Remove key in tags to reduce metrics count (#1494)

* Remove key in tags to reduce metrics count
Issue: https://github.com/knative/serving/issues/8609

Signed-off-by: Lance Liu <xuliuxl@cn.ibm.com>

* remove tag key for OpenCensus

Signed-off-by: Lance Liu <xuliuxl@cn.ibm.com>

controller/controller.go

@@ -452,7 +452,7 @@ func (c *Impl) processNextWorkItem() bool {
 		if err != nil {
 			status = falseString
 		}
-		c.statsReporter.ReportReconcile(time.Since(startTime), keyStr, status)
+		c.statsReporter.ReportReconcile(time.Since(startTime), status)
 	}()
 
 	// Embed the key into the logger and attach that to the context we pass

controller/stats_reporter.go

@@ -46,7 +46,6 @@ var (
 	// - length between 1 and 255 inclusive
 	// - characters are printable US-ASCII
 	reconcilerTagKey = tag.MustNewKey("reconciler")
-	keyTagKey        = tag.MustNewKey("key")
 	successTagKey    = tag.MustNewKey("success")
 )
 
@@ -167,12 +166,12 @@ func init() {
 		Description: "Number of reconcile operations",
 		Measure:     reconcileCountStat,
 		Aggregation: view.Count(),
-		TagKeys:     []tag.Key{reconcilerTagKey, keyTagKey, successTagKey},
+		TagKeys:     []tag.Key{reconcilerTagKey, successTagKey},
 	}, {
 		Description: "Latency of reconcile operations",
 		Measure:     reconcileLatencyStat,
 		Aggregation: reconcileDistribution,
-		TagKeys:     []tag.Key{reconcilerTagKey, keyTagKey, successTagKey},
+		TagKeys:     []tag.Key{reconcilerTagKey, successTagKey},
 	}}
 	views = append(views, wp.DefaultViews()...)
 	views = append(views, rp.DefaultViews()...)
@@ -192,7 +191,7 @@ type StatsReporter interface {
 	ReportQueueDepth(v int64) error
 
 	// ReportReconcile reports the count and latency metrics for a reconcile operation
-	ReportReconcile(duration time.Duration, key, success string) error
+	ReportReconcile(duration time.Duration, success string) error
 }
 
 // Reporter holds cached metric objects to report metrics
@@ -234,11 +233,10 @@ func (r *reporter) ReportQueueDepth(v int64) error {
 }
 
 // ReportReconcile reports the count and latency metrics for a reconcile operation
-func (r *reporter) ReportReconcile(duration time.Duration, key, success string) error {
+func (r *reporter) ReportReconcile(duration time.Duration, success string) error {
 	ctx, err := tag.New(
 		context.Background(),
 		tag.Insert(reconcilerTagKey, r.reconciler),
-		tag.Insert(keyTagKey, key),
 		tag.Insert(successTagKey, success))
 	if err != nil {
 		return err

controller/stats_reporter_test.go

@@ -68,7 +68,6 @@ func TestReportReconcile(t *testing.T) {
 	r, _ := NewStatsReporter("testreconciler")
 	wantTags := map[string]string{
 		"reconciler": "testreconciler",
-		"key":        "test/key",
 		"success":    "true",
 	}
 
@@ -81,11 +80,11 @@ func TestReportReconcile(t *testing.T) {
 		initialReconcileLatency = d[0].Data.(*view.DistributionData).Sum()
 	}
 
-	expectSuccess(t, func() error { return r.ReportReconcile(10*time.Millisecond, "test/key", "true") })
+	expectSuccess(t, func() error { return r.ReportReconcile(10*time.Millisecond, "true") })
 	metricstest.CheckCountData(t, "reconcile_count", wantTags, initialReconcileCount+1)
 	metricstest.CheckDistributionData(t, "reconcile_latency", wantTags, 1, initialReconcileLatency+10, initialReconcileLatency+10)
 
-	expectSuccess(t, func() error { return r.ReportReconcile(15*time.Millisecond, "test/key", "true") })
+	expectSuccess(t, func() error { return r.ReportReconcile(15*time.Millisecond, "true") })
 	metricstest.CheckCountData(t, "reconcile_count", wantTags, initialReconcileCount+2)
 	metricstest.CheckDistributionData(t, "reconcile_latency", wantTags, 2, initialReconcileLatency+10, initialReconcileLatency+15)
 }

controller/testing/fake_stats_reporter.go

@@ -31,7 +31,7 @@ type FakeStatsReporter struct {
 // FakeReconcileStatData is used to record the calls to ReportReconcile
 type FakeReconcileStatData struct {
 	Duration time.Duration
-	Key, Success string
+	Success  string
 }
 
 // ReportQueueDepth records the call and returns success.
@@ -43,10 +43,10 @@ func (r *FakeStatsReporter) ReportQueueDepth(v int64) error {
 }
 
 // ReportReconcile records the call and returns success.
-func (r *FakeStatsReporter) ReportReconcile(duration time.Duration, key, success string) error {
+func (r *FakeStatsReporter) ReportReconcile(duration time.Duration, success string) error {
 	r.Lock.Lock()
 	defer r.Lock.Unlock()
-	r.reconcileData = append(r.reconcileData, FakeReconcileStatData{duration, key, success})
+	r.reconcileData = append(r.reconcileData, FakeReconcileStatData{duration, success})
 	return nil
 }
 

controller/testing/fake_stats_reporter_test.go

@@ -38,8 +38,8 @@ func TestReportQueueDepth(t *testing.T) {
 
 func TestReportReconcile(t *testing.T) {
 	r := &FakeStatsReporter{}
-	r.ReportReconcile(time.Duration(123), "testkey", "False")
+	r.ReportReconcile(time.Duration(123), "False")
-	if got, want := r.GetReconcileData(), []FakeReconcileStatData{{time.Duration(123), "testkey", "False"}}; !reflect.DeepEqual(want, got) {
+	if got, want := r.GetReconcileData(), []FakeReconcileStatData{{time.Duration(123), "False"}}; !reflect.DeepEqual(want, got) {
 		t.Errorf("reconcile data len: want: %v, got: %v", want, got)
 	}
 }