Merge pull request #106845 from jdnurme/controller-metrics

Controller metrics

staging/src/k8s.io/component-base/metrics/prometheus/controllers/metrics.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package controllers
+
+import (
+	"sync"
+
+	k8smetrics "k8s.io/component-base/metrics"
+	"k8s.io/component-base/metrics/legacyregistry"
+)
+
+var (
+	once sync.Once
+)
+
+// ControllerMetrics includes all the metrics of the proxy server.
+type ControllerMetrics struct {
+	controllerInstanceCount *k8smetrics.GaugeVec
+}
+
+// NewControllerMetrics create a new ControllerMetrics, configured with default metric names.
+func NewControllerMetrics() *ControllerMetrics {
+	controllerInstanceCount := k8smetrics.NewGaugeVec(
+		&k8smetrics.GaugeOpts{
+			Name:           "running_managed_controllers",
+			Help:           "Indicates where instances of a controller are currently running",
+			StabilityLevel: k8smetrics.ALPHA,
+		},
+		[]string{"name", "manager"},
+	)
+	controllerMetrics := &ControllerMetrics{
+		controllerInstanceCount: controllerInstanceCount,
+	}
+	once.Do(func() {
+		controllerMetrics.Register()
+	})
+	return controllerMetrics
+}
+
+func (a *ControllerMetrics) Register() {
+	legacyregistry.MustRegister(a.controllerInstanceCount)
+}
+
+// ControllerStarted sets the controllerInstanceCount to 1.
+// These values use set instead of inc/dec to avoid accidentally double counting
+// a controller that starts but fails to properly signal when it crashes.
+func (a *ControllerMetrics) ControllerStarted(name string, manager string) {
+	a.controllerInstanceCount.With(k8smetrics.Labels{"name": name, "manager": manager}).Set(float64(1))
+}
+
+// ControllerStopped sets the controllerInstanceCount to 0.
+func (a *ControllerMetrics) ControllerStopped(name string, manager string) {
+	a.controllerInstanceCount.With(k8smetrics.Labels{"name": name, "manager": manager}).Set(float64(0))
+}