[prometheusremotewritereceiver] add sample stats headers

Author: perebaj

.chloggen/add-sample-stats-headers.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: 'enhancement'
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: 'prometheusremotewritereceiver'
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add a count of all successfully written samples when elements were processed.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [37277]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

receiver/prometheusremotewritereceiver/receiver.go

@@ -231,14 +231,15 @@ func (prw *prometheusRemoteWriteReceiver) parseProto(contentType string) (promco
 
 // translateV2 translates a v2 remote-write request into OTLP metrics.
 // translate is not feature complete.
-//
-//nolint:unparam
 func (prw *prometheusRemoteWriteReceiver) translateV2(_ context.Context, req *writev2.Request) (pmetric.Metrics, promremote.WriteResponseStats, error) {
 	var (
 		badRequestErrors error
 		otelMetrics      = pmetric.NewMetrics()
 		labelsBuilder    = labels.NewScratchBuilder(0)
-		stats            = promremote.WriteResponseStats{}
+		// More about stats: https://github.com/prometheus/docs/blob/main/docs/specs/prw/remote_write_spec_2_0.md#required-written-response-headers
+		// TODO: add histograms and exemplars to the stats. Histograms can be added after this PR be merged. Ref #39864
+		// Exemplars should be implemented to add them to the stats.
+		stats = promremote.WriteResponseStats{}
 		// The key is composed by: resource_hash:scope_name:scope_version:metric_name:unit:type
 		metricCache = make(map[uint64]pmetric.Metric)
 	)
@@ -367,9 +368,11 @@ func (prw *prometheusRemoteWriteReceiver) translateV2(_ context.Context, req *wr
 		// Otherwise, we append the samples to the existing metric.
 		switch ts.Metadata.Type {
 		case writev2.Metadata_METRIC_TYPE_GAUGE:
-			addNumberDatapoints(metric.Gauge().DataPoints(), ls, ts)
+			addNumberDatapoints(metric.Gauge().DataPoints(), ls, ts, &stats)
+			stats.Confirmed = true
 		case writev2.Metadata_METRIC_TYPE_COUNTER:
-			addNumberDatapoints(metric.Sum().DataPoints(), ls, ts)
+			addNumberDatapoints(metric.Sum().DataPoints(), ls, ts, &stats)
+			stats.Confirmed = true
 		case writev2.Metadata_METRIC_TYPE_HISTOGRAM:
 			addHistogramDatapoints(metric.Histogram().DataPoints(), ls, ts)
 		case writev2.Metadata_METRIC_TYPE_SUMMARY:
@@ -400,7 +403,7 @@ func parseJobAndInstance(dest pcommon.Map, job, instance string) {
 }
 
 // addNumberDatapoints adds the labels to the datapoints attributes.
-func addNumberDatapoints(datapoints pmetric.NumberDataPointSlice, ls labels.Labels, ts writev2.TimeSeries) {
+func addNumberDatapoints(datapoints pmetric.NumberDataPointSlice, ls labels.Labels, ts writev2.TimeSeries, stats *promremote.WriteResponseStats) {
 	// Add samples from the timeseries
 	for _, sample := range ts.Samples {
 		dp := datapoints.AppendEmpty()
@@ -418,6 +421,7 @@ func addNumberDatapoints(datapoints pmetric.NumberDataPointSlice, ls labels.Labe
 			}
 			attributes.PutStr(l.Name, l.Value)
 		}
+		stats.Samples++
 	}
 }
 

receiver/prometheusremotewritereceiver/receiver_test.go

@@ -87,34 +87,65 @@ func setupMetricsReceiver(t *testing.T) *prometheusRemoteWriteReceiver {
 
 func TestHandlePRWContentTypeNegotiation(t *testing.T) {
 	for _, tc := range []struct {
-		name         string
-		contentType  string
-		expectedCode int
+		name          string
+		contentType   string
+		expectedCode  int
+		expectedStats remote.WriteResponseStats
 	}{
 		{
 			name:         "no content type",
 			contentType:  "",
 			expectedCode: http.StatusUnsupportedMediaType,
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  false,
+				Samples:    0,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 		{
 			name:         "unsupported content type",
 			contentType:  "application/json",
 			expectedCode: http.StatusUnsupportedMediaType,
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  false,
+				Samples:    0,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 		{
 			name:         "x-protobuf/no proto parameter",
 			contentType:  "application/x-protobuf",
 			expectedCode: http.StatusUnsupportedMediaType,
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  false,
+				Samples:    0,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 		{
 			name:         "x-protobuf/v1 proto parameter",
 			contentType:  fmt.Sprintf("application/x-protobuf;proto=%s", promconfig.RemoteWriteProtoMsgV1),
 			expectedCode: http.StatusUnsupportedMediaType,
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  false,
+				Samples:    0,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 		{
 			name:         "x-protobuf/v2 proto parameter",
 			contentType:  fmt.Sprintf("application/x-protobuf;proto=%s", promconfig.RemoteWriteProtoMsgV2),
 			expectedCode: http.StatusNoContent,
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  true,
+				Samples:    0,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
@@ -170,6 +201,12 @@ func TestTranslateV2(t *testing.T) {
 				},
 			},
 			expectError: "missing metric name in labels",
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  false,
+				Samples:    0,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 		{
 			name: "duplicate label",
@@ -183,6 +220,12 @@ func TestTranslateV2(t *testing.T) {
 				},
 			},
 			expectError: `duplicate label "__name__" in labels`,
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  false,
+				Samples:    0,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 		{
 			name: "UnitRef bigger than symbols length",
@@ -266,7 +309,12 @@ func TestTranslateV2(t *testing.T) {
 
 				return expected
 			}(),
-			expectedStats: remote.WriteResponseStats{},
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  true,
+				Samples:    3,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 		{
 			name: "timeseries with different scopes",
@@ -342,7 +390,12 @@ func TestTranslateV2(t *testing.T) {
 
 				return expected
 			}(),
-			expectedStats: remote.WriteResponseStats{},
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  true,
+				Samples:    3,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 		{
 			name: "separate timeseries - same labels - should be same datapointslice",
@@ -426,6 +479,12 @@ func TestTranslateV2(t *testing.T) {
 
 				return expected
 			}(),
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  true,
+				Samples:    3,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 		{
 			name: "service with target_info metric",
@@ -488,6 +547,12 @@ func TestTranslateV2(t *testing.T) {
 
 				return metrics
 			}(),
+			expectedStats: remote.WriteResponseStats{
+				Confirmed:  true,
+				Samples:    1,
+				Histograms: 0,
+				Exemplars:  0,
+			},
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {