Add a build info metric

cmd/postgres_exporter/postgres_exporter.go

@@ -22,13 +22,26 @@ import (
 "github.com/prometheus/client_golang/prometheus"
 "github.com/prometheus/client_golang/prometheus/promhttp"
 "github.com/prometheus/common/log"
+"github.com/prometheus/common/version"
 "gopkg.in/alecthomas/kingpin.v2"
 "gopkg.in/yaml.v2"
 )
 
+// Branch is set during build to the git branch.
+var Branch string
+
+// BuildDate is set during build to the ISO-8601 date and time.
+var BuildDate string
+
+// Revision is set during build to the git commit revision.
+var Revision string
+
 // Version is set during build to the git describe version
 // (semantic version)-(commitish) form.
-var Version = "0.0.1"
+var Version = "0.0.1-rev"
+
+// VersionShort is set during build to the semantic version.
+var VersionShort = "0.0.1"
 
 var (
 listenAddress = kingpin.Flag("web.listen-address", "Address to listen on for web interface and telemetry.").Default(":9187").Envar("PG_EXPORTER_WEB_LISTEN_ADDRESS").String()
@@ -1641,6 +1654,13 @@ func main() {
 exporter.servers.Close()
 }()
 
+// Setup build info metric.
+version.Branch = Branch
+version.BuildDate = BuildDate
+version.Revision = Revision
+version.Version = VersionShort
+prometheus.MustRegister(version.NewCollector("postgres_exporter"))
+
 prometheus.MustRegister(exporter)
 
 http.Handle(*metricPath, promhttp.Handler())

magefile.go

@@ -119,6 +119,31 @@ var goDirs []string
 var goPkgs []string
 var goCmds []string
 
+var branch = func() string {
+if v := os.Getenv("BRANCH"); v != "" {
+return v
+}
+out, _ := sh.Output("git", "rev-parse", "--abbrev-ref", "HEAD")
+
+return out
+}()
+
+var buildDate = func() string {
+if v := os.Getenv("BUILDDATE"); v != "" {
+return v
+}
+return time.Now().Format("2006-01-02T15:04:05-0700")
+}()
+
+var revision = func() string {
+if v := os.Getenv("REVISION"); v != "" {
+return v
+}
+out, _ := sh.Output("git", "rev-parse", "HEAD")
+
+return out
+}()
+
 var version = func() string {
 if v := os.Getenv("VERSION"); v != "" {
 return v
@@ -533,7 +558,11 @@ func IntegrationTestBinary() error {
 if (changed && (err == nil)) || os.IsNotExist(err) {
 return sh.RunWith(map[string]string{"CGO_ENABLED": "0"}, "go", "test", "./cmd/postgres_exporter",
 "-c", "-tags", "integration",
-"-a", "-ldflags", "-extldflags '-static'", "-X", fmt.Sprintf("main.Version=%s", version),
+"-a", "-ldflags", "-extldflags '-static'",
+"-X", fmt.Sprintf("main.Branch=%s", branch),
+"-X", fmt.Sprintf("main.BuildDate=%s", buildDate),
+"-X", fmt.Sprintf("main.Revision=%s", revision),
+"-X", fmt.Sprintf("main.VersionShort=%s", versionShort),
 "-o", "postgres_exporter_integration_test", "-cover", "-covermode", "count")
 }
 return err