[servicegraphprocessor, servicegraphconnector] Measure latency in sec…

…onds instead of milliseconds (open-telemetry#27665)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->

Measures latency in seconds instead of milliseconds, as the metric name
indicates. Previously, milliseconds was used. This unit is still
available via the feature gate
`processor.servicegraph.legacyLatencyUnitMs`.

This is a breaking change.

**Link to tracking Issue:** <Issue number if applicable>  open-telemetry#27488

**Testing:** <Describe what testing was performed and which tests were
added.> Tests are updated

**Documentation:** <Describe the documentation added.>

---------

Co-authored-by: Curtis Robert <92119472+crobert-1@users.noreply.github.com>
Co-authored-by: Juraci Paixão Kröhling <juraci@kroehling.de>

.chloggen/servicegraph-fix-time-unit.yaml

@@ -0,0 +1,31 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: servicegraphprocessor, servicegraphconnector
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Measure latency in seconds instead of milliseconds
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [27488]
+
+# (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: |
+  Measures latency in seconds instead of milliseconds, as the metric name indicates.
+  Previously, milliseconds was used.
+  This unit is still available via the feature gate `processor.servicegraph.legacyLatencyUnitMs`.
+  This is a breaking change.
+
+# 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: []

processor/servicegraphprocessor/factory.go

@@ -22,9 +22,10 @@ const (
 	connectorStability                    = component.StabilityLevelDevelopment
 	virtualNodeFeatureGateID              = "processor.servicegraph.virtualNode"
 	legacyLatencyMetricNamesFeatureGateID = "processor.servicegraph.legacyLatencyMetricNames"
+	legacyLatencyUnitMs                   = "processor.servicegraph.legacyLatencyUnitMs"
 )
 
-var virtualNodeFeatureGate, legacyMetricNamesFeatureGate *featuregate.Gate
+var virtualNodeFeatureGate, legacyMetricNamesFeatureGate, legacyLatencyUnitMsFeatureGate *featuregate.Gate
 
 func init() {
 	virtualNodeFeatureGate = featuregate.GlobalRegistry().MustRegister(
@@ -40,6 +41,12 @@ func init() {
 		featuregate.WithRegisterDescription("When enabled, processor uses legacy latency metric names."),
 		featuregate.WithRegisterReferenceURL("https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/18743,https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/16578"),
 	)
+	legacyLatencyUnitMsFeatureGate = featuregate.GlobalRegistry().MustRegister(
+		legacyLatencyUnitMs,
+		featuregate.StageAlpha, // Alpha because we want it disabled by default.
+		featuregate.WithRegisterDescription("When enabled, processor reports latency in milliseconds, instead of seconds."),
+		featuregate.WithRegisterReferenceURL("https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/27488"),
+	)
 }
 
 // NewFactory creates a factory for the servicegraph processor.

processor/servicegraphprocessor/factory_test.go

@@ -22,17 +22,17 @@ func TestNewProcessor(t *testing.T) {
 	}{
 		{
 			name:                            "simplest config (use defaults)",
-			expectedLatencyHistogramBuckets: defaultLatencyHistogramBucketsMs,
+			expectedLatencyHistogramBuckets: defaultLatencyHistogramBuckets,
 		},
 		{
 			name:                            "latency histogram configured with catch-all bucket to check no additional catch-all bucket inserted",
 			latencyHistogramBuckets:         []time.Duration{2 * time.Millisecond},
-			expectedLatencyHistogramBuckets: []float64{2},
+			expectedLatencyHistogramBuckets: []float64{0.002},
 		},
 		{
 			name:                            "full config with no catch-all bucket and check the catch-all bucket is inserted",
 			latencyHistogramBuckets:         []time.Duration{2 * time.Millisecond},
-			expectedLatencyHistogramBuckets: []float64{2},
+			expectedLatencyHistogramBuckets: []float64{0.002},
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
@@ -64,17 +64,17 @@ func TestNewConnector(t *testing.T) {
 	}{
 		{
 			name:                            "simplest config (use defaults)",
-			expectedLatencyHistogramBuckets: defaultLatencyHistogramBucketsMs,
+			expectedLatencyHistogramBuckets: defaultLatencyHistogramBuckets,
 		},
 		{
 			name:                            "latency histogram configured with catch-all bucket to check no additional catch-all bucket inserted",
 			latencyHistogramBuckets:         []time.Duration{2 * time.Millisecond},
-			expectedLatencyHistogramBuckets: []float64{2},
+			expectedLatencyHistogramBuckets: []float64{0.002},
 		},
 		{
 			name:                            "full config with no catch-all bucket and check the catch-all bucket is inserted",
 			latencyHistogramBuckets:         []time.Duration{2 * time.Millisecond},
-			expectedLatencyHistogramBuckets: []float64{2},
+			expectedLatencyHistogramBuckets: []float64{0.002},
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {

processor/servicegraphprocessor/processor.go

@@ -33,9 +33,13 @@ const (
 )
 
 var (
-	defaultLatencyHistogramBucketsMs = []float64{
+	legacyDefaultLatencyHistogramBuckets = []float64{
 		2, 4, 6, 8, 10, 50, 100, 200, 400, 800, 1000, 1400, 2000, 5000, 10_000, 15_000,
 	}
+	defaultLatencyHistogramBuckets = []float64{
+		0.002, 0.004, 0.006, 0.008, 0.01, 0.05, 0.1, 0.2, 0.4, 0.8, 1, 1.4, 2, 5, 10, 15,
+	}
+
 	defaultPeerAttributes = []string{
 		semconv.AttributeDBName, semconv.AttributeNetSockPeerAddr, semconv.AttributeNetPeerName, semconv.AttributeRPCService, semconv.AttributeNetSockPeerName, semconv.AttributeNetPeerName, semconv.AttributeHTTPURL, semconv.AttributeHTTPTarget,
 	}
@@ -78,9 +82,12 @@ type serviceGraphProcessor struct {
 func newProcessor(logger *zap.Logger, config component.Config) *serviceGraphProcessor {
 	pConfig := config.(*Config)
 
-	bounds := defaultLatencyHistogramBucketsMs
+	bounds := defaultLatencyHistogramBuckets
+	if legacyLatencyUnitMsFeatureGate.IsEnabled() {
+		bounds = legacyDefaultLatencyHistogramBuckets
+	}
 	if pConfig.LatencyHistogramBuckets != nil {
-		bounds = mapDurationsToMillis(pConfig.LatencyHistogramBuckets)
+		bounds = mapDurationsToFloat(pConfig.LatencyHistogramBuckets)
 	}
 
 	if pConfig.CacheLoop <= 0 {
@@ -254,7 +261,7 @@ func (p *serviceGraphProcessor) aggregateMetrics(ctx context.Context, td ptrace.
 						e.TraceID = traceID
 						e.ConnectionType = connectionType
 						e.ClientService = serviceName
-						e.ClientLatencySec = float64(span.EndTimestamp()-span.StartTimestamp()) / float64(time.Millisecond.Nanoseconds())
+						e.ClientLatencySec = spanDuration(span)
 						e.Failed = e.Failed || span.Status().Code() == ptrace.StatusCodeError
 						p.upsertDimensions(clientKind, e.Dimensions, rAttributes, span.Attributes())
 
@@ -267,7 +274,7 @@ func (p *serviceGraphProcessor) aggregateMetrics(ctx context.Context, td ptrace.
 						if dbName, ok := findAttributeValue(semconv.AttributeDBName, rAttributes, span.Attributes()); ok {
 							e.ConnectionType = store.Database
 							e.ServerService = dbName
-							e.ServerLatencySec = float64(span.EndTimestamp()-span.StartTimestamp()) / float64(time.Millisecond.Nanoseconds())
+							e.ServerLatencySec = spanDuration(span)
 						}
 					})
 				case ptrace.SpanKindConsumer:
@@ -281,7 +288,7 @@ func (p *serviceGraphProcessor) aggregateMetrics(ctx context.Context, td ptrace.
 						e.TraceID = traceID
 						e.ConnectionType = connectionType
 						e.ServerService = serviceName
-						e.ServerLatencySec = float64(span.EndTimestamp()-span.StartTimestamp()) / float64(time.Millisecond.Nanoseconds())
+						e.ServerLatencySec = spanDuration(span)
 						e.Failed = e.Failed || span.Status().Code() == ptrace.StatusCodeError
 						p.upsertDimensions(serverKind, e.Dimensions, rAttributes, span.Attributes())
 					})
@@ -655,16 +662,26 @@ func (p *serviceGraphProcessor) cleanCache() {
 	p.seriesMutex.Unlock()
 }
 
-// durationToMillis converts the given duration to the number of milliseconds it represents.
-// Note that this can return sub-millisecond (i.e. < 1ms) values as well.
-func durationToMillis(d time.Duration) float64 {
-	return float64(d.Nanoseconds()) / float64(time.Millisecond.Nanoseconds())
+// spanDuration returns the duration of the given span in seconds (legacy ms).
+func spanDuration(span ptrace.Span) float64 {
+	if legacyLatencyUnitMsFeatureGate.IsEnabled() {
+		return float64(span.EndTimestamp()-span.StartTimestamp()) / float64(time.Millisecond.Nanoseconds())
+	}
+	return float64(span.EndTimestamp()-span.StartTimestamp()) / float64(time.Second.Nanoseconds())
+}
+
+// durationToFloat converts the given duration to the number of seconds (legacy ms) it represents.
+func durationToFloat(d time.Duration) float64 {
+	if legacyLatencyUnitMsFeatureGate.IsEnabled() {
+		return float64(d.Milliseconds())
+	}
+	return d.Seconds()
 }
 
-func mapDurationsToMillis(vs []time.Duration) []float64 {
+func mapDurationsToFloat(vs []time.Duration) []float64 {
 	vsm := make([]float64, len(vs))
 	for i, v := range vs {
-		vsm[i] = durationToMillis(v)
+		vsm[i] = durationToFloat(v)
 	}
 	return vsm
 }

processor/servicegraphprocessor/processor_test.go

@@ -123,12 +123,10 @@ func TestConnectorShutdown(t *testing.T) {
 }
 
 func TestProcessorConsume(t *testing.T) {
-	// set virtual node feature
-	_ = featuregate.GlobalRegistry().Set(virtualNodeFeatureGate.ID(), true)
-
 	for _, tc := range []struct {
 		name          string
 		cfg           Config
+		gates         []*featuregate.Gate
 		sampleTraces  ptrace.Traces
 		verifyMetrics func(t *testing.T, md pmetric.Metrics)
 	}{
@@ -155,6 +153,7 @@ func TestProcessorConsume(t *testing.T) {
 					TTL:      time.Nanosecond,
 				},
 			},
+			gates:        []*featuregate.Gate{virtualNodeFeatureGate},
 			sampleTraces: incompleteClientTraces(),
 			verifyMetrics: func(t *testing.T, md pmetric.Metrics) {
 				v, ok := md.ResourceMetrics().At(0).ScopeMetrics().At(0).Metrics().At(0).Sum().DataPoints().At(0).Attributes().Get("server")
@@ -172,6 +171,7 @@ func TestProcessorConsume(t *testing.T) {
 					TTL:      time.Nanosecond,
 				},
 			},
+			gates:        []*featuregate.Gate{virtualNodeFeatureGate},
 			sampleTraces: incompleteServerTraces(false),
 			verifyMetrics: func(t *testing.T, md pmetric.Metrics) {
 				v, ok := md.ResourceMetrics().At(0).ScopeMetrics().At(0).Metrics().At(0).Sum().DataPoints().At(0).Attributes().Get("client")
@@ -189,13 +189,32 @@ func TestProcessorConsume(t *testing.T) {
 					TTL:      time.Nanosecond,
 				},
 			},
+			gates:        []*featuregate.Gate{virtualNodeFeatureGate},
 			sampleTraces: incompleteServerTraces(true),
 			verifyMetrics: func(t *testing.T, md pmetric.Metrics) {
 				assert.Equal(t, 0, md.MetricCount())
 			},
 		},
+		{
+			name: "complete traces with legacy latency metrics",
+			cfg: Config{
+				MetricsExporter: "mock",
+				Dimensions:      []string{"some-attribute", "non-existing-attribute"},
+				Store: StoreConfig{
+					MaxItems: 10,
+					TTL:      time.Nanosecond,
+				},
+			}, sampleTraces: buildSampleTrace(t, "val"),
+			gates:         []*featuregate.Gate{virtualNodeFeatureGate, legacyLatencyUnitMsFeatureGate},
+			verifyMetrics: verifyHappyCaseMetricsWithDuration(1000),
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
+			// Set feature gates
+			for _, gate := range tc.gates {
+				require.NoError(t, featuregate.GlobalRegistry().Set(gate.ID(), true))
+			}
+
 			// Prepare
 			p := newProcessor(zaptest.NewLogger(t), &tc.cfg)
 			p.tracesConsumer = consumertest.NewNop()
@@ -224,11 +243,13 @@ func TestProcessorConsume(t *testing.T) {
 
 			// Shutdown the processor
 			assert.NoError(t, p.Shutdown(context.Background()))
+
+			// Unset feature gates
+			for _, gate := range tc.gates {
+				require.NoError(t, featuregate.GlobalRegistry().Set(gate.ID(), false))
+			}
 		})
 	}
-
-	// unset virtual node feature
-	_ = featuregate.GlobalRegistry().Set(virtualNodeFeatureGate.ID(), false)
 }
 
 func TestConnectorConsume(t *testing.T) {
@@ -296,27 +317,33 @@ func TestProcessor_MetricsFlushInterval(t *testing.T) {
 }
 
 func verifyHappyCaseMetrics(t *testing.T, md pmetric.Metrics) {
-	assert.Equal(t, 3, md.MetricCount())
+	verifyHappyCaseMetricsWithDuration(1)(t, md)
+}
 
-	rms := md.ResourceMetrics()
-	assert.Equal(t, 1, rms.Len())
+func verifyHappyCaseMetricsWithDuration(durationSum float64) func(t *testing.T, md pmetric.Metrics) {
+	return func(t *testing.T, md pmetric.Metrics) {
+		assert.Equal(t, 3, md.MetricCount())
 
-	sms := rms.At(0).ScopeMetrics()
-	assert.Equal(t, 1, sms.Len())
+		rms := md.ResourceMetrics()
+		assert.Equal(t, 1, rms.Len())
 
-	ms := sms.At(0).Metrics()
-	assert.Equal(t, 3, ms.Len())
+		sms := rms.At(0).ScopeMetrics()
+		assert.Equal(t, 1, sms.Len())
 
-	mCount := ms.At(0)
-	verifyCount(t, mCount)
+		ms := sms.At(0).Metrics()
+		assert.Equal(t, 3, ms.Len())
 
-	mServerDuration := ms.At(1)
-	assert.Equal(t, "traces_service_graph_request_server_seconds", mServerDuration.Name())
-	verifyDuration(t, mServerDuration)
+		mCount := ms.At(0)
+		verifyCount(t, mCount)
 
-	mClientDuration := ms.At(2)
-	assert.Equal(t, "traces_service_graph_request_client_seconds", mClientDuration.Name())
-	verifyDuration(t, mClientDuration)
+		mServerDuration := ms.At(1)
+		assert.Equal(t, "traces_service_graph_request_server_seconds", mServerDuration.Name())
+		verifyDuration(t, mServerDuration, durationSum)
+
+		mClientDuration := ms.At(2)
+		assert.Equal(t, "traces_service_graph_request_client_seconds", mClientDuration.Name())
+		verifyDuration(t, mClientDuration, durationSum)
+	}
 }
 
 func verifyCount(t *testing.T, m pmetric.Metric) {
@@ -339,13 +366,13 @@ func verifyCount(t *testing.T, m pmetric.Metric) {
 	verifyAttr(t, attributes, "client_some-attribute", "val")
 }
 
-func verifyDuration(t *testing.T, m pmetric.Metric) {
+func verifyDuration(t *testing.T, m pmetric.Metric, durationSum float64) {
 	assert.Equal(t, pmetric.MetricTypeHistogram, m.Type())
 	dps := m.Histogram().DataPoints()
 	assert.Equal(t, 1, dps.Len())
 
 	dp := dps.At(0)
-	assert.Equal(t, float64(1000), dp.Sum()) // Duration: 1sec
+	assert.Equal(t, durationSum, dp.Sum()) // Duration: 1sec
 	assert.Equal(t, uint64(1), dp.Count())
 	buckets := pcommon.NewUInt64Slice()
 	buckets.FromRaw([]uint64{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0})
@@ -526,7 +553,7 @@ func TestUpdateDurationMetrics(t *testing.T) {
 		reqClientDurationSecondsSum:          make(map[string]float64),
 		reqClientDurationSecondsCount:        make(map[string]uint64),
 		reqClientDurationSecondsBucketCounts: make(map[string][]uint64),
-		reqDurationBounds:                    defaultLatencyHistogramBucketsMs,
+		reqDurationBounds:                    defaultLatencyHistogramBuckets,
 		keyToMetric:                          make(map[string]metricSeries),
 		config: &Config{
 			Dimensions: []string{},