add metrics for rootcacertpublisher controller

pkg/controller/certificates/rootcacertpublisher/BUILD

@@ -2,7 +2,10 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
-    srcs = ["publisher.go"],
+    srcs = [
+        "metrics.go",
+        "publisher.go",
+    ],
     importpath = "k8s.io/kubernetes/pkg/controller/certificates/rootcacertpublisher",
     visibility = ["//visibility:public"],
     deps = [
@@ -16,6 +19,8 @@ go_library(
         "//staging/src/k8s.io/client-go/listers/core/v1:go_default_library",
         "//staging/src/k8s.io/client-go/tools/cache:go_default_library",
         "//staging/src/k8s.io/client-go/util/workqueue:go_default_library",
+        "//staging/src/k8s.io/component-base/metrics:go_default_library",
+        "//staging/src/k8s.io/component-base/metrics/legacyregistry:go_default_library",
         "//staging/src/k8s.io/component-base/metrics/prometheus/ratelimiter:go_default_library",
         "//vendor/k8s.io/klog/v2:go_default_library",
     ],
@@ -23,15 +28,21 @@ go_library(
 
 go_test(
     name = "go_default_test",
-    srcs = ["publisher_test.go"],
+    srcs = [
+        "metrics_test.go",
+        "publisher_test.go",
+    ],
     embed = [":go_default_library"],
     deps = [
         "//pkg/controller:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/api/errors:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/diff:go_default_library",
         "//staging/src/k8s.io/client-go/informers:go_default_library",
         "//staging/src/k8s.io/client-go/kubernetes/fake:go_default_library",
+        "//staging/src/k8s.io/component-base/metrics/legacyregistry:go_default_library",
+        "//staging/src/k8s.io/component-base/metrics/testutil:go_default_library",
     ],
 )
 

pkg/controller/certificates/rootcacertpublisher/metrics.go

@@ -0,0 +1,72 @@
+/*
+Copyright 2020 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 rootcacertpublisher
+
+import (
+	"strconv"
+	"sync"
+	"time"
+
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/component-base/metrics"
+	"k8s.io/component-base/metrics/legacyregistry"
+)
+
+// RootCACertPublisher - subsystem name used by root_ca_cert_publisher
+const RootCACertPublisher = "root_ca_cert_publisher"
+
+var (
+	syncCounter = metrics.NewCounterVec(
+		&metrics.CounterOpts{
+			Subsystem:      RootCACertPublisher,
+			Name:           "sync_total",
+			Help:           "Number of namespace syncs happened in root ca cert publisher.",
+			StabilityLevel: metrics.ALPHA,
+		},
+		[]string{"namespace", "code"},
+	)
+	syncLatency = metrics.NewHistogramVec(
+		&metrics.HistogramOpts{
+			Subsystem:      RootCACertPublisher,
+			Name:           "sync_duration_seconds",
+			Help:           "Number of namespace syncs happened in root ca cert publisher.",
+			Buckets:        metrics.ExponentialBuckets(0.001, 2, 15),
+			StabilityLevel: metrics.ALPHA,
+		},
+		[]string{"namespace", "code"},
+	)
+)
+
+func recordMetrics(start time.Time, ns string, err error) {
+	code := "500"
+	if err == nil {
+		code = "200"
+	} else if se, ok := err.(*apierrors.StatusError); ok && se.Status().Code != 0 {
+		code = strconv.Itoa(int(se.Status().Code))
+	}
+	syncLatency.WithLabelValues(ns, code).Observe(time.Since(start).Seconds())
+	syncCounter.WithLabelValues(ns, code).Inc()
+}
+
+var once sync.Once
+
+func registerMetrics() {
+	once.Do(func() {
+		legacyregistry.MustRegister(syncCounter)
+		legacyregistry.MustRegister(syncLatency)
+	})
+}

pkg/controller/certificates/rootcacertpublisher/metrics_test.go

@@ -0,0 +1,97 @@
+/*
+Copyright 2020 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 rootcacertpublisher
+
+import (
+	"errors"
+	"strings"
+	"testing"
+	"time"
+
+	corev1 "k8s.io/api/core/v1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/component-base/metrics/legacyregistry"
+	"k8s.io/component-base/metrics/testutil"
+)
+
+func TestSyncCounter(t *testing.T) {
+	testCases := []struct {
+		desc    string
+		err     error
+		metrics []string
+		want    string
+	}{
+		{
+			desc: "nil error",
+			err:  nil,
+			metrics: []string{
+				"root_ca_cert_publisher_sync_total",
+			},
+			want: `
+# HELP root_ca_cert_publisher_sync_total [ALPHA] Number of namespace syncs happened in root ca cert publisher.
+# TYPE root_ca_cert_publisher_sync_total counter
+root_ca_cert_publisher_sync_total{code="200",namespace="test-ns"} 1
+				`,
+		},
+		{
+			desc: "kube api error",
+			err:  apierrors.NewNotFound(corev1.Resource("configmap"), "test-configmap"),
+			metrics: []string{
+				"root_ca_cert_publisher_sync_total",
+			},
+			want: `
+# HELP root_ca_cert_publisher_sync_total [ALPHA] Number of namespace syncs happened in root ca cert publisher.
+# TYPE root_ca_cert_publisher_sync_total counter
+root_ca_cert_publisher_sync_total{code="404",namespace="test-ns"} 1
+				`,
+		},
+		{
+			desc: "kube api error without code",
+			err:  &apierrors.StatusError{},
+			metrics: []string{
+				"root_ca_cert_publisher_sync_total",
+			},
+			want: `
+# HELP root_ca_cert_publisher_sync_total [ALPHA] Number of namespace syncs happened in root ca cert publisher.
+# TYPE root_ca_cert_publisher_sync_total counter
+root_ca_cert_publisher_sync_total{code="500",namespace="test-ns"} 1
+				`,
+		},
+		{
+			desc: "general error",
+			err:  errors.New("test"),
+			metrics: []string{
+				"root_ca_cert_publisher_sync_total",
+			},
+			want: `
+# HELP root_ca_cert_publisher_sync_total [ALPHA] Number of namespace syncs happened in root ca cert publisher.
+# TYPE root_ca_cert_publisher_sync_total counter
+root_ca_cert_publisher_sync_total{code="500",namespace="test-ns"} 1
+				`,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			recordMetrics(time.Now(), "test-ns", tc.err)
+			defer syncCounter.Reset()
+			if err := testutil.GatherAndCompare(legacyregistry.DefaultGatherer, strings.NewReader(tc.want), tc.metrics...); err != nil {
+				t.Fatal(err)
+			}
+		})
+	}
+}

pkg/controller/certificates/rootcacertpublisher/publisher.go

@@ -40,6 +40,10 @@ import (
 // to access api-server
 const RootCACertConfigMapName = "kube-root-ca.crt"
 
+func init() {
+	registerMetrics()
+}
+
 // NewPublisher construct a new controller which would manage the configmap
 // which stores certificates in each namespace. It will make sure certificate
 // configmap exists in each namespace.
@@ -170,16 +174,17 @@ func (c *Publisher) processNextWorkItem() bool {
 	return true
 }
 
-func (c *Publisher) syncNamespace(ns string) error {
+func (c *Publisher) syncNamespace(ns string) (err error) {
 	startTime := time.Now()
 	defer func() {
+		recordMetrics(startTime, ns, err)
 		klog.V(4).Infof("Finished syncing namespace %q (%v)", ns, time.Since(startTime))
 	}()
 
 	cm, err := c.cmLister.ConfigMaps(ns).Get(RootCACertConfigMapName)
 	switch {
 	case apierrors.IsNotFound(err):
-		_, err := c.client.CoreV1().ConfigMaps(ns).Create(context.TODO(), &v1.ConfigMap{
+		_, err = c.client.CoreV1().ConfigMaps(ns).Create(context.TODO(), &v1.ConfigMap{
 			ObjectMeta: metav1.ObjectMeta{
 				Name: RootCACertConfigMapName,
 			},