vendor: update buildkit with typed errors support

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

vendor/github.com/prometheus/client_golang/prometheus/build_info.go

@@ -0,0 +1,29 @@
+// Copyright 2019 The Prometheus 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.
+
+// +build go1.12
+
+package prometheus
+
+import "runtime/debug"
+
+// readBuildInfo is a wrapper around debug.ReadBuildInfo for Go 1.12+.
+func readBuildInfo() (path, version, sum string) {
+	path, version, sum = "unknown", "unknown", "unknown"
+	if bi, ok := debug.ReadBuildInfo(); ok {
+		path = bi.Main.Path
+		version = bi.Main.Version
+		sum = bi.Main.Sum
+	}
+	return
+}

vendor/github.com/prometheus/client_golang/prometheus/build_info_pre_1.12.go

@@ -0,0 +1,22 @@
+// Copyright 2019 The Prometheus 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.
+
+// +build !go1.12
+
+package prometheus
+
+// readBuildInfo is a wrapper around debug.ReadBuildInfo for Go versions before
+// 1.12. Remove this whole file once the minimum supported Go version is 1.12.
+func readBuildInfo() (path, version, sum string) {
+	return "unknown", "unknown", "unknown"
+}

vendor/github.com/prometheus/client_golang/prometheus/counter.go

@@ -17,6 +17,7 @@ import (
 	"errors"
 	"math"
 	"sync/atomic"
+	"time"
 
 	dto "github.com/prometheus/client_model/go"
 )
@@ -42,11 +43,27 @@ type Counter interface {
 	Add(float64)
 }
 
+// ExemplarAdder is implemented by Counters that offer the option of adding a
+// value to the Counter together with an exemplar. Its AddWithExemplar method
+// works like the Add method of the Counter interface but also replaces the
+// currently saved exemplar (if any) with a new one, created from the provided
+// value, the current time as timestamp, and the provided labels. Empty Labels
+// will lead to a valid (label-less) exemplar. But if Labels is nil, the current
+// exemplar is left in place. AddWithExemplar panics if the value is < 0, if any
+// of the provided labels are invalid, or if the provided labels contain more
+// than 64 runes in total.
+type ExemplarAdder interface {
+	AddWithExemplar(value float64, exemplar Labels)
+}
+
 // CounterOpts is an alias for Opts. See there for doc comments.
 type CounterOpts Opts
 
 // NewCounter creates a new Counter based on the provided CounterOpts.
 //
+// The returned implementation also implements ExemplarAdder. It is safe to
+// perform the corresponding type assertion.
+//
 // The returned implementation tracks the counter value in two separate
 // variables, a float64 and a uint64. The latter is used to track calls of the
 // Inc method and calls of the Add method with a value that can be represented
@@ -61,7 +78,7 @@ func NewCounter(opts CounterOpts) Counter {
 		nil,
 		opts.ConstLabels,
 	)
-	result := &counter{desc: desc, labelPairs: desc.constLabelPairs}
+	result := &counter{desc: desc, labelPairs: desc.constLabelPairs, now: time.Now}
 	result.init(result) // Init self-collection.
 	return result
 }
@@ -78,6 +95,9 @@ type counter struct {
 	desc *Desc
 
 	labelPairs []*dto.LabelPair
+	exemplar   atomic.Value // Containing nil or a *dto.Exemplar.
+
+	now func() time.Time // To mock out time.Now() for testing.
 }
 
 func (c *counter) Desc() *Desc {
@@ -88,6 +108,7 @@ func (c *counter) Add(v float64) {
 	if v < 0 {
 		panic(errors.New("counter cannot decrease in value"))
 	}
+
 	ival := uint64(v)
 	if float64(ival) == v {
 		atomic.AddUint64(&c.valInt, ival)
@@ -103,6 +124,11 @@ func (c *counter) Add(v float64) {
 	}
 }
 
+func (c *counter) AddWithExemplar(v float64, e Labels) {
+	c.Add(v)
+	c.updateExemplar(v, e)
+}
+
 func (c *counter) Inc() {
 	atomic.AddUint64(&c.valInt, 1)
 }
@@ -112,7 +138,23 @@ func (c *counter) Write(out *dto.Metric) error {
 	ival := atomic.LoadUint64(&c.valInt)
 	val := fval + float64(ival)
 
-	return populateMetric(CounterValue, val, c.labelPairs, out)
+	var exemplar *dto.Exemplar
+	if e := c.exemplar.Load(); e != nil {
+		exemplar = e.(*dto.Exemplar)
+	}
+
+	return populateMetric(CounterValue, val, c.labelPairs, exemplar, out)
+}
+
+func (c *counter) updateExemplar(v float64, l Labels) {
+	if l == nil {
+		return
+	}
+	e, err := newExemplar(v, c.now(), l)
+	if err != nil {
+		panic(err)
+	}
+	c.exemplar.Store(e)
 }
 
 // CounterVec is a Collector that bundles a set of Counters that all share the
@@ -138,7 +180,7 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 			if len(lvs) != len(desc.variableLabels) {
 				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
 			}
-			result := &counter{desc: desc, labelPairs: makeLabelPairs(desc, lvs)}
+			result := &counter{desc: desc, labelPairs: makeLabelPairs(desc, lvs), now: time.Now}
 			result.init(result) // Init self-collection.
 			return result
 		}),
@@ -267,6 +309,8 @@ type CounterFunc interface {
 // provided function must be concurrency-safe. The function should also honor
 // the contract for a Counter (values only go up, not down), but compliance will
 // not be checked.
+//
+// Check out the ExampleGaugeFunc examples for the similar GaugeFunc.
 func NewCounterFunc(opts CounterOpts, function func() float64) CounterFunc {
 	return newValueFunc(NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),

vendor/github.com/prometheus/client_golang/prometheus/desc.go

@@ -19,6 +19,8 @@ import (
 	"sort"
 	"strings"
 
+	"github.com/cespare/xxhash/v2"
+	//lint:ignore SA1019 Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
 	"github.com/prometheus/common/model"
 
@@ -126,24 +128,24 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 		return d
 	}
 
-	vh := hashNew()
+	xxh := xxhash.New()
 	for _, val := range labelValues {
-		vh = hashAdd(vh, val)
-		vh = hashAddByte(vh, separatorByte)
+		xxh.WriteString(val)
+		xxh.Write(separatorByteSlice)
 	}
-	d.id = vh
+	d.id = xxh.Sum64()
 	// Sort labelNames so that order doesn't matter for the hash.
 	sort.Strings(labelNames)
 	// Now hash together (in this order) the help string and the sorted
 	// label names.
-	lh := hashNew()
-	lh = hashAdd(lh, help)
-	lh = hashAddByte(lh, separatorByte)
+	xxh.Reset()
+	xxh.WriteString(help)
+	xxh.Write(separatorByteSlice)
 	for _, labelName := range labelNames {
-		lh = hashAdd(lh, labelName)
-		lh = hashAddByte(lh, separatorByte)
+		xxh.WriteString(labelName)
+		xxh.Write(separatorByteSlice)
 	}
-	d.dimHash = lh
+	d.dimHash = xxh.Sum64()
 
 	d.constLabelPairs = make([]*dto.LabelPair, 0, len(constLabels))
 	for n, v := range constLabels {

vendor/github.com/prometheus/client_golang/prometheus/doc.go

@@ -84,25 +84,21 @@
 // of those four metric types can be found in the Prometheus docs:
 // https://prometheus.io/docs/concepts/metric_types/
 //
-// A fifth "type" of metric is Untyped. It behaves like a Gauge, but signals the
-// Prometheus server not to assume anything about its type.
-//
-// In addition to the fundamental metric types Gauge, Counter, Summary,
-// Histogram, and Untyped, a very important part of the Prometheus data model is
-// the partitioning of samples along dimensions called labels, which results in
+// In addition to the fundamental metric types Gauge, Counter, Summary, and
+// Histogram, a very important part of the Prometheus data model is the
+// partitioning of samples along dimensions called labels, which results in
 // metric vectors. The fundamental types are GaugeVec, CounterVec, SummaryVec,
-// HistogramVec, and UntypedVec.
+// and HistogramVec.
 //
 // While only the fundamental metric types implement the Metric interface, both
 // the metrics and their vector versions implement the Collector interface. A
 // Collector manages the collection of a number of Metrics, but for convenience,
-// a Metric can also “collect itself”. Note that Gauge, Counter, Summary,
-// Histogram, and Untyped are interfaces themselves while GaugeVec, CounterVec,
-// SummaryVec, HistogramVec, and UntypedVec are not.
+// a Metric can also “collect itself”. Note that Gauge, Counter, Summary, and
+// Histogram are interfaces themselves while GaugeVec, CounterVec, SummaryVec,
+// and HistogramVec are not.
 //
 // To create instances of Metrics and their vector versions, you need a suitable
-// …Opts struct, i.e. GaugeOpts, CounterOpts, SummaryOpts, HistogramOpts, or
-// UntypedOpts.
+// …Opts struct, i.e. GaugeOpts, CounterOpts, SummaryOpts, or HistogramOpts.
 //
 // Custom Collectors and constant Metrics
 //
@@ -118,13 +114,16 @@
 // existing numbers into Prometheus Metrics during collection. An own
 // implementation of the Collector interface is perfect for that. You can create
 // Metric instances “on the fly” using NewConstMetric, NewConstHistogram, and
-// NewConstSummary (and their respective Must… versions). That will happen in
-// the Collect method. The Describe method has to return separate Desc
-// instances, representative of the “throw-away” metrics to be created later.
-// NewDesc comes in handy to create those Desc instances. Alternatively, you
-// could return no Desc at all, which will mark the Collector “unchecked”.  No
-// checks are performed at registration time, but metric consistency will still
-// be ensured at scrape time, i.e. any inconsistencies will lead to scrape
+// NewConstSummary (and their respective Must… versions). NewConstMetric is used
+// for all metric types with just a float64 as their value: Counter, Gauge, and
+// a special “type” called Untyped. Use the latter if you are not sure if the
+// mirrored metric is a Counter or a Gauge. Creation of the Metric instance
+// happens in the Collect method. The Describe method has to return separate
+// Desc instances, representative of the “throw-away” metrics to be created
+// later.  NewDesc comes in handy to create those Desc instances. Alternatively,
+// you could return no Desc at all, which will mark the Collector “unchecked”.
+// No checks are performed at registration time, but metric consistency will
+// still be ensured at scrape time, i.e. any inconsistencies will lead to scrape
 // errors. Thus, with unchecked Collectors, the responsibility to not collect
 // metrics that lead to inconsistencies in the total scrape result lies with the
 // implementer of the Collector. While this is not a desirable state, it is
@@ -183,7 +182,6 @@
 // method can then expose the gathered metrics in some way. Usually, the metrics
 // are served via HTTP on the /metrics endpoint. That's happening in the example
 // above. The tools to expose metrics via HTTP are in the promhttp sub-package.
-// (The top-level functions in the prometheus package are deprecated.)
 //
 // Pushing to the Pushgateway
 //

vendor/github.com/prometheus/client_golang/prometheus/gauge.go

@@ -123,7 +123,7 @@ func (g *gauge) Sub(val float64) {
 
 func (g *gauge) Write(out *dto.Metric) error {
 	val := math.Float64frombits(atomic.LoadUint64(&g.valBits))
-	return populateMetric(GaugeValue, val, g.labelPairs, out)
+	return populateMetric(GaugeValue, val, g.labelPairs, nil, out)
 }
 
 // GaugeVec is a Collector that bundles a set of Gauges that all share the same
@@ -273,9 +273,12 @@ type GaugeFunc interface {
 // NewGaugeFunc creates a new GaugeFunc based on the provided GaugeOpts. The
 // value reported is determined by calling the given function from within the
 // Write method. Take into account that metric collection may happen
-// concurrently. If that results in concurrent calls to Write, like in the case
-// where a GaugeFunc is directly registered with Prometheus, the provided
-// function must be concurrency-safe.
+// concurrently. Therefore, it must be safe to call the provided function
+// concurrently.
+//
+// NewGaugeFunc is a good way to create an “info” style metric with a constant
+// value of 1. Example:
+// https://github.com/prometheus/common/blob/8558a5b7db3c84fa38b4766966059a7bd5bfa2ee/version/info.go#L36-L56
 func NewGaugeFunc(opts GaugeOpts, function func() float64) GaugeFunc {
 	return newValueFunc(NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),

vendor/github.com/prometheus/client_golang/prometheus/go_collector.go

@@ -36,7 +36,7 @@ type goCollector struct {
 	msMaxAge        time.Duration           // Maximum allowed age of old memstats.
 }
 
-// NewGoCollector returns a collector which exports metrics about the current Go
+// NewGoCollector returns a collector that exports metrics about the current Go
 // process. This includes memory stats. To collect those, runtime.ReadMemStats
 // is called. This requires to “stop the world”, which usually only happens for
 // garbage collection (GC). Take the following implications into account when
@@ -73,7 +73,7 @@ func NewGoCollector() Collector {
 			nil, nil),
 		gcDesc: NewDesc(
 			"go_gc_duration_seconds",
-			"A summary of the GC invocation durations.",
+			"A summary of the pause duration of garbage collection cycles.",
 			nil, nil),
 		goInfoDesc: NewDesc(
 			"go_info",
@@ -364,3 +364,33 @@ type memStatsMetrics []struct {
 	eval    func(*runtime.MemStats) float64
 	valType ValueType
 }
+
+// NewBuildInfoCollector returns a collector collecting a single metric
+// "go_build_info" with the constant value 1 and three labels "path", "version",
+// and "checksum". Their label values contain the main module path, version, and
+// checksum, respectively. The labels will only have meaningful values if the
+// binary is built with Go module support and from source code retrieved from
+// the source repository (rather than the local file system). This is usually
+// accomplished by building from outside of GOPATH, specifying the full address
+// of the main package, e.g. "GO111MODULE=on go run
+// github.com/prometheus/client_golang/examples/random". If built without Go
+// module support, all label values will be "unknown". If built with Go module
+// support but using the source code from the local file system, the "path" will
+// be set appropriately, but "checksum" will be empty and "version" will be
+// "(devel)".
+//
+// This collector uses only the build information for the main module. See
+// https://github.com/povilasv/prommod for an example of a collector for the
+// module dependencies.
+func NewBuildInfoCollector() Collector {
+	path, version, sum := readBuildInfo()
+	c := &selfCollector{MustNewConstMetric(
+		NewDesc(
+			"go_build_info",
+			"Build information about the main Go module.",
+			nil, Labels{"path": path, "version": version, "checksum": sum},
+		),
+		GaugeValue, 1)}
+	c.init(c.self)
+	return c
+}

vendor/github.com/prometheus/client_golang/prometheus/histogram.go

@@ -20,7 +20,9 @@ import (
 	"sort"
 	"sync"
 	"sync/atomic"
+	"time"
 
+	//lint:ignore SA1019 Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
 
 	dto "github.com/prometheus/client_model/go"
@@ -138,7 +140,7 @@ type HistogramOpts struct {
 	// better covered by target labels set by the scraping Prometheus
 	// server, or by one specific metric (e.g. a build_info or a
 	// machine_role metric). See also
-	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels,-not-static-scraped-labels
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
 	ConstLabels Labels
 
 	// Buckets defines the buckets into which observations are counted. Each
@@ -151,6 +153,10 @@ type HistogramOpts struct {
 
 // NewHistogram creates a new Histogram based on the provided HistogramOpts. It
 // panics if the buckets in HistogramOpts are not in strictly increasing order.
+//
+// The returned implementation also implements ExemplarObserver. It is safe to
+// perform the corresponding type assertion. Exemplars are tracked separately
+// for each bucket.
 func NewHistogram(opts HistogramOpts) Histogram {
 	return newHistogram(
 		NewDesc(
@@ -187,7 +193,8 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 		desc:        desc,
 		upperBounds: opts.Buckets,
 		labelPairs:  makeLabelPairs(desc, labelValues),
-		counts:      [2]*histogramCounts{&histogramCounts{}, &histogramCounts{}},
+		counts:      [2]*histogramCounts{{}, {}},
+		now:         time.Now,
 	}
 	for i, upperBound := range h.upperBounds {
 		if i < len(h.upperBounds)-1 {
@@ -205,9 +212,10 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 		}
 	}
 	// Finally we know the final length of h.upperBounds and can make buckets
-	// for both counts:
+	// for both counts as well as exemplars:
 	h.counts[0].buckets = make([]uint64, len(h.upperBounds))
 	h.counts[1].buckets = make([]uint64, len(h.upperBounds))
+	h.exemplars = make([]atomic.Value, len(h.upperBounds)+1)
 
 	h.init(h) // Init self-collection.
 	return h
@@ -254,6 +262,9 @@ type histogram struct {
 
 	upperBounds []float64
 	labelPairs  []*dto.LabelPair
+	exemplars   []atomic.Value // One more than buckets (to include +Inf), each a *dto.Exemplar.
+
+	now func() time.Time // To mock out time.Now() for testing.
 }
 
 func (h *histogram) Desc() *Desc {
@@ -261,36 +272,13 @@ func (h *histogram) Desc() *Desc {
 }
 
 func (h *histogram) Observe(v float64) {
-	// TODO(beorn7): For small numbers of buckets (<30), a linear search is
-	// slightly faster than the binary search. If we really care, we could
-	// switch from one search strategy to the other depending on the number
-	// of buckets.
-	//
-	// Microbenchmarks (BenchmarkHistogramNoLabels):
-	// 11 buckets: 38.3 ns/op linear - binary 48.7 ns/op
-	// 100 buckets: 78.1 ns/op linear - binary 54.9 ns/op
-	// 300 buckets: 154 ns/op linear - binary 61.6 ns/op
-	i := sort.SearchFloat64s(h.upperBounds, v)
+	h.observe(v, h.findBucket(v))
+}
 
-	// We increment h.countAndHotIdx so that the counter in the lower
-	// 63 bits gets incremented. At the same time, we get the new value
-	// back, which we can use to find the currently-hot counts.
-	n := atomic.AddUint64(&h.countAndHotIdx, 1)
-	hotCounts := h.counts[n>>63]
-
-	if i < len(h.upperBounds) {
-		atomic.AddUint64(&hotCounts.buckets[i], 1)
-	}
-	for {
-		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
-		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
-		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
-			break
-		}
-	}
-	// Increment count last as we take it as a signal that the observation
-	// is complete.
-	atomic.AddUint64(&hotCounts.count, 1)
+func (h *histogram) ObserveWithExemplar(v float64, e Labels) {
+	i := h.findBucket(v)
+	h.observe(v, i)
+	h.updateExemplar(v, i, e)
 }
 
 func (h *histogram) Write(out *dto.Metric) error {
@@ -329,6 +317,18 @@ func (h *histogram) Write(out *dto.Metric) error {
 			CumulativeCount: proto.Uint64(cumCount),
 			UpperBound:      proto.Float64(upperBound),
 		}
+		if e := h.exemplars[i].Load(); e != nil {
+			his.Bucket[i].Exemplar = e.(*dto.Exemplar)
+		}
+	}
+	// If there is an exemplar for the +Inf bucket, we have to add that bucket explicitly.
+	if e := h.exemplars[len(h.upperBounds)].Load(); e != nil {
+		b := &dto.Bucket{
+			CumulativeCount: proto.Uint64(count),
+			UpperBound:      proto.Float64(math.Inf(1)),
+			Exemplar:        e.(*dto.Exemplar),
+		}
+		his.Bucket = append(his.Bucket, b)
 	}
 
 	out.Histogram = his
@@ -352,6 +352,57 @@ func (h *histogram) Write(out *dto.Metric) error {
 	return nil
 }
 
+// findBucket returns the index of the bucket for the provided value, or
+// len(h.upperBounds) for the +Inf bucket.
+func (h *histogram) findBucket(v float64) int {
+	// TODO(beorn7): For small numbers of buckets (<30), a linear search is
+	// slightly faster than the binary search. If we really care, we could
+	// switch from one search strategy to the other depending on the number
+	// of buckets.
+	//
+	// Microbenchmarks (BenchmarkHistogramNoLabels):
+	// 11 buckets: 38.3 ns/op linear - binary 48.7 ns/op
+	// 100 buckets: 78.1 ns/op linear - binary 54.9 ns/op
+	// 300 buckets: 154 ns/op linear - binary 61.6 ns/op
+	return sort.SearchFloat64s(h.upperBounds, v)
+}
+
+// observe is the implementation for Observe without the findBucket part.
+func (h *histogram) observe(v float64, bucket int) {
+	// We increment h.countAndHotIdx so that the counter in the lower
+	// 63 bits gets incremented. At the same time, we get the new value
+	// back, which we can use to find the currently-hot counts.
+	n := atomic.AddUint64(&h.countAndHotIdx, 1)
+	hotCounts := h.counts[n>>63]
+
+	if bucket < len(h.upperBounds) {
+		atomic.AddUint64(&hotCounts.buckets[bucket], 1)
+	}
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			break
+		}
+	}
+	// Increment count last as we take it as a signal that the observation
+	// is complete.
+	atomic.AddUint64(&hotCounts.count, 1)
+}
+
+// updateExemplar replaces the exemplar for the provided bucket. With empty
+// labels, it's a no-op. It panics if any of the labels is invalid.
+func (h *histogram) updateExemplar(v float64, bucket int, l Labels) {
+	if l == nil {
+		return
+	}
+	e, err := newExemplar(v, h.now(), l)
+	if err != nil {
+		panic(err)
+	}
+	h.exemplars[bucket].Store(e)
+}
+
 // HistogramVec is a Collector that bundles a set of Histograms that all share the
 // same Desc, but have different values for their variable labels. This is used
 // if you want to count the same thing partitioned by various dimensions
@@ -556,7 +607,7 @@ func NewConstHistogram(
 }
 
 // MustNewConstHistogram is a version of NewConstHistogram that panics where
-// NewConstMetric would have returned an error.
+// NewConstHistogram would have returned an error.
 func MustNewConstHistogram(
 	desc *Desc,
 	count uint64,

vendor/github.com/prometheus/client_golang/prometheus/http.go

@@ -1,505 +0,0 @@
-// Copyright 2014 The Prometheus 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 prometheus
-
-import (
-	"bufio"
-	"compress/gzip"
-	"io"
-	"net"
-	"net/http"
-	"strconv"
-	"strings"
-	"sync"
-	"time"
-
-	"github.com/prometheus/common/expfmt"
-)
-
-// TODO(beorn7): Remove this whole file. It is a partial mirror of
-// promhttp/http.go (to avoid circular import chains) where everything HTTP
-// related should live. The functions here are just for avoiding
-// breakage. Everything is deprecated.
-
-const (
-	contentTypeHeader     = "Content-Type"
-	contentEncodingHeader = "Content-Encoding"
-	acceptEncodingHeader  = "Accept-Encoding"
-)
-
-var gzipPool = sync.Pool{
-	New: func() interface{} {
-		return gzip.NewWriter(nil)
-	},
-}
-
-// Handler returns an HTTP handler for the DefaultGatherer. It is
-// already instrumented with InstrumentHandler (using "prometheus" as handler
-// name).
-//
-// Deprecated: Please note the issues described in the doc comment of
-// InstrumentHandler. You might want to consider using promhttp.Handler instead.
-func Handler() http.Handler {
-	return InstrumentHandler("prometheus", UninstrumentedHandler())
-}
-
-// UninstrumentedHandler returns an HTTP handler for the DefaultGatherer.
-//
-// Deprecated: Use promhttp.HandlerFor(DefaultGatherer, promhttp.HandlerOpts{})
-// instead. See there for further documentation.
-func UninstrumentedHandler() http.Handler {
-	return http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
-		mfs, err := DefaultGatherer.Gather()
-		if err != nil {
-			httpError(rsp, err)
-			return
-		}
-
-		contentType := expfmt.Negotiate(req.Header)
-		header := rsp.Header()
-		header.Set(contentTypeHeader, string(contentType))
-
-		w := io.Writer(rsp)
-		if gzipAccepted(req.Header) {
-			header.Set(contentEncodingHeader, "gzip")
-			gz := gzipPool.Get().(*gzip.Writer)
-			defer gzipPool.Put(gz)
-
-			gz.Reset(w)
-			defer gz.Close()
-
-			w = gz
-		}
-
-		enc := expfmt.NewEncoder(w, contentType)
-
-		for _, mf := range mfs {
-			if err := enc.Encode(mf); err != nil {
-				httpError(rsp, err)
-				return
-			}
-		}
-	})
-}
-
-var instLabels = []string{"method", "code"}
-
-type nower interface {
-	Now() time.Time
-}
-
-type nowFunc func() time.Time
-
-func (n nowFunc) Now() time.Time {
-	return n()
-}
-
-var now nower = nowFunc(func() time.Time {
-	return time.Now()
-})
-
-// InstrumentHandler wraps the given HTTP handler for instrumentation. It
-// registers four metric collectors (if not already done) and reports HTTP
-// metrics to the (newly or already) registered collectors: http_requests_total
-// (CounterVec), http_request_duration_microseconds (Summary),
-// http_request_size_bytes (Summary), http_response_size_bytes (Summary). Each
-// has a constant label named "handler" with the provided handlerName as
-// value. http_requests_total is a metric vector partitioned by HTTP method
-// (label name "method") and HTTP status code (label name "code").
-//
-// Deprecated: InstrumentHandler has several issues. Use the tooling provided in
-// package promhttp instead. The issues are the following: (1) It uses Summaries
-// rather than Histograms. Summaries are not useful if aggregation across
-// multiple instances is required. (2) It uses microseconds as unit, which is
-// deprecated and should be replaced by seconds. (3) The size of the request is
-// calculated in a separate goroutine. Since this calculator requires access to
-// the request header, it creates a race with any writes to the header performed
-// during request handling.  httputil.ReverseProxy is a prominent example for a
-// handler performing such writes. (4) It has additional issues with HTTP/2, cf.
-// https://github.com/prometheus/client_golang/issues/272.
-func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFunc {
-	return InstrumentHandlerFunc(handlerName, handler.ServeHTTP)
-}
-
-// InstrumentHandlerFunc wraps the given function for instrumentation. It
-// otherwise works in the same way as InstrumentHandler (and shares the same
-// issues).
-//
-// Deprecated: InstrumentHandlerFunc is deprecated for the same reasons as
-// InstrumentHandler is. Use the tooling provided in package promhttp instead.
-func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
-	return InstrumentHandlerFuncWithOpts(
-		SummaryOpts{
-			Subsystem:   "http",
-			ConstLabels: Labels{"handler": handlerName},
-			Objectives:  map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
-		},
-		handlerFunc,
-	)
-}
-
-// InstrumentHandlerWithOpts works like InstrumentHandler (and shares the same
-// issues) but provides more flexibility (at the cost of a more complex call
-// syntax). As InstrumentHandler, this function registers four metric
-// collectors, but it uses the provided SummaryOpts to create them. However, the
-// fields "Name" and "Help" in the SummaryOpts are ignored. "Name" is replaced
-// by "requests_total", "request_duration_microseconds", "request_size_bytes",
-// and "response_size_bytes", respectively. "Help" is replaced by an appropriate
-// help string. The names of the variable labels of the http_requests_total
-// CounterVec are "method" (get, post, etc.), and "code" (HTTP status code).
-//
-// If InstrumentHandlerWithOpts is called as follows, it mimics exactly the
-// behavior of InstrumentHandler:
-//
-//     prometheus.InstrumentHandlerWithOpts(
-//         prometheus.SummaryOpts{
-//              Subsystem:   "http",
-//              ConstLabels: prometheus.Labels{"handler": handlerName},
-//         },
-//         handler,
-//     )
-//
-// Technical detail: "requests_total" is a CounterVec, not a SummaryVec, so it
-// cannot use SummaryOpts. Instead, a CounterOpts struct is created internally,
-// and all its fields are set to the equally named fields in the provided
-// SummaryOpts.
-//
-// Deprecated: InstrumentHandlerWithOpts is deprecated for the same reasons as
-// InstrumentHandler is. Use the tooling provided in package promhttp instead.
-func InstrumentHandlerWithOpts(opts SummaryOpts, handler http.Handler) http.HandlerFunc {
-	return InstrumentHandlerFuncWithOpts(opts, handler.ServeHTTP)
-}
-
-// InstrumentHandlerFuncWithOpts works like InstrumentHandlerFunc (and shares
-// the same issues) but provides more flexibility (at the cost of a more complex
-// call syntax). See InstrumentHandlerWithOpts for details how the provided
-// SummaryOpts are used.
-//
-// Deprecated: InstrumentHandlerFuncWithOpts is deprecated for the same reasons
-// as InstrumentHandler is. Use the tooling provided in package promhttp instead.
-func InstrumentHandlerFuncWithOpts(opts SummaryOpts, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
-	reqCnt := NewCounterVec(
-		CounterOpts{
-			Namespace:   opts.Namespace,
-			Subsystem:   opts.Subsystem,
-			Name:        "requests_total",
-			Help:        "Total number of HTTP requests made.",
-			ConstLabels: opts.ConstLabels,
-		},
-		instLabels,
-	)
-	if err := Register(reqCnt); err != nil {
-		if are, ok := err.(AlreadyRegisteredError); ok {
-			reqCnt = are.ExistingCollector.(*CounterVec)
-		} else {
-			panic(err)
-		}
-	}
-
-	opts.Name = "request_duration_microseconds"
-	opts.Help = "The HTTP request latencies in microseconds."
-	reqDur := NewSummary(opts)
-	if err := Register(reqDur); err != nil {
-		if are, ok := err.(AlreadyRegisteredError); ok {
-			reqDur = are.ExistingCollector.(Summary)
-		} else {
-			panic(err)
-		}
-	}
-
-	opts.Name = "request_size_bytes"
-	opts.Help = "The HTTP request sizes in bytes."
-	reqSz := NewSummary(opts)
-	if err := Register(reqSz); err != nil {
-		if are, ok := err.(AlreadyRegisteredError); ok {
-			reqSz = are.ExistingCollector.(Summary)
-		} else {
-			panic(err)
-		}
-	}
-
-	opts.Name = "response_size_bytes"
-	opts.Help = "The HTTP response sizes in bytes."
-	resSz := NewSummary(opts)
-	if err := Register(resSz); err != nil {
-		if are, ok := err.(AlreadyRegisteredError); ok {
-			resSz = are.ExistingCollector.(Summary)
-		} else {
-			panic(err)
-		}
-	}
-
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		now := time.Now()
-
-		delegate := &responseWriterDelegator{ResponseWriter: w}
-		out := computeApproximateRequestSize(r)
-
-		_, cn := w.(http.CloseNotifier)
-		_, fl := w.(http.Flusher)
-		_, hj := w.(http.Hijacker)
-		_, rf := w.(io.ReaderFrom)
-		var rw http.ResponseWriter
-		if cn && fl && hj && rf {
-			rw = &fancyResponseWriterDelegator{delegate}
-		} else {
-			rw = delegate
-		}
-		handlerFunc(rw, r)
-
-		elapsed := float64(time.Since(now)) / float64(time.Microsecond)
-
-		method := sanitizeMethod(r.Method)
-		code := sanitizeCode(delegate.status)
-		reqCnt.WithLabelValues(method, code).Inc()
-		reqDur.Observe(elapsed)
-		resSz.Observe(float64(delegate.written))
-		reqSz.Observe(float64(<-out))
-	})
-}
-
-func computeApproximateRequestSize(r *http.Request) <-chan int {
-	// Get URL length in current goroutine for avoiding a race condition.
-	// HandlerFunc that runs in parallel may modify the URL.
-	s := 0
-	if r.URL != nil {
-		s += len(r.URL.String())
-	}
-
-	out := make(chan int, 1)
-
-	go func() {
-		s += len(r.Method)
-		s += len(r.Proto)
-		for name, values := range r.Header {
-			s += len(name)
-			for _, value := range values {
-				s += len(value)
-			}
-		}
-		s += len(r.Host)
-
-		// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
-
-		if r.ContentLength != -1 {
-			s += int(r.ContentLength)
-		}
-		out <- s
-		close(out)
-	}()
-
-	return out
-}
-
-type responseWriterDelegator struct {
-	http.ResponseWriter
-
-	status      int
-	written     int64
-	wroteHeader bool
-}
-
-func (r *responseWriterDelegator) WriteHeader(code int) {
-	r.status = code
-	r.wroteHeader = true
-	r.ResponseWriter.WriteHeader(code)
-}
-
-func (r *responseWriterDelegator) Write(b []byte) (int, error) {
-	if !r.wroteHeader {
-		r.WriteHeader(http.StatusOK)
-	}
-	n, err := r.ResponseWriter.Write(b)
-	r.written += int64(n)
-	return n, err
-}
-
-type fancyResponseWriterDelegator struct {
-	*responseWriterDelegator
-}
-
-func (f *fancyResponseWriterDelegator) CloseNotify() <-chan bool {
-	//lint:ignore SA1019 http.CloseNotifier is deprecated but we don't want to
-	//remove support from client_golang yet.
-	return f.ResponseWriter.(http.CloseNotifier).CloseNotify()
-}
-
-func (f *fancyResponseWriterDelegator) Flush() {
-	f.ResponseWriter.(http.Flusher).Flush()
-}
-
-func (f *fancyResponseWriterDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-	return f.ResponseWriter.(http.Hijacker).Hijack()
-}
-
-func (f *fancyResponseWriterDelegator) ReadFrom(r io.Reader) (int64, error) {
-	if !f.wroteHeader {
-		f.WriteHeader(http.StatusOK)
-	}
-	n, err := f.ResponseWriter.(io.ReaderFrom).ReadFrom(r)
-	f.written += n
-	return n, err
-}
-
-func sanitizeMethod(m string) string {
-	switch m {
-	case "GET", "get":
-		return "get"
-	case "PUT", "put":
-		return "put"
-	case "HEAD", "head":
-		return "head"
-	case "POST", "post":
-		return "post"
-	case "DELETE", "delete":
-		return "delete"
-	case "CONNECT", "connect":
-		return "connect"
-	case "OPTIONS", "options":
-		return "options"
-	case "NOTIFY", "notify":
-		return "notify"
-	default:
-		return strings.ToLower(m)
-	}
-}
-
-func sanitizeCode(s int) string {
-	switch s {
-	case 100:
-		return "100"
-	case 101:
-		return "101"
-
-	case 200:
-		return "200"
-	case 201:
-		return "201"
-	case 202:
-		return "202"
-	case 203:
-		return "203"
-	case 204:
-		return "204"
-	case 205:
-		return "205"
-	case 206:
-		return "206"
-
-	case 300:
-		return "300"
-	case 301:
-		return "301"
-	case 302:
-		return "302"
-	case 304:
-		return "304"
-	case 305:
-		return "305"
-	case 307:
-		return "307"
-
-	case 400:
-		return "400"
-	case 401:
-		return "401"
-	case 402:
-		return "402"
-	case 403:
-		return "403"
-	case 404:
-		return "404"
-	case 405:
-		return "405"
-	case 406:
-		return "406"
-	case 407:
-		return "407"
-	case 408:
-		return "408"
-	case 409:
-		return "409"
-	case 410:
-		return "410"
-	case 411:
-		return "411"
-	case 412:
-		return "412"
-	case 413:
-		return "413"
-	case 414:
-		return "414"
-	case 415:
-		return "415"
-	case 416:
-		return "416"
-	case 417:
-		return "417"
-	case 418:
-		return "418"
-
-	case 500:
-		return "500"
-	case 501:
-		return "501"
-	case 502:
-		return "502"
-	case 503:
-		return "503"
-	case 504:
-		return "504"
-	case 505:
-		return "505"
-
-	case 428:
-		return "428"
-	case 429:
-		return "429"
-	case 431:
-		return "431"
-	case 511:
-		return "511"
-
-	default:
-		return strconv.Itoa(s)
-	}
-}
-
-// gzipAccepted returns whether the client will accept gzip-encoded content.
-func gzipAccepted(header http.Header) bool {
-	a := header.Get(acceptEncodingHeader)
-	parts := strings.Split(a, ",")
-	for _, part := range parts {
-		part = strings.TrimSpace(part)
-		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
-			return true
-		}
-	}
-	return false
-}
-
-// httpError removes any content-encoding header and then calls http.Error with
-// the provided error and http.StatusInternalServerErrer. Error contents is
-// supposed to be uncompressed plain text. However, same as with a plain
-// http.Error, any header settings will be void if the header has already been
-// sent. The error message will still be written to the writer, but it will
-// probably be of limited use.
-func httpError(rsp http.ResponseWriter, err error) {
-	rsp.Header().Del(contentEncodingHeader)
-	http.Error(
-		rsp,
-		"An error has occurred while serving metrics:\n\n"+err.Error(),
-		http.StatusInternalServerError,
-	)
-}

vendor/github.com/prometheus/client_golang/prometheus/metric.go

@@ -17,12 +17,14 @@ import (
 	"strings"
 	"time"
 
+	//lint:ignore SA1019 Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/common/model"
 
 	dto "github.com/prometheus/client_model/go"
 )
 
-const separatorByte byte = 255
+var separatorByteSlice = []byte{model.SeparatorByte} // For convenient use with xxhash.
 
 // A Metric models a single sample value with its meta data being exported to
 // Prometheus. Implementations of Metric in this package are Gauge, Counter,

vendor/github.com/prometheus/client_golang/prometheus/observer.go

@@ -50,3 +50,15 @@ type ObserverVec interface {
 
 	Collector
 }
+
+// ExemplarObserver is implemented by Observers that offer the option of
+// observing a value together with an exemplar. Its ObserveWithExemplar method
+// works like the Observe method of an Observer but also replaces the currently
+// saved exemplar (if any) with a new one, created from the provided value, the
+// current time as timestamp, and the provided Labels. Empty Labels will lead to
+// a valid (label-less) exemplar. But if Labels is nil, the current exemplar is
+// left in place. ObserveWithExemplar panics if any of the provided labels are
+// invalid or if the provided labels contain more than 64 runes in total.
+type ExemplarObserver interface {
+	ObserveWithExemplar(value float64, exemplar Labels)
+}

vendor/github.com/prometheus/client_golang/prometheus/process_collector.go

@@ -16,8 +16,6 @@ package prometheus
 import (
 	"errors"
 	"os"
-
-	"github.com/prometheus/procfs"
 )
 
 type processCollector struct {
@@ -59,20 +57,9 @@ type ProcessCollectorOpts struct {
 // collector for the current process with an empty namespace string and no error
 // reporting.
 //
-// Currently, the collector depends on a Linux-style proc filesystem and
-// therefore only exports metrics for Linux.
-//
-// Note: An older version of this function had the following signature:
-//
-//     NewProcessCollector(pid int, namespace string) Collector
-//
-// Most commonly, it was called as
-//
-//     NewProcessCollector(os.Getpid(), "")
-//
-// The following call of the current version is equivalent to the above:
-//
-//     NewProcessCollector(ProcessCollectorOpts{})
+// The collector only works on operating systems with a Linux-style proc
+// filesystem and on Microsoft Windows. On other operating systems, it will not
+// collect any metrics.
 func NewProcessCollector(opts ProcessCollectorOpts) Collector {
 	ns := ""
 	if len(opts.Namespace) > 0 {
@@ -126,7 +113,7 @@ func NewProcessCollector(opts ProcessCollectorOpts) Collector {
 	}
 
 	// Set up process metric collection if supported by the runtime.
-	if _, err := procfs.NewStat(); err == nil {
+	if canCollectProcess() {
 		c.collectFn = c.processCollect
 	} else {
 		c.collectFn = func(ch chan<- Metric) {
@@ -153,46 +140,6 @@ func (c *processCollector) Collect(ch chan<- Metric) {
 	c.collectFn(ch)
 }
 
-func (c *processCollector) processCollect(ch chan<- Metric) {
-	pid, err := c.pidFn()
-	if err != nil {
-		c.reportError(ch, nil, err)
-		return
-	}
-
-	p, err := procfs.NewProc(pid)
-	if err != nil {
-		c.reportError(ch, nil, err)
-		return
-	}
-
-	if stat, err := p.NewStat(); err == nil {
-		ch <- MustNewConstMetric(c.cpuTotal, CounterValue, stat.CPUTime())
-		ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(stat.VirtualMemory()))
-		ch <- MustNewConstMetric(c.rss, GaugeValue, float64(stat.ResidentMemory()))
-		if startTime, err := stat.StartTime(); err == nil {
-			ch <- MustNewConstMetric(c.startTime, GaugeValue, startTime)
-		} else {
-			c.reportError(ch, c.startTime, err)
-		}
-	} else {
-		c.reportError(ch, nil, err)
-	}
-
-	if fds, err := p.FileDescriptorsLen(); err == nil {
-		ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(fds))
-	} else {
-		c.reportError(ch, c.openFDs, err)
-	}
-
-	if limits, err := p.NewLimits(); err == nil {
-		ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(limits.OpenFiles))
-		ch <- MustNewConstMetric(c.maxVsize, GaugeValue, float64(limits.AddressSpace))
-	} else {
-		c.reportError(ch, nil, err)
-	}
-}
-
 func (c *processCollector) reportError(ch chan<- Metric, desc *Desc, err error) {
 	if !c.reportErrors {
 		return

vendor/github.com/prometheus/client_golang/prometheus/process_collector_other.go

@@ -0,0 +1,65 @@
+// Copyright 2019 The Prometheus 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.
+
+// +build !windows
+
+package prometheus
+
+import (
+	"github.com/prometheus/procfs"
+)
+
+func canCollectProcess() bool {
+	_, err := procfs.NewDefaultFS()
+	return err == nil
+}
+
+func (c *processCollector) processCollect(ch chan<- Metric) {
+	pid, err := c.pidFn()
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+
+	p, err := procfs.NewProc(pid)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+
+	if stat, err := p.Stat(); err == nil {
+		ch <- MustNewConstMetric(c.cpuTotal, CounterValue, stat.CPUTime())
+		ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(stat.VirtualMemory()))
+		ch <- MustNewConstMetric(c.rss, GaugeValue, float64(stat.ResidentMemory()))
+		if startTime, err := stat.StartTime(); err == nil {
+			ch <- MustNewConstMetric(c.startTime, GaugeValue, startTime)
+		} else {
+			c.reportError(ch, c.startTime, err)
+		}
+	} else {
+		c.reportError(ch, nil, err)
+	}
+
+	if fds, err := p.FileDescriptorsLen(); err == nil {
+		ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(fds))
+	} else {
+		c.reportError(ch, c.openFDs, err)
+	}
+
+	if limits, err := p.Limits(); err == nil {
+		ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(limits.OpenFiles))
+		ch <- MustNewConstMetric(c.maxVsize, GaugeValue, float64(limits.AddressSpace))
+	} else {
+		c.reportError(ch, nil, err)
+	}
+}

vendor/github.com/prometheus/client_golang/prometheus/process_collector_windows.go

@@ -0,0 +1,116 @@
+// Copyright 2019 The Prometheus 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 prometheus
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+func canCollectProcess() bool {
+	return true
+}
+
+var (
+	modpsapi    = syscall.NewLazyDLL("psapi.dll")
+	modkernel32 = syscall.NewLazyDLL("kernel32.dll")
+
+	procGetProcessMemoryInfo  = modpsapi.NewProc("GetProcessMemoryInfo")
+	procGetProcessHandleCount = modkernel32.NewProc("GetProcessHandleCount")
+)
+
+type processMemoryCounters struct {
+	// System interface description
+	// https://docs.microsoft.com/en-us/windows/desktop/api/psapi/ns-psapi-process_memory_counters_ex
+
+	// Refer to the Golang internal implementation
+	// https://golang.org/src/internal/syscall/windows/psapi_windows.go
+	_                          uint32
+	PageFaultCount             uint32
+	PeakWorkingSetSize         uintptr
+	WorkingSetSize             uintptr
+	QuotaPeakPagedPoolUsage    uintptr
+	QuotaPagedPoolUsage        uintptr
+	QuotaPeakNonPagedPoolUsage uintptr
+	QuotaNonPagedPoolUsage     uintptr
+	PagefileUsage              uintptr
+	PeakPagefileUsage          uintptr
+	PrivateUsage               uintptr
+}
+
+func getProcessMemoryInfo(handle windows.Handle) (processMemoryCounters, error) {
+	mem := processMemoryCounters{}
+	r1, _, err := procGetProcessMemoryInfo.Call(
+		uintptr(handle),
+		uintptr(unsafe.Pointer(&mem)),
+		uintptr(unsafe.Sizeof(mem)),
+	)
+	if r1 != 1 {
+		return mem, err
+	} else {
+		return mem, nil
+	}
+}
+
+func getProcessHandleCount(handle windows.Handle) (uint32, error) {
+	var count uint32
+	r1, _, err := procGetProcessHandleCount.Call(
+		uintptr(handle),
+		uintptr(unsafe.Pointer(&count)),
+	)
+	if r1 != 1 {
+		return 0, err
+	} else {
+		return count, nil
+	}
+}
+
+func (c *processCollector) processCollect(ch chan<- Metric) {
+	h, err := windows.GetCurrentProcess()
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+
+	var startTime, exitTime, kernelTime, userTime windows.Filetime
+	err = windows.GetProcessTimes(h, &startTime, &exitTime, &kernelTime, &userTime)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+	ch <- MustNewConstMetric(c.startTime, GaugeValue, float64(startTime.Nanoseconds()/1e9))
+	ch <- MustNewConstMetric(c.cpuTotal, CounterValue, fileTimeToSeconds(kernelTime)+fileTimeToSeconds(userTime))
+
+	mem, err := getProcessMemoryInfo(h)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+	ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(mem.PrivateUsage))
+	ch <- MustNewConstMetric(c.rss, GaugeValue, float64(mem.WorkingSetSize))
+
+	handles, err := getProcessHandleCount(h)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+	ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(handles))
+	ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(16*1024*1024)) // Windows has a hard-coded max limit, not per-process.
+}
+
+func fileTimeToSeconds(ft windows.Filetime) float64 {
+	return float64(uint64(ft.HighDateTime)<<32+uint64(ft.LowDateTime)) / 1e7
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator.go

@@ -53,15 +53,21 @@ func (r *responseWriterDelegator) Written() int64 {
 }
 
 func (r *responseWriterDelegator) WriteHeader(code int) {
+	if r.observeWriteHeader != nil && !r.wroteHeader {
+		// Only call observeWriteHeader for the 1st time. It's a bug if
+		// WriteHeader is called more than once, but we want to protect
+		// against it here. Note that we still delegate the WriteHeader
+		// to the original ResponseWriter to not mask the bug from it.
+		r.observeWriteHeader(code)
+	}
 	r.status = code
 	r.wroteHeader = true
 	r.ResponseWriter.WriteHeader(code)
-	if r.observeWriteHeader != nil {
-		r.observeWriteHeader(code)
-	}
 }
 
 func (r *responseWriterDelegator) Write(b []byte) (int, error) {
+	// If applicable, call WriteHeader here so that observeWriteHeader is
+	// handled appropriately.
 	if !r.wroteHeader {
 		r.WriteHeader(http.StatusOK)
 	}
@@ -82,12 +88,19 @@ func (d closeNotifierDelegator) CloseNotify() <-chan bool {
 	return d.ResponseWriter.(http.CloseNotifier).CloseNotify()
 }
 func (d flusherDelegator) Flush() {
+	// If applicable, call WriteHeader here so that observeWriteHeader is
+	// handled appropriately.
+	if !d.wroteHeader {
+		d.WriteHeader(http.StatusOK)
+	}
 	d.ResponseWriter.(http.Flusher).Flush()
 }
 func (d hijackerDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
 	return d.ResponseWriter.(http.Hijacker).Hijack()
 }
 func (d readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
+	// If applicable, call WriteHeader here so that observeWriteHeader is
+	// handled appropriately.
 	if !d.wroteHeader {
 		d.WriteHeader(http.StatusOK)
 	}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go

@@ -84,10 +84,32 @@ func Handler() http.Handler {
 // instrumentation. Use the InstrumentMetricHandler function to apply the same
 // kind of instrumentation as it is used by the Handler function.
 func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
-	var inFlightSem chan struct{}
+	var (
+		inFlightSem chan struct{}
+		errCnt      = prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Name: "promhttp_metric_handler_errors_total",
+				Help: "Total number of internal errors encountered by the promhttp metric handler.",
+			},
+			[]string{"cause"},
+		)
+	)
+
 	if opts.MaxRequestsInFlight > 0 {
 		inFlightSem = make(chan struct{}, opts.MaxRequestsInFlight)
 	}
+	if opts.Registry != nil {
+		// Initialize all possibilites that can occur below.
+		errCnt.WithLabelValues("gathering")
+		errCnt.WithLabelValues("encoding")
+		if err := opts.Registry.Register(errCnt); err != nil {
+			if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+				errCnt = are.ExistingCollector.(*prometheus.CounterVec)
+			} else {
+				panic(err)
+			}
+		}
+	}
 
 	h := http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
 		if inFlightSem != nil {
@@ -106,6 +128,7 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
 			if opts.ErrorLog != nil {
 				opts.ErrorLog.Println("error gathering metrics:", err)
 			}
+			errCnt.WithLabelValues("gathering").Inc()
 			switch opts.ErrorHandling {
 			case PanicOnError:
 				panic(err)
@@ -121,7 +144,12 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
 			}
 		}
 
-		contentType := expfmt.Negotiate(req.Header)
+		var contentType expfmt.Format
+		if opts.EnableOpenMetrics {
+			contentType = expfmt.NegotiateIncludingOpenMetrics(req.Header)
+		} else {
+			contentType = expfmt.Negotiate(req.Header)
+		}
 		header := rsp.Header()
 		header.Set(contentTypeHeader, string(contentType))
 
@@ -139,27 +167,40 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
 
 		enc := expfmt.NewEncoder(w, contentType)
 
-		var lastErr error
-		for _, mf := range mfs {
-			if err := enc.Encode(mf); err != nil {
-				lastErr = err
-				if opts.ErrorLog != nil {
-					opts.ErrorLog.Println("error encoding and sending metric family:", err)
-				}
-				switch opts.ErrorHandling {
-				case PanicOnError:
-					panic(err)
-				case ContinueOnError:
-					// Handled later.
-				case HTTPErrorOnError:
-					httpError(rsp, err)
-					return
-				}
+		// handleError handles the error according to opts.ErrorHandling
+		// and returns true if we have to abort after the handling.
+		handleError := func(err error) bool {
+			if err == nil {
+				return false
 			}
+			if opts.ErrorLog != nil {
+				opts.ErrorLog.Println("error encoding and sending metric family:", err)
+			}
+			errCnt.WithLabelValues("encoding").Inc()
+			switch opts.ErrorHandling {
+			case PanicOnError:
+				panic(err)
+			case HTTPErrorOnError:
+				// We cannot really send an HTTP error at this
+				// point because we most likely have written
+				// something to rsp already. But at least we can
+				// stop sending.
+				return true
+			}
+			// Do nothing in all other cases, including ContinueOnError.
+			return false
 		}
 
-		if lastErr != nil {
-			httpError(rsp, lastErr)
+		for _, mf := range mfs {
+			if handleError(enc.Encode(mf)) {
+				return
+			}
+		}
+		if closer, ok := enc.(expfmt.Closer); ok {
+			// This in particular takes care of the final "# EOF\n" line for OpenMetrics.
+			if handleError(closer.Close()) {
+				return
+			}
 		}
 	})
 
@@ -231,14 +272,22 @@ type HandlerErrorHandling int
 // errors are encountered.
 const (
 	// Serve an HTTP status code 500 upon the first error
-	// encountered. Report the error message in the body.
+	// encountered. Report the error message in the body. Note that HTTP
+	// errors cannot be served anymore once the beginning of a regular
+	// payload has been sent. Thus, in the (unlikely) case that encoding the
+	// payload into the negotiated wire format fails, serving the response
+	// will simply be aborted. Set an ErrorLog in HandlerOpts to detect
+	// those errors.
 	HTTPErrorOnError HandlerErrorHandling = iota
 	// Ignore errors and try to serve as many metrics as possible.  However,
 	// if no metrics can be served, serve an HTTP status code 500 and the
 	// last error message in the body. Only use this in deliberate "best
-	// effort" metrics collection scenarios. It is recommended to at least
-	// log errors (by providing an ErrorLog in HandlerOpts) to not mask
-	// errors completely.
+	// effort" metrics collection scenarios. In this case, it is highly
+	// recommended to provide other means of detecting errors: By setting an
+	// ErrorLog in HandlerOpts, the errors are logged. By providing a
+	// Registry in HandlerOpts, the exposed metrics include an error counter
+	// "promhttp_metric_handler_errors_total", which can be used for
+	// alerts.
 	ContinueOnError
 	// Panic upon the first error encountered (useful for "crash only" apps).
 	PanicOnError
@@ -261,6 +310,18 @@ type HandlerOpts struct {
 	// logged regardless of the configured ErrorHandling provided ErrorLog
 	// is not nil.
 	ErrorHandling HandlerErrorHandling
+	// If Registry is not nil, it is used to register a metric
+	// "promhttp_metric_handler_errors_total", partitioned by "cause". A
+	// failed registration causes a panic. Note that this error counter is
+	// different from the instrumentation you get from the various
+	// InstrumentHandler... helpers. It counts errors that don't necessarily
+	// result in a non-2xx HTTP status code. There are two typical cases:
+	// (1) Encoding errors that only happen after streaming of the HTTP body
+	// has already started (and the status code 200 has been sent). This
+	// should only happen with custom collectors. (2) Collection errors with
+	// no effect on the HTTP status code because ErrorHandling is set to
+	// ContinueOnError.
+	Registry prometheus.Registerer
 	// If DisableCompression is true, the handler will never compress the
 	// response, even if requested by the client.
 	DisableCompression bool
@@ -279,6 +340,16 @@ type HandlerOpts struct {
 	// away). Until the implementation is improved, it is recommended to
 	// implement a separate timeout in potentially slow Collectors.
 	Timeout time.Duration
+	// If true, the experimental OpenMetrics encoding is added to the
+	// possible options during content negotiation. Note that Prometheus
+	// 2.5.0+ will negotiate OpenMetrics as first priority. OpenMetrics is
+	// the only way to transmit exemplars. However, the move to OpenMetrics
+	// is not completely transparent. Most notably, the values of "quantile"
+	// labels of Summaries and "le" labels of Histograms are formatted with
+	// a trailing ".0" if they would otherwise look like integer numbers
+	// (which changes the identity of the resulting series on the Prometheus
+	// server).
+	EnableOpenMetrics bool
 }
 
 // gzipAccepted returns whether the client will accept gzip-encoded content.
@@ -295,11 +366,9 @@ func gzipAccepted(header http.Header) bool {
 }
 
 // httpError removes any content-encoding header and then calls http.Error with
-// the provided error and http.StatusInternalServerErrer. Error contents is
-// supposed to be uncompressed plain text. However, same as with a plain
-// http.Error, any header settings will be void if the header has already been
-// sent. The error message will still be written to the writer, but it will
-// probably be of limited use.
+// the provided error and http.StatusInternalServerError. Error contents is
+// supposed to be uncompressed plain text. Same as with a plain http.Error, this
+// must not be called if the header or any payload has already been sent.
 func httpError(rsp http.ResponseWriter, err error) {
 	rsp.Header().Del(contentEncodingHeader)
 	http.Error(

vendor/github.com/prometheus/client_golang/prometheus/registry.go

@@ -25,6 +25,8 @@ import (
 	"sync"
 	"unicode/utf8"
 
+	"github.com/cespare/xxhash/v2"
+	//lint:ignore SA1019 Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
 	"github.com/prometheus/common/expfmt"
 
@@ -74,7 +76,7 @@ func NewRegistry() *Registry {
 // NewPedanticRegistry returns a registry that checks during collection if each
 // collected Metric is consistent with its reported Desc, and if the Desc has
 // actually been registered with the registry. Unchecked Collectors (those whose
-// Describe methed does not yield any descriptors) are excluded from the check.
+// Describe method does not yield any descriptors) are excluded from the check.
 //
 // Usually, a Registry will be happy as long as the union of all collected
 // Metrics is consistent and valid even if some metrics are not consistent with
@@ -266,7 +268,7 @@ func (r *Registry) Register(c Collector) error {
 		descChan           = make(chan *Desc, capDescChan)
 		newDescIDs         = map[uint64]struct{}{}
 		newDimHashesByName = map[string]uint64{}
-		collectorID        uint64 // Just a sum of all desc IDs.
+		collectorID        uint64 // All desc IDs XOR'd together.
 		duplicateDescErr   error
 	)
 	go func() {
@@ -293,12 +295,12 @@ func (r *Registry) Register(c Collector) error {
 		if _, exists := r.descIDs[desc.id]; exists {
 			duplicateDescErr = fmt.Errorf("descriptor %s already exists with the same fully-qualified name and const label values", desc)
 		}
-		// If it is not a duplicate desc in this collector, add it to
+		// If it is not a duplicate desc in this collector, XOR it to
 		// the collectorID.  (We allow duplicate descs within the same
 		// collector, but their existence must be a no-op.)
 		if _, exists := newDescIDs[desc.id]; !exists {
 			newDescIDs[desc.id] = struct{}{}
-			collectorID += desc.id
+			collectorID ^= desc.id
 		}
 
 		// Are all the label names and the help string consistent with
@@ -325,9 +327,17 @@ func (r *Registry) Register(c Collector) error {
 		return nil
 	}
 	if existing, exists := r.collectorsByID[collectorID]; exists {
-		return AlreadyRegisteredError{
-			ExistingCollector: existing,
-			NewCollector:      c,
+		switch e := existing.(type) {
+		case *wrappingCollector:
+			return AlreadyRegisteredError{
+				ExistingCollector: e.unwrapRecursively(),
+				NewCollector:      c,
+			}
+		default:
+			return AlreadyRegisteredError{
+				ExistingCollector: e,
+				NewCollector:      c,
+			}
 		}
 	}
 	// If the collectorID is new, but at least one of the descs existed
@@ -352,7 +362,7 @@ func (r *Registry) Unregister(c Collector) bool {
 	var (
 		descChan    = make(chan *Desc, capDescChan)
 		descIDs     = map[uint64]struct{}{}
-		collectorID uint64 // Just a sum of the desc IDs.
+		collectorID uint64 // All desc IDs XOR'd together.
 	)
 	go func() {
 		c.Describe(descChan)
@@ -360,7 +370,7 @@ func (r *Registry) Unregister(c Collector) bool {
 	}()
 	for desc := range descChan {
 		if _, exists := descIDs[desc.id]; !exists {
-			collectorID += desc.id
+			collectorID ^= desc.id
 			descIDs[desc.id] = struct{}{}
 		}
 	}
@@ -867,9 +877,9 @@ func checkMetricConsistency(
 	}
 
 	// Is the metric unique (i.e. no other metric with the same name and the same labels)?
-	h := hashNew()
-	h = hashAdd(h, name)
-	h = hashAddByte(h, separatorByte)
+	h := xxhash.New()
+	h.WriteString(name)
+	h.Write(separatorByteSlice)
 	// Make sure label pairs are sorted. We depend on it for the consistency
 	// check.
 	if !sort.IsSorted(labelPairSorter(dtoMetric.Label)) {
@@ -880,18 +890,19 @@ func checkMetricConsistency(
 		dtoMetric.Label = copiedLabels
 	}
 	for _, lp := range dtoMetric.Label {
-		h = hashAdd(h, lp.GetName())
-		h = hashAddByte(h, separatorByte)
-		h = hashAdd(h, lp.GetValue())
-		h = hashAddByte(h, separatorByte)
+		h.WriteString(lp.GetName())
+		h.Write(separatorByteSlice)
+		h.WriteString(lp.GetValue())
+		h.Write(separatorByteSlice)
 	}
-	if _, exists := metricHashes[h]; exists {
+	hSum := h.Sum64()
+	if _, exists := metricHashes[hSum]; exists {
 		return fmt.Errorf(
 			"collected metric %q { %s} was collected before with the same name and label values",
 			name, dtoMetric,
 		)
 	}
-	metricHashes[h] = struct{}{}
+	metricHashes[hSum] = struct{}{}
 	return nil
 }
 

vendor/github.com/prometheus/client_golang/prometheus/summary.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/beorn7/perks/quantile"
+	//lint:ignore SA1019 Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
 
 	dto "github.com/prometheus/client_model/go"
@@ -39,7 +40,7 @@ const quantileLabel = "quantile"
 // A typical use-case is the observation of request latencies. By default, a
 // Summary provides the median, the 90th and the 99th percentile of the latency
 // as rank estimations. However, the default behavior will change in the
-// upcoming v0.10 of the library. There will be no rank estimations at all by
+// upcoming v1.0.0 of the library. There will be no rank estimations at all by
 // default. For a sane transition, it is recommended to set the desired rank
 // estimations explicitly.
 //
@@ -58,16 +59,8 @@ type Summary interface {
 	Observe(float64)
 }
 
-// DefObjectives are the default Summary quantile values.
-//
-// Deprecated: DefObjectives will not be used as the default objectives in
-// v0.10 of the library. The default Summary will have no quantiles then.
-var (
-	DefObjectives = map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001}
-
-	errQuantileLabelNotAllowed = fmt.Errorf(
-		"%q is not allowed as label name in summaries", quantileLabel,
-	)
+var errQuantileLabelNotAllowed = fmt.Errorf(
+	"%q is not allowed as label name in summaries", quantileLabel,
 )
 
 // Default values for SummaryOpts.
@@ -86,7 +79,7 @@ const (
 // mandatory to set Name to a non-empty string. While all other fields are
 // optional and can safely be left at their zero value, it is recommended to set
 // a help string and to explicitly set the Objectives field to the desired value
-// as the default value will change in the upcoming v0.10 of the library.
+// as the default value will change in the upcoming v1.0.0 of the library.
 type SummaryOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Summary (created by joining these components with
@@ -123,14 +116,8 @@ type SummaryOpts struct {
 	// Objectives defines the quantile rank estimates with their respective
 	// absolute error. If Objectives[q] = e, then the value reported for q
 	// will be the φ-quantile value for some φ between q-e and q+e.  The
-	// default value is DefObjectives. It is used if Objectives is left at
-	// its zero value (i.e. nil). To create a Summary without Objectives,
-	// set it to an empty map (i.e. map[float64]float64{}).
-	//
-	// Note that the current value of DefObjectives is deprecated. It will
-	// be replaced by an empty map in v0.10 of the library. Please
-	// explicitly set Objectives to the desired value to avoid problems
-	// during the transition.
+	// default value is an empty map, resulting in a summary without
+	// quantiles.
 	Objectives map[float64]float64
 
 	// MaxAge defines the duration for which an observation stays relevant
@@ -199,7 +186,7 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	}
 
 	if opts.Objectives == nil {
-		opts.Objectives = DefObjectives
+		opts.Objectives = map[float64]float64{}
 	}
 
 	if opts.MaxAge < 0 {
@@ -222,7 +209,7 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 		s := &noObjectivesSummary{
 			desc:       desc,
 			labelPairs: makeLabelPairs(desc, labelValues),
-			counts:     [2]*summaryCounts{&summaryCounts{}, &summaryCounts{}},
+			counts:     [2]*summaryCounts{{}, {}},
 		}
 		s.init(s) // Init self-collection.
 		return s

vendor/github.com/prometheus/client_golang/prometheus/value.go

@@ -16,8 +16,12 @@ package prometheus
 import (
 	"fmt"
 	"sort"
+	"time"
+	"unicode/utf8"
 
+	//lint:ignore SA1019 Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/ptypes"
 
 	dto "github.com/prometheus/client_model/go"
 )
@@ -25,7 +29,8 @@ import (
 // ValueType is an enumeration of metric types that represent a simple value.
 type ValueType int
 
-// Possible values for the ValueType enum.
+// Possible values for the ValueType enum. Use UntypedValue to mark a metric
+// with an unknown type.
 const (
 	_ ValueType = iota
 	CounterValue
@@ -69,7 +74,7 @@ func (v *valueFunc) Desc() *Desc {
 }
 
 func (v *valueFunc) Write(out *dto.Metric) error {
-	return populateMetric(v.valType, v.function(), v.labelPairs, out)
+	return populateMetric(v.valType, v.function(), v.labelPairs, nil, out)
 }
 
 // NewConstMetric returns a metric with one fixed value that cannot be
@@ -116,19 +121,20 @@ func (m *constMetric) Desc() *Desc {
 }
 
 func (m *constMetric) Write(out *dto.Metric) error {
-	return populateMetric(m.valType, m.val, m.labelPairs, out)
+	return populateMetric(m.valType, m.val, m.labelPairs, nil, out)
 }
 
 func populateMetric(
 	t ValueType,
 	v float64,
 	labelPairs []*dto.LabelPair,
+	e *dto.Exemplar,
 	m *dto.Metric,
 ) error {
 	m.Label = labelPairs
 	switch t {
 	case CounterValue:
-		m.Counter = &dto.Counter{Value: proto.Float64(v)}
+		m.Counter = &dto.Counter{Value: proto.Float64(v), Exemplar: e}
 	case GaugeValue:
 		m.Gauge = &dto.Gauge{Value: proto.Float64(v)}
 	case UntypedValue:
@@ -160,3 +166,40 @@ func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 	sort.Sort(labelPairSorter(labelPairs))
 	return labelPairs
 }
+
+// ExemplarMaxRunes is the max total number of runes allowed in exemplar labels.
+const ExemplarMaxRunes = 64
+
+// newExemplar creates a new dto.Exemplar from the provided values. An error is
+// returned if any of the label names or values are invalid or if the total
+// number of runes in the label names and values exceeds ExemplarMaxRunes.
+func newExemplar(value float64, ts time.Time, l Labels) (*dto.Exemplar, error) {
+	e := &dto.Exemplar{}
+	e.Value = proto.Float64(value)
+	tsProto, err := ptypes.TimestampProto(ts)
+	if err != nil {
+		return nil, err
+	}
+	e.Timestamp = tsProto
+	labelPairs := make([]*dto.LabelPair, 0, len(l))
+	var runes int
+	for name, value := range l {
+		if !checkLabelName(name) {
+			return nil, fmt.Errorf("exemplar label name %q is invalid", name)
+		}
+		runes += utf8.RuneCountInString(name)
+		if !utf8.ValidString(value) {
+			return nil, fmt.Errorf("exemplar label value %q is not valid UTF-8", value)
+		}
+		runes += utf8.RuneCountInString(value)
+		labelPairs = append(labelPairs, &dto.LabelPair{
+			Name:  proto.String(name),
+			Value: proto.String(value),
+		})
+	}
+	if runes > ExemplarMaxRunes {
+		return nil, fmt.Errorf("exemplar labels have %d runes, exceeding the limit of %d", runes, ExemplarMaxRunes)
+	}
+	e.Label = labelPairs
+	return e, nil
+}

vendor/github.com/prometheus/client_golang/prometheus/vec.go

@@ -24,7 +24,7 @@ import (
 // their label values. metricVec is not used directly (and therefore
 // unexported). It is used as a building block for implementations of vectors of
 // a given metric type, like GaugeVec, CounterVec, SummaryVec, and HistogramVec.
-// It also handles label currying. It uses basicMetricVec internally.
+// It also handles label currying.
 type metricVec struct {
 	*metricMap
 
@@ -91,6 +91,18 @@ func (m *metricVec) Delete(labels Labels) bool {
 	return m.metricMap.deleteByHashWithLabels(h, labels, m.curry)
 }
 
+// Without explicit forwarding of Describe, Collect, Reset, those methods won't
+// show up in GoDoc.
+
+// Describe implements Collector.
+func (m *metricVec) Describe(ch chan<- *Desc) { m.metricMap.Describe(ch) }
+
+// Collect implements Collector.
+func (m *metricVec) Collect(ch chan<- Metric) { m.metricMap.Collect(ch) }
+
+// Reset deletes all metrics in this vector.
+func (m *metricVec) Reset() { m.metricMap.Reset() }
+
 func (m *metricVec) curryWith(labels Labels) (*metricVec, error) {
 	var (
 		newCurry []curriedLabelValue

vendor/github.com/prometheus/client_golang/prometheus/wrap.go

@@ -17,6 +17,7 @@ import (
 	"fmt"
 	"sort"
 
+	//lint:ignore SA1019 Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
 
 	dto "github.com/prometheus/client_model/go"
@@ -27,11 +28,18 @@ import (
 // registered with the wrapped Registerer in a modified way. The modified
 // Collector adds the provided Labels to all Metrics it collects (as
 // ConstLabels). The Metrics collected by the unmodified Collector must not
-// duplicate any of those labels.
+// duplicate any of those labels. Wrapping a nil value is valid, resulting
+// in a no-op Registerer.
 //
 // WrapRegistererWith provides a way to add fixed labels to a subset of
 // Collectors. It should not be used to add fixed labels to all metrics exposed.
 //
+// Conflicts between Collectors registered through the original Registerer with
+// Collectors registered through the wrapping Registerer will still be
+// detected. Any AlreadyRegisteredError returned by the Register method of
+// either Registerer will contain the ExistingCollector in the form it was
+// provided to the respective registry.
+//
 // The Collector example demonstrates a use of WrapRegistererWith.
 func WrapRegistererWith(labels Labels, reg Registerer) Registerer {
 	return &wrappingRegisterer{
@@ -44,6 +52,7 @@ func WrapRegistererWith(labels Labels, reg Registerer) Registerer {
 // Registerer. Collectors registered with the returned Registerer will be
 // registered with the wrapped Registerer in a modified way. The modified
 // Collector adds the provided prefix to the name of all Metrics it collects.
+// Wrapping a nil value is valid, resulting in a no-op Registerer.
 //
 // WrapRegistererWithPrefix is useful to have one place to prefix all metrics of
 // a sub-system. To make this work, register metrics of the sub-system with the
@@ -54,6 +63,12 @@ func WrapRegistererWith(labels Labels, reg Registerer) Registerer {
 // (see NewGoCollector) and the process collector (see NewProcessCollector). (In
 // fact, those metrics are already prefixed with “go_” or “process_”,
 // respectively.)
+//
+// Conflicts between Collectors registered through the original Registerer with
+// Collectors registered through the wrapping Registerer will still be
+// detected. Any AlreadyRegisteredError returned by the Register method of
+// either Registerer will contain the ExistingCollector in the form it was
+// provided to the respective registry.
 func WrapRegistererWithPrefix(prefix string, reg Registerer) Registerer {
 	return &wrappingRegisterer{
 		wrappedRegisterer: reg,
@@ -68,6 +83,9 @@ type wrappingRegisterer struct {
 }
 
 func (r *wrappingRegisterer) Register(c Collector) error {
+	if r.wrappedRegisterer == nil {
+		return nil
+	}
 	return r.wrappedRegisterer.Register(&wrappingCollector{
 		wrappedCollector: c,
 		prefix:           r.prefix,
@@ -76,6 +94,9 @@ func (r *wrappingRegisterer) Register(c Collector) error {
 }
 
 func (r *wrappingRegisterer) MustRegister(cs ...Collector) {
+	if r.wrappedRegisterer == nil {
+		return
+	}
 	for _, c := range cs {
 		if err := r.Register(c); err != nil {
 			panic(err)
@@ -84,6 +105,9 @@ func (r *wrappingRegisterer) MustRegister(cs ...Collector) {
 }
 
 func (r *wrappingRegisterer) Unregister(c Collector) bool {
+	if r.wrappedRegisterer == nil {
+		return false
+	}
 	return r.wrappedRegisterer.Unregister(&wrappingCollector{
 		wrappedCollector: c,
 		prefix:           r.prefix,
@@ -123,6 +147,15 @@ func (c *wrappingCollector) Describe(ch chan<- *Desc) {
 	}
 }
 
+func (c *wrappingCollector) unwrapRecursively() Collector {
+	switch wc := c.wrappedCollector.(type) {
+	case *wrappingCollector:
+		return wc.unwrapRecursively()
+	default:
+		return wc
+	}
+}
+
 type wrappingMetric struct {
 	wrappedMetric Metric
 	prefix        string