Add metrics about KnativeServing CR edits

pkg/reconciler/knativeserving/controller.go

@@ -22,7 +22,6 @@ import (
 	"github.com/go-logr/zapr"
 	mf "github.com/jcrossley3/manifestival"
 	"go.uber.org/zap"
-	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/clientcmd"
 	deploymentinformer "knative.dev/pkg/client/injection/kube/informers/apps/v1/deployment"
@@ -56,7 +55,7 @@ func NewController(
 	c := &Reconciler{
 		Base:                 rbase.NewBase(ctx, controllerAgentName, cmw),
 		knativeServingLister: knativeServingInformer.Lister(),
-		servings:             sets.String{},
+		servings:             map[string]int64{},
 	}
 
 	koDataDir := os.Getenv("KO_DATA_PATH")

pkg/reconciler/knativeserving/knativeserving_controller.go

@@ -17,6 +17,7 @@ limitations under the License.
 package knativeserving
 
 import (
+	"fmt"
 	"context"
 
 	mf "github.com/jcrossley3/manifestival"
@@ -28,7 +29,7 @@ import (
 	apierrs "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
-	"k8s.io/apimachinery/pkg/util/sets"
+
 	"k8s.io/client-go/tools/cache"
 
 	"knative.dev/pkg/controller"
@@ -40,7 +41,10 @@ import (
 )
 
 const (
-	finalizerName = "delete-knative-serving-manifest"
+	finalizerName  = "delete-knative-serving-manifest"
+	creationChange = "creation"
+	editChange     = "edit"
+	deletionChange = "deletion"
 )
 
 var (
@@ -54,7 +58,7 @@ type Reconciler struct {
 	// Listers index properties about resources
 	knativeServingLister listers.KnativeServingLister
 	config               mf.Manifest
-	servings             sets.String
+	servings             map[string]int64
 }
 
 // Check that our Reconciler implements controller.Reconciler
@@ -74,17 +78,33 @@ func (r *Reconciler) Reconcile(ctx context.Context, key string) error {
 	original, err := r.knativeServingLister.KnativeServings(namespace).Get(name)
 	if apierrs.IsNotFound(err) {
 		return nil
-
 	} else if err != nil {
 		r.Logger.Error(err, "Error getting KnativeServing")
 		return err
 	}
 	if original.GetDeletionTimestamp() != nil {
-		r.servings.Delete(key)
+		if _, ok := r.servings[key]; ok {
+			delete(r.servings, key)
+			r.StatsReporter.ReportKnativeservingChange(key, deletionChange)
+		}
 		return r.delete(original)
 	}
-	// Keep track of the number of KnativeServings in the cluster
-	r.servings.Insert(key)
+	// Keep track of the number and generation of KnativeServings in the cluster.
+	newGen := original.Generation
+	if oldGen, ok := r.servings[key]; ok {
+		if newGen > oldGen {
+			r.StatsReporter.ReportKnativeservingChange(key, editChange)
+		} else if newGen < oldGen {
+			return fmt.Errorf("reconciling obsolete generation of KnativeServing %s: newGen = %d and oldGen = %d", key, newGen, oldGen)
+		}
+	} else {
+		// No metrics are emitted when newGen > 1: the first reconciling of
+		// a new operator on an existing KnativeServing resource.
+		if newGen == 1 {
+			r.StatsReporter.ReportKnativeservingChange(key, creationChange)
+		}
+	}
+	r.servings[key] = newGen
 
 	// Don't modify the informers copy.
 	knativeServing := original.DeepCopy()
@@ -231,7 +251,7 @@ func (r *Reconciler) delete(instance *servingv1alpha1.KnativeServing) error {
 	if len(instance.GetFinalizers()) == 0 || instance.GetFinalizers()[0] != finalizerName {
 		return nil
 	}
-	if r.servings.Len() == 0 {
+	if len(r.servings) == 0 {
 		if err := r.config.DeleteAll(&metav1.DeleteOptions{}); err != nil {
 			return err
 		}

pkg/reconciler/reconciler.go

@@ -62,6 +62,9 @@ type Base struct {
 	// Kubernetes API.
 	Recorder record.EventRecorder
 
+	// StatsReporter reports reconciler's metrics.
+	StatsReporter StatsReporter
+
 	// Sugared logger is easier to use but is not as performant as the
 	// raw logger. In performance critical paths, call logger.Desugar()
 	// and use the returned raw logger instead. In addition to the
@@ -100,13 +103,20 @@ func NewBase(ctx context.Context, controllerAgentName string, cmw configmap.Watc
 		}()
 	}
 
+	// Create metrics reporter
+	statsReporter, err := NewStatsReporter(controllerAgentName)
+	if err != nil {
+		logger.Fatal(err)
+	}
+
 	base := &Base{
 		KubeClientSet:           kubeClient,
 		SharedClientSet:         sharedclient.Get(ctx),
 		KnativeServingClientSet: servingclient.Get(ctx),
 		DynamicClientSet:        dynamicclient.Get(ctx),
 		ConfigMapWatcher:        cmw,
 		Recorder:                recorder,
+		StatsReporter:           statsReporter,
 		Logger:                  logger,
 	}
 

pkg/reconciler/reconciler_test.go

@@ -49,4 +49,7 @@ func TestNewBase(t *testing.T) {
 	if r.Recorder == nil {
 		t.Fatal("Expected NewBase to add a Recorder")
 	}
+	if r.StatsReporter == nil {
+		t.Fatal("Expected NewBase to add a StatsReporter")
+	}
 }

pkg/reconciler/stats_reporter.go

@@ -0,0 +1,100 @@
+/*
+Copyright 2019 The Knative 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 reconciler
+
+import (
+	"context"
+
+	"go.opencensus.io/stats"
+	"go.opencensus.io/stats/view"
+	"go.opencensus.io/tag"
+	"knative.dev/pkg/metrics"
+)
+
+const (
+	knativeservingChangeCountName = "knativeserving_change_count"
+)
+
+var (
+	knativeservingChangeCountStat = stats.Int64(
+		knativeservingChangeCountName,
+		"Number of changes to the KnativeServing Custom Resource where a change can be creation, edit, or deletion",
+		stats.UnitDimensionless)
+	// Create the tag keys that will be used to add tags to our measurements.
+	// Tag keys must conform to the restrictions described in
+	// go.opencensus.io/tag/validate.go. Currently those restrictions are:
+	// - length between 1 and 255 inclusive
+	// - characters are printable US-ASCII
+	reconcilerNameTagKey             = tag.MustNewKey("reconciler_name")
+	knativeservingResourceNameTagKey = tag.MustNewKey("knativeserving_resource_name")
+	changeTagKey                     = tag.MustNewKey("change")
+)
+
+func init() {
+	// Create views to see our measurements. This can return an error if
+	// a previously-registered view has the same name with a different value.
+	// View name defaults to the measure name if unspecified.
+	views := []*view.View{{
+		Description: knativeservingChangeCountStat.Description(),
+		Measure:     knativeservingChangeCountStat,
+		Aggregation: view.Count(),
+		TagKeys:     []tag.Key{reconcilerNameTagKey, knativeservingResourceNameTagKey, changeTagKey},
+	}}
+
+	if err := view.Register(views...); err != nil {
+		panic(err)
+	}
+}
+
+// StatsReporter defines the interface for sending metrics.
+type StatsReporter interface {
+	// ReportKnativeServingChange reports the count of KnativeServing changes.
+	ReportKnativeservingChange(knativeservingResourceName, change string) error
+}
+
+// reporter holds cached metric objects to report metrics.
+type reporter struct {
+	reconcilerName string
+	ctx            context.Context
+}
+
+// NewStatsReporter creates a reporter that collects and reports metrics.
+func NewStatsReporter(reconcilerName string) (StatsReporter, error) {
+	// Reconciler tag is static. Create a context containing that and cache it.
+	ctx, err := tag.New(
+		context.Background(),
+		tag.Insert(reconcilerNameTagKey, reconcilerName))
+	if err != nil {
+		return nil, err
+	}
+	return &reporter{reconcilerName: reconcilerName, ctx: ctx}, nil
+}
+
+// ReportKnativeServingChange reports the number of changes to the KnativeServing
+// Custom Resource where a change can be creation, edit, or deletion.
+func (r *reporter) ReportKnativeservingChange(knativeservingResourceName, change string) error {
+	ctx, err := tag.New(
+		r.ctx,
+		tag.Insert(knativeservingResourceNameTagKey, knativeservingResourceName),
+		tag.Insert(changeTagKey, change))
+	if err != nil {
+		return err
+	}
+
+	metrics.Record(ctx, knativeservingChangeCountStat.M(1))
+	return nil
+}

pkg/reconciler/stats_reporter_test.go

@@ -0,0 +1,65 @@
+/*
+Copyright 2019 The Knative 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 reconciler
+
+import (
+	"testing"
+
+	"go.opencensus.io/stats/view"
+	"go.opencensus.io/tag"
+	"knative.dev/pkg/metrics/metricstest"
+)
+
+const (
+	testReconcilerName             = "test_reconciler"
+	testKnativeservingResourceName = "ns/name"
+)
+
+func TestNewStatsReporter(t *testing.T) {
+	r, err := NewStatsReporter(testReconcilerName)
+	if err != nil {
+		t.Errorf("Failed to create reporter: %v", err)
+	}
+
+	m := tag.FromContext(r.(*reporter).ctx)
+	v, ok := m.Value(reconcilerNameTagKey)
+	if !ok {
+		t.Fatalf("Expected tag %q", reconcilerNameTagKey)
+	}
+	if v != testReconcilerName {
+		t.Fatalf("Expected %q for tag %q, got %q", testReconcilerName, reconcilerNameTagKey, v)
+	}
+}
+
+func TestReportKnativeServingChange(t *testing.T) {
+	r, _ := NewStatsReporter(testReconcilerName)
+	wantTags := map[string]string{
+		reconcilerNameTagKey.Name():             testReconcilerName,
+		knativeservingResourceNameTagKey.Name(): testKnativeservingResourceName,
+		changeTagKey.Name():                     "creation",
+	}
+	countWas := int64(0)
+	if d, err := view.RetrieveData(knativeservingChangeCountName); err == nil && len(d) == 1 {
+		countWas = d[0].Data.(*view.CountData).Value
+	}
+
+	if err := r.ReportKnativeservingChange(testKnativeservingResourceName, "creation"); err != nil {
+		t.Error(err)
+	}
+
+	metricstest.CheckCountData(t, knativeservingChangeCountName, wantTags, countWas+1)
+}