == backoff.Stop {
+			// throw away the batch
+			err = fmt.Errorf("max elapsed time expired: %w", err)
+			return err
+		}
+
+		var delay time.Duration
+
+		if backoffDelay > throttle {
+			delay = backoffDelay
+		} else {
+			if expBackoff.GetElapsedTime()+throttle > expBackoff.MaxElapsedTime {
+				err = fmt.Errorf("max elapsed time expired when respecting server throttle: %w", err)
+				return err
+			}
+
+			// Respect server throttling.
+			delay = throttle
+		}
+
+		// back-off, but get interrupted when shutting down or request is cancelled or timed out.
+		err = func() error {
+			dt := time.NewTimer(delay)
+			defer dt.Stop()
+
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			case <-c.stopCh:
+				return fmt.Errorf("interrupted due to shutdown: %w", err)
+			case <-dt.C:
+			}
+
+			return nil
+		}()
+
+		if err != nil {
+			return err
+		}
+
+	}
+}
+
+func shouldRetry(code codes.Code) bool {
+	switch code {
+	case codes.OK:
+		// Success. This function should not be called for this code, the best we
+		// can do is tell the caller not to retry.
+		return false
+
+	case codes.Canceled,
+		codes.DeadlineExceeded,
+		codes.ResourceExhausted,
+		codes.Aborted,
+		codes.OutOfRange,
+		codes.Unavailable,
+		codes.DataLoss:
+		// These are retryable errors.
+		return true
+
+	case codes.Unknown,
+		codes.InvalidArgument,
+		codes.Unauthenticated,
+		codes.PermissionDenied,
+		codes.NotFound,
+		codes.AlreadyExists,
+		codes.FailedPrecondition,
+		codes.Unimplemented,
+		codes.Internal:
+		// These are fatal errors, don't retry.
+		return false
+
+	default:
+		// Don't retry on unknown codes.
+		return false
+	}
+}
+
+func getThrottleDuration(status *status.Status) time.Duration {
+	// See if throttling information is available.
+	for _, detail := range status.Details() {
+		if t, ok := detail.(*errdetails.RetryInfo); ok {
+			if t.RetryDelay.Seconds > 0 || t.RetryDelay.Nanos > 0 {
+				// We are throttled. Wait before retrying as requested by the server.
+				return time.Duration(t.RetryDelay.Seconds)*time.Second + time.Duration(t.RetryDelay.Nanos)*time.Nanosecond
+			}
+			return 0
+		}
+	}
+	return 0
+}
+
+func newExponentialBackoff(rs otlpconfig.RetrySettings) *backoff.ExponentialBackOff {
+	// Do not use NewExponentialBackOff since it calls Reset and the code here must
+	// call Reset after changing the InitialInterval (this saves an unnecessary call to Now).
+	expBackoff := &backoff.ExponentialBackOff{
+		InitialInterval:     rs.InitialInterval,
+		RandomizationFactor: backoff.DefaultRandomizationFactor,
+		Multiplier:          backoff.DefaultMultiplier,
+		MaxInterval:         rs.MaxInterval,
+		MaxElapsedTime:      rs.MaxElapsedTime,
+		Stop:                backoff.Stop,
+		Clock:               backoff.SystemClock,
+	}
+	expBackoff.Reset()
+
+	return expBackoff
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig/envconfig.go

@@ -0,0 +1,195 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpconfig
+
+import (
+	"crypto/tls"
+	"fmt"
+	"io/ioutil"
+	"net/url"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"go.opentelemetry.io/otel"
+)
+
+var httpSchemeRegexp = regexp.MustCompile(`(?i)^(http://|https://)`)
+
+func ApplyGRPCEnvConfigs(cfg *Config) {
+	e := EnvOptionsReader{
+		GetEnv:   os.Getenv,
+		ReadFile: ioutil.ReadFile,
+	}
+
+	e.ApplyGRPCEnvConfigs(cfg)
+}
+
+func ApplyHTTPEnvConfigs(cfg *Config) {
+	e := EnvOptionsReader{
+		GetEnv:   os.Getenv,
+		ReadFile: ioutil.ReadFile,
+	}
+
+	e.ApplyHTTPEnvConfigs(cfg)
+}
+
+type EnvOptionsReader struct {
+	GetEnv   func(string) string
+	ReadFile func(filename string) ([]byte, error)
+}
+
+func (e *EnvOptionsReader) ApplyHTTPEnvConfigs(cfg *Config) {
+	opts := e.GetOptionsFromEnv()
+	for _, opt := range opts {
+		opt.ApplyHTTPOption(cfg)
+	}
+}
+
+func (e *EnvOptionsReader) ApplyGRPCEnvConfigs(cfg *Config) {
+	opts := e.GetOptionsFromEnv()
+	for _, opt := range opts {
+		opt.ApplyGRPCOption(cfg)
+	}
+}
+
+func (e *EnvOptionsReader) GetOptionsFromEnv() []GenericOption {
+	var opts []GenericOption
+
+	// Endpoint
+	if v, ok := e.getEnvValue("ENDPOINT"); ok {
+		if isInsecureEndpoint(v) {
+			opts = append(opts, WithInsecure())
+		} else {
+			opts = append(opts, WithSecure())
+		}
+
+		opts = append(opts, WithEndpoint(trimSchema(v)))
+	}
+	if v, ok := e.getEnvValue("TRACES_ENDPOINT"); ok {
+		if isInsecureEndpoint(v) {
+			opts = append(opts, WithInsecure())
+		} else {
+			opts = append(opts, WithSecure())
+		}
+
+		opts = append(opts, WithEndpoint(trimSchema(v)))
+	}
+
+	// Certificate File
+	if path, ok := e.getEnvValue("CERTIFICATE"); ok {
+		if tls, err := e.readTLSConfig(path); err == nil {
+			opts = append(opts, WithTLSClientConfig(tls))
+		} else {
+			otel.Handle(fmt.Errorf("failed to configure otlp exporter certificate '%s': %w", path, err))
+		}
+	}
+	if path, ok := e.getEnvValue("TRACES_CERTIFICATE"); ok {
+		if tls, err := e.readTLSConfig(path); err == nil {
+			opts = append(opts, WithTLSClientConfig(tls))
+		} else {
+			otel.Handle(fmt.Errorf("failed to configure otlp traces exporter certificate '%s': %w", path, err))
+		}
+	}
+
+	// Headers
+	if h, ok := e.getEnvValue("HEADERS"); ok {
+		opts = append(opts, WithHeaders(stringToHeader(h)))
+	}
+	if h, ok := e.getEnvValue("TRACES_HEADERS"); ok {
+		opts = append(opts, WithHeaders(stringToHeader(h)))
+	}
+
+	// Compression
+	if c, ok := e.getEnvValue("COMPRESSION"); ok {
+		opts = append(opts, WithCompression(stringToCompression(c)))
+	}
+	if c, ok := e.getEnvValue("TRACES_COMPRESSION"); ok {
+		opts = append(opts, WithCompression(stringToCompression(c)))
+	}
+	// Timeout
+	if t, ok := e.getEnvValue("TIMEOUT"); ok {
+		if d, err := strconv.Atoi(t); err == nil {
+			opts = append(opts, WithTimeout(time.Duration(d)*time.Millisecond))
+		}
+	}
+	if t, ok := e.getEnvValue("TRACES_TIMEOUT"); ok {
+		if d, err := strconv.Atoi(t); err == nil {
+			opts = append(opts, WithTimeout(time.Duration(d)*time.Millisecond))
+		}
+	}
+
+	return opts
+}
+
+func isInsecureEndpoint(endpoint string) bool {
+	return strings.HasPrefix(strings.ToLower(endpoint), "http://") || strings.HasPrefix(strings.ToLower(endpoint), "unix://")
+}
+
+func trimSchema(endpoint string) string {
+	return httpSchemeRegexp.ReplaceAllString(endpoint, "")
+}
+
+// getEnvValue gets an OTLP environment variable value of the specified key using the GetEnv function.
+// This function already prepends the OTLP prefix to all key lookup.
+func (e *EnvOptionsReader) getEnvValue(key string) (string, bool) {
+	v := strings.TrimSpace(e.GetEnv(fmt.Sprintf("OTEL_EXPORTER_OTLP_%s", key)))
+	return v, v != ""
+}
+
+func (e *EnvOptionsReader) readTLSConfig(path string) (*tls.Config, error) {
+	b, err := e.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	return CreateTLSConfig(b)
+}
+
+func stringToCompression(value string) Compression {
+	switch value {
+	case "gzip":
+		return GzipCompression
+	}
+
+	return NoCompression
+}
+
+func stringToHeader(value string) map[string]string {
+	headersPairs := strings.Split(value, ",")
+	headers := make(map[string]string)
+
+	for _, header := range headersPairs {
+		nameValue := strings.SplitN(header, "=", 2)
+		if len(nameValue) < 2 {
+			continue
+		}
+		name, err := url.QueryUnescape(nameValue[0])
+		if err != nil {
+			continue
+		}
+		trimmedName := strings.TrimSpace(name)
+		value, err := url.QueryUnescape(nameValue[1])
+		if err != nil {
+			continue
+		}
+		trimmedValue := strings.TrimSpace(value)
+
+		headers[trimmedName] = trimmedValue
+	}
+
+	return headers
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig/options.go

@@ -0,0 +1,270 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpconfig // import "go.opentelemetry.io/otel/exporters/otlp/internal/otlpconfig"
+
+import (
+	"crypto/tls"
+	"fmt"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+)
+
+const (
+	// DefaultMaxAttempts describes how many times the driver
+	// should retry the sending of the payload in case of a
+	// retryable error.
+	DefaultMaxAttempts int = 5
+	// DefaultTracesPath is a default URL path for endpoint that
+	// receives spans.
+	DefaultTracesPath string = "/v1/traces"
+	// DefaultBackoff is a default base backoff time used in the
+	// exponential backoff strategy.
+	DefaultBackoff time.Duration = 300 * time.Millisecond
+	// DefaultTimeout is a default max waiting time for the backend to process
+	// each span batch.
+	DefaultTimeout time.Duration = 10 * time.Second
+)
+
+var (
+	// defaultRetrySettings is a default settings for the retry policy.
+	defaultRetrySettings = RetrySettings{
+		Enabled:         true,
+		InitialInterval: 5 * time.Second,
+		MaxInterval:     30 * time.Second,
+		MaxElapsedTime:  time.Minute,
+	}
+)
+
+type (
+	SignalConfig struct {
+		Endpoint    string
+		Insecure    bool
+		TLSCfg      *tls.Config
+		Headers     map[string]string
+		Compression Compression
+		Timeout     time.Duration
+		URLPath     string
+
+		// gRPC configurations
+		GRPCCredentials credentials.TransportCredentials
+	}
+
+	Config struct {
+		// Signal specific configurations
+		Traces SignalConfig
+
+		// HTTP configurations
+		MaxAttempts int
+		Backoff     time.Duration
+
+		// gRPC configurations
+		ReconnectionPeriod time.Duration
+		ServiceConfig      string
+		DialOptions        []grpc.DialOption
+		RetrySettings      RetrySettings
+	}
+)
+
+func NewDefaultConfig() Config {
+	c := Config{
+		Traces: SignalConfig{
+			Endpoint:    fmt.Sprintf("%s:%d", DefaultCollectorHost, DefaultCollectorPort),
+			URLPath:     DefaultTracesPath,
+			Compression: NoCompression,
+			Timeout:     DefaultTimeout,
+		},
+		MaxAttempts:   DefaultMaxAttempts,
+		Backoff:       DefaultBackoff,
+		RetrySettings: defaultRetrySettings,
+	}
+
+	return c
+}
+
+type (
+	// GenericOption applies an option to the HTTP or gRPC driver.
+	GenericOption interface {
+		ApplyHTTPOption(*Config)
+		ApplyGRPCOption(*Config)
+
+		// A private method to prevent users implementing the
+		// interface and so future additions to it will not
+		// violate compatibility.
+		private()
+	}
+
+	// HTTPOption applies an option to the HTTP driver.
+	HTTPOption interface {
+		ApplyHTTPOption(*Config)
+
+		// A private method to prevent users implementing the
+		// interface and so future additions to it will not
+		// violate compatibility.
+		private()
+	}
+
+	// GRPCOption applies an option to the gRPC driver.
+	GRPCOption interface {
+		ApplyGRPCOption(*Config)
+
+		// A private method to prevent users implementing the
+		// interface and so future additions to it will not
+		// violate compatibility.
+		private()
+	}
+)
+
+// genericOption is an option that applies the same logic
+// for both gRPC and HTTP.
+type genericOption struct {
+	fn func(*Config)
+}
+
+func (g *genericOption) ApplyGRPCOption(cfg *Config) {
+	g.fn(cfg)
+}
+
+func (g *genericOption) ApplyHTTPOption(cfg *Config) {
+	g.fn(cfg)
+}
+
+func (genericOption) private() {}
+
+func newGenericOption(fn func(cfg *Config)) GenericOption {
+	return &genericOption{fn: fn}
+}
+
+// splitOption is an option that applies different logics
+// for gRPC and HTTP.
+type splitOption struct {
+	httpFn func(*Config)
+	grpcFn func(*Config)
+}
+
+func (g *splitOption) ApplyGRPCOption(cfg *Config) {
+	g.grpcFn(cfg)
+}
+
+func (g *splitOption) ApplyHTTPOption(cfg *Config) {
+	g.httpFn(cfg)
+}
+
+func (splitOption) private() {}
+
+func newSplitOption(httpFn func(cfg *Config), grpcFn func(cfg *Config)) GenericOption {
+	return &splitOption{httpFn: httpFn, grpcFn: grpcFn}
+}
+
+// httpOption is an option that is only applied to the HTTP driver.
+type httpOption struct {
+	fn func(*Config)
+}
+
+func (h *httpOption) ApplyHTTPOption(cfg *Config) {
+	h.fn(cfg)
+}
+
+func (httpOption) private() {}
+
+func NewHTTPOption(fn func(cfg *Config)) HTTPOption {
+	return &httpOption{fn: fn}
+}
+
+// grpcOption is an option that is only applied to the gRPC driver.
+type grpcOption struct {
+	fn func(*Config)
+}
+
+func (h *grpcOption) ApplyGRPCOption(cfg *Config) {
+	h.fn(cfg)
+}
+
+func (grpcOption) private() {}
+
+func NewGRPCOption(fn func(cfg *Config)) GRPCOption {
+	return &grpcOption{fn: fn}
+}
+
+// Generic Options
+
+func WithEndpoint(endpoint string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Endpoint = endpoint
+	})
+}
+
+func WithCompression(compression Compression) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Compression = compression
+	})
+}
+
+func WithURLPath(urlPath string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.URLPath = urlPath
+	})
+}
+
+func WithRetry(settings RetrySettings) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.RetrySettings = settings
+	})
+}
+
+func WithTLSClientConfig(tlsCfg *tls.Config) GenericOption {
+	return newSplitOption(func(cfg *Config) {
+		cfg.Traces.TLSCfg = tlsCfg.Clone()
+	}, func(cfg *Config) {
+		cfg.Traces.GRPCCredentials = credentials.NewTLS(tlsCfg)
+	})
+}
+
+func WithInsecure() GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Insecure = true
+	})
+}
+
+func WithSecure() GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Insecure = false
+	})
+}
+
+func WithHeaders(headers map[string]string) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Headers = headers
+	})
+}
+
+func WithTimeout(duration time.Duration) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Traces.Timeout = duration
+	})
+}
+
+func WithMaxAttempts(maxAttempts int) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.MaxAttempts = maxAttempts
+	})
+}
+
+func WithBackoff(duration time.Duration) GenericOption {
+	return newGenericOption(func(cfg *Config) {
+		cfg.Backoff = duration
+	})
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig/optiontypes.go

@@ -0,0 +1,64 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpconfig // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig"
+
+import "time"
+
+const (
+	// DefaultCollectorPort is the port the Exporter will attempt connect to
+	// if no collector port is provided.
+	DefaultCollectorPort uint16 = 4317
+	// DefaultCollectorHost is the host address the Exporter will attempt
+	// connect to if no collector address is provided.
+	DefaultCollectorHost string = "localhost"
+)
+
+// Compression describes the compression used for payloads sent to the
+// collector.
+type Compression int
+
+const (
+	// NoCompression tells the driver to send payloads without
+	// compression.
+	NoCompression Compression = iota
+	// GzipCompression tells the driver to send payloads after
+	// compressing them with gzip.
+	GzipCompression
+)
+
+// Marshaler describes the kind of message format sent to the collector
+type Marshaler int
+
+const (
+	// MarshalProto tells the driver to send using the protobuf binary format.
+	MarshalProto Marshaler = iota
+	// MarshalJSON tells the driver to send using json format.
+	MarshalJSON
+)
+
+// RetrySettings defines configuration for retrying batches in case of export failure
+// using an exponential backoff.
+type RetrySettings struct {
+	// Enabled indicates whether to not retry sending batches in case of export failure.
+	Enabled bool
+	// InitialInterval the time to wait after the first failure before retrying.
+	InitialInterval time.Duration
+	// MaxInterval is the upper bound on backoff interval. Once this value is reached the delay between
+	// consecutive retries will always be `MaxInterval`.
+	MaxInterval time.Duration
+	// MaxElapsedTime is the maximum amount of time (including retries) spent trying to send a request/batch.
+	// Once this value is reached, the data is discarded.
+	MaxElapsedTime time.Duration
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig/tls.go

@@ -0,0 +1,34 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlpconfig
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+)
+
+// CreateTLSConfig creates a tls.Config from a raw certificate bytes
+// to verify a server certificate.
+func CreateTLSConfig(certBytes []byte) (*tls.Config, error) {
+	cp := x509.NewCertPool()
+	if ok := cp.AppendCertsFromPEM(certBytes); !ok {
+		return nil, errors.New("failed to append certificate to the cert pool")
+	}
+
+	return &tls.Config{
+		RootCAs: cp,
+	}, nil
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/tracetransform/attribute.go

@@ -0,0 +1,141 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tracetransform
+
+import (
+	"reflect"
+
+	"go.opentelemetry.io/otel/attribute"
+	commonpb "go.opentelemetry.io/proto/otlp/common/v1"
+
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+// Attributes transforms a slice of KeyValues into a slice of OTLP attribute key-values.
+func Attributes(attrs []attribute.KeyValue) []*commonpb.KeyValue {
+	if len(attrs) == 0 {
+		return nil
+	}
+
+	out := make([]*commonpb.KeyValue, 0, len(attrs))
+	for _, kv := range attrs {
+		out = append(out, toAttribute(kv))
+	}
+	return out
+}
+
+// ResourceAttributes transforms a Resource into a slice of OTLP attribute key-values.
+func ResourceAttributes(resource *resource.Resource) []*commonpb.KeyValue {
+	if resource.Len() == 0 {
+		return nil
+	}
+
+	out := make([]*commonpb.KeyValue, 0, resource.Len())
+	for iter := resource.Iter(); iter.Next(); {
+		out = append(out, toAttribute(iter.Attribute()))
+	}
+
+	return out
+}
+
+func toAttribute(v attribute.KeyValue) *commonpb.KeyValue {
+	result := &commonpb.KeyValue{
+		Key:   string(v.Key),
+		Value: new(commonpb.AnyValue),
+	}
+	switch v.Value.Type() {
+	case attribute.BOOL:
+		result.Value.Value = &commonpb.AnyValue_BoolValue{
+			BoolValue: v.Value.AsBool(),
+		}
+	case attribute.INT64:
+		result.Value.Value = &commonpb.AnyValue_IntValue{
+			IntValue: v.Value.AsInt64(),
+		}
+	case attribute.FLOAT64:
+		result.Value.Value = &commonpb.AnyValue_DoubleValue{
+			DoubleValue: v.Value.AsFloat64(),
+		}
+	case attribute.STRING:
+		result.Value.Value = &commonpb.AnyValue_StringValue{
+			StringValue: v.Value.AsString(),
+		}
+	case attribute.ARRAY:
+		result.Value.Value = &commonpb.AnyValue_ArrayValue{
+			ArrayValue: &commonpb.ArrayValue{
+				Values: arrayValues(v),
+			},
+		}
+	default:
+		result.Value.Value = &commonpb.AnyValue_StringValue{
+			StringValue: "INVALID",
+		}
+	}
+	return result
+}
+
+func arrayValues(kv attribute.KeyValue) []*commonpb.AnyValue {
+	a := kv.Value.AsArray()
+	aType := reflect.TypeOf(a)
+	var valueFunc func(reflect.Value) *commonpb.AnyValue
+	switch aType.Elem().Kind() {
+	case reflect.Bool:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_BoolValue{
+					BoolValue: v.Bool(),
+				},
+			}
+		}
+	case reflect.Int, reflect.Int64:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_IntValue{
+					IntValue: v.Int(),
+				},
+			}
+		}
+	case reflect.Uintptr:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_IntValue{
+					IntValue: int64(v.Uint()),
+				},
+			}
+		}
+	case reflect.Float64:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_DoubleValue{
+					DoubleValue: v.Float(),
+				},
+			}
+		}
+	case reflect.String:
+		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
+			return &commonpb.AnyValue{
+				Value: &commonpb.AnyValue_StringValue{
+					StringValue: v.String(),
+				},
+			}
+		}
+	}
+
+	results := make([]*commonpb.AnyValue, aType.Len())
+	for i, aValue := 0, reflect.ValueOf(a); i < aValue.Len(); i++ {
+		results[i] = valueFunc(aValue.Index(i))
+	}
+	return results
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/tracetransform/instrumentation.go

@@ -0,0 +1,31 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tracetransform
+
+import (
+	commonpb "go.opentelemetry.io/proto/otlp/common/v1"
+
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+)
+
+func InstrumentationLibrary(il instrumentation.Library) *commonpb.InstrumentationLibrary {
+	if il == (instrumentation.Library{}) {
+		return nil
+	}
+	return &commonpb.InstrumentationLibrary{
+		Name:    il.Name,
+		Version: il.Version,
+	}
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/tracetransform/resource.go

@@ -0,0 +1,29 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tracetransform
+
+import (
+	resourcepb "go.opentelemetry.io/proto/otlp/resource/v1"
+
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+// Resource transforms a Resource into an OTLP Resource.
+func Resource(r *resource.Resource) *resourcepb.Resource {
+	if r == nil {
+		return nil
+	}
+	return &resourcepb.Resource{Attributes: ResourceAttributes(r)}
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/tracetransform/span.go

@@ -0,0 +1,218 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tracetransform
+
+import (
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
+
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+	"go.opentelemetry.io/otel/trace"
+)
+
+const (
+	maxEventsPerSpan = 128
+)
+
+// Spans transforms a slice of OpenTelemetry spans into a slice of OTLP
+// ResourceSpans.
+func Spans(sdl []tracesdk.ReadOnlySpan) []*tracepb.ResourceSpans {
+	if len(sdl) == 0 {
+		return nil
+	}
+
+	rsm := make(map[attribute.Distinct]*tracepb.ResourceSpans)
+
+	type ilsKey struct {
+		r  attribute.Distinct
+		il instrumentation.Library
+	}
+	ilsm := make(map[ilsKey]*tracepb.InstrumentationLibrarySpans)
+
+	var resources int
+	for _, sd := range sdl {
+		if sd == nil {
+			continue
+		}
+
+		rKey := sd.Resource().Equivalent()
+		iKey := ilsKey{
+			r:  rKey,
+			il: sd.InstrumentationLibrary(),
+		}
+		ils, iOk := ilsm[iKey]
+		if !iOk {
+			// Either the resource or instrumentation library were unknown.
+			ils = &tracepb.InstrumentationLibrarySpans{
+				InstrumentationLibrary: InstrumentationLibrary(sd.InstrumentationLibrary()),
+				Spans:                  []*tracepb.Span{},
+			}
+		}
+		ils.Spans = append(ils.Spans, span(sd))
+		ilsm[iKey] = ils
+
+		rs, rOk := rsm[rKey]
+		if !rOk {
+			resources++
+			// The resource was unknown.
+			rs = &tracepb.ResourceSpans{
+				Resource:                    Resource(sd.Resource()),
+				InstrumentationLibrarySpans: []*tracepb.InstrumentationLibrarySpans{ils},
+			}
+			rsm[rKey] = rs
+			continue
+		}
+
+		// The resource has been seen before. Check if the instrumentation
+		// library lookup was unknown because if so we need to add it to the
+		// ResourceSpans. Otherwise, the instrumentation library has already
+		// been seen and the append we did above will be included it in the
+		// InstrumentationLibrarySpans reference.
+		if !iOk {
+			rs.InstrumentationLibrarySpans = append(rs.InstrumentationLibrarySpans, ils)
+		}
+	}
+
+	// Transform the categorized map into a slice
+	rss := make([]*tracepb.ResourceSpans, 0, resources)
+	for _, rs := range rsm {
+		rss = append(rss, rs)
+	}
+	return rss
+}
+
+// span transforms a Span into an OTLP span.
+func span(sd tracesdk.ReadOnlySpan) *tracepb.Span {
+	if sd == nil {
+		return nil
+	}
+
+	tid := sd.SpanContext().TraceID()
+	sid := sd.SpanContext().SpanID()
+
+	s := &tracepb.Span{
+		TraceId:                tid[:],
+		SpanId:                 sid[:],
+		TraceState:             sd.SpanContext().TraceState().String(),
+		Status:                 status(sd.Status().Code, sd.Status().Description),
+		StartTimeUnixNano:      uint64(sd.StartTime().UnixNano()),
+		EndTimeUnixNano:        uint64(sd.EndTime().UnixNano()),
+		Links:                  links(sd.Links()),
+		Kind:                   spanKind(sd.SpanKind()),
+		Name:                   sd.Name(),
+		Attributes:             Attributes(sd.Attributes()),
+		Events:                 spanEvents(sd.Events()),
+		DroppedAttributesCount: uint32(sd.DroppedAttributes()),
+		DroppedEventsCount:     uint32(sd.DroppedEvents()),
+		DroppedLinksCount:      uint32(sd.DroppedLinks()),
+	}
+
+	if psid := sd.Parent().SpanID(); psid.IsValid() {
+		s.ParentSpanId = psid[:]
+	}
+
+	return s
+}
+
+// status transform a span code and message into an OTLP span status.
+func status(status codes.Code, message string) *tracepb.Status {
+	var c tracepb.Status_StatusCode
+	switch status {
+	case codes.Error:
+		c = tracepb.Status_STATUS_CODE_ERROR
+	default:
+		c = tracepb.Status_STATUS_CODE_OK
+	}
+	return &tracepb.Status{
+		Code:    c,
+		Message: message,
+	}
+}
+
+// links transforms span Links to OTLP span links.
+func links(links []trace.Link) []*tracepb.Span_Link {
+	if len(links) == 0 {
+		return nil
+	}
+
+	sl := make([]*tracepb.Span_Link, 0, len(links))
+	for _, otLink := range links {
+		// This redefinition is necessary to prevent otLink.*ID[:] copies
+		// being reused -- in short we need a new otLink per iteration.
+		otLink := otLink
+
+		tid := otLink.SpanContext.TraceID()
+		sid := otLink.SpanContext.SpanID()
+
+		sl = append(sl, &tracepb.Span_Link{
+			TraceId:    tid[:],
+			SpanId:     sid[:],
+			Attributes: Attributes(otLink.Attributes),
+		})
+	}
+	return sl
+}
+
+// spanEvents transforms span Events to an OTLP span events.
+func spanEvents(es []tracesdk.Event) []*tracepb.Span_Event {
+	if len(es) == 0 {
+		return nil
+	}
+
+	evCount := len(es)
+	if evCount > maxEventsPerSpan {
+		evCount = maxEventsPerSpan
+	}
+	events := make([]*tracepb.Span_Event, 0, evCount)
+	nEvents := 0
+
+	// Transform message events
+	for _, e := range es {
+		if nEvents >= maxEventsPerSpan {
+			break
+		}
+		nEvents++
+		events = append(events,
+			&tracepb.Span_Event{
+				Name:         e.Name,
+				TimeUnixNano: uint64(e.Time.UnixNano()),
+				Attributes:   Attributes(e.Attributes),
+				// TODO (rghetia) : Add Drop Counts when supported.
+			},
+		)
+	}
+
+	return events
+}
+
+// spanKind transforms a SpanKind to an OTLP span kind.
+func spanKind(kind trace.SpanKind) tracepb.Span_SpanKind {
+	switch kind {
+	case trace.SpanKindInternal:
+		return tracepb.Span_SPAN_KIND_INTERNAL
+	case trace.SpanKindClient:
+		return tracepb.Span_SPAN_KIND_CLIENT
+	case trace.SpanKindServer:
+		return tracepb.Span_SPAN_KIND_SERVER
+	case trace.SpanKindProducer:
+		return tracepb.Span_SPAN_KIND_PRODUCER
+	case trace.SpanKindConsumer:
+		return tracepb.Span_SPAN_KIND_CONSUMER
+	default:
+		return tracepb.Span_SPAN_KIND_UNSPECIFIED
+	}
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
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+      including but not limited to software source code, documentation
+      source, and configuration files.
+
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+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
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+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
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+      form, that is based on (or derived from) the Work and for which the
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+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
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+
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+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
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+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
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+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc/client.go

@@ -0,0 +1,110 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptracegrpc // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/connection"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig"
+
+	"google.golang.org/grpc"
+
+	coltracepb "go.opentelemetry.io/proto/otlp/collector/trace/v1"
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
+)
+
+type client struct {
+	connection *connection.Connection
+
+	lock         sync.Mutex
+	tracesClient coltracepb.TraceServiceClient
+}
+
+var _ otlptrace.Client = (*client)(nil)
+
+var (
+	errNoClient = errors.New("no client")
+)
+
+// NewClient creates a new gRPC trace client.
+func NewClient(opts ...Option) otlptrace.Client {
+	cfg := otlpconfig.NewDefaultConfig()
+	otlpconfig.ApplyGRPCEnvConfigs(&cfg)
+	for _, opt := range opts {
+		opt.applyGRPCOption(&cfg)
+	}
+
+	c := &client{}
+	c.connection = connection.NewConnection(cfg, cfg.Traces, c.handleNewConnection)
+
+	return c
+}
+
+func (c *client) handleNewConnection(cc *grpc.ClientConn) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if cc != nil {
+		c.tracesClient = coltracepb.NewTraceServiceClient(cc)
+	} else {
+		c.tracesClient = nil
+	}
+}
+
+// Start establishes a connection to the collector.
+func (c *client) Start(ctx context.Context) error {
+	return c.connection.StartConnection(ctx)
+}
+
+// Stop shuts down the connection to the collector.
+func (c *client) Stop(ctx context.Context) error {
+	return c.connection.Shutdown(ctx)
+}
+
+// UploadTraces sends a batch of spans to the collector.
+func (c *client) UploadTraces(ctx context.Context, protoSpans []*tracepb.ResourceSpans) error {
+	if !c.connection.Connected() {
+		return fmt.Errorf("traces exporter is disconnected from the server %s: %w", c.connection.SCfg.Endpoint, c.connection.LastConnectError())
+	}
+
+	ctx, cancel := c.connection.ContextWithStop(ctx)
+	defer cancel()
+	ctx, tCancel := context.WithTimeout(ctx, c.connection.SCfg.Timeout)
+	defer tCancel()
+
+	ctx = c.connection.ContextWithMetadata(ctx)
+	err := func() error {
+		c.lock.Lock()
+		defer c.lock.Unlock()
+		if c.tracesClient == nil {
+			return errNoClient
+		}
+		return c.connection.DoRequest(ctx, func(ctx context.Context) error {
+			_, err := c.tracesClient.Export(ctx, &coltracepb.ExportTraceServiceRequest{
+				ResourceSpans: protoSpans,
+			})
+			return err
+		})
+	}()
+	if err != nil {
+		c.connection.SetStateDisconnected(err)
+	}
+	return err
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc/exporter.go

@@ -0,0 +1,31 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptracegrpc // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+)
+
+// New constructs a new Exporter and starts it.
+func New(ctx context.Context, opts ...Option) (*otlptrace.Exporter, error) {
+	return otlptrace.New(ctx, NewClient(opts...))
+}
+
+// NewUnstarted constructs a new Exporter and does not start it.
+func NewUnstarted(opts ...Option) *otlptrace.Exporter {
+	return otlptrace.NewUnstarted(NewClient(opts...))
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc/go.mod

@@ -0,0 +1,78 @@
+module go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc
+
+go 1.15
+
+require (
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/otel v1.0.0-RC1
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.0.0-RC1
+	go.opentelemetry.io/otel/sdk v1.0.0-RC1
+	go.opentelemetry.io/proto/otlp v0.9.0
+	google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013
+	google.golang.org/grpc v1.38.0
+	google.golang.org/protobuf v1.26.0
+)
+
+replace go.opentelemetry.io/otel => ../../../..
+
+replace go.opentelemetry.io/otel/sdk => ../../../../sdk
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../
+
+replace go.opentelemetry.io/otel/metric => ../../../../metric
+
+replace go.opentelemetry.io/otel/oteltest => ../../../../oteltest
+
+replace go.opentelemetry.io/otel/trace => ../../../../trace
+
+replace go.opentelemetry.io/otel/bridge/opencensus => ../../../../bridge/opencensus
+
+replace go.opentelemetry.io/otel/bridge/opentracing => ../../../../bridge/opentracing
+
+replace go.opentelemetry.io/otel/example/jaeger => ../../../../example/jaeger
+
+replace go.opentelemetry.io/otel/example/namedtracer => ../../../../example/namedtracer
+
+replace go.opentelemetry.io/otel/example/opencensus => ../../../../example/opencensus
+
+replace go.opentelemetry.io/otel/example/otel-collector => ../../../../example/otel-collector
+
+replace go.opentelemetry.io/otel/example/prom-collector => ../../../../example/prom-collector
+
+replace go.opentelemetry.io/otel/example/prometheus => ../../../../example/prometheus
+
+replace go.opentelemetry.io/otel/example/zipkin => ../../../../example/zipkin
+
+replace go.opentelemetry.io/otel/exporters/prometheus => ../../../prometheus
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ./
+
+replace go.opentelemetry.io/otel/exporters/jaeger => ../../../jaeger
+
+replace go.opentelemetry.io/otel/exporters/zipkin => ../../../zipkin
+
+replace go.opentelemetry.io/otel/internal/tools => ../../../../internal/tools
+
+replace go.opentelemetry.io/otel/sdk/export/metric => ../../../../sdk/export/metric
+
+replace go.opentelemetry.io/otel/sdk/metric => ../../../../sdk/metric
+
+replace go.opentelemetry.io/otel/example/passthrough => ../../../../example/passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp => ../otlptracehttp
+
+replace go.opentelemetry.io/otel/internal/metric => ../../../../internal/metric
+
+replace go.opentelemetry.io/otel/exporters/metric/prometheus => ../../../metric/prometheus
+
+replace go.opentelemetry.io/otel/exporters/trace/jaeger => ../../../trace/jaeger
+
+replace go.opentelemetry.io/otel/exporters/trace/zipkin => ../../../trace/zipkin
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric => ../../otlpmetric
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc => ../../otlpmetric/otlpmetricgrpc
+
+replace go.opentelemetry.io/otel/exporters/stdout/stdoutmetric => ../../../stdout/stdoutmetric
+
+replace go.opentelemetry.io/otel/exporters/stdout/stdouttrace => ../../../stdout/stdouttrace

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc/go.sum

@@ -0,0 +1,123 @@
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+github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
+github.com/cenkalti/backoff/v4 v4.1.1 h1:G2HAfAmvm/GcKan2oOQpBXOd2tT2G57ZnZGWa1PxPBQ=
+github.com/cenkalti/backoff/v4 v4.1.1/go.mod h1:scbssz8iZGpm3xbr14ovlUdkxfGXNInqkPWOWmG2CLw=
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vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc/options.go

@@ -0,0 +1,132 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptracegrpc // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+
+import (
+	"fmt"
+	"time"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+)
+
+// Option applies an option to the gRPC driver.
+type Option interface {
+	applyGRPCOption(*otlpconfig.Config)
+}
+
+// RetrySettings defines configuration for retrying batches in case of export failure
+// using an exponential backoff.
+type RetrySettings otlpconfig.RetrySettings
+
+type wrappedOption struct {
+	otlpconfig.GRPCOption
+}
+
+func (w wrappedOption) applyGRPCOption(cfg *otlpconfig.Config) {
+	w.ApplyGRPCOption(cfg)
+}
+
+// WithInsecure disables client transport security for the exporter's gRPC connection
+// just like grpc.WithInsecure() https://pkg.go.dev/google.golang.org/grpc#WithInsecure
+// does. Note, by default, client security is required unless WithInsecure is used.
+func WithInsecure() Option {
+	return wrappedOption{otlpconfig.WithInsecure()}
+}
+
+// WithEndpoint allows one to set the endpoint that the exporter will
+// connect to the collector on. If unset, it will instead try to use
+// connect to DefaultCollectorHost:DefaultCollectorPort.
+func WithEndpoint(endpoint string) Option {
+	return wrappedOption{otlpconfig.WithEndpoint(endpoint)}
+}
+
+// WithReconnectionPeriod allows one to set the delay between next connection attempt
+// after failing to connect with the collector.
+func WithReconnectionPeriod(rp time.Duration) Option {
+	return wrappedOption{otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.ReconnectionPeriod = rp
+	})}
+}
+
+func compressorToCompression(compressor string) otlpconfig.Compression {
+	switch compressor {
+	case "gzip":
+		return otlpconfig.GzipCompression
+	}
+
+	otel.Handle(fmt.Errorf("invalid compression type: '%s', using no compression as default", compressor))
+	return otlpconfig.NoCompression
+}
+
+// WithCompressor will set the compressor for the gRPC client to use when sending requests.
+// It is the responsibility of the caller to ensure that the compressor set has been registered
+// with google.golang.org/grpc/encoding. This can be done by encoding.RegisterCompressor. Some
+// compressors auto-register on import, such as gzip, which can be registered by calling
+// `import _ "google.golang.org/grpc/encoding/gzip"`.
+func WithCompressor(compressor string) Option {
+	return wrappedOption{otlpconfig.WithCompression(compressorToCompression(compressor))}
+}
+
+// WithHeaders will send the provided headers with gRPC requests.
+func WithHeaders(headers map[string]string) Option {
+	return wrappedOption{otlpconfig.WithHeaders(headers)}
+}
+
+// WithTLSCredentials allows the connection to use TLS credentials
+// when talking to the server. It takes in grpc.TransportCredentials instead
+// of say a Certificate file or a tls.Certificate, because the retrieving of
+// these credentials can be done in many ways e.g. plain file, in code tls.Config
+// or by certificate rotation, so it is up to the caller to decide what to use.
+func WithTLSCredentials(creds credentials.TransportCredentials) Option {
+	return wrappedOption{otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.Traces.GRPCCredentials = creds
+	})}
+}
+
+// WithServiceConfig defines the default gRPC service config used.
+func WithServiceConfig(serviceConfig string) Option {
+	return wrappedOption{otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.ServiceConfig = serviceConfig
+	})}
+}
+
+// WithDialOption opens support to any grpc.DialOption to be used. If it conflicts
+// with some other configuration the GRPC specified via the collector the ones here will
+// take preference since they are set last.
+func WithDialOption(opts ...grpc.DialOption) Option {
+	return wrappedOption{otlpconfig.NewGRPCOption(func(cfg *otlpconfig.Config) {
+		cfg.DialOptions = opts
+	})}
+}
+
+// WithTimeout tells the driver the max waiting time for the backend to process
+// each spans batch. If unset, the default will be 10 seconds.
+func WithTimeout(duration time.Duration) Option {
+	return wrappedOption{otlpconfig.WithTimeout(duration)}
+}
+
+// WithRetry configures the retry policy for transient errors that may occurs when
+// exporting traces. An exponential back-off algorithm is used to
+// ensure endpoints are not overwhelmed with retries. If unset, the default
+// ensure endpoints are not overwhelmed with retries. If unset, the default
+// retry policy will retry after 5 seconds and increase exponentially after each
+// error for a total of 1 minute.
+func WithRetry(settings RetrySettings) Option {
+	return wrappedOption{otlpconfig.WithRetry(otlpconfig.RetrySettings(settings))}
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
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+      where such license applies only to those patent claims licensable
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+      Contribution(s) alone or by combination of their Contribution(s)
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+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
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+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
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+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
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+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp/client.go

@@ -0,0 +1,280 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptracehttp
+
+import (
+	"bytes"
+	"compress/gzip"
+	"context"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"net"
+	"net/http"
+	"path"
+	"strings"
+	"time"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig"
+
+	"google.golang.org/protobuf/proto"
+
+	"go.opentelemetry.io/otel"
+	coltracepb "go.opentelemetry.io/proto/otlp/collector/trace/v1"
+)
+
+const contentTypeProto = "application/x-protobuf"
+
+// Keep it in sync with golang's DefaultTransport from net/http! We
+// have our own copy to avoid handling a situation where the
+// DefaultTransport is overwritten with some different implementation
+// of http.RoundTripper or it's modified by other package.
+var ourTransport = &http.Transport{
+	Proxy: http.ProxyFromEnvironment,
+	DialContext: (&net.Dialer{
+		Timeout:   30 * time.Second,
+		KeepAlive: 30 * time.Second,
+	}).DialContext,
+	ForceAttemptHTTP2:     true,
+	MaxIdleConns:          100,
+	IdleConnTimeout:       90 * time.Second,
+	TLSHandshakeTimeout:   10 * time.Second,
+	ExpectContinueTimeout: 1 * time.Second,
+}
+
+type client struct {
+	name       string
+	cfg        otlpconfig.SignalConfig
+	generalCfg otlpconfig.Config
+	client     *http.Client
+	stopCh     chan struct{}
+}
+
+var _ otlptrace.Client = (*client)(nil)
+
+// NewClient creates a new HTTP trace client.
+func NewClient(opts ...Option) otlptrace.Client {
+	cfg := otlpconfig.NewDefaultConfig()
+	otlpconfig.ApplyHTTPEnvConfigs(&cfg)
+	for _, opt := range opts {
+		opt.applyHTTPOption(&cfg)
+	}
+
+	for pathPtr, defaultPath := range map[*string]string{
+		&cfg.Traces.URLPath: defaultTracesPath,
+	} {
+		tmp := strings.TrimSpace(*pathPtr)
+		if tmp == "" {
+			tmp = defaultPath
+		} else {
+			tmp = path.Clean(tmp)
+			if !path.IsAbs(tmp) {
+				tmp = fmt.Sprintf("/%s", tmp)
+			}
+		}
+		*pathPtr = tmp
+	}
+	if cfg.MaxAttempts <= 0 {
+		cfg.MaxAttempts = defaultMaxAttempts
+	}
+	if cfg.MaxAttempts > defaultMaxAttempts {
+		cfg.MaxAttempts = defaultMaxAttempts
+	}
+	if cfg.Backoff <= 0 {
+		cfg.Backoff = defaultBackoff
+	}
+
+	httpClient := &http.Client{
+		Transport: ourTransport,
+		Timeout:   cfg.Traces.Timeout,
+	}
+	if cfg.Traces.TLSCfg != nil {
+		transport := ourTransport.Clone()
+		transport.TLSClientConfig = cfg.Traces.TLSCfg
+		httpClient.Transport = transport
+	}
+
+	stopCh := make(chan struct{})
+	return &client{
+		name:       "traces",
+		cfg:        cfg.Traces,
+		generalCfg: cfg,
+		stopCh:     stopCh,
+		client:     httpClient,
+	}
+}
+
+// Start does nothing in a HTTP client
+func (d *client) Start(ctx context.Context) error {
+	// nothing to do
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+	return nil
+}
+
+// Stop shuts down the client and interrupt any in-flight request.
+func (d *client) Stop(ctx context.Context) error {
+	close(d.stopCh)
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+	return nil
+}
+
+// UploadTraces sends a batch of spans to the collector.
+func (d *client) UploadTraces(ctx context.Context, protoSpans []*tracepb.ResourceSpans) error {
+	pbRequest := &coltracepb.ExportTraceServiceRequest{
+		ResourceSpans: protoSpans,
+	}
+	rawRequest, err := proto.Marshal(pbRequest)
+	if err != nil {
+		return err
+	}
+	return d.send(ctx, rawRequest)
+}
+
+func (d *client) send(ctx context.Context, rawRequest []byte) error {
+	address := fmt.Sprintf("%s://%s%s", d.getScheme(), d.cfg.Endpoint, d.cfg.URLPath)
+	var cancel context.CancelFunc
+	ctx, cancel = d.contextWithStop(ctx)
+	defer cancel()
+	for i := 0; i < d.generalCfg.MaxAttempts; i++ {
+		response, err := d.singleSend(ctx, rawRequest, address)
+		if err != nil {
+			return err
+		}
+		// We don't care about the body, so try to read it
+		// into /dev/null and close it immediately. The
+		// reading part is to facilitate connection reuse.
+		_, _ = io.Copy(ioutil.Discard, response.Body)
+		_ = response.Body.Close()
+		switch response.StatusCode {
+		case http.StatusOK:
+			return nil
+		case http.StatusTooManyRequests:
+			fallthrough
+		case http.StatusServiceUnavailable:
+			select {
+			case <-time.After(getWaitDuration(d.generalCfg.Backoff, i)):
+				continue
+			case <-ctx.Done():
+				return ctx.Err()
+			}
+		default:
+			return fmt.Errorf("failed to send %s to %s with HTTP status %s", d.name, address, response.Status)
+		}
+	}
+	return fmt.Errorf("failed to send data to %s after %d tries", address, d.generalCfg.MaxAttempts)
+}
+
+func (d *client) getScheme() string {
+	if d.cfg.Insecure {
+		return "http"
+	}
+	return "https"
+}
+
+func getWaitDuration(backoff time.Duration, i int) time.Duration {
+	// Strategy: after nth failed attempt, attempt resending after
+	// k * initialBackoff + jitter, where k is a random number in
+	// range [0, 2^n-1), and jitter is a random percentage of
+	// initialBackoff from [-5%, 5%).
+	//
+	// Based on
+	// https://en.wikipedia.org/wiki/Exponential_backoff#Example_exponential_backoff_algorithm
+	//
+	// Jitter is our addition.
+
+	// There won't be an overflow, since i is capped to
+	// defaultMaxAttempts (5).
+	upperK := (int64)(1) << (i + 1)
+	jitterPercent := (rand.Float64() - 0.5) / 10.
+	jitter := jitterPercent * (float64)(backoff)
+	k := rand.Int63n(upperK)
+	return (time.Duration)(k)*backoff + (time.Duration)(jitter)
+}
+
+func (d *client) contextWithStop(ctx context.Context) (context.Context, context.CancelFunc) {
+	// Unify the parent context Done signal with the client's stop
+	// channel.
+	ctx, cancel := context.WithCancel(ctx)
+	go func(ctx context.Context, cancel context.CancelFunc) {
+		select {
+		case <-ctx.Done():
+			// Nothing to do, either cancelled or deadline
+			// happened.
+		case <-d.stopCh:
+			cancel()
+		}
+	}(ctx, cancel)
+	return ctx, cancel
+}
+
+func (d *client) singleSend(ctx context.Context, rawRequest []byte, address string) (*http.Response, error) {
+	request, err := http.NewRequestWithContext(ctx, http.MethodPost, address, nil)
+	if err != nil {
+		return nil, err
+	}
+	bodyReader, contentLength, headers := d.prepareBody(rawRequest)
+	// Not closing bodyReader through defer, the HTTP Client's
+	// Transport will do it for us
+	request.Body = bodyReader
+	request.ContentLength = contentLength
+	for key, values := range headers {
+		for _, value := range values {
+			request.Header.Add(key, value)
+		}
+	}
+	return d.client.Do(request)
+}
+
+func (d *client) prepareBody(rawRequest []byte) (io.ReadCloser, int64, http.Header) {
+	var bodyReader io.ReadCloser
+	headers := http.Header{}
+	for k, v := range d.cfg.Headers {
+		headers.Set(k, v)
+	}
+	contentLength := (int64)(len(rawRequest))
+	headers.Set("Content-Type", contentTypeProto)
+	requestReader := bytes.NewBuffer(rawRequest)
+	switch Compression(d.cfg.Compression) {
+	case NoCompression:
+		bodyReader = ioutil.NopCloser(requestReader)
+	case GzipCompression:
+		preader, pwriter := io.Pipe()
+		go func() {
+			defer pwriter.Close()
+			gzipper := gzip.NewWriter(pwriter)
+			defer gzipper.Close()
+			_, err := io.Copy(gzipper, requestReader)
+			if err != nil {
+				otel.Handle(fmt.Errorf("otlphttp: failed to gzip request: %v", err))
+			}
+		}()
+		headers.Set("Content-Encoding", "gzip")
+		bodyReader = preader
+		contentLength = -1
+	}
+	return bodyReader, contentLength, headers
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp/doc.go

@@ -0,0 +1,22 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package otlptracehttp a client that sends traces to the collector
+using HTTP with binary protobuf payloads.
+
+This package is currently in a Release Candidate phase. Backwards incompatible changes
+may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+*/
+package otlptracehttp // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp/exporter.go

@@ -0,0 +1,31 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptracehttp // import "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+)
+
+// New constructs a new Exporter and starts it.
+func New(ctx context.Context, opts ...Option) (*otlptrace.Exporter, error) {
+	return otlptrace.New(ctx, NewClient(opts...))
+}
+
+// NewUnstarted constructs a new Exporter and does not start it.
+func NewUnstarted(opts ...Option) *otlptrace.Exporter {
+	return otlptrace.NewUnstarted(NewClient(opts...))
+}

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp/go.mod

@@ -0,0 +1,75 @@
+module go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp
+
+go 1.15
+
+require (
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/otel v1.0.0-RC1
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.0.0-RC1
+	go.opentelemetry.io/proto/otlp v0.9.0
+	google.golang.org/protobuf v1.26.0
+)
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ../
+
+replace go.opentelemetry.io/otel => ../../../..
+
+replace go.opentelemetry.io/otel/bridge/opencensus => ../../../../bridge/opencensus
+
+replace go.opentelemetry.io/otel/bridge/opentracing => ../../../../bridge/opentracing
+
+replace go.opentelemetry.io/otel/example/jaeger => ../../../../example/jaeger
+
+replace go.opentelemetry.io/otel/example/namedtracer => ../../../../example/namedtracer
+
+replace go.opentelemetry.io/otel/example/opencensus => ../../../../example/opencensus
+
+replace go.opentelemetry.io/otel/example/otel-collector => ../../../../example/otel-collector
+
+replace go.opentelemetry.io/otel/example/passthrough => ../../../../example/passthrough
+
+replace go.opentelemetry.io/otel/example/prom-collector => ../../../../example/prom-collector
+
+replace go.opentelemetry.io/otel/example/prometheus => ../../../../example/prometheus
+
+replace go.opentelemetry.io/otel/example/zipkin => ../../../../example/zipkin
+
+replace go.opentelemetry.io/otel/exporters/prometheus => ../../../prometheus
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ../otlptracegrpc
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp => ./
+
+replace go.opentelemetry.io/otel/exporters/jaeger => ../../../jaeger
+
+replace go.opentelemetry.io/otel/exporters/zipkin => ../../../zipkin
+
+replace go.opentelemetry.io/otel/internal/tools => ../../../../internal/tools
+
+replace go.opentelemetry.io/otel/metric => ../../../../metric
+
+replace go.opentelemetry.io/otel/oteltest => ../../../../oteltest
+
+replace go.opentelemetry.io/otel/sdk => ../../../../sdk
+
+replace go.opentelemetry.io/otel/sdk/export/metric => ../../../../sdk/export/metric
+
+replace go.opentelemetry.io/otel/sdk/metric => ../../../../sdk/metric
+
+replace go.opentelemetry.io/otel/trace => ../../../../trace
+
+replace go.opentelemetry.io/otel/internal/metric => ../../../../internal/metric
+
+replace go.opentelemetry.io/otel/exporters/metric/prometheus => ../../../metric/prometheus
+
+replace go.opentelemetry.io/otel/exporters/trace/jaeger => ../../../trace/jaeger
+
+replace go.opentelemetry.io/otel/exporters/trace/zipkin => ../../../trace/zipkin
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric => ../../otlpmetric
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc => ../../otlpmetric/otlpmetricgrpc
+
+replace go.opentelemetry.io/otel/exporters/stdout/stdoutmetric => ../../../stdout/stdoutmetric
+
+replace go.opentelemetry.io/otel/exporters/stdout/stdouttrace => ../../../stdout/stdouttrace

vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp/go.sum

@@ -0,0 +1,122 @@
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+golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
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+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
+google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
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vendor/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp/options.go

@@ -0,0 +1,126 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otlptracehttp
+
+import (
+	"crypto/tls"
+	"time"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/internal/otlpconfig"
+)
+
+const (
+	// defaultMaxAttempts describes how many times the driver
+	// should retry the sending of the payload in case of a
+	// retryable error.
+	defaultMaxAttempts int = 5
+	// defaultTracesPath is a default URL path for endpoint that
+	// receives spans.
+	defaultTracesPath string = "/v1/traces"
+	// defaultBackoff is a default base backoff time used in the
+	// exponential backoff strategy.
+	defaultBackoff time.Duration = 300 * time.Millisecond
+)
+
+// Compression describes the compression used for payloads sent to the
+// collector.
+type Compression otlpconfig.Compression
+
+const (
+	// NoCompression tells the driver to send payloads without
+	// compression.
+	NoCompression = Compression(otlpconfig.NoCompression)
+	// GzipCompression tells the driver to send payloads after
+	// compressing them with gzip.
+	GzipCompression = Compression(otlpconfig.GzipCompression)
+)
+
+// Option applies an option to the HTTP client.
+type Option interface {
+	applyHTTPOption(*otlpconfig.Config)
+}
+
+// RetrySettings defines configuration for retrying batches in case of export failure
+// using an exponential backoff.
+type RetrySettings otlpconfig.RetrySettings
+
+type wrappedOption struct {
+	otlpconfig.HTTPOption
+}
+
+func (w wrappedOption) applyHTTPOption(cfg *otlpconfig.Config) {
+	w.ApplyHTTPOption(cfg)
+}
+
+// WithEndpoint allows one to set the address of the collector
+// endpoint that the driver will use to send spans. If
+// unset, it will instead try to use
+// the default endpoint (localhost:4317). Note that the endpoint
+// must not contain any URL path.
+func WithEndpoint(endpoint string) Option {
+	return wrappedOption{otlpconfig.WithEndpoint(endpoint)}
+}
+
+// WithCompression tells the driver to compress the sent data.
+func WithCompression(compression Compression) Option {
+	return wrappedOption{otlpconfig.WithCompression(otlpconfig.Compression(compression))}
+}
+
+// WithURLPath allows one to override the default URL path used
+// for sending traces. If unset, default ("/v1/traces") will be used.
+func WithURLPath(urlPath string) Option {
+	return wrappedOption{otlpconfig.WithURLPath(urlPath)}
+}
+
+// WithMaxAttempts allows one to override how many times the driver
+// will try to send the payload in case of retryable errors.
+// The max attempts is limited to at most 5 retries. If unset,
+// default (5) will be used.
+func WithMaxAttempts(maxAttempts int) Option {
+	return wrappedOption{otlpconfig.WithMaxAttempts(maxAttempts)}
+}
+
+// WithBackoff tells the driver to use the duration as a base of the
+// exponential backoff strategy. If unset, default (300ms) will be
+// used.
+func WithBackoff(duration time.Duration) Option {
+	return wrappedOption{otlpconfig.WithBackoff(duration)}
+}
+
+// WithTLSClientConfig can be used to set up a custom TLS
+// configuration for the client used to send payloads to the
+// collector. Use it if you want to use a custom certificate.
+func WithTLSClientConfig(tlsCfg *tls.Config) Option {
+	return wrappedOption{otlpconfig.WithTLSClientConfig(tlsCfg)}
+}
+
+// WithInsecure tells the driver to connect to the collector using the
+// HTTP scheme, instead of HTTPS.
+func WithInsecure() Option {
+	return wrappedOption{otlpconfig.WithInsecure()}
+}
+
+// WithHeaders allows one to tell the driver to send additional HTTP
+// headers with the payloads. Specifying headers like Content-Length,
+// Content-Encoding and Content-Type may result in a broken driver.
+func WithHeaders(headers map[string]string) Option {
+	return wrappedOption{otlpconfig.WithHeaders(headers)}
+}
+
+// WithTimeout tells the driver the max waiting time for the backend to process
+// each spans batch.  If unset, the default will be 10 seconds.
+func WithTimeout(duration time.Duration) Option {
+	return wrappedOption{otlpconfig.WithTimeout(duration)}
+}

vendor/go.opentelemetry.io/otel/get_main_pkgs.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -euo pipefail
+
+top_dir='.'
+if [[ $# -gt 0 ]]; then
+    top_dir="${1}"
+fi
+
+p=$(pwd)
+mod_dirs=()
+
+# Note `mapfile` does not exist in older bash versions:
+# https://stackoverflow.com/questions/41475261/need-alternative-to-readarray-mapfile-for-script-on-older-version-of-bash
+
+while IFS= read -r line; do
+    mod_dirs+=("$line")
+done < <(find "${top_dir}" -type f -name 'go.mod' -exec dirname {} \; | sort)
+
+for mod_dir in "${mod_dirs[@]}"; do
+    cd "${mod_dir}"
+
+    while IFS= read -r line; do
+        echo ".${line#${p}}"
+    done < <(go list --find -f '{{.Name}}|{{.Dir}}' ./... | grep '^main|' | cut -f 2- -d '|')
+    cd "${p}"
+done

vendor/go.opentelemetry.io/otel/go.mod

@@ -0,0 +1,74 @@
+module go.opentelemetry.io/otel
+
+go 1.15
+
+require (
+	github.com/google/go-cmp v0.5.6
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/otel/oteltest v1.0.0-RC1
+	go.opentelemetry.io/otel/trace v1.0.0-RC1
+)
+
+replace go.opentelemetry.io/otel => ./
+
+replace go.opentelemetry.io/otel/bridge/opencensus => ./bridge/opencensus
+
+replace go.opentelemetry.io/otel/bridge/opentracing => ./bridge/opentracing
+
+replace go.opentelemetry.io/otel/example/jaeger => ./example/jaeger
+
+replace go.opentelemetry.io/otel/example/namedtracer => ./example/namedtracer
+
+replace go.opentelemetry.io/otel/example/opencensus => ./example/opencensus
+
+replace go.opentelemetry.io/otel/example/otel-collector => ./example/otel-collector
+
+replace go.opentelemetry.io/otel/example/prom-collector => ./example/prom-collector
+
+replace go.opentelemetry.io/otel/example/prometheus => ./example/prometheus
+
+replace go.opentelemetry.io/otel/example/zipkin => ./example/zipkin
+
+replace go.opentelemetry.io/otel/exporters/prometheus => ./exporters/prometheus
+
+replace go.opentelemetry.io/otel/exporters/jaeger => ./exporters/jaeger
+
+replace go.opentelemetry.io/otel/exporters/zipkin => ./exporters/zipkin
+
+replace go.opentelemetry.io/otel/internal/tools => ./internal/tools
+
+replace go.opentelemetry.io/otel/sdk => ./sdk
+
+replace go.opentelemetry.io/otel/internal/metric => ./internal/metric
+
+replace go.opentelemetry.io/otel/metric => ./metric
+
+replace go.opentelemetry.io/otel/oteltest => ./oteltest
+
+replace go.opentelemetry.io/otel/sdk/export/metric => ./sdk/export/metric
+
+replace go.opentelemetry.io/otel/sdk/metric => ./sdk/metric
+
+replace go.opentelemetry.io/otel/trace => ./trace
+
+replace go.opentelemetry.io/otel/example/passthrough => ./example/passthrough
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace => ./exporters/otlp/otlptrace
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc => ./exporters/otlp/otlptrace/otlptracegrpc
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp => ./exporters/otlp/otlptrace/otlptracehttp
+
+replace go.opentelemetry.io/otel/exporters/metric/prometheus => ./exporters/metric/prometheus
+
+replace go.opentelemetry.io/otel/exporters/trace/jaeger => ./exporters/trace/jaeger
+
+replace go.opentelemetry.io/otel/exporters/trace/zipkin => ./exporters/trace/zipkin
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric => ./exporters/otlp/otlpmetric
+
+replace go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc => ./exporters/otlp/otlpmetric/otlpmetricgrpc
+
+replace go.opentelemetry.io/otel/exporters/stdout/stdoutmetric => ./exporters/stdout/stdoutmetric
+
+replace go.opentelemetry.io/otel/exporters/stdout/stdouttrace => ./exporters/stdout/stdouttrace

vendor/go.opentelemetry.io/otel/go.sum

@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.5.6 h1:BKbKCqvP6I+rmFHt06ZmyQtvB8xAkWdhFyr0ZUNZcxQ=
+github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

vendor/go.opentelemetry.io/otel/handler.go

@@ -0,0 +1,89 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otel // import "go.opentelemetry.io/otel"
+
+import (
+	"log"
+	"os"
+	"sync"
+	"sync/atomic"
+)
+
+var (
+	// globalErrorHandler provides an ErrorHandler that can be used
+	// throughout an OpenTelemetry instrumented project. When a user
+	// specified ErrorHandler is registered (`SetErrorHandler`) all calls to
+	// `Handle` and will be delegated to the registered ErrorHandler.
+	globalErrorHandler = &loggingErrorHandler{
+		l: log.New(os.Stderr, "", log.LstdFlags),
+	}
+
+	// delegateErrorHandlerOnce ensures that a user provided ErrorHandler is
+	// only ever registered once.
+	delegateErrorHandlerOnce sync.Once
+
+	// Comiple time check that loggingErrorHandler implements ErrorHandler.
+	_ ErrorHandler = (*loggingErrorHandler)(nil)
+)
+
+// loggingErrorHandler logs all errors to STDERR.
+type loggingErrorHandler struct {
+	delegate atomic.Value
+
+	l *log.Logger
+}
+
+// setDelegate sets the ErrorHandler delegate if one is not already set.
+func (h *loggingErrorHandler) setDelegate(d ErrorHandler) {
+	if h.delegate.Load() != nil {
+		// Delegate already registered
+		return
+	}
+	h.delegate.Store(d)
+}
+
+// Handle implements ErrorHandler.
+func (h *loggingErrorHandler) Handle(err error) {
+	if d := h.delegate.Load(); d != nil {
+		d.(ErrorHandler).Handle(err)
+		return
+	}
+	h.l.Print(err)
+}
+
+// GetErrorHandler returns the global ErrorHandler instance. If no ErrorHandler
+// instance has been set (`SetErrorHandler`), the default ErrorHandler which
+// logs errors to STDERR is returned.
+func GetErrorHandler() ErrorHandler {
+	return globalErrorHandler
+}
+
+// SetErrorHandler sets the global ErrorHandler to be h.
+func SetErrorHandler(h ErrorHandler) {
+	delegateErrorHandlerOnce.Do(func() {
+		current := GetErrorHandler()
+		if current == h {
+			return
+		}
+		if internalHandler, ok := current.(*loggingErrorHandler); ok {
+			internalHandler.setDelegate(h)
+		}
+	})
+}
+
+// Handle is a convience function for ErrorHandler().Handle(err)
+func Handle(err error) {
+	GetErrorHandler().Handle(err)
+}

vendor/go.opentelemetry.io/otel/internal/baggage/baggage.go

@@ -0,0 +1,43 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package baggage provides base types and functionality to store and retrieve
+baggage in Go context. This package exists because the OpenTracing bridge to
+OpenTelemetry needs to synchronize state whenever baggage for a context is
+modified and that context contains an OpenTracing span. If it were not for
+this need this package would not need to exist and the
+`go.opentelemetry.io/otel/baggage` package would be the singular place where
+W3C baggage is handled.
+*/
+package baggage
+
+// List is the collection of baggage members. The W3C allows for duplicates,
+// but OpenTelemetry does not, therefore, this is represented as a map.
+type List map[string]Item
+
+// Item is the value and metadata properties part of a list-member.
+type Item struct {
+	Value      string
+	Properties []Property
+}
+
+// Property is a metadata entry for a list-member.
+type Property struct {
+	Key, Value string
+
+	// HasValue indicates if a zero-value value means the property does not
+	// have a value or if it was the zero-value.
+	HasValue bool
+}

vendor/go.opentelemetry.io/otel/internal/baggage/context.go

@@ -0,0 +1,95 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package baggage
+
+import "context"
+
+type baggageContextKeyType int
+
+const baggageKey baggageContextKeyType = iota
+
+// SetHookFunc is a callback called when storing baggage in the context.
+type SetHookFunc func(context.Context, List) context.Context
+
+// GetHookFunc is a callback called when getting baggage from the context.
+type GetHookFunc func(context.Context, List) List
+
+type baggageState struct {
+	list List
+
+	setHook SetHookFunc
+	getHook GetHookFunc
+}
+
+// ContextWithSetHook returns a copy of parent with hook configured to be
+// invoked every time ContextWithBaggage is called.
+//
+// Passing nil SetHookFunc creates a context with no set hook to call.
+func ContextWithSetHook(parent context.Context, hook SetHookFunc) context.Context {
+	var s baggageState
+	switch v := parent.Value(baggageKey).(type) {
+	case baggageState:
+		s = v
+	}
+
+	s.setHook = hook
+	return context.WithValue(parent, baggageKey, s)
+}
+
+// ContextWithGetHook returns a copy of parent with hook configured to be
+// invoked every time FromContext is called.
+//
+// Passing nil GetHookFunc creates a context with no get hook to call.
+func ContextWithGetHook(parent context.Context, hook GetHookFunc) context.Context {
+	var s baggageState
+	switch v := parent.Value(baggageKey).(type) {
+	case baggageState:
+		s = v
+	}
+
+	s.getHook = hook
+	return context.WithValue(parent, baggageKey, s)
+}
+
+// ContextWithList returns a copy of parent with baggage. Passing nil list
+// returns a context without any baggage.
+func ContextWithList(parent context.Context, list List) context.Context {
+	var s baggageState
+	switch v := parent.Value(baggageKey).(type) {
+	case baggageState:
+		s = v
+	}
+
+	s.list = list
+	ctx := context.WithValue(parent, baggageKey, s)
+	if s.setHook != nil {
+		ctx = s.setHook(ctx, list)
+	}
+
+	return ctx
+}
+
+// ListFromContext returns the baggage contained in ctx.
+func ListFromContext(ctx context.Context) List {
+	switch v := ctx.Value(baggageKey).(type) {
+	case baggageState:
+		if v.getHook != nil {
+			return v.getHook(ctx, v.list)
+		}
+		return v.list
+	default:
+		return nil
+	}
+}

vendor/go.opentelemetry.io/otel/internal/global/propagator.go

@@ -0,0 +1,82 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package global
+
+import (
+	"context"
+	"sync"
+
+	"go.opentelemetry.io/otel/propagation"
+)
+
+// textMapPropagator is a default TextMapPropagator that delegates calls to a
+// registered delegate if one is set, otherwise it defaults to delegating the
+// calls to a the default no-op propagation.TextMapPropagator.
+type textMapPropagator struct {
+	mtx      sync.Mutex
+	once     sync.Once
+	delegate propagation.TextMapPropagator
+	noop     propagation.TextMapPropagator
+}
+
+// Compile-time guarantee that textMapPropagator implements the
+// propagation.TextMapPropagator interface.
+var _ propagation.TextMapPropagator = (*textMapPropagator)(nil)
+
+func newTextMapPropagator() *textMapPropagator {
+	return &textMapPropagator{
+		noop: propagation.NewCompositeTextMapPropagator(),
+	}
+}
+
+// SetDelegate sets a delegate propagation.TextMapPropagator that all calls are
+// forwarded to. Delegation can only be performed once, all subsequent calls
+// perform no delegation.
+func (p *textMapPropagator) SetDelegate(delegate propagation.TextMapPropagator) {
+	if delegate == nil {
+		return
+	}
+
+	p.mtx.Lock()
+	p.once.Do(func() { p.delegate = delegate })
+	p.mtx.Unlock()
+}
+
+// effectiveDelegate returns the current delegate of p if one is set,
+// otherwise the default noop TextMapPropagator is returned. This method
+// can be called concurrently.
+func (p *textMapPropagator) effectiveDelegate() propagation.TextMapPropagator {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+	if p.delegate != nil {
+		return p.delegate
+	}
+	return p.noop
+}
+
+// Inject set cross-cutting concerns from the Context into the carrier.
+func (p *textMapPropagator) Inject(ctx context.Context, carrier propagation.TextMapCarrier) {
+	p.effectiveDelegate().Inject(ctx, carrier)
+}
+
+// Extract reads cross-cutting concerns from the carrier into a Context.
+func (p *textMapPropagator) Extract(ctx context.Context, carrier propagation.TextMapCarrier) context.Context {
+	return p.effectiveDelegate().Extract(ctx, carrier)
+}
+
+// Fields returns the keys whose values are set with Inject.
+func (p *textMapPropagator) Fields() []string {
+	return p.effectiveDelegate().Fields()
+}

vendor/go.opentelemetry.io/otel/internal/global/state.go

@@ -0,0 +1,106 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package global
+
+import (
+	"sync"
+	"sync/atomic"
+
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/trace"
+)
+
+type (
+	tracerProviderHolder struct {
+		tp trace.TracerProvider
+	}
+
+	propagatorsHolder struct {
+		tm propagation.TextMapPropagator
+	}
+)
+
+var (
+	globalTracer      = defaultTracerValue()
+	globalPropagators = defaultPropagatorsValue()
+
+	delegateTraceOnce             sync.Once
+	delegateTextMapPropagatorOnce sync.Once
+)
+
+// TracerProvider is the internal implementation for global.TracerProvider.
+func TracerProvider() trace.TracerProvider {
+	return globalTracer.Load().(tracerProviderHolder).tp
+}
+
+// SetTracerProvider is the internal implementation for global.SetTracerProvider.
+func SetTracerProvider(tp trace.TracerProvider) {
+	delegateTraceOnce.Do(func() {
+		current := TracerProvider()
+		if current == tp {
+			// Setting the provider to the prior default is nonsense, panic.
+			// Panic is acceptable because we are likely still early in the
+			// process lifetime.
+			panic("invalid TracerProvider, the global instance cannot be reinstalled")
+		} else if def, ok := current.(*tracerProvider); ok {
+			def.setDelegate(tp)
+		}
+
+	})
+	globalTracer.Store(tracerProviderHolder{tp: tp})
+}
+
+// TextMapPropagator is the internal implementation for global.TextMapPropagator.
+func TextMapPropagator() propagation.TextMapPropagator {
+	return globalPropagators.Load().(propagatorsHolder).tm
+}
+
+// SetTextMapPropagator is the internal implementation for global.SetTextMapPropagator.
+func SetTextMapPropagator(p propagation.TextMapPropagator) {
+	// For the textMapPropagator already returned by TextMapPropagator
+	// delegate to p.
+	delegateTextMapPropagatorOnce.Do(func() {
+		if current := TextMapPropagator(); current == p {
+			// Setting the provider to the prior default is nonsense, panic.
+			// Panic is acceptable because we are likely still early in the
+			// process lifetime.
+			panic("invalid TextMapPropagator, the global instance cannot be reinstalled")
+		} else if def, ok := current.(*textMapPropagator); ok {
+			def.SetDelegate(p)
+		}
+	})
+	// Return p when subsequent calls to TextMapPropagator are made.
+	globalPropagators.Store(propagatorsHolder{tm: p})
+}
+
+func defaultTracerValue() *atomic.Value {
+	v := &atomic.Value{}
+	v.Store(tracerProviderHolder{tp: &tracerProvider{}})
+	return v
+}
+
+func defaultPropagatorsValue() *atomic.Value {
+	v := &atomic.Value{}
+	v.Store(propagatorsHolder{tm: newTextMapPropagator()})
+	return v
+}
+
+// ResetForTest restores the initial global state, for testing purposes.
+func ResetForTest() {
+	globalTracer = defaultTracerValue()
+	globalPropagators = defaultPropagatorsValue()
+	delegateTraceOnce = sync.Once{}
+	delegateTextMapPropagatorOnce = sync.Once{}
+}

vendor/go.opentelemetry.io/otel/internal/global/trace.go

@@ -0,0 +1,191 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package global
+
+/*
+This file contains the forwarding implementation of the TracerProvider used as
+the default global instance. Prior to initialization of an SDK, Tracers
+returned by the global TracerProvider will provide no-op functionality. This
+means that all Span created prior to initialization are no-op Spans.
+
+Once an SDK has been initialized, all provided no-op Tracers are swapped for
+Tracers provided by the SDK defined TracerProvider. However, any Span started
+prior to this initialization does not change its behavior. Meaning, the Span
+remains a no-op Span.
+
+The implementation to track and swap Tracers locks all new Tracer creation
+until the swap is complete. This assumes that this operation is not
+performance-critical. If that assumption is incorrect, be sure to configure an
+SDK prior to any Tracer creation.
+*/
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// tracerProvider is a placeholder for a configured SDK TracerProvider.
+//
+// All TracerProvider functionality is forwarded to a delegate once
+// configured.
+type tracerProvider struct {
+	mtx      sync.Mutex
+	tracers  map[il]*tracer
+	delegate trace.TracerProvider
+}
+
+// Compile-time guarantee that tracerProvider implements the TracerProvider
+// interface.
+var _ trace.TracerProvider = &tracerProvider{}
+
+// setDelegate configures p to delegate all TracerProvider functionality to
+// provider.
+//
+// All Tracers provided prior to this function call are switched out to be
+// Tracers provided by provider.
+//
+// It is guaranteed by the caller that this happens only once.
+func (p *tracerProvider) setDelegate(provider trace.TracerProvider) {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+
+	p.delegate = provider
+
+	if len(p.tracers) == 0 {
+		return
+	}
+
+	for _, t := range p.tracers {
+		t.setDelegate(provider)
+	}
+
+	p.tracers = nil
+}
+
+// Tracer implements TracerProvider.
+func (p *tracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.Tracer {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+
+	if p.delegate != nil {
+		return p.delegate.Tracer(name, opts...)
+	}
+
+	// At this moment it is guaranteed that no sdk is installed, save the tracer in the tracers map.
+
+	key := il{
+		name:    name,
+		version: trace.NewTracerConfig(opts...).InstrumentationVersion(),
+	}
+
+	if p.tracers == nil {
+		p.tracers = make(map[il]*tracer)
+	}
+
+	if val, ok := p.tracers[key]; ok {
+		return val
+	}
+
+	t := &tracer{name: name, opts: opts, provider: p}
+	p.tracers[key] = t
+	return t
+}
+
+type il struct {
+	name    string
+	version string
+}
+
+// tracer is a placeholder for a trace.Tracer.
+//
+// All Tracer functionality is forwarded to a delegate once configured.
+// Otherwise, all functionality is forwarded to a NoopTracer.
+type tracer struct {
+	name     string
+	opts     []trace.TracerOption
+	provider *tracerProvider
+
+	delegate atomic.Value
+}
+
+// Compile-time guarantee that tracer implements the trace.Tracer interface.
+var _ trace.Tracer = &tracer{}
+
+// setDelegate configures t to delegate all Tracer functionality to Tracers
+// created by provider.
+//
+// All subsequent calls to the Tracer methods will be passed to the delegate.
+//
+// It is guaranteed by the caller that this happens only once.
+func (t *tracer) setDelegate(provider trace.TracerProvider) {
+	t.delegate.Store(provider.Tracer(t.name, t.opts...))
+}
+
+// Start implements trace.Tracer by forwarding the call to t.delegate if
+// set, otherwise it forwards the call to a NoopTracer.
+func (t *tracer) Start(ctx context.Context, name string, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
+	delegate := t.delegate.Load()
+	if delegate != nil {
+		return delegate.(trace.Tracer).Start(ctx, name, opts...)
+	}
+
+	s := nonRecordingSpan{sc: trace.SpanContextFromContext(ctx), tracer: t}
+	ctx = trace.ContextWithSpan(ctx, s)
+	return ctx, s
+}
+
+// nonRecordingSpan is a minimal implementation of a Span that wraps a
+// SpanContext. It performs no operations other than to return the wrapped
+// SpanContext.
+type nonRecordingSpan struct {
+	sc     trace.SpanContext
+	tracer *tracer
+}
+
+var _ trace.Span = nonRecordingSpan{}
+
+// SpanContext returns the wrapped SpanContext.
+func (s nonRecordingSpan) SpanContext() trace.SpanContext { return s.sc }
+
+// IsRecording always returns false.
+func (nonRecordingSpan) IsRecording() bool { return false }
+
+// SetStatus does nothing.
+func (nonRecordingSpan) SetStatus(codes.Code, string) {}
+
+// SetError does nothing.
+func (nonRecordingSpan) SetError(bool) {}
+
+// SetAttributes does nothing.
+func (nonRecordingSpan) SetAttributes(...attribute.KeyValue) {}
+
+// End does nothing.
+func (nonRecordingSpan) End(...trace.SpanEndOption) {}
+
+// RecordError does nothing.
+func (nonRecordingSpan) RecordError(error, ...trace.EventOption) {}
+
+// AddEvent does nothing.
+func (nonRecordingSpan) AddEvent(string, ...trace.EventOption) {}
+
+// SetName does nothing.
+func (nonRecordingSpan) SetName(string) {}
+
+func (s nonRecordingSpan) TracerProvider() trace.TracerProvider { return s.tracer.provider }

vendor/go.opentelemetry.io/otel/internal/rawhelpers.go

@@ -0,0 +1,55 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal
+
+import (
+	"math"
+	"unsafe"
+)
+
+func BoolToRaw(b bool) uint64 {
+	if b {
+		return 1
+	}
+	return 0
+}
+
+func RawToBool(r uint64) bool {
+	return r != 0
+}
+
+func Int64ToRaw(i int64) uint64 {
+	return uint64(i)
+}
+
+func RawToInt64(r uint64) int64 {
+	return int64(r)
+}
+
+func Float64ToRaw(f float64) uint64 {
+	return math.Float64bits(f)
+}
+
+func RawToFloat64(r uint64) float64 {
+	return math.Float64frombits(r)
+}
+
+func RawPtrToFloat64Ptr(r *uint64) *float64 {
+	return (*float64)(unsafe.Pointer(r))
+}
+
+func RawPtrToInt64Ptr(r *uint64) *int64 {
+	return (*int64)(unsafe.Pointer(r))
+}

vendor/go.opentelemetry.io/otel/pre_release.sh

@@ -0,0 +1,95 @@
+#!/bin/bash
+
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -e
+
+help()
+{
+   printf "\n"
+   printf "Usage: $0 -t tag\n"
+   printf "\t-t Unreleased tag. Update all go.mod with this tag.\n"
+   exit 1 # Exit script after printing help
+}
+
+while getopts "t:" opt
+do
+   case "$opt" in
+      t ) TAG="$OPTARG" ;;
+      ? ) help ;; # Print help
+   esac
+done
+
+# Print help in case parameters are empty
+if [ -z "$TAG" ]
+then
+   printf "Tag is missing\n";
+   help
+fi
+
+# Validate semver
+SEMVER_REGEX="^v(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)(\\-[0-9A-Za-z-]+(\\.[0-9A-Za-z-]+)*)?(\\+[0-9A-Za-z-]+(\\.[0-9A-Za-z-]+)*)?$"
+if [[ "${TAG}" =~ ${SEMVER_REGEX} ]]; then
+	printf "${TAG} is valid semver tag.\n"
+else
+	printf "${TAG} is not a valid semver tag.\n"
+	exit -1
+fi
+
+TAG_FOUND=`git tag --list ${TAG}`
+if [[ ${TAG_FOUND} = ${TAG} ]] ; then
+        printf "Tag ${TAG} already exists\n"
+        exit -1
+fi
+
+# Get version for version.go
+OTEL_VERSION=$(echo "${TAG}" | grep -o '^v[0-9]\+\.[0-9]\+\.[0-9]\+')
+# Strip leading v
+OTEL_VERSION="${OTEL_VERSION#v}"
+
+cd $(dirname $0)
+
+if ! git diff --quiet; then \
+	printf "Working tree is not clean, can't proceed with the release process\n"
+	git status
+	git diff
+	exit 1
+fi
+
+# Update version.go
+cp ./version.go ./version.go.bak
+sed "s/\(return \"\)[0-9]*\.[0-9]*\.[0-9]*\"/\1${OTEL_VERSION}\"/" ./version.go.bak >./version.go
+rm -f ./version.go.bak
+
+# Update go.mod
+git checkout -b pre_release_${TAG} main
+PACKAGE_DIRS=$(find . -mindepth 2 -type f -name 'go.mod' -exec dirname {} \; | egrep -v 'tools' | sed 's/^\.\///' | sort)
+
+for dir in $PACKAGE_DIRS; do
+	cp "${dir}/go.mod" "${dir}/go.mod.bak"
+	sed "s/opentelemetry.io\/otel\([^ ]*\) v[0-9]*\.[0-9]*\.[0-9]/opentelemetry.io\/otel\1 ${TAG}/" "${dir}/go.mod.bak" >"${dir}/go.mod"
+	rm -f "${dir}/go.mod.bak"
+done
+
+# Run lint to update go.sum
+make lint
+
+# Add changes and commit.
+git add .
+make ci
+git commit -m "Prepare for releasing $TAG"
+
+printf "Now run following to verify the changes.\ngit diff main\n"
+printf "\nThen push the changes to upstream\n"

vendor/go.opentelemetry.io/otel/propagation.go

@@ -0,0 +1,31 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otel // import "go.opentelemetry.io/otel"
+
+import (
+	"go.opentelemetry.io/otel/internal/global"
+	"go.opentelemetry.io/otel/propagation"
+)
+
+// GetTextMapPropagator returns the global TextMapPropagator. If none has been
+// set, a No-Op TextMapPropagator is returned.
+func GetTextMapPropagator() propagation.TextMapPropagator {
+	return global.TextMapPropagator()
+}
+
+// SetTextMapPropagator sets propagator as the global TextMapPropagator.
+func SetTextMapPropagator(propagator propagation.TextMapPropagator) {
+	global.SetTextMapPropagator(propagator)
+}

vendor/go.opentelemetry.io/otel/propagation/baggage.go

@@ -0,0 +1,58 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package propagation // import "go.opentelemetry.io/otel/propagation"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/baggage"
+)
+
+const baggageHeader = "baggage"
+
+// Baggage is a propagator that supports the W3C Baggage format.
+//
+// This propagates user-defined baggage associated with a trace. The complete
+// specification is defined at https://w3c.github.io/baggage/.
+type Baggage struct{}
+
+var _ TextMapPropagator = Baggage{}
+
+// Inject sets baggage key-values from ctx into the carrier.
+func (b Baggage) Inject(ctx context.Context, carrier TextMapCarrier) {
+	bStr := baggage.FromContext(ctx).String()
+	if bStr != "" {
+		carrier.Set(baggageHeader, bStr)
+	}
+}
+
+// Extract returns a copy of parent with the baggage from the carrier added.
+func (b Baggage) Extract(parent context.Context, carrier TextMapCarrier) context.Context {
+	bStr := carrier.Get(baggageHeader)
+	if bStr == "" {
+		return parent
+	}
+
+	bag, err := baggage.Parse(bStr)
+	if err != nil {
+		return parent
+	}
+	return baggage.ContextWithBaggage(parent, bag)
+}
+
+// Fields returns the keys who's values are set with Inject.
+func (b Baggage) Fields() []string {
+	return []string{baggageHeader}
+}

vendor/go.opentelemetry.io/otel/propagation/doc.go

@@ -0,0 +1,27 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package propagation contains OpenTelemetry context propagators.
+
+This package is currently in a Release Candidate phase. Backwards incompatible changes
+may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+
+OpenTelemetry propagators are used to extract and inject context data from and
+into messages exchanged by applications. The propagator supported by this
+package is the W3C Trace Context encoding
+(https://www.w3.org/TR/trace-context/), and W3C Baggage
+(https://w3c.github.io/baggage/).
+*/
+package propagation // import "go.opentelemetry.io/otel/propagation"

vendor/go.opentelemetry.io/otel/propagation/propagation.go

@@ -0,0 +1,127 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package propagation // import "go.opentelemetry.io/otel/propagation"
+
+import (
+	"context"
+	"net/http"
+)
+
+// TextMapCarrier is the storage medium used by a TextMapPropagator.
+type TextMapCarrier interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Get returns the value associated with the passed key.
+	Get(key string) string
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Set stores the key-value pair.
+	Set(key string, value string)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Keys lists the keys stored in this carrier.
+	Keys() []string
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+// HeaderCarrier adapts http.Header to satisfy the TextMapCarrier interface.
+type HeaderCarrier http.Header
+
+// Get returns the value associated with the passed key.
+func (hc HeaderCarrier) Get(key string) string {
+	return http.Header(hc).Get(key)
+}
+
+// Set stores the key-value pair.
+func (hc HeaderCarrier) Set(key string, value string) {
+	http.Header(hc).Set(key, value)
+}
+
+// Keys lists the keys stored in this carrier.
+func (hc HeaderCarrier) Keys() []string {
+	keys := make([]string, 0, len(hc))
+	for k := range hc {
+		keys = append(keys, k)
+	}
+	return keys
+}
+
+// TextMapPropagator propagates cross-cutting concerns as key-value text
+// pairs within a carrier that travels in-band across process boundaries.
+type TextMapPropagator interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Inject set cross-cutting concerns from the Context into the carrier.
+	Inject(ctx context.Context, carrier TextMapCarrier)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Extract reads cross-cutting concerns from the carrier into a Context.
+	Extract(ctx context.Context, carrier TextMapCarrier) context.Context
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Fields returns the keys who's values are set with Inject.
+	Fields() []string
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+type compositeTextMapPropagator []TextMapPropagator
+
+func (p compositeTextMapPropagator) Inject(ctx context.Context, carrier TextMapCarrier) {
+	for _, i := range p {
+		i.Inject(ctx, carrier)
+	}
+}
+
+func (p compositeTextMapPropagator) Extract(ctx context.Context, carrier TextMapCarrier) context.Context {
+	for _, i := range p {
+		ctx = i.Extract(ctx, carrier)
+	}
+	return ctx
+}
+
+func (p compositeTextMapPropagator) Fields() []string {
+	unique := make(map[string]struct{})
+	for _, i := range p {
+		for _, k := range i.Fields() {
+			unique[k] = struct{}{}
+		}
+	}
+
+	fields := make([]string, 0, len(unique))
+	for k := range unique {
+		fields = append(fields, k)
+	}
+	return fields
+}
+
+// NewCompositeTextMapPropagator returns a unified TextMapPropagator from the
+// group of passed TextMapPropagator. This allows different cross-cutting
+// concerns to be propagates in a unified manner.
+//
+// The returned TextMapPropagator will inject and extract cross-cutting
+// concerns in the order the TextMapPropagators were provided. Additionally,
+// the Fields method will return a de-duplicated slice of the keys that are
+// set with the Inject method.
+func NewCompositeTextMapPropagator(p ...TextMapPropagator) TextMapPropagator {
+	return compositeTextMapPropagator(p)
+}

vendor/go.opentelemetry.io/otel/propagation/trace_context.go

@@ -0,0 +1,157 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package propagation // import "go.opentelemetry.io/otel/propagation"
+
+import (
+	"context"
+	"encoding/hex"
+	"fmt"
+	"regexp"
+
+	"go.opentelemetry.io/otel/trace"
+)
+
+const (
+	supportedVersion  = 0
+	maxVersion        = 254
+	traceparentHeader = "traceparent"
+	tracestateHeader  = "tracestate"
+)
+
+// TraceContext is a propagator that supports the W3C Trace Context format
+// (https://www.w3.org/TR/trace-context/)
+//
+// This propagator will propagate the traceparent and tracestate headers to
+// guarantee traces are not broken. It is up to the users of this propagator
+// to choose if they want to participate in a trace by modifying the
+// traceparent header and relevant parts of the tracestate header containing
+// their proprietary information.
+type TraceContext struct{}
+
+var _ TextMapPropagator = TraceContext{}
+var traceCtxRegExp = regexp.MustCompile("^(?P<version>[0-9a-f]{2})-(?P<traceID>[a-f0-9]{32})-(?P<spanID>[a-f0-9]{16})-(?P<traceFlags>[a-f0-9]{2})(?:-.*)?$")
+
+// Inject set tracecontext from the Context into the carrier.
+func (tc TraceContext) Inject(ctx context.Context, carrier TextMapCarrier) {
+	sc := trace.SpanContextFromContext(ctx)
+	if !sc.IsValid() {
+		return
+	}
+
+	carrier.Set(tracestateHeader, sc.TraceState().String())
+
+	// Clear all flags other than the trace-context supported sampling bit.
+	flags := sc.TraceFlags() & trace.FlagsSampled
+
+	h := fmt.Sprintf("%.2x-%s-%s-%s",
+		supportedVersion,
+		sc.TraceID(),
+		sc.SpanID(),
+		flags)
+	carrier.Set(traceparentHeader, h)
+}
+
+// Extract reads tracecontext from the carrier into a returned Context.
+//
+// The returned Context will be a copy of ctx and contain the extracted
+// tracecontext as the remote SpanContext. If the extracted tracecontext is
+// invalid, the passed ctx will be returned directly instead.
+func (tc TraceContext) Extract(ctx context.Context, carrier TextMapCarrier) context.Context {
+	sc := tc.extract(carrier)
+	if !sc.IsValid() {
+		return ctx
+	}
+	return trace.ContextWithRemoteSpanContext(ctx, sc)
+}
+
+func (tc TraceContext) extract(carrier TextMapCarrier) trace.SpanContext {
+	h := carrier.Get(traceparentHeader)
+	if h == "" {
+		return trace.SpanContext{}
+	}
+
+	matches := traceCtxRegExp.FindStringSubmatch(h)
+
+	if len(matches) == 0 {
+		return trace.SpanContext{}
+	}
+
+	if len(matches) < 5 { // four subgroups plus the overall match
+		return trace.SpanContext{}
+	}
+
+	if len(matches[1]) != 2 {
+		return trace.SpanContext{}
+	}
+	ver, err := hex.DecodeString(matches[1])
+	if err != nil {
+		return trace.SpanContext{}
+	}
+	version := int(ver[0])
+	if version > maxVersion {
+		return trace.SpanContext{}
+	}
+
+	if version == 0 && len(matches) != 5 { // four subgroups plus the overall match
+		return trace.SpanContext{}
+	}
+
+	if len(matches[2]) != 32 {
+		return trace.SpanContext{}
+	}
+
+	var scc trace.SpanContextConfig
+
+	scc.TraceID, err = trace.TraceIDFromHex(matches[2][:32])
+	if err != nil {
+		return trace.SpanContext{}
+	}
+
+	if len(matches[3]) != 16 {
+		return trace.SpanContext{}
+	}
+	scc.SpanID, err = trace.SpanIDFromHex(matches[3])
+	if err != nil {
+		return trace.SpanContext{}
+	}
+
+	if len(matches[4]) != 2 {
+		return trace.SpanContext{}
+	}
+	opts, err := hex.DecodeString(matches[4])
+	if err != nil || len(opts) < 1 || (version == 0 && opts[0] > 2) {
+		return trace.SpanContext{}
+	}
+	// Clear all flags other than the trace-context supported sampling bit.
+	scc.TraceFlags = trace.TraceFlags(opts[0]) & trace.FlagsSampled
+
+	// Ignore the error returned here. Failure to parse tracestate MUST NOT
+	// affect the parsing of traceparent according to the W3C tracecontext
+	// specification.
+	scc.TraceState, _ = trace.ParseTraceState(carrier.Get(tracestateHeader))
+	scc.Remote = true
+
+	sc := trace.NewSpanContext(scc)
+	if !sc.IsValid() {
+		return trace.SpanContext{}
+	}
+
+	return sc
+}
+
+// Fields returns the keys who's values are set with Inject.
+func (tc TraceContext) Fields() []string {
+	return []string{traceparentHeader, tracestateHeader}
+}

vendor/go.opentelemetry.io/otel/sdk/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/go.opentelemetry.io/otel/sdk/instrumentation/library.go

@@ -0,0 +1,36 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package instrumentation provides an instrumentation library structure to be
+passed to both the OpenTelemetry Tracer and Meter components.
+
+This package is currently in a Release Candidate phase. Backwards incompatible changes
+may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+
+For more information see
+[this](https://github.com/open-telemetry/oteps/blob/main/text/0083-component.md).
+*/
+package instrumentation // import "go.opentelemetry.io/otel/sdk/instrumentation"
+
+// Library represents the instrumentation library.
+type Library struct {
+	// Name is the name of the instrumentation library. This should be the
+	// Go package name of that library.
+	Name string
+	// Version is the version of the instrumentation library.
+	Version string
+	// SchemaURL of the telemetry emitted by the library.
+	SchemaURL string
+}

vendor/go.opentelemetry.io/otel/sdk/internal/internal.go

@@ -0,0 +1,37 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal // import "go.opentelemetry.io/otel/sdk/internal"
+
+import (
+	"fmt"
+	"time"
+
+	"go.opentelemetry.io/otel"
+)
+
+// UserAgent is the user agent to be added to the outgoing
+// requests from the exporters.
+var UserAgent = fmt.Sprintf("opentelemetry-go/%s", otel.Version())
+
+// MonotonicEndTime returns the end time at present
+// but offset from start, monotonically.
+//
+// The monotonic clock is used in subtractions hence
+// the duration since start added back to start gives
+// end as a monotonic time.
+// See https://golang.org/pkg/time/#hdr-Monotonic_Clocks
+func MonotonicEndTime(start time.Time) time.Time {
+	return start.Add(time.Since(start))
+}

vendor/go.opentelemetry.io/otel/sdk/internal/sanitize.go

@@ -0,0 +1,50 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal
+
+import (
+	"strings"
+	"unicode"
+)
+
+const labelKeySizeLimit = 100
+
+// Sanitize returns a string that is trunacated to 100 characters if it's too
+// long, and replaces non-alphanumeric characters to underscores.
+func Sanitize(s string) string {
+	if len(s) == 0 {
+		return s
+	}
+	if len(s) > labelKeySizeLimit {
+		s = s[:labelKeySizeLimit]
+	}
+	s = strings.Map(sanitizeRune, s)
+	if unicode.IsDigit(rune(s[0])) {
+		s = "key_" + s
+	}
+	if s[0] == '_' {
+		s = "key" + s
+	}
+	return s
+}
+
+// converts anything that is not a letter or digit to an underscore
+func sanitizeRune(r rune) rune {
+	if unicode.IsLetter(r) || unicode.IsDigit(r) {
+		return r
+	}
+	// Everything else turns into an underscore
+	return '_'
+}

vendor/go.opentelemetry.io/otel/sdk/resource/auto.go

@@ -0,0 +1,72 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"context"
+	"errors"
+	"fmt"
+)
+
+var (
+	// ErrPartialResource is returned by a detector when complete source
+	// information for a Resource is unavailable or the source information
+	// contains invalid values that are omitted from the returned Resource.
+	ErrPartialResource = errors.New("partial resource")
+)
+
+// Detector detects OpenTelemetry resource information
+type Detector interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Detect returns an initialized Resource based on gathered information.
+	// If the source information to construct a Resource contains invalid
+	// values, a Resource is returned with the valid parts of the source
+	// information used for initialization along with an appropriately
+	// wrapped ErrPartialResource error.
+	Detect(ctx context.Context) (*Resource, error)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+// Detect calls all input detectors sequentially and merges each result with the previous one.
+// It returns the merged error too.
+func Detect(ctx context.Context, detectors ...Detector) (*Resource, error) {
+	var autoDetectedRes *Resource
+	var errInfo []string
+	for _, detector := range detectors {
+		if detector == nil {
+			continue
+		}
+		res, err := detector.Detect(ctx)
+		if err != nil {
+			errInfo = append(errInfo, err.Error())
+			if !errors.Is(err, ErrPartialResource) {
+				continue
+			}
+		}
+		autoDetectedRes, err = Merge(autoDetectedRes, res)
+		if err != nil {
+			errInfo = append(errInfo, err.Error())
+		}
+	}
+
+	var aggregatedError error
+	if len(errInfo) > 0 {
+		aggregatedError = fmt.Errorf("detecting resources: %s", errInfo)
+	}
+	return autoDetectedRes, aggregatedError
+}

vendor/go.opentelemetry.io/otel/sdk/resource/builtin.go

@@ -0,0 +1,107 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+)
+
+type (
+	// telemetrySDK is a Detector that provides information about
+	// the OpenTelemetry SDK used.  This Detector is included as a
+	// builtin. If these resource attributes are not wanted, use
+	// the WithTelemetrySDK(nil) or WithoutBuiltin() options to
+	// explicitly disable them.
+	telemetrySDK struct{}
+
+	// host is a Detector that provides information about the host
+	// being run on. This Detector is included as a builtin. If
+	// these resource attributes are not wanted, use the
+	// WithHost(nil) or WithoutBuiltin() options to explicitly
+	// disable them.
+	host struct{}
+
+	stringDetector struct {
+		schemaURL string
+		K         attribute.Key
+		F         func() (string, error)
+	}
+
+	defaultServiceNameDetector struct{}
+)
+
+var (
+	_ Detector = telemetrySDK{}
+	_ Detector = host{}
+	_ Detector = stringDetector{}
+	_ Detector = defaultServiceNameDetector{}
+)
+
+// Detect returns a *Resource that describes the OpenTelemetry SDK used.
+func (telemetrySDK) Detect(context.Context) (*Resource, error) {
+	return NewWithAttributes(
+		semconv.SchemaURL,
+		semconv.TelemetrySDKNameKey.String("opentelemetry"),
+		semconv.TelemetrySDKLanguageKey.String("go"),
+		semconv.TelemetrySDKVersionKey.String(otel.Version()),
+	), nil
+}
+
+// Detect returns a *Resource that describes the host being run on.
+func (host) Detect(ctx context.Context) (*Resource, error) {
+	return StringDetector(semconv.SchemaURL, semconv.HostNameKey, os.Hostname).Detect(ctx)
+}
+
+// StringDetector returns a Detector that will produce a *Resource
+// containing the string as a value corresponding to k. The resulting Resource
+// will have the specified schemaURL.
+func StringDetector(schemaURL string, k attribute.Key, f func() (string, error)) Detector {
+	return stringDetector{schemaURL: schemaURL, K: k, F: f}
+}
+
+// Detect implements Detector.
+func (sd stringDetector) Detect(ctx context.Context) (*Resource, error) {
+	value, err := sd.F()
+	if err != nil {
+		return nil, fmt.Errorf("%s: %w", string(sd.K), err)
+	}
+	a := sd.K.String(value)
+	if !a.Valid() {
+		return nil, fmt.Errorf("invalid attribute: %q -> %q", a.Key, a.Value.Emit())
+	}
+	return NewWithAttributes(sd.schemaURL, sd.K.String(value)), nil
+}
+
+// Detect implements Detector
+func (defaultServiceNameDetector) Detect(ctx context.Context) (*Resource, error) {
+	return StringDetector(
+		semconv.SchemaURL,
+		semconv.ServiceNameKey,
+		func() (string, error) {
+			executable, err := os.Executable()
+			if err != nil {
+				return "unknown_service:go", nil
+			}
+			return "unknown_service:" + filepath.Base(executable), nil
+		},
+	).Detect(ctx)
+}

vendor/go.opentelemetry.io/otel/sdk/resource/config.go

@@ -0,0 +1,94 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/attribute"
+)
+
+// config contains configuration for Resource creation.
+type config struct {
+	// detectors that will be evaluated.
+	detectors []Detector
+	// SchemaURL to associate with the Resource.
+	schemaURL string
+}
+
+// Option is the interface that applies a configuration option.
+type Option interface {
+	// apply sets the Option value of a config.
+	apply(*config)
+}
+
+// WithAttributes adds attributes to the configured Resource.
+func WithAttributes(attributes ...attribute.KeyValue) Option {
+	return WithDetectors(detectAttributes{attributes})
+}
+
+type detectAttributes struct {
+	attributes []attribute.KeyValue
+}
+
+func (d detectAttributes) Detect(context.Context) (*Resource, error) {
+	return NewSchemaless(d.attributes...), nil
+}
+
+// WithDetectors adds detectors to be evaluated for the configured resource.
+func WithDetectors(detectors ...Detector) Option {
+	return detectorsOption{detectors: detectors}
+}
+
+type detectorsOption struct {
+	detectors []Detector
+}
+
+func (o detectorsOption) apply(cfg *config) {
+	cfg.detectors = append(cfg.detectors, o.detectors...)
+}
+
+// WithBuiltinDetectors adds the built detectors to the configured resource.
+func WithBuiltinDetectors() Option {
+	return WithDetectors(telemetrySDK{},
+		host{},
+		fromEnv{})
+}
+
+// WithFromEnv adds attributes from environment variables to the configured resource.
+func WithFromEnv() Option {
+	return WithDetectors(fromEnv{})
+}
+
+// WithHost adds attributes from the host to the configured resource.
+func WithHost() Option {
+	return WithDetectors(host{})
+}
+
+// WithTelemetrySDK adds TelemetrySDK version info to the configured resource.
+func WithTelemetrySDK() Option {
+	return WithDetectors(telemetrySDK{})
+}
+
+// WithSchemaURL sets the schema URL for the configured resource.
+func WithSchemaURL(schemaURL string) Option {
+	return schemaURLOption(schemaURL)
+}
+
+type schemaURLOption string
+
+func (o schemaURLOption) apply(cfg *config) {
+	cfg.schemaURL = string(o)
+}

vendor/go.opentelemetry.io/otel/sdk/resource/doc.go

@@ -0,0 +1,31 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package resource provides detecting and representing resources.
+//
+// This package is currently in a Release Candidate phase. Backwards incompatible changes
+// may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+//
+// The fundamental struct is a Resource which holds identifying information
+// about the entities for which telemetry is exported.
+//
+// To automatically construct Resources from an environment a Detector
+// interface is defined. Implementations of this interface can be passed to
+// the Detect function to generate a Resource from the merged information.
+//
+// To load a user defined Resource from the environment variable
+// OTEL_RESOURCE_ATTRIBUTES the FromEnv Detector can be used. It will interpret
+// the value as a list of comma delimited key/value pairs
+// (e.g. `<key1>=<value1>,<key2>=<value2>,...`).
+package resource // import "go.opentelemetry.io/otel/sdk/resource"

vendor/go.opentelemetry.io/otel/sdk/resource/env.go

@@ -0,0 +1,96 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"strings"
+
+	"go.opentelemetry.io/otel/attribute"
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+)
+
+const (
+	// resourceAttrKey is the environment variable name OpenTelemetry Resource information will be read from.
+	resourceAttrKey = "OTEL_RESOURCE_ATTRIBUTES"
+
+	// svcNameKey is the environment variable name that Service Name information will be read from.
+	svcNameKey = "OTEL_SERVICE_NAME"
+)
+
+var (
+	// errMissingValue is returned when a resource value is missing.
+	errMissingValue = fmt.Errorf("%w: missing value", ErrPartialResource)
+)
+
+// fromEnv is a Detector that implements the Detector and collects
+// resources from environment.  This Detector is included as a
+// builtin.
+type fromEnv struct{}
+
+// compile time assertion that FromEnv implements Detector interface
+var _ Detector = fromEnv{}
+
+// Detect collects resources from environment
+func (fromEnv) Detect(context.Context) (*Resource, error) {
+	attrs := strings.TrimSpace(os.Getenv(resourceAttrKey))
+	svcName := strings.TrimSpace(os.Getenv(svcNameKey))
+
+	if attrs == "" && svcName == "" {
+		return Empty(), nil
+	}
+
+	var res *Resource
+
+	if svcName != "" {
+		res = NewSchemaless(semconv.ServiceNameKey.String(svcName))
+	}
+
+	r2, err := constructOTResources(attrs)
+
+	// Ensure that the resource with the service name from OTEL_SERVICE_NAME
+	// takes precedence, if it was defined.
+	res, err2 := Merge(r2, res)
+
+	if err == nil {
+		err = err2
+	} else if err2 != nil {
+		err = fmt.Errorf("detecting resources: %s", []string{err.Error(), err2.Error()})
+	}
+
+	return res, err
+}
+
+func constructOTResources(s string) (*Resource, error) {
+	pairs := strings.Split(s, ",")
+	attrs := []attribute.KeyValue{}
+	var invalid []string
+	for _, p := range pairs {
+		field := strings.SplitN(p, "=", 2)
+		if len(field) != 2 {
+			invalid = append(invalid, p)
+			continue
+		}
+		k, v := strings.TrimSpace(field[0]), strings.TrimSpace(field[1])
+		attrs = append(attrs, attribute.String(k, v))
+	}
+	var err error
+	if len(invalid) > 0 {
+		err = fmt.Errorf("%w: %v", errMissingValue, invalid)
+	}
+	return NewSchemaless(attrs...), err
+}

vendor/go.opentelemetry.io/otel/sdk/resource/os.go

@@ -0,0 +1,40 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"context"
+	"strings"
+
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+)
+
+type osTypeDetector struct{}
+
+// Detect returns a *Resource that describes the operating system type the
+// service is running on.
+func (osTypeDetector) Detect(ctx context.Context) (*Resource, error) {
+	osType := runtimeOS()
+
+	return NewWithAttributes(
+		semconv.SchemaURL,
+		semconv.OSTypeKey.String(strings.ToLower(osType)),
+	), nil
+}
+
+// WithOSType adds an attribute with the operating system type to the configured Resource.
+func WithOSType() Option {
+	return WithDetectors(osTypeDetector{})
+}

vendor/go.opentelemetry.io/otel/sdk/resource/process.go

@@ -0,0 +1,238 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/user"
+	"path/filepath"
+	"runtime"
+
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+)
+
+type pidProvider func() int
+type executablePathProvider func() (string, error)
+type commandArgsProvider func() []string
+type ownerProvider func() (*user.User, error)
+type runtimeNameProvider func() string
+type runtimeVersionProvider func() string
+type runtimeOSProvider func() string
+type runtimeArchProvider func() string
+
+var (
+	defaultPidProvider            pidProvider            = os.Getpid
+	defaultExecutablePathProvider executablePathProvider = os.Executable
+	defaultCommandArgsProvider    commandArgsProvider    = func() []string { return os.Args }
+	defaultOwnerProvider          ownerProvider          = user.Current
+	defaultRuntimeNameProvider    runtimeNameProvider    = func() string { return runtime.Compiler }
+	defaultRuntimeVersionProvider runtimeVersionProvider = runtime.Version
+	defaultRuntimeOSProvider      runtimeOSProvider      = func() string { return runtime.GOOS }
+	defaultRuntimeArchProvider    runtimeArchProvider    = func() string { return runtime.GOARCH }
+)
+
+var (
+	pid            = defaultPidProvider
+	executablePath = defaultExecutablePathProvider
+	commandArgs    = defaultCommandArgsProvider
+	owner          = defaultOwnerProvider
+	runtimeName    = defaultRuntimeNameProvider
+	runtimeVersion = defaultRuntimeVersionProvider
+	runtimeOS      = defaultRuntimeOSProvider
+	runtimeArch    = defaultRuntimeArchProvider
+)
+
+func setDefaultOSProviders() {
+	setOSProviders(
+		defaultPidProvider,
+		defaultExecutablePathProvider,
+		defaultCommandArgsProvider,
+	)
+}
+
+func setOSProviders(
+	pidProvider pidProvider,
+	executablePathProvider executablePathProvider,
+	commandArgsProvider commandArgsProvider,
+) {
+	pid = pidProvider
+	executablePath = executablePathProvider
+	commandArgs = commandArgsProvider
+}
+
+func setDefaultRuntimeProviders() {
+	setRuntimeProviders(
+		defaultRuntimeNameProvider,
+		defaultRuntimeVersionProvider,
+		defaultRuntimeOSProvider,
+		defaultRuntimeArchProvider,
+	)
+}
+
+func setRuntimeProviders(
+	runtimeNameProvider runtimeNameProvider,
+	runtimeVersionProvider runtimeVersionProvider,
+	runtimeOSProvider runtimeOSProvider,
+	runtimeArchProvider runtimeArchProvider,
+) {
+	runtimeName = runtimeNameProvider
+	runtimeVersion = runtimeVersionProvider
+	runtimeOS = runtimeOSProvider
+	runtimeArch = runtimeArchProvider
+}
+
+func setDefaultUserProviders() {
+	setUserProviders(defaultOwnerProvider)
+}
+
+func setUserProviders(ownerProvider ownerProvider) {
+	owner = ownerProvider
+}
+
+type processPIDDetector struct{}
+type processExecutableNameDetector struct{}
+type processExecutablePathDetector struct{}
+type processCommandArgsDetector struct{}
+type processOwnerDetector struct{}
+type processRuntimeNameDetector struct{}
+type processRuntimeVersionDetector struct{}
+type processRuntimeDescriptionDetector struct{}
+
+// Detect returns a *Resource that describes the process identifier (PID) of the
+// executing process.
+func (processPIDDetector) Detect(ctx context.Context) (*Resource, error) {
+	return NewWithAttributes(semconv.SchemaURL, semconv.ProcessPIDKey.Int(pid())), nil
+}
+
+// Detect returns a *Resource that describes the name of the process executable.
+func (processExecutableNameDetector) Detect(ctx context.Context) (*Resource, error) {
+	executableName := filepath.Base(commandArgs()[0])
+
+	return NewWithAttributes(semconv.SchemaURL, semconv.ProcessExecutableNameKey.String(executableName)), nil
+}
+
+// Detect returns a *Resource that describes the full path of the process executable.
+func (processExecutablePathDetector) Detect(ctx context.Context) (*Resource, error) {
+	executablePath, err := executablePath()
+	if err != nil {
+		return nil, err
+	}
+
+	return NewWithAttributes(semconv.SchemaURL, semconv.ProcessExecutablePathKey.String(executablePath)), nil
+}
+
+// Detect returns a *Resource that describes all the command arguments as received
+// by the process.
+func (processCommandArgsDetector) Detect(ctx context.Context) (*Resource, error) {
+	return NewWithAttributes(semconv.SchemaURL, semconv.ProcessCommandArgsKey.Array(commandArgs())), nil
+}
+
+// Detect returns a *Resource that describes the username of the user that owns the
+// process.
+func (processOwnerDetector) Detect(ctx context.Context) (*Resource, error) {
+	owner, err := owner()
+	if err != nil {
+		return nil, err
+	}
+
+	return NewWithAttributes(semconv.SchemaURL, semconv.ProcessOwnerKey.String(owner.Username)), nil
+}
+
+// Detect returns a *Resource that describes the name of the compiler used to compile
+// this process image.
+func (processRuntimeNameDetector) Detect(ctx context.Context) (*Resource, error) {
+	return NewWithAttributes(semconv.SchemaURL, semconv.ProcessRuntimeNameKey.String(runtimeName())), nil
+}
+
+// Detect returns a *Resource that describes the version of the runtime of this process.
+func (processRuntimeVersionDetector) Detect(ctx context.Context) (*Resource, error) {
+	return NewWithAttributes(semconv.SchemaURL, semconv.ProcessRuntimeVersionKey.String(runtimeVersion())), nil
+}
+
+// Detect returns a *Resource that describes the runtime of this process.
+func (processRuntimeDescriptionDetector) Detect(ctx context.Context) (*Resource, error) {
+	runtimeDescription := fmt.Sprintf(
+		"go version %s %s/%s", runtimeVersion(), runtimeOS(), runtimeArch())
+
+	return NewWithAttributes(
+		semconv.SchemaURL,
+		semconv.ProcessRuntimeDescriptionKey.String(runtimeDescription),
+	), nil
+}
+
+// WithProcessPID adds an attribute with the process identifier (PID) to the
+// configured Resource.
+func WithProcessPID() Option {
+	return WithDetectors(processPIDDetector{})
+}
+
+// WithProcessExecutableName adds an attribute with the name of the process
+// executable to the configured Resource.
+func WithProcessExecutableName() Option {
+	return WithDetectors(processExecutableNameDetector{})
+}
+
+// WithProcessExecutablePath adds an attribute with the full path to the process
+// executable to the configured Resource.
+func WithProcessExecutablePath() Option {
+	return WithDetectors(processExecutablePathDetector{})
+}
+
+// WithProcessCommandArgs adds an attribute with all the command arguments (including
+// the command/executable itself) as received by the process the configured Resource.
+func WithProcessCommandArgs() Option {
+	return WithDetectors(processCommandArgsDetector{})
+}
+
+// WithProcessOwner adds an attribute with the username of the user that owns the process
+// to the configured Resource.
+func WithProcessOwner() Option {
+	return WithDetectors(processOwnerDetector{})
+}
+
+// WithProcessRuntimeName adds an attribute with the name of the runtime of this
+// process to the configured Resource.
+func WithProcessRuntimeName() Option {
+	return WithDetectors(processRuntimeNameDetector{})
+}
+
+// WithProcessRuntimeVersion adds an attribute with the version of the runtime of
+// this process to the configured Resource.
+func WithProcessRuntimeVersion() Option {
+	return WithDetectors(processRuntimeVersionDetector{})
+}
+
+// WithProcessRuntimeDescription adds an attribute with an additional description
+// about the runtime of the process to the configured Resource.
+func WithProcessRuntimeDescription() Option {
+	return WithDetectors(processRuntimeDescriptionDetector{})
+}
+
+// WithProcess adds all the Process attributes to the configured Resource.
+// See individual WithProcess* functions to configure specific attributes.
+func WithProcess() Option {
+	return WithDetectors(
+		processPIDDetector{},
+		processExecutableNameDetector{},
+		processExecutablePathDetector{},
+		processCommandArgsDetector{},
+		processOwnerDetector{},
+		processRuntimeNameDetector{},
+		processRuntimeVersionDetector{},
+		processRuntimeDescriptionDetector{},
+	)
+}

vendor/go.opentelemetry.io/otel/sdk/resource/resource.go

@@ -0,0 +1,256 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+)
+
+// Resource describes an entity about which identifying information
+// and metadata is exposed.  Resource is an immutable object,
+// equivalent to a map from key to unique value.
+//
+// Resources should be passed and stored as pointers
+// (`*resource.Resource`).  The `nil` value is equivalent to an empty
+// Resource.
+type Resource struct {
+	attrs     attribute.Set
+	schemaURL string
+}
+
+var (
+	emptyResource Resource
+
+	defaultResource = func(r *Resource, err error) *Resource {
+		if err != nil {
+			otel.Handle(err)
+		}
+		return r
+	}(Detect(context.Background(), defaultServiceNameDetector{}, fromEnv{}, telemetrySDK{}))
+)
+
+var (
+	errMergeConflictSchemaURL = errors.New("cannot merge resource due to conflicting Schema URL")
+)
+
+// New returns a Resource combined from the user-provided detectors.
+func New(ctx context.Context, opts ...Option) (*Resource, error) {
+	cfg := config{}
+	for _, opt := range opts {
+		opt.apply(&cfg)
+	}
+
+	resource, err := Detect(ctx, cfg.detectors...)
+
+	var err2 error
+	resource, err2 = Merge(resource, &Resource{schemaURL: cfg.schemaURL})
+	if err == nil {
+		err = err2
+	} else if err2 != nil {
+		err = fmt.Errorf("detecting resources: %s", []string{err.Error(), err2.Error()})
+	}
+
+	return resource, err
+}
+
+// NewWithAttributes creates a resource from attrs and associates the resource with a
+// schema URL. If attrs contains duplicate keys, the last value will be used. If attrs
+// contains any invalid items those items will be dropped. The attrs are assumed to be
+// in a schema identified by schemaURL.
+func NewWithAttributes(schemaURL string, attrs ...attribute.KeyValue) *Resource {
+	resource := NewSchemaless(attrs...)
+	resource.schemaURL = schemaURL
+	return resource
+}
+
+// NewSchemaless creates a resource from attrs. If attrs contains duplicate keys,
+// the last value will be used. If attrs contains any invalid items those items will
+// be dropped. The resource will not be associated with a schema URL. If the schema
+// of the attrs is known use NewWithAttributes instead.
+func NewSchemaless(attrs ...attribute.KeyValue) *Resource {
+	if len(attrs) == 0 {
+		return &emptyResource
+	}
+
+	// Ensure attributes comply with the specification:
+	// https://github.com/open-telemetry/opentelemetry-specification/blob/v1.0.1/specification/common/common.md#attributes
+	s, _ := attribute.NewSetWithFiltered(attrs, func(kv attribute.KeyValue) bool {
+		return kv.Valid()
+	})
+
+	// If attrs only contains invalid entries do not allocate a new resource.
+	if s.Len() == 0 {
+		return &emptyResource
+	}
+
+	return &Resource{attrs: s} //nolint
+}
+
+// String implements the Stringer interface and provides a
+// human-readable form of the resource.
+//
+// Avoid using this representation as the key in a map of resources,
+// use Equivalent() as the key instead.
+func (r *Resource) String() string {
+	if r == nil {
+		return ""
+	}
+	return r.attrs.Encoded(attribute.DefaultEncoder())
+}
+
+// Attributes returns a copy of attributes from the resource in a sorted order.
+// To avoid allocating a new slice, use an iterator.
+func (r *Resource) Attributes() []attribute.KeyValue {
+	if r == nil {
+		r = Empty()
+	}
+	return r.attrs.ToSlice()
+}
+
+func (r *Resource) SchemaURL() string {
+	return r.schemaURL
+}
+
+// Iter returns an interator of the Resource attributes.
+// This is ideal to use if you do not want a copy of the attributes.
+func (r *Resource) Iter() attribute.Iterator {
+	if r == nil {
+		r = Empty()
+	}
+	return r.attrs.Iter()
+}
+
+// Equal returns true when a Resource is equivalent to this Resource.
+func (r *Resource) Equal(eq *Resource) bool {
+	if r == nil {
+		r = Empty()
+	}
+	if eq == nil {
+		eq = Empty()
+	}
+	return r.Equivalent() == eq.Equivalent()
+}
+
+// Merge creates a new resource by combining resource a and b.
+//
+// If there are common keys between resource a and b, then the value
+// from resource b will overwrite the value from resource a, even
+// if resource b's value is empty.
+//
+// The SchemaURL of the resources will be merged according to the spec rules:
+// https://github.com/open-telemetry/opentelemetry-specification/blob/bad49c714a62da5493f2d1d9bafd7ebe8c8ce7eb/specification/resource/sdk.md#merge
+// If the resources have different non-empty schemaURL an empty resource and an error
+// will be returned.
+func Merge(a, b *Resource) (*Resource, error) {
+	if a == nil && b == nil {
+		return Empty(), nil
+	}
+	if a == nil {
+		return b, nil
+	}
+	if b == nil {
+		return a, nil
+	}
+
+	// Merge the schema URL.
+	var schemaURL string
+	if a.schemaURL == "" {
+		schemaURL = b.schemaURL
+	} else if b.schemaURL == "" {
+		schemaURL = a.schemaURL
+	} else if a.schemaURL == b.schemaURL {
+		schemaURL = a.schemaURL
+	} else {
+		return Empty(), errMergeConflictSchemaURL
+	}
+
+	// Note: 'b' attributes will overwrite 'a' with last-value-wins in attribute.Key()
+	// Meaning this is equivalent to: append(a.Attributes(), b.Attributes()...)
+	mi := attribute.NewMergeIterator(b.Set(), a.Set())
+	combine := make([]attribute.KeyValue, 0, a.Len()+b.Len())
+	for mi.Next() {
+		combine = append(combine, mi.Label())
+	}
+	merged := NewWithAttributes(schemaURL, combine...)
+	return merged, nil
+}
+
+// Empty returns an instance of Resource with no attributes.  It is
+// equivalent to a `nil` Resource.
+func Empty() *Resource {
+	return &emptyResource
+}
+
+// Default returns an instance of Resource with a default
+// "service.name" and OpenTelemetrySDK attributes
+func Default() *Resource {
+	return defaultResource
+}
+
+// Environment returns an instance of Resource with attributes
+// extracted from the OTEL_RESOURCE_ATTRIBUTES environment variable.
+func Environment() *Resource {
+	detector := &fromEnv{}
+	resource, err := detector.Detect(context.Background())
+	if err != nil {
+		otel.Handle(err)
+	}
+	return resource
+}
+
+// Equivalent returns an object that can be compared for equality
+// between two resources.  This value is suitable for use as a key in
+// a map.
+func (r *Resource) Equivalent() attribute.Distinct {
+	return r.Set().Equivalent()
+}
+
+// Set returns the equivalent *attribute.Set of this resources attributes.
+func (r *Resource) Set() *attribute.Set {
+	if r == nil {
+		r = Empty()
+	}
+	return &r.attrs
+}
+
+// MarshalJSON encodes the resource attributes as a JSON list of { "Key":
+// "...", "Value": ... } pairs in order sorted by key.
+func (r *Resource) MarshalJSON() ([]byte, error) {
+	if r == nil {
+		r = Empty()
+	}
+	return r.attrs.MarshalJSON()
+}
+
+// Len returns the number of unique key-values in this Resource.
+func (r *Resource) Len() int {
+	if r == nil {
+		return 0
+	}
+	return r.attrs.Len()
+}
+
+// Encoded returns an encoded representation of the resource.
+func (r *Resource) Encoded(enc attribute.Encoder) string {
+	if r == nil {
+		return ""
+	}
+	return r.attrs.Encoded(enc)
+}

vendor/go.opentelemetry.io/otel/sdk/trace/attributesmap.go

@@ -0,0 +1,91 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"container/list"
+
+	"go.opentelemetry.io/otel/attribute"
+)
+
+// attributesMap is a capped map of attributes, holding the most recent attributes.
+// Eviction is done via a LRU method, the oldest entry is removed to create room for a new entry.
+// Updates are allowed and they refresh the usage of the key.
+//
+// This is based from https://github.com/hashicorp/golang-lru/blob/master/simplelru/lru.go
+// With a subset of the its operations and specific for holding attribute.KeyValue
+type attributesMap struct {
+	attributes   map[attribute.Key]*list.Element
+	evictList    *list.List
+	droppedCount int
+	capacity     int
+}
+
+func newAttributesMap(capacity int) *attributesMap {
+	lm := &attributesMap{
+		attributes: make(map[attribute.Key]*list.Element),
+		evictList:  list.New(),
+		capacity:   capacity,
+	}
+	return lm
+}
+
+func (am *attributesMap) add(kv attribute.KeyValue) {
+	// Check for existing item
+	if ent, ok := am.attributes[kv.Key]; ok {
+		am.evictList.MoveToFront(ent)
+		ent.Value = &kv
+		return
+	}
+
+	// Add new item
+	entry := am.evictList.PushFront(&kv)
+	am.attributes[kv.Key] = entry
+
+	// Verify size not exceeded
+	if am.evictList.Len() > am.capacity {
+		am.removeOldest()
+		am.droppedCount++
+	}
+}
+
+// toKeyValue copies the attributesMap into a slice of attribute.KeyValue and
+// returns it. If the map is empty, a nil is returned.
+// TODO: Is it more efficient to return a pointer to the slice?
+func (am *attributesMap) toKeyValue() []attribute.KeyValue {
+	len := am.evictList.Len()
+	if len == 0 {
+		return nil
+	}
+
+	attributes := make([]attribute.KeyValue, 0, len)
+	for ent := am.evictList.Back(); ent != nil; ent = ent.Prev() {
+		if value, ok := ent.Value.(*attribute.KeyValue); ok {
+			attributes = append(attributes, *value)
+		}
+	}
+
+	return attributes
+}
+
+// removeOldest removes the oldest item from the cache.
+func (am *attributesMap) removeOldest() {
+	ent := am.evictList.Back()
+	if ent != nil {
+		am.evictList.Remove(ent)
+		kv := ent.Value.(*attribute.KeyValue)
+		delete(am.attributes, kv.Key)
+	}
+}

vendor/go.opentelemetry.io/otel/sdk/trace/batch_span_processor.go

@@ -0,0 +1,334 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"go.opentelemetry.io/otel"
+)
+
+// Defaults for BatchSpanProcessorOptions.
+const (
+	DefaultMaxQueueSize       = 2048
+	DefaultBatchTimeout       = 5000 * time.Millisecond
+	DefaultExportTimeout      = 30000 * time.Millisecond
+	DefaultMaxExportBatchSize = 512
+)
+
+type BatchSpanProcessorOption func(o *BatchSpanProcessorOptions)
+
+type BatchSpanProcessorOptions struct {
+	// MaxQueueSize is the maximum queue size to buffer spans for delayed processing. If the
+	// queue gets full it drops the spans. Use BlockOnQueueFull to change this behavior.
+	// The default value of MaxQueueSize is 2048.
+	MaxQueueSize int
+
+	// BatchTimeout is the maximum duration for constructing a batch. Processor
+	// forcefully sends available spans when timeout is reached.
+	// The default value of BatchTimeout is 5000 msec.
+	BatchTimeout time.Duration
+
+	// ExportTimeout specifies the maximum duration for exporting spans. If the timeout
+	// is reached, the export will be cancelled.
+	// The default value of ExportTimeout is 30000 msec.
+	ExportTimeout time.Duration
+
+	// MaxExportBatchSize is the maximum number of spans to process in a single batch.
+	// If there are more than one batch worth of spans then it processes multiple batches
+	// of spans one batch after the other without any delay.
+	// The default value of MaxExportBatchSize is 512.
+	MaxExportBatchSize int
+
+	// BlockOnQueueFull blocks onEnd() and onStart() method if the queue is full
+	// AND if BlockOnQueueFull is set to true.
+	// Blocking option should be used carefully as it can severely affect the performance of an
+	// application.
+	BlockOnQueueFull bool
+}
+
+// batchSpanProcessor is a SpanProcessor that batches asynchronously-received
+// spans and sends them to a trace.Exporter when complete.
+type batchSpanProcessor struct {
+	e SpanExporter
+	o BatchSpanProcessorOptions
+
+	queue   chan ReadOnlySpan
+	dropped uint32
+
+	batch      []ReadOnlySpan
+	batchMutex sync.Mutex
+	timer      *time.Timer
+	stopWait   sync.WaitGroup
+	stopOnce   sync.Once
+	stopCh     chan struct{}
+}
+
+var _ SpanProcessor = (*batchSpanProcessor)(nil)
+
+// NewBatchSpanProcessor creates a new SpanProcessor that will send completed
+// span batches to the exporter with the supplied options.
+//
+// If the exporter is nil, the span processor will preform no action.
+func NewBatchSpanProcessor(exporter SpanExporter, options ...BatchSpanProcessorOption) SpanProcessor {
+	o := BatchSpanProcessorOptions{
+		BatchTimeout:       DefaultBatchTimeout,
+		ExportTimeout:      DefaultExportTimeout,
+		MaxQueueSize:       DefaultMaxQueueSize,
+		MaxExportBatchSize: DefaultMaxExportBatchSize,
+	}
+	for _, opt := range options {
+		opt(&o)
+	}
+	bsp := &batchSpanProcessor{
+		e:      exporter,
+		o:      o,
+		batch:  make([]ReadOnlySpan, 0, o.MaxExportBatchSize),
+		timer:  time.NewTimer(o.BatchTimeout),
+		queue:  make(chan ReadOnlySpan, o.MaxQueueSize),
+		stopCh: make(chan struct{}),
+	}
+
+	bsp.stopWait.Add(1)
+	go func() {
+		defer bsp.stopWait.Done()
+		bsp.processQueue()
+		bsp.drainQueue()
+	}()
+
+	return bsp
+}
+
+// OnStart method does nothing.
+func (bsp *batchSpanProcessor) OnStart(parent context.Context, s ReadWriteSpan) {}
+
+// OnEnd method enqueues a ReadOnlySpan for later processing.
+func (bsp *batchSpanProcessor) OnEnd(s ReadOnlySpan) {
+	// Do not enqueue spans if we are just going to drop them.
+	if bsp.e == nil {
+		return
+	}
+	bsp.enqueue(s)
+}
+
+// Shutdown flushes the queue and waits until all spans are processed.
+// It only executes once. Subsequent call does nothing.
+func (bsp *batchSpanProcessor) Shutdown(ctx context.Context) error {
+	var err error
+	bsp.stopOnce.Do(func() {
+		wait := make(chan struct{})
+		go func() {
+			close(bsp.stopCh)
+			bsp.stopWait.Wait()
+			if bsp.e != nil {
+				if err := bsp.e.Shutdown(ctx); err != nil {
+					otel.Handle(err)
+				}
+			}
+			close(wait)
+		}()
+		// Wait until the wait group is done or the context is cancelled
+		select {
+		case <-wait:
+		case <-ctx.Done():
+			err = ctx.Err()
+		}
+	})
+	return err
+}
+
+// ForceFlush exports all ended spans that have not yet been exported.
+func (bsp *batchSpanProcessor) ForceFlush(ctx context.Context) error {
+	var err error
+	if bsp.e != nil {
+		wait := make(chan error)
+		go func() {
+			wait <- bsp.exportSpans(ctx)
+			close(wait)
+		}()
+		// Wait until the export is finished or the context is cancelled/timed out
+		select {
+		case err = <-wait:
+		case <-ctx.Done():
+			err = ctx.Err()
+		}
+	}
+	return err
+}
+
+func WithMaxQueueSize(size int) BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.MaxQueueSize = size
+	}
+}
+
+func WithMaxExportBatchSize(size int) BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.MaxExportBatchSize = size
+	}
+}
+
+func WithBatchTimeout(delay time.Duration) BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.BatchTimeout = delay
+	}
+}
+
+func WithExportTimeout(timeout time.Duration) BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.ExportTimeout = timeout
+	}
+}
+
+func WithBlocking() BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.BlockOnQueueFull = true
+	}
+}
+
+// exportSpans is a subroutine of processing and draining the queue.
+func (bsp *batchSpanProcessor) exportSpans(ctx context.Context) error {
+	bsp.timer.Reset(bsp.o.BatchTimeout)
+
+	bsp.batchMutex.Lock()
+	defer bsp.batchMutex.Unlock()
+
+	if bsp.o.ExportTimeout > 0 {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, bsp.o.ExportTimeout)
+		defer cancel()
+	}
+
+	if l := len(bsp.batch); l > 0 {
+		err := bsp.e.ExportSpans(ctx, bsp.batch)
+
+		// A new batch is always created after exporting, even if the batch failed to be exported.
+		//
+		// It is up to the exporter to implement any type of retry logic if a batch is failing
+		// to be exported, since it is specific to the protocol and backend being sent to.
+		bsp.batch = bsp.batch[:0]
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// processQueue removes spans from the `queue` channel until processor
+// is shut down. It calls the exporter in batches of up to MaxExportBatchSize
+// waiting up to BatchTimeout to form a batch.
+func (bsp *batchSpanProcessor) processQueue() {
+	defer bsp.timer.Stop()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	for {
+		select {
+		case <-bsp.stopCh:
+			return
+		case <-bsp.timer.C:
+			if err := bsp.exportSpans(ctx); err != nil {
+				otel.Handle(err)
+			}
+		case sd := <-bsp.queue:
+			bsp.batchMutex.Lock()
+			bsp.batch = append(bsp.batch, sd)
+			shouldExport := len(bsp.batch) >= bsp.o.MaxExportBatchSize
+			bsp.batchMutex.Unlock()
+			if shouldExport {
+				if !bsp.timer.Stop() {
+					<-bsp.timer.C
+				}
+				if err := bsp.exportSpans(ctx); err != nil {
+					otel.Handle(err)
+				}
+			}
+		}
+	}
+}
+
+// drainQueue awaits the any caller that had added to bsp.stopWait
+// to finish the enqueue, then exports the final batch.
+func (bsp *batchSpanProcessor) drainQueue() {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	for {
+		select {
+		case sd := <-bsp.queue:
+			if sd == nil {
+				if err := bsp.exportSpans(ctx); err != nil {
+					otel.Handle(err)
+				}
+				return
+			}
+
+			bsp.batchMutex.Lock()
+			bsp.batch = append(bsp.batch, sd)
+			shouldExport := len(bsp.batch) == bsp.o.MaxExportBatchSize
+			bsp.batchMutex.Unlock()
+
+			if shouldExport {
+				if err := bsp.exportSpans(ctx); err != nil {
+					otel.Handle(err)
+				}
+			}
+		default:
+			close(bsp.queue)
+		}
+	}
+}
+
+func (bsp *batchSpanProcessor) enqueue(sd ReadOnlySpan) {
+	if !sd.SpanContext().IsSampled() {
+		return
+	}
+
+	// This ensures the bsp.queue<- below does not panic as the
+	// processor shuts down.
+	defer func() {
+		x := recover()
+		switch err := x.(type) {
+		case nil:
+			return
+		case runtime.Error:
+			if err.Error() == "send on closed channel" {
+				return
+			}
+		}
+		panic(x)
+	}()
+
+	select {
+	case <-bsp.stopCh:
+		return
+	default:
+	}
+
+	if bsp.o.BlockOnQueueFull {
+		bsp.queue <- sd
+		return
+	}
+
+	select {
+	case bsp.queue <- sd:
+	default:
+		atomic.AddUint32(&bsp.dropped, 1)
+	}
+}

vendor/go.opentelemetry.io/otel/sdk/trace/config.go

@@ -0,0 +1,68 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+// SpanLimits represents the limits of a span.
+type SpanLimits struct {
+	// AttributeCountLimit is the maximum allowed span attribute count.
+	AttributeCountLimit int
+
+	// EventCountLimit is the maximum allowed span event count.
+	EventCountLimit int
+
+	// LinkCountLimit is the maximum allowed span link count.
+	LinkCountLimit int
+
+	// AttributePerEventCountLimit is the maximum allowed attribute per span event count.
+	AttributePerEventCountLimit int
+
+	// AttributePerLinkCountLimit is the maximum allowed attribute per span link count.
+	AttributePerLinkCountLimit int
+}
+
+func (sl *SpanLimits) ensureDefault() {
+	if sl.EventCountLimit <= 0 {
+		sl.EventCountLimit = DefaultEventCountLimit
+	}
+	if sl.AttributeCountLimit <= 0 {
+		sl.AttributeCountLimit = DefaultAttributeCountLimit
+	}
+	if sl.LinkCountLimit <= 0 {
+		sl.LinkCountLimit = DefaultLinkCountLimit
+	}
+	if sl.AttributePerEventCountLimit <= 0 {
+		sl.AttributePerEventCountLimit = DefaultAttributePerEventCountLimit
+	}
+	if sl.AttributePerLinkCountLimit <= 0 {
+		sl.AttributePerLinkCountLimit = DefaultAttributePerLinkCountLimit
+	}
+}
+
+const (
+	// DefaultAttributeCountLimit is the default maximum allowed span attribute count.
+	DefaultAttributeCountLimit = 128
+
+	// DefaultEventCountLimit is the default maximum allowed span event count.
+	DefaultEventCountLimit = 128
+
+	// DefaultLinkCountLimit is the default maximum allowed span link count.
+	DefaultLinkCountLimit = 128
+
+	// DefaultAttributePerEventCountLimit is the default maximum allowed attribute per span event count.
+	DefaultAttributePerEventCountLimit = 128
+
+	// DefaultAttributePerLinkCountLimit is the default maximum allowed attribute per span link count.
+	DefaultAttributePerLinkCountLimit = 128
+)

vendor/go.opentelemetry.io/otel/sdk/trace/doc.go

@@ -0,0 +1,24 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package trace contains support for OpenTelemetry distributed tracing.
+
+This package is currently in a Release Candidate phase. Backwards incompatible changes
+may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+
+The following assumes a basic familiarity with OpenTelemetry concepts.
+See https://opentelemetry.io.
+*/
+package trace // import "go.opentelemetry.io/otel/sdk/trace"

vendor/go.opentelemetry.io/otel/sdk/trace/event.go

@@ -0,0 +1,37 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace
+
+import (
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+)
+
+// Event is a thing that happened during a Span's lifetime.
+type Event struct {
+	// Name is the name of this event
+	Name string
+
+	// Attributes describe the aspects of the event.
+	Attributes []attribute.KeyValue
+
+	// DroppedAttributeCount is the number of attributes that were not
+	// recorded due to configured limits being reached.
+	DroppedAttributeCount int
+
+	// Time at which this event was recorded.
+	Time time.Time
+}

vendor/go.opentelemetry.io/otel/sdk/trace/evictedqueue.go

@@ -0,0 +1,38 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+type evictedQueue struct {
+	queue        []interface{}
+	capacity     int
+	droppedCount int
+}
+
+func newEvictedQueue(capacity int) *evictedQueue {
+	eq := &evictedQueue{
+		capacity: capacity,
+		queue:    make([]interface{}, 0),
+	}
+
+	return eq
+}
+
+func (eq *evictedQueue) add(value interface{}) {
+	if len(eq.queue) == eq.capacity {
+		eq.queue = eq.queue[1:]
+		eq.droppedCount++
+	}
+	eq.queue = append(eq.queue, value)
+}

vendor/go.opentelemetry.io/otel/sdk/trace/id_generator.go

@@ -0,0 +1,77 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	crand "crypto/rand"
+	"encoding/binary"
+	"math/rand"
+	"sync"
+
+	"go.opentelemetry.io/otel/trace"
+)
+
+// IDGenerator allows custom generators for TraceID and SpanID.
+type IDGenerator interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// NewIDs returns a new trace and span ID.
+	NewIDs(ctx context.Context) (trace.TraceID, trace.SpanID)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// NewSpanID returns a ID for a new span in the trace with traceID.
+	NewSpanID(ctx context.Context, traceID trace.TraceID) trace.SpanID
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+type randomIDGenerator struct {
+	sync.Mutex
+	randSource *rand.Rand
+}
+
+var _ IDGenerator = &randomIDGenerator{}
+
+// NewSpanID returns a non-zero span ID from a randomly-chosen sequence.
+func (gen *randomIDGenerator) NewSpanID(ctx context.Context, traceID trace.TraceID) trace.SpanID {
+	gen.Lock()
+	defer gen.Unlock()
+	sid := trace.SpanID{}
+	gen.randSource.Read(sid[:])
+	return sid
+}
+
+// NewIDs returns a non-zero trace ID and a non-zero span ID from a
+// randomly-chosen sequence.
+func (gen *randomIDGenerator) NewIDs(ctx context.Context) (trace.TraceID, trace.SpanID) {
+	gen.Lock()
+	defer gen.Unlock()
+	tid := trace.TraceID{}
+	gen.randSource.Read(tid[:])
+	sid := trace.SpanID{}
+	gen.randSource.Read(sid[:])
+	return tid, sid
+}
+
+func defaultIDGenerator() IDGenerator {
+	gen := &randomIDGenerator{}
+	var rngSeed int64
+	_ = binary.Read(crand.Reader, binary.LittleEndian, &rngSeed)
+	gen.randSource = rand.New(rand.NewSource(rngSeed))
+	return gen
+}

vendor/go.opentelemetry.io/otel/sdk/trace/provider.go

@@ -0,0 +1,345 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"sync/atomic"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/trace"
+
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+const (
+	defaultTracerName = "go.opentelemetry.io/otel/sdk/tracer"
+)
+
+// tracerProviderConfig
+type tracerProviderConfig struct {
+	// processors contains collection of SpanProcessors that are processing pipeline
+	// for spans in the trace signal.
+	// SpanProcessors registered with a TracerProvider and are called at the start
+	// and end of a Span's lifecycle, and are called in the order they are
+	// registered.
+	processors []SpanProcessor
+
+	// sampler is the default sampler used when creating new spans.
+	sampler Sampler
+
+	// idGenerator is used to generate all Span and Trace IDs when needed.
+	idGenerator IDGenerator
+
+	// spanLimits defines the attribute, event, and link limits for spans.
+	spanLimits SpanLimits
+
+	// resource contains attributes representing an entity that produces telemetry.
+	resource *resource.Resource
+}
+
+type TracerProvider struct {
+	mu             sync.Mutex
+	namedTracer    map[instrumentation.Library]*tracer
+	spanProcessors atomic.Value
+	sampler        Sampler
+	idGenerator    IDGenerator
+	spanLimits     SpanLimits
+	resource       *resource.Resource
+}
+
+var _ trace.TracerProvider = &TracerProvider{}
+
+// NewTracerProvider returns a new and configured TracerProvider.
+//
+// By default the returned TracerProvider is configured with:
+//  - a ParentBased(AlwaysSample) Sampler
+//  - a random number IDGenerator
+//  - the resource.Default() Resource
+//  - the default SpanLimits.
+//
+// The passed opts are used to override these default values and configure the
+// returned TracerProvider appropriately.
+func NewTracerProvider(opts ...TracerProviderOption) *TracerProvider {
+	o := &tracerProviderConfig{}
+
+	for _, opt := range opts {
+		opt.apply(o)
+	}
+
+	ensureValidTracerProviderConfig(o)
+
+	tp := &TracerProvider{
+		namedTracer: make(map[instrumentation.Library]*tracer),
+		sampler:     o.sampler,
+		idGenerator: o.idGenerator,
+		spanLimits:  o.spanLimits,
+		resource:    o.resource,
+	}
+
+	for _, sp := range o.processors {
+		tp.RegisterSpanProcessor(sp)
+	}
+
+	return tp
+}
+
+// Tracer returns a Tracer with the given name and options. If a Tracer for
+// the given name and options does not exist it is created, otherwise the
+// existing Tracer is returned.
+//
+// If name is empty, DefaultTracerName is used instead.
+//
+// This method is safe to be called concurrently.
+func (p *TracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.Tracer {
+	c := trace.NewTracerConfig(opts...)
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if name == "" {
+		name = defaultTracerName
+	}
+	il := instrumentation.Library{
+		Name:      name,
+		Version:   c.InstrumentationVersion(),
+		SchemaURL: c.SchemaURL(),
+	}
+	t, ok := p.namedTracer[il]
+	if !ok {
+		t = &tracer{
+			provider:               p,
+			instrumentationLibrary: il,
+		}
+		p.namedTracer[il] = t
+	}
+	return t
+}
+
+// RegisterSpanProcessor adds the given SpanProcessor to the list of SpanProcessors
+func (p *TracerProvider) RegisterSpanProcessor(s SpanProcessor) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	new := spanProcessorStates{}
+	if old, ok := p.spanProcessors.Load().(spanProcessorStates); ok {
+		new = append(new, old...)
+	}
+	newSpanSync := &spanProcessorState{
+		sp:    s,
+		state: &sync.Once{},
+	}
+	new = append(new, newSpanSync)
+	p.spanProcessors.Store(new)
+}
+
+// UnregisterSpanProcessor removes the given SpanProcessor from the list of SpanProcessors
+func (p *TracerProvider) UnregisterSpanProcessor(s SpanProcessor) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	spss := spanProcessorStates{}
+	old, ok := p.spanProcessors.Load().(spanProcessorStates)
+	if !ok || len(old) == 0 {
+		return
+	}
+	spss = append(spss, old...)
+
+	// stop the span processor if it is started and remove it from the list
+	var stopOnce *spanProcessorState
+	var idx int
+	for i, sps := range spss {
+		if sps.sp == s {
+			stopOnce = sps
+			idx = i
+		}
+	}
+	if stopOnce != nil {
+		stopOnce.state.Do(func() {
+			if err := s.Shutdown(context.Background()); err != nil {
+				otel.Handle(err)
+			}
+		})
+	}
+	if len(spss) > 1 {
+		copy(spss[idx:], spss[idx+1:])
+	}
+	spss[len(spss)-1] = nil
+	spss = spss[:len(spss)-1]
+
+	p.spanProcessors.Store(spss)
+}
+
+// ForceFlush immediately exports all spans that have not yet been exported for
+// all the registered span processors.
+func (p *TracerProvider) ForceFlush(ctx context.Context) error {
+	spss, ok := p.spanProcessors.Load().(spanProcessorStates)
+	if !ok {
+		return fmt.Errorf("failed to load span processors")
+	}
+	if len(spss) == 0 {
+		return nil
+	}
+
+	for _, sps := range spss {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+		}
+
+		if err := sps.sp.ForceFlush(ctx); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Shutdown shuts down the span processors in the order they were registered.
+func (p *TracerProvider) Shutdown(ctx context.Context) error {
+	spss, ok := p.spanProcessors.Load().(spanProcessorStates)
+	if !ok {
+		return fmt.Errorf("failed to load span processors")
+	}
+	if len(spss) == 0 {
+		return nil
+	}
+
+	for _, sps := range spss {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+		}
+
+		var err error
+		sps.state.Do(func() {
+			err = sps.sp.Shutdown(ctx)
+		})
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+type TracerProviderOption interface {
+	apply(*tracerProviderConfig)
+}
+
+type traceProviderOptionFunc func(*tracerProviderConfig)
+
+func (fn traceProviderOptionFunc) apply(cfg *tracerProviderConfig) {
+	fn(cfg)
+}
+
+// WithSyncer registers the exporter with the TracerProvider using a
+// SimpleSpanProcessor.
+//
+// This is not recommended for production use. The synchronous nature of the
+// SimpleSpanProcessor that will wrap the exporter make it good for testing,
+// debugging, or showing examples of other feature, but it will be slow and
+// have a high computation resource usage overhead. The WithBatcher option is
+// recommended for production use instead.
+func WithSyncer(e SpanExporter) TracerProviderOption {
+	return WithSpanProcessor(NewSimpleSpanProcessor(e))
+}
+
+// WithBatcher registers the exporter with the TracerProvider using a
+// BatchSpanProcessor configured with the passed opts.
+func WithBatcher(e SpanExporter, opts ...BatchSpanProcessorOption) TracerProviderOption {
+	return WithSpanProcessor(NewBatchSpanProcessor(e, opts...))
+}
+
+// WithSpanProcessor registers the SpanProcessor with a TracerProvider.
+func WithSpanProcessor(sp SpanProcessor) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg *tracerProviderConfig) {
+		cfg.processors = append(cfg.processors, sp)
+	})
+}
+
+// WithResource returns a TracerProviderOption that will configure the
+// Resource r as a TracerProvider's Resource. The configured Resource is
+// referenced by all the Tracers the TracerProvider creates. It represents the
+// entity producing telemetry.
+//
+// If this option is not used, the TracerProvider will use the
+// resource.Default() Resource by default.
+func WithResource(r *resource.Resource) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg *tracerProviderConfig) {
+		var err error
+		cfg.resource, err = resource.Merge(resource.Environment(), r)
+		if err != nil {
+			otel.Handle(err)
+		}
+	})
+}
+
+// WithIDGenerator returns a TracerProviderOption that will configure the
+// IDGenerator g as a TracerProvider's IDGenerator. The configured IDGenerator
+// is used by the Tracers the TracerProvider creates to generate new Span and
+// Trace IDs.
+//
+// If this option is not used, the TracerProvider will use a random number
+// IDGenerator by default.
+func WithIDGenerator(g IDGenerator) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg *tracerProviderConfig) {
+		if g != nil {
+			cfg.idGenerator = g
+		}
+	})
+}
+
+// WithSampler returns a TracerProviderOption that will configure the Sampler
+// s as a TracerProvider's Sampler. The configured Sampler is used by the
+// Tracers the TracerProvider creates to make their sampling decisions for the
+// Spans they create.
+//
+// If this option is not used, the TracerProvider will use a
+// ParentBased(AlwaysSample) Sampler by default.
+func WithSampler(s Sampler) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg *tracerProviderConfig) {
+		if s != nil {
+			cfg.sampler = s
+		}
+	})
+}
+
+// WithSpanLimits returns a TracerProviderOption that will configure the
+// SpanLimits sl as a TracerProvider's SpanLimits. The configured SpanLimits
+// are used used by the Tracers the TracerProvider and the Spans they create
+// to limit tracing resources used.
+//
+// If this option is not used, the TracerProvider will use the default
+// SpanLimits.
+func WithSpanLimits(sl SpanLimits) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg *tracerProviderConfig) {
+		cfg.spanLimits = sl
+	})
+}
+
+// ensureValidTracerProviderConfig ensures that given TracerProviderConfig is valid.
+func ensureValidTracerProviderConfig(cfg *tracerProviderConfig) {
+	if cfg.sampler == nil {
+		cfg.sampler = ParentBased(AlwaysSample())
+	}
+	if cfg.idGenerator == nil {
+		cfg.idGenerator = defaultIDGenerator()
+	}
+	cfg.spanLimits.ensureDefault()
+	if cfg.resource == nil {
+		cfg.resource = resource.Default()
+	}
+}

vendor/go.opentelemetry.io/otel/sdk/trace/sampling.go

@@ -0,0 +1,288 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// Sampler decides whether a trace should be sampled and exported.
+type Sampler interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// ShouldSample returns a SamplingResult based on a decision made from the
+	// passed parameters.
+	ShouldSample(parameters SamplingParameters) SamplingResult
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Description returns information describing the Sampler.
+	Description() string
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+// SamplingParameters contains the values passed to a Sampler.
+type SamplingParameters struct {
+	ParentContext context.Context
+	TraceID       trace.TraceID
+	Name          string
+	Kind          trace.SpanKind
+	Attributes    []attribute.KeyValue
+	Links         []trace.Link
+}
+
+// SamplingDecision indicates whether a span is dropped, recorded and/or sampled.
+type SamplingDecision uint8
+
+// Valid sampling decisions
+const (
+	// Drop will not record the span and all attributes/events will be dropped
+	Drop SamplingDecision = iota
+
+	// Record indicates the span's `IsRecording() == true`, but `Sampled` flag
+	// *must not* be set
+	RecordOnly
+
+	// RecordAndSample has span's `IsRecording() == true` and `Sampled` flag
+	// *must* be set
+	RecordAndSample
+)
+
+// SamplingResult conveys a SamplingDecision, set of Attributes and a Tracestate.
+type SamplingResult struct {
+	Decision   SamplingDecision
+	Attributes []attribute.KeyValue
+	Tracestate trace.TraceState
+}
+
+type traceIDRatioSampler struct {
+	traceIDUpperBound uint64
+	description       string
+}
+
+func (ts traceIDRatioSampler) ShouldSample(p SamplingParameters) SamplingResult {
+	psc := trace.SpanContextFromContext(p.ParentContext)
+	x := binary.BigEndian.Uint64(p.TraceID[0:8]) >> 1
+	if x < ts.traceIDUpperBound {
+		return SamplingResult{
+			Decision:   RecordAndSample,
+			Tracestate: psc.TraceState(),
+		}
+	}
+	return SamplingResult{
+		Decision:   Drop,
+		Tracestate: psc.TraceState(),
+	}
+}
+
+func (ts traceIDRatioSampler) Description() string {
+	return ts.description
+}
+
+// TraceIDRatioBased samples a given fraction of traces. Fractions >= 1 will
+// always sample. Fractions < 0 are treated as zero. To respect the
+// parent trace's `SampledFlag`, the `TraceIDRatioBased` sampler should be used
+// as a delegate of a `Parent` sampler.
+//nolint:revive // revive complains about stutter of `trace.TraceIDRatioBased`
+func TraceIDRatioBased(fraction float64) Sampler {
+	if fraction >= 1 {
+		return AlwaysSample()
+	}
+
+	if fraction <= 0 {
+		fraction = 0
+	}
+
+	return &traceIDRatioSampler{
+		traceIDUpperBound: uint64(fraction * (1 << 63)),
+		description:       fmt.Sprintf("TraceIDRatioBased{%g}", fraction),
+	}
+}
+
+type alwaysOnSampler struct{}
+
+func (as alwaysOnSampler) ShouldSample(p SamplingParameters) SamplingResult {
+	return SamplingResult{
+		Decision:   RecordAndSample,
+		Tracestate: trace.SpanContextFromContext(p.ParentContext).TraceState(),
+	}
+}
+
+func (as alwaysOnSampler) Description() string {
+	return "AlwaysOnSampler"
+}
+
+// AlwaysSample returns a Sampler that samples every trace.
+// Be careful about using this sampler in a production application with
+// significant traffic: a new trace will be started and exported for every
+// request.
+func AlwaysSample() Sampler {
+	return alwaysOnSampler{}
+}
+
+type alwaysOffSampler struct{}
+
+func (as alwaysOffSampler) ShouldSample(p SamplingParameters) SamplingResult {
+	return SamplingResult{
+		Decision:   Drop,
+		Tracestate: trace.SpanContextFromContext(p.ParentContext).TraceState(),
+	}
+}
+
+func (as alwaysOffSampler) Description() string {
+	return "AlwaysOffSampler"
+}
+
+// NeverSample returns a Sampler that samples no traces.
+func NeverSample() Sampler {
+	return alwaysOffSampler{}
+}
+
+// ParentBased returns a composite sampler which behaves differently,
+// based on the parent of the span. If the span has no parent,
+// the root(Sampler) is used to make sampling decision. If the span has
+// a parent, depending on whether the parent is remote and whether it
+// is sampled, one of the following samplers will apply:
+// - remoteParentSampled(Sampler) (default: AlwaysOn)
+// - remoteParentNotSampled(Sampler) (default: AlwaysOff)
+// - localParentSampled(Sampler) (default: AlwaysOn)
+// - localParentNotSampled(Sampler) (default: AlwaysOff)
+func ParentBased(root Sampler, samplers ...ParentBasedSamplerOption) Sampler {
+	return parentBased{
+		root:   root,
+		config: configureSamplersForParentBased(samplers),
+	}
+}
+
+type parentBased struct {
+	root   Sampler
+	config samplerConfig
+}
+
+func configureSamplersForParentBased(samplers []ParentBasedSamplerOption) samplerConfig {
+	c := samplerConfig{
+		remoteParentSampled:    AlwaysSample(),
+		remoteParentNotSampled: NeverSample(),
+		localParentSampled:     AlwaysSample(),
+		localParentNotSampled:  NeverSample(),
+	}
+
+	for _, so := range samplers {
+		so.apply(&c)
+	}
+
+	return c
+}
+
+// samplerConfig is a group of options for parentBased sampler.
+type samplerConfig struct {
+	remoteParentSampled, remoteParentNotSampled Sampler
+	localParentSampled, localParentNotSampled   Sampler
+}
+
+// ParentBasedSamplerOption configures the sampler for a particular sampling case.
+type ParentBasedSamplerOption interface {
+	apply(*samplerConfig)
+}
+
+// WithRemoteParentSampled sets the sampler for the case of sampled remote parent.
+func WithRemoteParentSampled(s Sampler) ParentBasedSamplerOption {
+	return remoteParentSampledOption{s}
+}
+
+type remoteParentSampledOption struct {
+	s Sampler
+}
+
+func (o remoteParentSampledOption) apply(config *samplerConfig) {
+	config.remoteParentSampled = o.s
+}
+
+// WithRemoteParentNotSampled sets the sampler for the case of remote parent
+// which is not sampled.
+func WithRemoteParentNotSampled(s Sampler) ParentBasedSamplerOption {
+	return remoteParentNotSampledOption{s}
+}
+
+type remoteParentNotSampledOption struct {
+	s Sampler
+}
+
+func (o remoteParentNotSampledOption) apply(config *samplerConfig) {
+	config.remoteParentNotSampled = o.s
+}
+
+// WithLocalParentSampled sets the sampler for the case of sampled local parent.
+func WithLocalParentSampled(s Sampler) ParentBasedSamplerOption {
+	return localParentSampledOption{s}
+}
+
+type localParentSampledOption struct {
+	s Sampler
+}
+
+func (o localParentSampledOption) apply(config *samplerConfig) {
+	config.localParentSampled = o.s
+}
+
+// WithLocalParentNotSampled sets the sampler for the case of local parent
+// which is not sampled.
+func WithLocalParentNotSampled(s Sampler) ParentBasedSamplerOption {
+	return localParentNotSampledOption{s}
+}
+
+type localParentNotSampledOption struct {
+	s Sampler
+}
+
+func (o localParentNotSampledOption) apply(config *samplerConfig) {
+	config.localParentNotSampled = o.s
+}
+
+func (pb parentBased) ShouldSample(p SamplingParameters) SamplingResult {
+	psc := trace.SpanContextFromContext(p.ParentContext)
+	if psc.IsValid() {
+		if psc.IsRemote() {
+			if psc.IsSampled() {
+				return pb.config.remoteParentSampled.ShouldSample(p)
+			}
+			return pb.config.remoteParentNotSampled.ShouldSample(p)
+		}
+
+		if psc.IsSampled() {
+			return pb.config.localParentSampled.ShouldSample(p)
+		}
+		return pb.config.localParentNotSampled.ShouldSample(p)
+	}
+	return pb.root.ShouldSample(p)
+}
+
+func (pb parentBased) Description() string {
+	return fmt.Sprintf("ParentBased{root:%s,remoteParentSampled:%s,"+
+		"remoteParentNotSampled:%s,localParentSampled:%s,localParentNotSampled:%s}",
+		pb.root.Description(),
+		pb.config.remoteParentSampled.Description(),
+		pb.config.remoteParentNotSampled.Description(),
+		pb.config.localParentSampled.Description(),
+		pb.config.localParentNotSampled.Description(),
+	)
+}

vendor/go.opentelemetry.io/otel/sdk/trace/simple_span_processor.go

@@ -0,0 +1,103 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"sync"
+
+	"go.opentelemetry.io/otel"
+)
+
+// simpleSpanProcessor is a SpanProcessor that synchronously sends all
+// completed Spans to a trace.Exporter immediately.
+type simpleSpanProcessor struct {
+	exporterMu sync.RWMutex
+	exporter   SpanExporter
+	stopOnce   sync.Once
+}
+
+var _ SpanProcessor = (*simpleSpanProcessor)(nil)
+
+// NewSimpleSpanProcessor returns a new SpanProcessor that will synchronously
+// send completed spans to the exporter immediately.
+//
+// This SpanProcessor is not recommended for production use. The synchronous
+// nature of this SpanProcessor make it good for testing, debugging, or
+// showing examples of other feature, but it will be slow and have a high
+// computation resource usage overhead. The BatchSpanProcessor is recommended
+// for production use instead.
+func NewSimpleSpanProcessor(exporter SpanExporter) SpanProcessor {
+	ssp := &simpleSpanProcessor{
+		exporter: exporter,
+	}
+	return ssp
+}
+
+// OnStart does nothing.
+func (ssp *simpleSpanProcessor) OnStart(context.Context, ReadWriteSpan) {}
+
+// OnEnd immediately exports a ReadOnlySpan.
+func (ssp *simpleSpanProcessor) OnEnd(s ReadOnlySpan) {
+	ssp.exporterMu.RLock()
+	defer ssp.exporterMu.RUnlock()
+
+	if ssp.exporter != nil && s.SpanContext().TraceFlags().IsSampled() {
+		if err := ssp.exporter.ExportSpans(context.Background(), []ReadOnlySpan{s}); err != nil {
+			otel.Handle(err)
+		}
+	}
+}
+
+// Shutdown shuts down the exporter this SimpleSpanProcessor exports to.
+func (ssp *simpleSpanProcessor) Shutdown(ctx context.Context) error {
+	var err error
+	ssp.stopOnce.Do(func() {
+		stopFunc := func(exp SpanExporter) (<-chan error, func()) {
+			done := make(chan error)
+			return done, func() { done <- exp.Shutdown(ctx) }
+		}
+
+		// The exporter field of the simpleSpanProcessor needs to be zeroed to
+		// signal it is shut down, meaning all subsequent calls to OnEnd will
+		// be gracefully ignored. This needs to be done synchronously to avoid
+		// any race condition.
+		//
+		// A closure is used to keep reference to the exporter and then the
+		// field is zeroed. This ensures the simpleSpanProcessor is shut down
+		// before the exporter. This order is important as it avoids a
+		// potential deadlock. If the exporter shut down operation generates a
+		// span, that span would need to be exported. Meaning, OnEnd would be
+		// called and try acquiring the lock that is held here.
+		ssp.exporterMu.Lock()
+		done, shutdown := stopFunc(ssp.exporter)
+		ssp.exporter = nil
+		ssp.exporterMu.Unlock()
+
+		go shutdown()
+
+		select {
+		case err = <-done:
+		case <-ctx.Done():
+			err = ctx.Err()
+		}
+	})
+	return err
+}
+
+// ForceFlush does nothing as there is no data to flush.
+func (ssp *simpleSpanProcessor) ForceFlush(context.Context) error {
+	return nil
+}

vendor/go.opentelemetry.io/otel/sdk/trace/snapshot.go

@@ -0,0 +1,138 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace
+
+import (
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// snapshot is an record of a spans state at a particular checkpointed time.
+// It is used as a read-only representation of that state.
+type snapshot struct {
+	name                   string
+	spanContext            trace.SpanContext
+	parent                 trace.SpanContext
+	spanKind               trace.SpanKind
+	startTime              time.Time
+	endTime                time.Time
+	attributes             []attribute.KeyValue
+	events                 []Event
+	links                  []trace.Link
+	status                 Status
+	childSpanCount         int
+	droppedAttributeCount  int
+	droppedEventCount      int
+	droppedLinkCount       int
+	resource               *resource.Resource
+	instrumentationLibrary instrumentation.Library
+}
+
+var _ ReadOnlySpan = snapshot{}
+
+func (s snapshot) private() {}
+
+// Name returns the name of the span.
+func (s snapshot) Name() string {
+	return s.name
+}
+
+// SpanContext returns the unique SpanContext that identifies the span.
+func (s snapshot) SpanContext() trace.SpanContext {
+	return s.spanContext
+}
+
+// Parent returns the unique SpanContext that identifies the parent of the
+// span if one exists. If the span has no parent the returned SpanContext
+// will be invalid.
+func (s snapshot) Parent() trace.SpanContext {
+	return s.parent
+}
+
+// SpanKind returns the role the span plays in a Trace.
+func (s snapshot) SpanKind() trace.SpanKind {
+	return s.spanKind
+}
+
+// StartTime returns the time the span started recording.
+func (s snapshot) StartTime() time.Time {
+	return s.startTime
+}
+
+// EndTime returns the time the span stopped recording. It will be zero if
+// the span has not ended.
+func (s snapshot) EndTime() time.Time {
+	return s.endTime
+}
+
+// Attributes returns the defining attributes of the span.
+func (s snapshot) Attributes() []attribute.KeyValue {
+	return s.attributes
+}
+
+// Links returns all the links the span has to other spans.
+func (s snapshot) Links() []trace.Link {
+	return s.links
+}
+
+// Events returns all the events that occurred within in the spans
+// lifetime.
+func (s snapshot) Events() []Event {
+	return s.events
+}
+
+// Status returns the spans status.
+func (s snapshot) Status() Status {
+	return s.status
+}
+
+// InstrumentationLibrary returns information about the instrumentation
+// library that created the span.
+func (s snapshot) InstrumentationLibrary() instrumentation.Library {
+	return s.instrumentationLibrary
+}
+
+// Resource returns information about the entity that produced the span.
+func (s snapshot) Resource() *resource.Resource {
+	return s.resource
+}
+
+// DroppedAttributes returns the number of attributes dropped by the span
+// due to limits being reached.
+func (s snapshot) DroppedAttributes() int {
+	return s.droppedAttributeCount
+}
+
+// DroppedLinks returns the number of links dropped by the span due to limits
+// being reached.
+func (s snapshot) DroppedLinks() int {
+	return s.droppedLinkCount
+}
+
+// DroppedEvents returns the number of events dropped by the span due to
+// limits being reached.
+func (s snapshot) DroppedEvents() int {
+	return s.droppedEventCount
+}
+
+// ChildSpanCount returns the count of spans that consider the span a
+// direct parent.
+func (s snapshot) ChildSpanCount() int {
+	return s.childSpanCount
+}

vendor/go.opentelemetry.io/otel/sdk/trace/span.go

@@ -0,0 +1,641 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"sync"
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+	"go.opentelemetry.io/otel/trace"
+
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	"go.opentelemetry.io/otel/sdk/internal"
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+// ReadOnlySpan allows reading information from the data structure underlying a
+// trace.Span. It is used in places where reading information from a span is
+// necessary but changing the span isn't necessary or allowed.
+//
+// Warning: methods may be added to this interface in minor releases.
+type ReadOnlySpan interface {
+	// Name returns the name of the span.
+	Name() string
+	// SpanContext returns the unique SpanContext that identifies the span.
+	SpanContext() trace.SpanContext
+	// Parent returns the unique SpanContext that identifies the parent of the
+	// span if one exists. If the span has no parent the returned SpanContext
+	// will be invalid.
+	Parent() trace.SpanContext
+	// SpanKind returns the role the span plays in a Trace.
+	SpanKind() trace.SpanKind
+	// StartTime returns the time the span started recording.
+	StartTime() time.Time
+	// EndTime returns the time the span stopped recording. It will be zero if
+	// the span has not ended.
+	EndTime() time.Time
+	// Attributes returns the defining attributes of the span.
+	Attributes() []attribute.KeyValue
+	// Links returns all the links the span has to other spans.
+	Links() []trace.Link
+	// Events returns all the events that occurred within in the spans
+	// lifetime.
+	Events() []Event
+	// Status returns the spans status.
+	Status() Status
+	// InstrumentationLibrary returns information about the instrumentation
+	// library that created the span.
+	InstrumentationLibrary() instrumentation.Library
+	// Resource returns information about the entity that produced the span.
+	Resource() *resource.Resource
+	// DroppedAttributes returns the number of attributes dropped by the span
+	// due to limits being reached.
+	DroppedAttributes() int
+	// DroppedLinks returns the number of links dropped by the span due to
+	// limits being reached.
+	DroppedLinks() int
+	// DroppedEvents returns the number of events dropped by the span due to
+	// limits being reached.
+	DroppedEvents() int
+	// ChildSpanCount returns the count of spans that consider the span a
+	// direct parent.
+	ChildSpanCount() int
+
+	// A private method to prevent users implementing the
+	// interface and so future additions to it will not
+	// violate compatibility.
+	private()
+}
+
+// ReadWriteSpan exposes the same methods as trace.Span and in addition allows
+// reading information from the underlying data structure.
+// This interface exposes the union of the methods of trace.Span (which is a
+// "write-only" span) and ReadOnlySpan. New methods for writing or reading span
+// information should be added under trace.Span or ReadOnlySpan, respectively.
+//
+// Warning: methods may be added to this interface in minor releases.
+type ReadWriteSpan interface {
+	trace.Span
+	ReadOnlySpan
+}
+
+// span is an implementation of the OpenTelemetry Span API representing the
+// individual component of a trace.
+type span struct {
+	// mu protects the contents of this span.
+	mu sync.Mutex
+
+	// parent holds the parent span of this span as a trace.SpanContext.
+	parent trace.SpanContext
+
+	// spanKind represents the kind of this span as a trace.SpanKind.
+	spanKind trace.SpanKind
+
+	// name is the name of this span.
+	name string
+
+	// startTime is the time at which this span was started.
+	startTime time.Time
+
+	// endTime is the time at which this span was ended. It contains the zero
+	// value of time.Time until the span is ended.
+	endTime time.Time
+
+	// status is the status of this span.
+	status Status
+
+	// childSpanCount holds the number of child spans created for this span.
+	childSpanCount int
+
+	// resource contains attributes representing an entity that produced this
+	// span.
+	resource *resource.Resource
+
+	// instrumentationLibrary defines the instrumentation library used to
+	// provide instrumentation.
+	instrumentationLibrary instrumentation.Library
+
+	// spanContext holds the SpanContext of this span.
+	spanContext trace.SpanContext
+
+	// attributes are capped at configured limit. When the capacity is reached
+	// an oldest entry is removed to create room for a new entry.
+	attributes *attributesMap
+
+	// events are stored in FIFO queue capped by configured limit.
+	events *evictedQueue
+
+	// links are stored in FIFO queue capped by configured limit.
+	links *evictedQueue
+
+	// executionTracerTaskEnd ends the execution tracer span.
+	executionTracerTaskEnd func()
+
+	// tracer is the SDK tracer that created this span.
+	tracer *tracer
+
+	// spanLimits holds the limits to this span.
+	spanLimits SpanLimits
+}
+
+var _ trace.Span = &span{}
+
+// SpanContext returns the SpanContext of this span.
+func (s *span) SpanContext() trace.SpanContext {
+	if s == nil {
+		return trace.SpanContext{}
+	}
+	return s.spanContext
+}
+
+// IsRecording returns if this span is being recorded. If this span has ended
+// this will return false.
+func (s *span) IsRecording() bool {
+	if s == nil {
+		return false
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	return !s.startTime.IsZero() && s.endTime.IsZero()
+}
+
+// SetStatus sets the status of the Span in the form of a code and a
+// description, overriding previous values set. The description is only
+// included in the set status when the code is for an error. If this span is
+// not being recorded than this method does nothing.
+func (s *span) SetStatus(code codes.Code, description string) {
+	if !s.IsRecording() {
+		return
+	}
+
+	status := Status{Code: code}
+	if code == codes.Error {
+		status.Description = description
+	}
+
+	s.mu.Lock()
+	s.status = status
+	s.mu.Unlock()
+}
+
+// SetAttributes sets attributes of this span.
+//
+// If a key from attributes already exists the value associated with that key
+// will be overwritten with the value contained in attributes.
+//
+// If this span is not being recorded than this method does nothing.
+func (s *span) SetAttributes(attributes ...attribute.KeyValue) {
+	if !s.IsRecording() {
+		return
+	}
+	s.copyToCappedAttributes(attributes...)
+}
+
+// End ends the span. This method does nothing if the span is already ended or
+// is not being recorded.
+//
+// The only SpanOption currently supported is WithTimestamp which will set the
+// end time for a Span's life-cycle.
+//
+// If this method is called while panicking an error event is added to the
+// Span before ending it and the panic is continued.
+func (s *span) End(options ...trace.SpanEndOption) {
+	// Do not start by checking if the span is being recorded which requires
+	// acquiring a lock. Make a minimal check that the span is not nil.
+	if s == nil {
+		return
+	}
+
+	// Store the end time as soon as possible to avoid artificially increasing
+	// the span's duration in case some operation below takes a while.
+	et := internal.MonotonicEndTime(s.startTime)
+
+	// Do relative expensive check now that we have an end time and see if we
+	// need to do any more processing.
+	if !s.IsRecording() {
+		return
+	}
+
+	if recovered := recover(); recovered != nil {
+		// Record but don't stop the panic.
+		defer panic(recovered)
+		s.addEvent(
+			semconv.ExceptionEventName,
+			trace.WithAttributes(
+				semconv.ExceptionTypeKey.String(typeStr(recovered)),
+				semconv.ExceptionMessageKey.String(fmt.Sprint(recovered)),
+			),
+		)
+	}
+
+	if s.executionTracerTaskEnd != nil {
+		s.executionTracerTaskEnd()
+	}
+
+	config := trace.NewSpanEndConfig(options...)
+
+	s.mu.Lock()
+	// Setting endTime to non-zero marks the span as ended and not recording.
+	if config.Timestamp().IsZero() {
+		s.endTime = et
+	} else {
+		s.endTime = config.Timestamp()
+	}
+	s.mu.Unlock()
+
+	sps, ok := s.tracer.provider.spanProcessors.Load().(spanProcessorStates)
+	mustExportOrProcess := ok && len(sps) > 0
+	if mustExportOrProcess {
+		for _, sp := range sps {
+			sp.sp.OnEnd(s.snapshot())
+		}
+	}
+}
+
+// RecordError will record err as a span event for this span. An additional call to
+// SetStatus is required if the Status of the Span should be set to Error, this method
+// does not change the Span status. If this span is not being recorded or err is nil
+// than this method does nothing.
+func (s *span) RecordError(err error, opts ...trace.EventOption) {
+	if s == nil || err == nil || !s.IsRecording() {
+		return
+	}
+
+	opts = append(opts, trace.WithAttributes(
+		semconv.ExceptionTypeKey.String(typeStr(err)),
+		semconv.ExceptionMessageKey.String(err.Error()),
+	))
+	s.addEvent(semconv.ExceptionEventName, opts...)
+}
+
+func typeStr(i interface{}) string {
+	t := reflect.TypeOf(i)
+	if t.PkgPath() == "" && t.Name() == "" {
+		// Likely a builtin type.
+		return t.String()
+	}
+	return fmt.Sprintf("%s.%s", t.PkgPath(), t.Name())
+}
+
+// AddEvent adds an event with the provided name and options. If this span is
+// not being recorded than this method does nothing.
+func (s *span) AddEvent(name string, o ...trace.EventOption) {
+	if !s.IsRecording() {
+		return
+	}
+	s.addEvent(name, o...)
+}
+
+func (s *span) addEvent(name string, o ...trace.EventOption) {
+	c := trace.NewEventConfig(o...)
+
+	// Discard over limited attributes
+	attributes := c.Attributes()
+	var discarded int
+	if len(attributes) > s.spanLimits.AttributePerEventCountLimit {
+		discarded = len(attributes) - s.spanLimits.AttributePerEventCountLimit
+		attributes = attributes[:s.spanLimits.AttributePerEventCountLimit]
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.events.add(Event{
+		Name:                  name,
+		Attributes:            attributes,
+		DroppedAttributeCount: discarded,
+		Time:                  c.Timestamp(),
+	})
+}
+
+// SetName sets the name of this span. If this span is not being recorded than
+// this method does nothing.
+func (s *span) SetName(name string) {
+	if !s.IsRecording() {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.name = name
+}
+
+// Name returns the name of this span.
+func (s *span) Name() string {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.name
+}
+
+// Name returns the SpanContext of this span's parent span.
+func (s *span) Parent() trace.SpanContext {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.parent
+}
+
+// SpanKind returns the SpanKind of this span.
+func (s *span) SpanKind() trace.SpanKind {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.spanKind
+}
+
+// StartTime returns the time this span started.
+func (s *span) StartTime() time.Time {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.startTime
+}
+
+// EndTime returns the time this span ended. For spans that have not yet
+// ended, the returned value will be the zero value of time.Time.
+func (s *span) EndTime() time.Time {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.endTime
+}
+
+// Attributes returns the attributes of this span.
+func (s *span) Attributes() []attribute.KeyValue {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.attributes.evictList.Len() == 0 {
+		return []attribute.KeyValue{}
+	}
+	return s.attributes.toKeyValue()
+}
+
+// Links returns the links of this span.
+func (s *span) Links() []trace.Link {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if len(s.links.queue) == 0 {
+		return []trace.Link{}
+	}
+	return s.interfaceArrayToLinksArray()
+}
+
+// Events returns the events of this span.
+func (s *span) Events() []Event {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if len(s.events.queue) == 0 {
+		return []Event{}
+	}
+	return s.interfaceArrayToEventArray()
+}
+
+// Status returns the status of this span.
+func (s *span) Status() Status {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.status
+}
+
+// InstrumentationLibrary returns the instrumentation.Library associated with
+// the Tracer that created this span.
+func (s *span) InstrumentationLibrary() instrumentation.Library {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.instrumentationLibrary
+}
+
+// Resource returns the Resource associated with the Tracer that created this
+// span.
+func (s *span) Resource() *resource.Resource {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.resource
+}
+
+func (s *span) addLink(link trace.Link) {
+	if !s.IsRecording() {
+		return
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	// Discard over limited attributes
+	if len(link.Attributes) > s.spanLimits.AttributePerLinkCountLimit {
+		link.DroppedAttributeCount = len(link.Attributes) - s.spanLimits.AttributePerLinkCountLimit
+		link.Attributes = link.Attributes[:s.spanLimits.AttributePerLinkCountLimit]
+	}
+
+	s.links.add(link)
+}
+
+// DroppedAttributes returns the number of attributes dropped by the span
+// due to limits being reached.
+func (s *span) DroppedAttributes() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.attributes.droppedCount
+}
+
+// DroppedLinks returns the number of links dropped by the span due to limits
+// being reached.
+func (s *span) DroppedLinks() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.links.droppedCount
+}
+
+// DroppedEvents returns the number of events dropped by the span due to
+// limits being reached.
+func (s *span) DroppedEvents() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.events.droppedCount
+}
+
+// ChildSpanCount returns the count of spans that consider the span a
+// direct parent.
+func (s *span) ChildSpanCount() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.childSpanCount
+}
+
+// TracerProvider returns a trace.TracerProvider that can be used to generate
+// additional Spans on the same telemetry pipeline as the current Span.
+func (s *span) TracerProvider() trace.TracerProvider {
+	return s.tracer.provider
+}
+
+// snapshot creates a read-only copy of the current state of the span.
+func (s *span) snapshot() ReadOnlySpan {
+	var sd snapshot
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	sd.endTime = s.endTime
+	sd.instrumentationLibrary = s.instrumentationLibrary
+	sd.name = s.name
+	sd.parent = s.parent
+	sd.resource = s.resource
+	sd.spanContext = s.spanContext
+	sd.spanKind = s.spanKind
+	sd.startTime = s.startTime
+	sd.status = s.status
+	sd.childSpanCount = s.childSpanCount
+
+	if s.attributes.evictList.Len() > 0 {
+		sd.attributes = s.attributes.toKeyValue()
+		sd.droppedAttributeCount = s.attributes.droppedCount
+	}
+	if len(s.events.queue) > 0 {
+		sd.events = s.interfaceArrayToEventArray()
+		sd.droppedEventCount = s.events.droppedCount
+	}
+	if len(s.links.queue) > 0 {
+		sd.links = s.interfaceArrayToLinksArray()
+		sd.droppedLinkCount = s.links.droppedCount
+	}
+	return &sd
+}
+
+func (s *span) interfaceArrayToLinksArray() []trace.Link {
+	linkArr := make([]trace.Link, 0)
+	for _, value := range s.links.queue {
+		linkArr = append(linkArr, value.(trace.Link))
+	}
+	return linkArr
+}
+
+func (s *span) interfaceArrayToEventArray() []Event {
+	eventArr := make([]Event, 0)
+	for _, value := range s.events.queue {
+		eventArr = append(eventArr, value.(Event))
+	}
+	return eventArr
+}
+
+func (s *span) copyToCappedAttributes(attributes ...attribute.KeyValue) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	for _, a := range attributes {
+		// Ensure attributes conform to the specification:
+		// https://github.com/open-telemetry/opentelemetry-specification/blob/v1.0.1/specification/common/common.md#attributes
+		if a.Valid() {
+			s.attributes.add(a)
+		}
+	}
+}
+
+func (s *span) addChild() {
+	if !s.IsRecording() {
+		return
+	}
+	s.mu.Lock()
+	s.childSpanCount++
+	s.mu.Unlock()
+}
+
+func (*span) private() {}
+
+func startSpanInternal(ctx context.Context, tr *tracer, name string, o *trace.SpanConfig) *span {
+	span := &span{}
+
+	provider := tr.provider
+
+	// If told explicitly to make this a new root use a zero value SpanContext
+	// as a parent which contains an invalid trace ID and is not remote.
+	var psc trace.SpanContext
+	if !o.NewRoot() {
+		psc = trace.SpanContextFromContext(ctx)
+	}
+
+	// If there is a valid parent trace ID, use it to ensure the continuity of
+	// the trace. Always generate a new span ID so other components can rely
+	// on a unique span ID, even if the Span is non-recording.
+	var tid trace.TraceID
+	var sid trace.SpanID
+	if !psc.TraceID().IsValid() {
+		tid, sid = provider.idGenerator.NewIDs(ctx)
+	} else {
+		tid = psc.TraceID()
+		sid = provider.idGenerator.NewSpanID(ctx, tid)
+	}
+
+	spanLimits := provider.spanLimits
+	span.attributes = newAttributesMap(spanLimits.AttributeCountLimit)
+	span.events = newEvictedQueue(spanLimits.EventCountLimit)
+	span.links = newEvictedQueue(spanLimits.LinkCountLimit)
+	span.spanLimits = spanLimits
+
+	samplingResult := provider.sampler.ShouldSample(SamplingParameters{
+		ParentContext: ctx,
+		TraceID:       tid,
+		Name:          name,
+		Kind:          o.SpanKind(),
+		Attributes:    o.Attributes(),
+		Links:         o.Links(),
+	})
+
+	scc := trace.SpanContextConfig{
+		TraceID:    tid,
+		SpanID:     sid,
+		TraceState: samplingResult.Tracestate,
+	}
+	if isSampled(samplingResult) {
+		scc.TraceFlags = psc.TraceFlags() | trace.FlagsSampled
+	} else {
+		scc.TraceFlags = psc.TraceFlags() &^ trace.FlagsSampled
+	}
+	span.spanContext = trace.NewSpanContext(scc)
+
+	if !isRecording(samplingResult) {
+		return span
+	}
+
+	startTime := o.Timestamp()
+	if startTime.IsZero() {
+		startTime = time.Now()
+	}
+	span.startTime = startTime
+
+	span.spanKind = trace.ValidateSpanKind(o.SpanKind())
+	span.name = name
+	span.parent = psc
+	span.resource = provider.resource
+	span.instrumentationLibrary = tr.instrumentationLibrary
+
+	span.SetAttributes(samplingResult.Attributes...)
+
+	return span
+}
+
+func isRecording(s SamplingResult) bool {
+	return s.Decision == RecordOnly || s.Decision == RecordAndSample
+}
+
+func isSampled(s SamplingResult) bool {
+	return s.Decision == RecordAndSample
+}
+
+// Status is the classified state of a Span.
+type Status struct {
+	// Code is an identifier of a Spans state classification.
+	Code codes.Code
+	// Message is a user hint about why that status was set. It is only
+	// applicable when Code is Error.
+	Description string
+}

vendor/go.opentelemetry.io/otel/sdk/trace/span_exporter.go

@@ -0,0 +1,47 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import "context"
+
+// SpanExporter handles the delivery of spans to external receivers. This is
+// the final component in the trace export pipeline.
+type SpanExporter interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// ExportSpans exports a batch of spans.
+	//
+	// This function is called synchronously, so there is no concurrency
+	// safety requirement. However, due to the synchronous calling pattern,
+	// it is critical that all timeouts and cancellations contained in the
+	// passed context must be honored.
+	//
+	// Any retry logic must be contained in this function. The SDK that
+	// calls this function will not implement any retry logic. All errors
+	// returned by this function are considered unrecoverable and will be
+	// reported to a configured error Handler.
+	ExportSpans(ctx context.Context, spans []ReadOnlySpan) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Shutdown notifies the exporter of a pending halt to operations. The
+	// exporter is expected to preform any cleanup or synchronization it
+	// requires while honoring all timeouts and cancellations contained in
+	// the passed context.
+	Shutdown(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}

vendor/go.opentelemetry.io/otel/sdk/trace/span_processor.go

@@ -0,0 +1,67 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"sync"
+)
+
+// SpanProcessor is a processing pipeline for spans in the trace signal.
+// SpanProcessors registered with a TracerProvider and are called at the start
+// and end of a Span's lifecycle, and are called in the order they are
+// registered.
+type SpanProcessor interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// OnStart is called when a span is started. It is called synchronously
+	// and should not block.
+	OnStart(parent context.Context, s ReadWriteSpan)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// OnEnd is called when span is finished. It is called synchronously and
+	// hence not block.
+	OnEnd(s ReadOnlySpan)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Shutdown is called when the SDK shuts down. Any cleanup or release of
+	// resources held by the processor should be done in this call.
+	//
+	// Calls to OnStart, OnEnd, or ForceFlush after this has been called
+	// should be ignored.
+	//
+	// All timeouts and cancellations contained in ctx must be honored, this
+	// should not block indefinitely.
+	Shutdown(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// ForceFlush exports all ended spans to the configured Exporter that have not yet
+	// been exported.  It should only be called when absolutely necessary, such as when
+	// using a FaaS provider that may suspend the process after an invocation, but before
+	// the Processor can export the completed spans.
+	ForceFlush(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+type spanProcessorState struct {
+	sp    SpanProcessor
+	state *sync.Once
+}
+type spanProcessorStates []*spanProcessorState

vendor/go.opentelemetry.io/otel/sdk/trace/tracer.go

@@ -0,0 +1,75 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	rt "runtime/trace"
+
+	"go.opentelemetry.io/otel/trace"
+
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+)
+
+type tracer struct {
+	provider               *TracerProvider
+	instrumentationLibrary instrumentation.Library
+}
+
+var _ trace.Tracer = &tracer{}
+
+// Start starts a Span and returns it along with a context containing it.
+//
+// The Span is created with the provided name and as a child of any existing
+// span context found in the passed context. The created Span will be
+// configured appropriately by any SpanOption passed. Any Timestamp option
+// passed will be used as the start time of the Span's life-cycle.
+func (tr *tracer) Start(ctx context.Context, name string, options ...trace.SpanStartOption) (context.Context, trace.Span) {
+	config := trace.NewSpanStartConfig(options...)
+
+	// For local spans created by this SDK, track child span count.
+	if p := trace.SpanFromContext(ctx); p != nil {
+		if sdkSpan, ok := p.(*span); ok {
+			sdkSpan.addChild()
+		}
+	}
+
+	span := startSpanInternal(ctx, tr, name, config)
+	for _, l := range config.Links() {
+		span.addLink(l)
+	}
+	span.SetAttributes(config.Attributes()...)
+
+	span.tracer = tr
+
+	if span.IsRecording() {
+		sps, _ := tr.provider.spanProcessors.Load().(spanProcessorStates)
+		for _, sp := range sps {
+			sp.sp.OnStart(ctx, span)
+		}
+	}
+
+	ctx, span.executionTracerTaskEnd = func(ctx context.Context) (context.Context, func()) {
+		if !rt.IsEnabled() {
+			// Avoid additional overhead if
+			// runtime/trace is not enabled.
+			return ctx, func() {}
+		}
+		nctx, task := rt.NewTask(ctx, name)
+		return nctx, task.End
+	}(ctx)
+
+	return trace.ContextWithSpan(ctx, span), span
+}

vendor/go.opentelemetry.io/otel/semconv/v1.4.0/doc.go

@@ -0,0 +1,23 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package semconv implements OpenTelemetry semantic conventions.
+//
+// This package is currently in a Release Candidate phase. Backwards incompatible changes
+// may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
+//
+// OpenTelemetry semantic conventions are agreed standardized naming
+// patterns for OpenTelemetry things. This package represents the conventions
+// as of the v1.4.0 version of the OpenTelemetry specification.
+package semconv // import "go.opentelemetry.io/otel/semconv/v1.4.0"