Add new build info metrics that contains more info (#13876)

* Add new build info metrics that contains more info

The goal was to add more information about Grafana. But rather than
just adding those to the current metrics I created a new metric
since its a common pattern in the prometheus community to expose that
info in a metric named `*_build_info`.

We keep the old metric to avoid introducing any breaking changes but
we should be able to remove it the next breaking change

pkg/cmd/grafana-server/main.go

@@ -80,7 +80,7 @@ func main() {
 	setting.BuildBranch = buildBranch
 	setting.IsEnterprise = extensions.IsEnterprise
 
-	metrics.M_Grafana_Version.WithLabelValues(version).Set(1)
+	metrics.SetBuildInformation(version, commit, buildBranch)
 
 	server := NewGrafanaServer()
 

pkg/metrics/metrics.go

@@ -58,7 +58,14 @@ var (
 	M_StatActive_Users       prometheus.Gauge
 	M_StatTotal_Orgs         prometheus.Gauge
 	M_StatTotal_Playlists    prometheus.Gauge
-	M_Grafana_Version        *prometheus.GaugeVec
+
+	// M_Grafana_Version is a gauge that contains build info about this binary
+	//
+	// Deprecated: use M_Grafana_Build_Version instead.
+	M_Grafana_Version *prometheus.GaugeVec
+
+	// grafanaBuildVersion is a gauge that contains build info about this binary
+	grafanaBuildVersion *prometheus.GaugeVec
 )
 
 func newCounterVecStartingAtZero(opts prometheus.CounterOpts, labels []string, labelValues ...string) *prometheus.CounterVec {
@@ -293,9 +300,25 @@ func init() {
 
 	M_Grafana_Version = prometheus.NewGaugeVec(prometheus.GaugeOpts{
 		Name:      "info",
-		Help:      "Information about the Grafana",
+		Help:      "Information about the Grafana. This metric is deprecated. please use `grafana_build_info`",
 		Namespace: exporterName,
 	}, []string{"version"})
+
+	grafanaBuildVersion = prometheus.NewGaugeVec(prometheus.GaugeOpts{
+		Name:      "build_info",
+		Help:      "A metric with a constant '1' value labeled by version, revision, branch, and goversion from which Grafana was built.",
+		Namespace: exporterName,
+	}, []string{"version", "revision", "branch", "goversion"})
+}
+
+// SetBuildInformation sets the build information for this binary
+func SetBuildInformation(version, revision, branch string) {
+	// We export this info twice for backwards compability.
+	// Once this have been released for some time we should be able to remote `M_Grafana_Version`
+	// The reason we added a new one is that its common practice in the prometheus community
+	// to name this metric `*_build_info` so its easy to do aggregation on all programs.
+	M_Grafana_Version.WithLabelValues(version).Set(1)
+	grafanaBuildVersion.WithLabelValues(version, revision, branch, runtime.Version()).Set(1)
 }
 
 func initMetricVars() {
@@ -334,7 +357,8 @@ func initMetricVars() {
 		M_StatActive_Users,
 		M_StatTotal_Orgs,
 		M_StatTotal_Playlists,
-		M_Grafana_Version)
+		M_Grafana_Version,
+		grafanaBuildVersion)
 
 }