imagetools inspect: add --format flag

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/moby/buildkit/version/version.go

@@ -0,0 +1,62 @@
+/*
+   Copyright The BuildKit Authors.
+   Copyright The containerd 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 version
+
+import (
+	"regexp"
+	"sync"
+)
+
+const (
+	defaultVersion = "0.0.0+unknown"
+)
+
+var (
+	// Package is filled at linking time
+	Package = "github.com/moby/buildkit"
+
+	// Version holds the complete version number. Filled in at linking time.
+	Version = defaultVersion
+
+	// Revision is filled with the VCS (e.g. git) revision being used to build
+	// the program at linking time.
+	Revision = ""
+)
+
+var (
+	reRelease *regexp.Regexp
+	reDev     *regexp.Regexp
+	reOnce    sync.Once
+)
+
+func UserAgent() string {
+	version := defaultVersion
+
+	reOnce.Do(func() {
+		reRelease = regexp.MustCompile(`^(v[0-9]+\.[0-9]+)\.[0-9]+$`)
+		reDev = regexp.MustCompile(`^(v[0-9]+\.[0-9]+)\.[0-9]+`)
+	})
+
+	if matches := reRelease.FindAllStringSubmatch(version, 1); len(matches) > 0 {
+		version = matches[0][1]
+	} else if matches := reDev.FindAllStringSubmatch(version, 1); len(matches) > 0 {
+		version = matches[0][1] + "-dev"
+	}
+
+	return "buildkit/" + version
+}