Restore legacy dapr_http_server_response_count HTTP metric (dapr#7656)

The legacy `dapr_http_server_response_count` metric had been removed
from being served. This metric was relied upon by users.

Adds metric back to be served when in legacy metric mode. Should be
backported and patch released in 1.13.

Signed-off-by: joshvanl <[email protected]>

Author: JoshVanL

pkg/diagnostics/http_monitoring.go

@@ -49,6 +49,7 @@ type httpMetrics struct {
 	serverResponseBytes *stats.Int64Measure
 	serverLatency       *stats.Float64Measure
 	serverRequestCount  *stats.Int64Measure
+	serverResponseCount *stats.Int64Measure
 
 	clientSentBytes        *stats.Int64Measure
 	clientReceivedBytes    *stats.Int64Measure
@@ -83,6 +84,10 @@ func newHTTPMetrics() *httpMetrics {
 			"http/server/request_count",
 			"Count of HTTP requests processed by the server.",
 			stats.UnitDimensionless),
+		serverResponseCount: stats.Int64(
+			"http/server/response_count",
+			"The number of HTTP responses",
+			stats.UnitDimensionless),
 		clientSentBytes: stats.Int64(
 			"http/client/sent_bytes",
 			"Total bytes sent in request body (not including headers)",
@@ -130,6 +135,10 @@ func (h *httpMetrics) ServerRequestCompleted(ctx context.Context, method, path,
 			ctx,
 			diagUtils.WithTags(h.serverLatency.Name(), appIDKey, h.appID, httpMethodKey, method, httpPathKey, path, httpStatusCodeKey, status),
 			h.serverLatency.M(elapsed))
+		stats.RecordWithTags(
+			ctx,
+			diagUtils.WithTags(h.serverResponseCount.Name(), appIDKey, h.appID, httpPathKey, path, httpMethodKey, method, httpStatusCodeKey, status),
+			h.serverResponseCount.M(1))
 	} else {
 		stats.RecordWithTags(
 			ctx,
@@ -234,7 +243,8 @@ func (h *httpMetrics) Init(appID string, legacy bool) error {
 		serverTags = []tag.Key{appIDKey, httpMethodKey, httpStatusCodeKey}
 		clientTags = []tag.Key{appIDKey, httpStatusCodeKey}
 	}
-	return view.Register(
+
+	views := []*view.View{
 		diagUtils.NewMeasureView(h.serverRequestBytes, tags, defaultSizeDistribution),
 		diagUtils.NewMeasureView(h.serverResponseBytes, tags, defaultSizeDistribution),
 		diagUtils.NewMeasureView(h.serverLatency, serverTags, defaultLatencyDistribution),
@@ -245,7 +255,13 @@ func (h *httpMetrics) Init(appID string, legacy bool) error {
 		diagUtils.NewMeasureView(h.clientCompletedCount, clientTags, view.Count()),
 		diagUtils.NewMeasureView(h.healthProbeRoundripLatency, []tag.Key{appIDKey, httpStatusCodeKey}, defaultLatencyDistribution),
 		diagUtils.NewMeasureView(h.healthProbeCompletedCount, []tag.Key{appIDKey, httpStatusCodeKey}, view.Count()),
-	)
+	}
+
+	if h.legacy {
+		views = append(views, diagUtils.NewMeasureView(h.serverResponseCount, serverTags, view.Count()))
+	}
+
+	return view.Register(views...)
 }
 
 // HTTPMiddleware is the middleware to track HTTP server-side requests.

tests/integration/suite/daprd/metrics/http/cardinality/high.go

@@ -73,6 +73,8 @@ func (h *high) Run(t *testing.T, ctx context.Context) {
 		h.daprd.HTTPGet2xx(t, ctx, "/v1.0/invoke/myapp/method/hi")
 		metrics := h.daprd.Metrics(t, ctx)
 		assert.Equal(t, 1, int(metrics["dapr_http_server_request_count|app_id:myapp|method:GET|path:/v1.0/invoke/myapp/method/hi|status:200"]))
+		assert.Equal(t, 1, int(metrics["dapr_http_server_response_count|app_id:myapp|method:GET|path:/v1.0/healthz|status:204"]))
+		assert.Equal(t, 1, int(metrics["dapr_http_server_response_count|app_id:myapp|method:GET|path:/v1.0/invoke/myapp/method/hi|status:200"]))
 	})
 
 	t.Run("state stores", func(t *testing.T) {

tests/integration/suite/daprd/metrics/http/cardinality/low.go

@@ -73,6 +73,8 @@ func (l *low) Run(t *testing.T, ctx context.Context) {
 		l.daprd.HTTPGet2xx(t, ctx, "/v1.0/invoke/myapp/method/hi")
 		metrics := l.daprd.Metrics(t, ctx)
 		assert.Equal(t, 1, int(metrics["dapr_http_server_request_count|app_id:myapp|method:InvokeService/myapp|status:200"]))
+		assert.NotContains(t, metrics, "dapr_http_server_response_count|app_id:myapp|method:GET|path:/v1.0/invoke/myapp/method/hi|status:200")
+		assert.NotContains(t, metrics, "dapr_http_server_response_count|app_id:myapp|method:GET|path:/v1.0/healthz|status:204 1.000000")
 	})
 
 	t.Run("state stores", func(t *testing.T) {