stats/opencensus: remove leading slash for per call metrics (#6141)

stats/opencensus/e2e_test.go

@@ -193,7 +193,7 @@ func (vi *viewInformation) Equal(vi2 *viewInformation) bool {
 // less. This must be called with non nil view information that is aggregated
 // with distribution data. Returns a nil error if correct count information
 // found, non nil error if correct information not found.
-func distributionDataLatencyCount(vi *viewInformation, countWant int64) error {
+func distributionDataLatencyCount(vi *viewInformation, countWant int64, wantTags [][]tag.Tag) error {
 	var totalCount int64
 	var largestIndexWithFive int
 	for i, bucket := range vi.aggBuckets {
@@ -204,9 +204,21 @@ func distributionDataLatencyCount(vi *viewInformation, countWant int64) error {
 			break
 		}
 	}
+	// Sort rows by string name. This is to take away non determinism in the row
+	// ordering passed to the Exporter, while keeping the row data.
+	sort.Slice(vi.rows, func(i, j int) bool {
+		return vi.rows[i].String() > vi.rows[j].String()
+	})
 	// Iterating through rows sums up data points for all methods. In this case,
 	// a data point for the unary and for the streaming RPC.
-	for _, row := range vi.rows {
+	for i, row := range vi.rows {
+		// The method names corresponding to unary and streaming call should
+		// have the leading slash removed.
+		if diff := cmp.Diff(row.Tags, wantTags[i], cmp.Comparer(func(a tag.Key, b tag.Key) bool {
+			return a.Name() == b.Name()
+		})); diff != "" {
+			return fmt.Errorf("wrong tag keys for unary method -got, +want: %v", diff)
+		}
 		// This could potentially have an extra measurement in buckets above 5s,
 		// but that's fine. Count of buckets that could contain up to 5s is a
 		// good enough assertion.
@@ -305,8 +317,9 @@ func (s) TestAllMetricsOneFunction(t *testing.T) {
 	cstk := tag.MustNewKey("grpc_client_status")
 	sstk := tag.MustNewKey("grpc_server_status")
 	wantMetrics := []struct {
-		metric *view.View
-		wantVI *viewInformation
+		metric   *view.View
+		wantVI   *viewInformation
+		wantTags [][]tag.Tag // for non determinstic (i.e. latency) metrics. First dimension represents rows.
 	}{
 		{
 			metric: ClientStartedRPCsView,
@@ -913,13 +926,63 @@ func (s) TestAllMetricsOneFunction(t *testing.T) {
 		},
 		{
 			metric: ClientRoundtripLatencyView,
+			wantTags: [][]tag.Tag{
+				{
+					{
+						Key:   cmtk,
+						Value: "grpc.testing.TestService/UnaryCall",
+					},
+				},
+				{
+					{
+						Key:   cmtk,
+						Value: "grpc.testing.TestService/FullDuplexCall",
+					},
+				},
+			},
 		},
 		{
 			metric: ServerLatencyView,
+			wantTags: [][]tag.Tag{
+				{
+					{
+						Key:   smtk,
+						Value: "grpc.testing.TestService/UnaryCall",
+					},
+				},
+				{
+					{
+						Key:   smtk,
+						Value: "grpc.testing.TestService/FullDuplexCall",
+					},
+				},
+			},
 		},
 		// Per call metrics:
 		{
 			metric: ClientAPILatencyView,
+			wantTags: [][]tag.Tag{
+				{
+					{
+						Key:   cmtk,
+						Value: "grpc.testing.TestService/UnaryCall",
+					},
+					{
+						Key:   cstk,
+						Value: "OK",
+					},
+				},
+				{
+					{
+						Key:   cmtk,
+						Value: "grpc.testing.TestService/FullDuplexCall",
+					},
+					{
+						Key:   cstk,
+						Value: "OK",
+					},
+				},
+			},
 		},
 	}
 	// Unregister all the views. Unregistering a view causes a synchronous
@@ -945,7 +1008,7 @@ func (s) TestAllMetricsOneFunction(t *testing.T) {
 			// RPCs have a context timeout of 5s, so all the recorded
 			// measurements (one per RPC - two total) should fall within 5
 			// second buckets.
-			if err := distributionDataLatencyCount(vi, 2); err != nil {
+			if err := distributionDataLatencyCount(vi, 2, wantMetric.wantTags); err != nil {
 				t.Fatalf("Invalid OpenCensus export view data for metric %v: %v", metricName, err)
 			}
 			continue

stats/opencensus/opencensus.go

@@ -104,7 +104,7 @@ func perCallTracesAndMetrics(err error, span *trace.Span, startTime time.Time, m
 	callLatency := float64(time.Since(startTime)) / float64(time.Millisecond)
 	ocstats.RecordWithOptions(context.Background(),
 		ocstats.WithTags(
-			tag.Upsert(keyClientMethod, method),
+			tag.Upsert(keyClientMethod, removeLeadingSlash(method)),
 			tag.Upsert(keyClientStatus, canonicalString(s.Code())),
 		),
 		ocstats.WithMeasurements(