add version command and add build information to metrics

Signed-off-by: David Christofas <dchristofas@owncloud.com>

konnectd/pkg/metrics/metrics.go

@@ -1,5 +1,7 @@
 package metrics
 
+import "github.com/prometheus/client_golang/prometheus"
+
 var (
 	// Namespace defines the namespace for the defines metrics.
 	Namespace = "ocis"
@@ -11,6 +13,7 @@ var (
 // Metrics defines the available metrics of this service.
 type Metrics struct {
 	// Counter  *prometheus.CounterVec
+	BuildInfo *prometheus.GaugeVec
 }
 
 // New initializes the available metrics.
@@ -22,11 +25,21 @@ func New() *Metrics {
 		// 	Name:      "greet_total",
 		// 	Help:      "How many greeting requests processed",
 		// }, []string{}),
+		BuildInfo: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Subsystem: Subsystem,
+			Name:      "build_info",
+			Help:      "Build Information",
+		}, []string{"version"}),
 	}
 
 	// prometheus.Register(
 	// 	m.Counter,
 	// )
 
+	_ = prometheus.Register(
+		m.BuildInfo,
+	)
+
 	return m
 }