adding retry event count metric for source (#2016)

* adding retry event count metric for source

Bump a few assorted dependencies to their latest versions (#2013)

* Bump a few assorted dependencies to their latest versions

* Use new uuid helper

* Some more slight adjustments

fixing boiler plate and format

* updates in format

* updates in format

* fixing minor errors

* Merge branch 'master' of https://github.com/knative/pkg

* fixing comment based on comment

* Update source/source_stats_reporter.go

Co-authored-by: Julian Friedman <julz.friedman@uk.ibm.com>

* adding changes based on comments

Co-authored-by: Julian Friedman <julz.friedman@uk.ibm.com>

source/source_stats_reporter.go

@@ -35,6 +35,12 @@ var (
 		stats.UnitDimensionless,
 	)
 
+	// retryEventCountM is a counter which records the number of events sent by the source in retries.
+	retryEventCountM = stats.Int64(
+		"retry_event_count",
+		"Number of retry events sent",
+		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:
@@ -51,6 +57,7 @@ var (
 	responseTimeout        = tag.MustNewKey(metricskey.LabelResponseTimeout)
 )
 
+// ReportArgs defines the arguments for reporting metrics.
 type ReportArgs struct {
 	Namespace     string
 	EventType     string
@@ -69,6 +76,7 @@ func init() {
 type StatsReporter interface {
 	// ReportEventCount captures the event count. It records one per call.
 	ReportEventCount(args *ReportArgs, responseCode int) error
+	ReportRetryEventCount(args *ReportArgs, responseCode int) error
 }
 
 var _ StatsReporter = (*reporter)(nil)
@@ -98,6 +106,15 @@ func (r *reporter) ReportEventCount(args *ReportArgs, responseCode int) error {
 	return nil
 }
 
+func (r *reporter) ReportRetryEventCount(args *ReportArgs, responseCode int) error {
+	ctx, err := r.generateTag(args, responseCode)
+	if err != nil {
+		return err
+	}
+	metrics.Record(ctx, retryEventCountM.M(1))
+	return nil
+}
+
 func (r *reporter) generateTag(args *ReportArgs, responseCode int) (context.Context, error) {
 	return tag.New(
 		r.ctx,
@@ -132,6 +149,12 @@ func register() {
 			Aggregation: view.Count(),
 			TagKeys:     tagKeys,
 		},
+		&view.View{
+			Description: retryEventCountM.Description(),
+			Measure:     retryEventCountM,
+			Aggregation: view.Count(),
+			TagKeys:     tagKeys,
+		},
 	); err != nil {
 		panic(err)
 	}

source/source_stats_reporter_test.go

@@ -51,14 +51,31 @@ func TestStatsReporter(t *testing.T) {
 		metricskey.LabelResponseCodeClass: "2xx",
 	}
 
-	// test ReportEventCount
+	retryWantTags := map[string]string{
+		metricskey.LabelNamespaceName:     "testns",
+		metricskey.LabelEventType:         "dev.knative.event",
+		metricskey.LabelEventSource:       "unit-test",
+		metricskey.LabelName:              "testsource",
+		metricskey.LabelResourceGroup:     "testresourcegroup",
+		metricskey.LabelResponseCode:      "503",
+		metricskey.LabelResponseCodeClass: "5xx",
+	}
+
+	// test ReportEventCount and ReportRetryEventCount
 	expectSuccess(t, func() error {
 		return r.ReportEventCount(args, http.StatusAccepted)
 	})
 	expectSuccess(t, func() error {
 		return r.ReportEventCount(args, http.StatusAccepted)
 	})
+	expectSuccess(t, func() error {
+		return r.ReportRetryEventCount(args, http.StatusServiceUnavailable)
+	})
+	expectSuccess(t, func() error {
+		return r.ReportRetryEventCount(args, http.StatusServiceUnavailable)
+	})
 	metricstest.CheckCountData(t, "event_count", wantTags, 2)
+	metricstest.CheckCountData(t, "retry_event_count", retryWantTags, 2)
 }
 
 func expectSuccess(t *testing.T, f func() error) {
@@ -75,5 +92,6 @@ func setup() {
 func resetMetrics() {
 	// OpenCensus metrics carry global state that need to be reset between unit tests.
 	metricstest.Unregister("event_count")
+	metricstest.Unregister("retry_event_count")
 	register()
 }