Merge pull request #6525 from simonpasquier/fix-6513

fix: register k8s metrics

pkg/k8sutil/metrics.go

@@ -28,10 +28,15 @@ type clientGoHTTPMetricAdapter struct {
 	duration *prometheus.SummaryVec
 }
 
+var _ = metrics.LatencyMetric(&clientGoHTTPMetricAdapter{})
+var _ = metrics.ResultMetric(&clientGoHTTPMetricAdapter{})
+
 type clientGoRateLimiterMetricAdapter struct {
 	duration *prometheus.SummaryVec
 }
 
+var _ = metrics.LatencyMetric(&clientGoRateLimiterMetricAdapter{})
+
 // MustRegisterClientGoMetrics registers k8s.io/client-go metrics.
 // It panics if it encounters an error (e.g. metrics already registered).
 func MustRegisterClientGoMetrics(registerer prometheus.Registerer) {
@@ -64,13 +69,23 @@ func MustRegisterClientGoMetrics(registerer prometheus.Registerer) {
 		),
 	}
 
+	// controller-runtime also calls metrics.Register() during init and this
+	// function can be called only once. To ensure that the k8s client metrics
+	// get updated, the global variables need to be set again here.
+	//
+	// Details:
+	// https://github.com/kubernetes-sigs/controller-runtime/blob/67b27f27e514bd9ac4cf9a2d84dec089ece95bf7/pkg/metrics/client_go_adapter.go#L42-L55
+	// https://github.com/kubernetes/client-go/blob/aa7909e7d7c0661792ba21b9e882f3cd6ad0ce53/tools/metrics/metrics.go#L129-L170
 	metrics.Register(
 		metrics.RegisterOpts{
 			RequestLatency:     httpMetrics,
 			RequestResult:      httpMetrics,
 			RateLimiterLatency: rateLimiterMetrics,
 		},
 	)
+	metrics.RequestLatency = httpMetrics
+	metrics.RequestResult = httpMetrics
+	metrics.RateLimiterLatency = rateLimiterMetrics
 
 	registerer.MustRegister(httpMetrics.count, httpMetrics.duration, rateLimiterMetrics.duration)
 }