Stub for runtime versioning for GoLang programs

version.go

package version

import (
	"bytes"
	"fmt"
	"runtime"
	"strings"

	"github.com/prometheus/client_golang/prometheus"
)

// Build information. Populated at build-time via build tags
// 
var (
	Version   string
	Revision  string
	Branch    string
	BuildDate string
	GoVersion = runtime.Version()
)

// Info returns version, branch and revision information.
func Info() string {
	return fmt.Sprintf("(version=%s, branch=%s, revision=%s)", Version, Branch, Revision)
}

// BuildContext returns goVersion and buildDate information.
func BuildContext() string {
	return fmt.Sprintf("(go_version=%s, build_date=%s)", GoVersion, BuildDate)
}

// NewCollector exports metrics about current version information into prometheus 
func NewCollector(appName string) *prometheus.GaugeVec {
	buildInfo := prometheus.NewGaugeVec(
		prometheus.GaugeOpts{
			Namespace: appName,
			Name:      "build_info",
			Help: fmt.Sprintf(
				"A metric with a constant '1' value labeled by version, revision, branch, and goversion from which %s was built.",
				appName,
			),
		},
		[]string{"version", "revision", "branch", "go_version"},
	)
	buildInfo.WithLabelValues(Version, Revision, Branch, GoVersion).Set(1)
  
	return buildInfo
}