Add process start time metric

Author: saikat-royc

pkg/metrics/metrics.go

@@ -111,6 +111,9 @@ type MetricsManager interface {
 	// status - the operation status, if not specified, i.e., status == nil, an
 	//          "Unknown" status of the passed-in operation is assumed.
 	RecordMetrics(op OperationKey, status OperationStatus, driverName string)
+
+	// GetRegistry() returns the metrics.KubeRegistry used by this metrics manager.
+	GetRegistry() k8smetrics.KubeRegistry
 }
 
 // OperationKey is a structure which holds information to
@@ -265,6 +268,7 @@ func (opMgr *operationMetricsManager) recordCancelMetric(val OperationValue, key
 
 func (opMgr *operationMetricsManager) init() {
 	opMgr.registry = k8smetrics.NewKubeRegistry()
+	k8smetrics.RegisterProcessStartTime(opMgr.registry.Register)
 	opMgr.opLatencyMetrics = k8smetrics.NewHistogramVec(
 		&k8smetrics.HistogramOpts{
 			Subsystem: subSystem,
@@ -327,6 +331,10 @@ func (opMgr *operationMetricsManager) StartMetricsEndpoint(pattern, addr string,
 	return srv, nil
 }
 
+func (opMgr *operationMetricsManager) GetRegistry() k8smetrics.KubeRegistry {
+	return opMgr.registry
+}
+
 // snapshotProvisionType represents which kind of snapshot a metric is
 type snapshotProvisionType string
 

pkg/metrics/metrics_test.go

@@ -44,8 +44,9 @@ var (
 )
 
 const (
-	httpPattern = "/metrics"
-	addr        = "localhost:0"
+	httpPattern            = "/metrics"
+	addr                   = "localhost:0"
+	processStartTimeMetric = "process_start_time_seconds"
 )
 
 type fakeOpStatus struct {
@@ -707,3 +708,24 @@ func containsMetrics(expectedMfs, gotMfs []*cmg.MetricFamily) bool {
 
 	return true
 }
+
+func TestProcessStartTimeMetricExist(t *testing.T) {
+	mgr, wg, srv := initMgr()
+	defer shutdown(srv, wg)
+	metricsFamilies, err := mgr.GetRegistry().Gather()
+	if err != nil {
+		t.Fatalf("Error fetching metrics: %v", err)
+	}
+
+	for _, metricsFamily := range metricsFamilies {
+		if metricsFamily.GetName() == processStartTimeMetric {
+			return
+		}
+		m := metricsFamily.GetMetric()
+		if m[0].GetGauge().GetValue() <= 0 {
+			t.Fatalf("Expected non zero timestamp for process start time")
+		}
+	}
+
+	t.Fatalf("Metrics does not contain %v. Scraped content: %v", processStartTimeMetric, metricsFamilies)
+}