Add GC controller metrics

Author: carreter

pkg/server/leases/gc_controller.go

@@ -26,6 +26,7 @@ import (
 	coordinationv1 "k8s.io/client-go/kubernetes/typed/coordination/v1"
 	"k8s.io/klog/v2"
 	"k8s.io/utils/clock"
+	"sigs.k8s.io/apiserver-network-proxy/pkg/server/metrics"
 	"sigs.k8s.io/apiserver-network-proxy/pkg/util"
 )
 
@@ -70,6 +71,8 @@ func (c *GarbageCollectionController) gc(ctx context.Context) {
 			klog.V(4).Infof("Lease %v was already deleted", lease.Name)
 		} else if err != nil {
 			klog.Errorf("Could not delete lease %v: %v", lease.Name, err)
+		} else {
+			metrics.Metrics.CulledLeasesInc()
 		}
 	}
 }

pkg/server/metrics/metrics.go

@@ -56,6 +56,7 @@ type ServerMetrics struct {
 	dialFailures      *prometheus.CounterVec
 	streamPackets     *prometheus.CounterVec
 	streamErrors      *prometheus.CounterVec
+	culledLeases      prometheus.Counter
 }
 
 // newServerMetrics create a new ServerMetrics, configured with default metric names.
@@ -148,6 +149,12 @@ func newServerMetrics() *ServerMetrics {
 			"reason",
 		},
 	)
+	culledLeases := prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: Namespace,
+		Subsystem: Subsystem,
+		Name:      "culled_leases_count",
+		Help:      "Count of expired leases that the lease garbage collection controller has culled.",
+	})
 	streamPackets := commonmetrics.MakeStreamPacketsTotalMetric(Namespace, Subsystem)
 	streamErrors := commonmetrics.MakeStreamErrorsTotalMetric(Namespace, Subsystem)
 	prometheus.MustRegister(endpointLatencies)
@@ -161,6 +168,7 @@ func newServerMetrics() *ServerMetrics {
 	prometheus.MustRegister(dialFailures)
 	prometheus.MustRegister(streamPackets)
 	prometheus.MustRegister(streamErrors)
+	prometheus.MustRegister(culledLeases)
 	return &ServerMetrics{
 		endpointLatencies: endpointLatencies,
 		frontendLatencies: frontendLatencies,
@@ -173,6 +181,7 @@ func newServerMetrics() *ServerMetrics {
 		dialFailures:      dialFailures,
 		streamPackets:     streamPackets,
 		streamErrors:      streamErrors,
+		culledLeases:      culledLeases,
 	}
 }
 
@@ -190,6 +199,11 @@ func (s *ServerMetrics) Reset() {
 	s.streamErrors.Reset()
 }
 
+// CulledLeasesInc increments the number of leases that the GC controller has culled.
+func (s *ServerMetrics) CulledLeasesInc() {
+	s.culledLeases.Inc()
+}
+
 // ObserveDialLatency records the latency of dial to the remote endpoint.
 func (s *ServerMetrics) ObserveDialLatency(elapsed time.Duration) {
 	s.endpointLatencies.WithLabelValues().Observe(elapsed.Seconds())