[connector/spanmetrics] Improve consistency between metrics generated…

… by spanmetricsconnector (open-telemetry#34485)

**Link to tracking Issue:** open-telemetry#33227 open-telemetry#32818

**Documentation:** added an entry to the changelog explaining the
deprecated metrics.

---------

Signed-off-by: Israel Blancas <iblancasa@gmail.com>
Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>
Co-authored-by: Murphy Chen <minquan.chen@daocloud.io>
Co-authored-by: Rafael Pax <rpax@users.noreply.github.com>
Co-authored-by: Juraci Paixão Kröhling <juraci@kroehling.de>

.chloggen/feat_33227.yaml

@@ -0,0 +1,29 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: spanmetricsconnector
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Improve consistency between metrics generated by spanmetricsconnector. Added traces.span.metrics as default namespace 
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [33227, 32818]
+
+# (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: "Default namespace for the generated metrics is traces.span.metrics now. |
+  The deprecated metrics are: calls, duration and events. |
+  The feature flag connector.spanmetrics.legacyLatencyMetricNames was added to revert the behavior."
+
+# 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]

connector/spanmetricsconnector/README.md

@@ -111,7 +111,7 @@ The following settings can be optionally configured:
    cumulative temporality to avoid memory leaks and correct metric timestamp resets.
 - `aggregation_temporality` (default: `AGGREGATION_TEMPORALITY_CUMULATIVE`): Defines the aggregation temporality of the generated metrics. 
   One of either `AGGREGATION_TEMPORALITY_CUMULATIVE` or `AGGREGATION_TEMPORALITY_DELTA`.
-- `namespace`: Defines the namespace of the generated metrics. If `namespace` provided, generated metric name will be added `namespace.` prefix.
+- `namespace` (default: `traces.span.metrics`): Defines the namespace of the generated metrics. If `namespace` provided, generated metric name will be added `namespace.` prefix.
 - `metrics_flush_interval` (default: `60s`): Defines the flush interval of the generated metrics.
 - `metrics_expiration` (default: `0`): Defines the expiration time as `time.Duration`, after which, if no new spans are received, metrics will no longer be exported. Setting to `0` means the metrics will never expire (default behavior).
 - `metric_timestamp_cache_size` (default `1000`): Only relevant for delta temporality span metrics. Controls the size of the cache used to keep track of a metric's TimestampUnixNano the last time it was flushed. When a metric is evicted from the cache, its next data point will indicate a "reset" in the series. Downstream components converting from delta to cumulative, like `prometheusexporter`, may handle these resets by setting cumulative counters back to 0.
@@ -122,6 +122,8 @@ The following settings can be optionally configured:
   - `dimensions`: (mandatory if `enabled`) the list of the span's event attributes to add as dimensions to the events metric, which will be included _on top of_ the common and configured `dimensions` for span and resource attributes.
 - `resource_metrics_key_attributes`: Filter the resource attributes used to produce the resource metrics key map hash. Use this in case changing resource attributes (e.g. process id) are breaking counter metrics.
 
+The feature gate `connector.spanmetrics.legacyMetricNames` (disabled by default) controls the connector to use legacy metric names.
+
 ## Examples
 
 The following is a simple example usage of the `spanmetrics` connector.

connector/spanmetricsconnector/config_test.go

@@ -50,6 +50,7 @@ func TestLoadConfig(t *testing.T) {
 					{Name: "http.method", Default: &defaultMethod},
 					{Name: "http.status_code", Default: (*string)(nil)},
 				},
+				Namespace:                DefaultNamespace,
 				DimensionsCacheSize:      1500,
 				ResourceMetricsCacheSize: 1600,
 				MetricsFlushInterval:     30 * time.Second,
@@ -70,6 +71,7 @@ func TestLoadConfig(t *testing.T) {
 		{
 			id: component.NewIDWithName(metadata.Type, "exponential_histogram"),
 			expected: &Config{
+				Namespace:                DefaultNamespace,
 				AggregationTemporality:   cumulative,
 				DimensionsCacheSize:      defaultDimensionsCacheSize,
 				ResourceMetricsCacheSize: defaultResourceMetricsCacheSize,
@@ -103,6 +105,7 @@ func TestLoadConfig(t *testing.T) {
 				MetricsFlushInterval:     60 * time.Second,
 				Histogram:                HistogramConfig{Disable: false, Unit: defaultUnit},
 				Exemplars:                ExemplarsConfig{Enabled: true},
+				Namespace:                DefaultNamespace,
 			},
 		},
 		{
@@ -114,6 +117,7 @@ func TestLoadConfig(t *testing.T) {
 				MetricsFlushInterval:     60 * time.Second,
 				Histogram:                HistogramConfig{Disable: false, Unit: defaultUnit},
 				Exemplars:                ExemplarsConfig{Enabled: true, MaxPerDataPoint: &defaultMaxPerDatapoint},
+				Namespace:                DefaultNamespace,
 			},
 		},
 		{
@@ -125,6 +129,7 @@ func TestLoadConfig(t *testing.T) {
 				ResourceMetricsKeyAttributes: []string{"service.name", "telemetry.sdk.language", "telemetry.sdk.name"},
 				MetricsFlushInterval:         60 * time.Second,
 				Histogram:                    HistogramConfig{Disable: false, Unit: defaultUnit},
+				Namespace:                    DefaultNamespace,
 			},
 		},
 		{
@@ -136,6 +141,7 @@ func TestLoadConfig(t *testing.T) {
 				ResourceMetricsCacheSize: defaultResourceMetricsCacheSize,
 				MetricsFlushInterval:     60 * time.Second,
 				Histogram:                HistogramConfig{Disable: false, Unit: defaultUnit},
+				Namespace:                DefaultNamespace,
 			},
 		},
 		{
@@ -146,6 +152,7 @@ func TestLoadConfig(t *testing.T) {
 				ResourceMetricsCacheSize: defaultResourceMetricsCacheSize,
 				MetricsFlushInterval:     60 * time.Second,
 				Histogram:                HistogramConfig{Disable: false, Unit: defaultUnit},
+				Namespace:                DefaultNamespace,
 			},
 			extraAssertions: func(config *Config) {
 				assert.Equal(t, defaultDeltaTimestampCacheSize, config.GetDeltaTimestampCacheSize())

connector/spanmetricsconnector/connector.go

@@ -295,22 +295,28 @@ func (p *connectorImp) buildMetrics() pmetric.Metrics {
 			return startTime
 		}
 
+		metricsNamespace := p.config.Namespace
+		if legacyMetricNamesFeatureGate.IsEnabled() && metricsNamespace == DefaultNamespace {
+			metricsNamespace = ""
+		}
+
 		sums := rawMetrics.sums
 		metric := sm.Metrics().AppendEmpty()
-		metric.SetName(buildMetricName(p.config.Namespace, metricNameCalls))
+		metric.SetName(buildMetricName(metricsNamespace, metricNameCalls))
 		sums.BuildMetrics(metric, startTimeGenerator, timestamp, p.config.GetAggregationTemporality())
+
 		if !p.config.Histogram.Disable {
 			histograms := rawMetrics.histograms
 			metric = sm.Metrics().AppendEmpty()
-			metric.SetName(buildMetricName(p.config.Namespace, metricNameDuration))
+			metric.SetName(buildMetricName(metricsNamespace, metricNameDuration))
 			metric.SetUnit(p.config.Histogram.Unit.String())
 			histograms.BuildMetrics(metric, startTimeGenerator, timestamp, p.config.GetAggregationTemporality())
 		}
 
 		events := rawMetrics.events
 		if p.events.Enabled {
 			metric = sm.Metrics().AppendEmpty()
-			metric.SetName(buildMetricName(p.config.Namespace, metricNameEvents))
+			metric.SetName(buildMetricName(metricsNamespace, metricNameEvents))
 			events.BuildMetrics(metric, startTimeGenerator, timestamp, p.config.GetAggregationTemporality())
 		}
 

connector/spanmetricsconnector/connector_test.go

@@ -18,6 +18,7 @@ import (
 	"go.opentelemetry.io/collector/connector/connectortest"
 	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/consumer/consumertest"
+	"go.opentelemetry.io/collector/featuregate"
 	"go.opentelemetry.io/collector/pdata/pcommon"
 	"go.opentelemetry.io/collector/pdata/pmetric"
 	"go.opentelemetry.io/collector/pdata/ptrace"
@@ -1053,53 +1054,80 @@ func BenchmarkConnectorConsumeTraces(b *testing.B) {
 }
 
 func TestExcludeDimensionsConsumeTraces(t *testing.T) {
-	excludeDimensions := []string{"span.kind", "span.name", "totallyWrongNameDoesNotAffectAnything"}
-	p, err := newConnectorImp(stringp("defaultNullValue"), explicitHistogramsConfig, disabledExemplarsConfig, disabledEventsConfig, cumulative, 0, []string{}, 1000, clockwork.NewFakeClock(), excludeDimensions...)
-	require.NoError(t, err)
-	traces := buildSampleTrace()
 
-	// Test
-	ctx := metadata.NewIncomingContext(context.Background(), nil)
+	testcases := []struct {
+		dsc                string
+		featureGateEnabled bool
+	}{
+		{
+			dsc:                fmt.Sprintf("%s enabled", legacyMetricNamesFeatureGateID),
+			featureGateEnabled: true,
+		},
+		{
+			dsc:                fmt.Sprintf("%s disabled", legacyMetricNamesFeatureGateID),
+			featureGateEnabled: false,
+		},
+	}
 
-	err = p.ConsumeTraces(ctx, traces)
-	require.NoError(t, err)
-	metrics := p.buildMetrics()
+	excludeDimensions := []string{"span.kind", "span.name", "totallyWrongNameDoesNotAffectAnything"}
+	for _, tc := range testcases {
+		tc := tc
+		t.Run(tc.dsc, func(t *testing.T) {
+			// Set feature gate value
+			previousValue := legacyMetricNamesFeatureGate.IsEnabled()
+			require.NoError(t, featuregate.GlobalRegistry().Set(legacyMetricNamesFeatureGate.ID(), tc.featureGateEnabled))
+			defer func() {
+				require.NoError(t, featuregate.GlobalRegistry().Set(legacyMetricNamesFeatureGate.ID(), previousValue))
+			}()
+
+			p, err := newConnectorImp(stringp("defaultNullValue"), explicitHistogramsConfig, disabledExemplarsConfig, disabledEventsConfig, cumulative, 0, []string{}, 1000, clockwork.NewFakeClock(), excludeDimensions...)
+			require.NoError(t, err)
+			traces := buildSampleTrace()
 
-	for i := 0; i < metrics.ResourceMetrics().Len(); i++ {
-		rm := metrics.ResourceMetrics().At(i)
-		ism := rm.ScopeMetrics()
-		// Checking all metrics, naming notice: ilmC/mC - C here is for Counter.
-		for ilmC := 0; ilmC < ism.Len(); ilmC++ {
-			m := ism.At(ilmC).Metrics()
-			for mC := 0; mC < m.Len(); mC++ {
-				metric := m.At(mC)
-				// We check only sum and histogram metrics here, because for now only they are present in this module.
+			ctx := metadata.NewIncomingContext(context.Background(), nil)
 
-				switch metric.Type() {
-				case pmetric.MetricTypeExponentialHistogram, pmetric.MetricTypeHistogram:
-					{
-						dp := metric.Histogram().DataPoints()
-						for dpi := 0; dpi < dp.Len(); dpi++ {
-							for attributeKey := range dp.At(dpi).Attributes().AsRaw() {
-								assert.NotContains(t, excludeDimensions, attributeKey)
-							}
+			err = p.ConsumeTraces(ctx, traces)
+			require.NoError(t, err)
+			metrics := p.buildMetrics()
 
-						}
-					}
-				case pmetric.MetricTypeEmpty, pmetric.MetricTypeGauge, pmetric.MetricTypeSum, pmetric.MetricTypeSummary:
-					{
-						dp := metric.Sum().DataPoints()
-						for dpi := 0; dpi < dp.Len(); dpi++ {
-							for attributeKey := range dp.At(dpi).Attributes().AsRaw() {
-								assert.NotContains(t, excludeDimensions, attributeKey)
+			for i := 0; i < metrics.ResourceMetrics().Len(); i++ {
+				rm := metrics.ResourceMetrics().At(i)
+				ism := rm.ScopeMetrics()
+				// Checking all metrics, naming notice: ilmC/mC - C here is for Counter.
+				for ilmC := 0; ilmC < ism.Len(); ilmC++ {
+					m := ism.At(ilmC).Metrics()
+					for mC := 0; mC < m.Len(); mC++ {
+						metric := m.At(mC)
+						// We check only sum and histogram metrics here, because for now only they are present in this module.
+
+						switch metric.Type() {
+						case pmetric.MetricTypeExponentialHistogram, pmetric.MetricTypeHistogram:
+							{
+								dp := metric.Histogram().DataPoints()
+								for dpi := 0; dpi < dp.Len(); dpi++ {
+									for attributeKey := range dp.At(dpi).Attributes().AsRaw() {
+										assert.NotContains(t, excludeDimensions, attributeKey)
+									}
+
+								}
+							}
+						case pmetric.MetricTypeEmpty, pmetric.MetricTypeGauge, pmetric.MetricTypeSum, pmetric.MetricTypeSummary:
+							{
+								dp := metric.Sum().DataPoints()
+								for dpi := 0; dpi < dp.Len(); dpi++ {
+									for attributeKey := range dp.At(dpi).Attributes().AsRaw() {
+										assert.NotContains(t, excludeDimensions, attributeKey)
+									}
+								}
 							}
+
 						}
-					}
 
+					}
 				}
-
 			}
-		}
+
+		})
 	}
 
 }

connector/spanmetricsconnector/factory.go

@@ -13,10 +13,28 @@ import (
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/connector"
 	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/featuregate"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/connector/spanmetricsconnector/internal/metadata"
 )
 
+const (
+	DefaultNamespace               = "traces.span.metrics"
+	legacyMetricNamesFeatureGateID = "connector.spanmetrics.legacyMetricNames"
+)
+
+var legacyMetricNamesFeatureGate *featuregate.Gate
+
+func init() {
+	// TODO: Remove this feature gate when the legacy metric names are removed.
+	legacyMetricNamesFeatureGate = featuregate.GlobalRegistry().MustRegister(
+		legacyMetricNamesFeatureGateID,
+		featuregate.StageAlpha, // Alpha because we want it disabled by default.
+		featuregate.WithRegisterDescription("When enabled, connector uses legacy metric names."),
+		featuregate.WithRegisterReferenceURL("https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/33227"),
+	)
+}
+
 // NewFactory creates a factory for the spanmetrics connector.
 func NewFactory() connector.Factory {
 	return connector.NewFactory(
@@ -33,6 +51,7 @@ func createDefaultConfig() component.Config {
 		ResourceMetricsCacheSize: defaultResourceMetricsCacheSize,
 		MetricsFlushInterval:     60 * time.Second,
 		Histogram:                HistogramConfig{Disable: false, Unit: defaultUnit},
+		Namespace:                DefaultNamespace,
 	}
 }
 

connector/spanmetricsconnector/go.mod

@@ -15,6 +15,7 @@ require (
 	go.opentelemetry.io/collector/connector v0.108.2-0.20240829190554-7da6b618a7ee
 	go.opentelemetry.io/collector/consumer v0.108.2-0.20240829190554-7da6b618a7ee
 	go.opentelemetry.io/collector/consumer/consumertest v0.108.2-0.20240829190554-7da6b618a7ee
+	go.opentelemetry.io/collector/featuregate v1.14.2-0.20240829190554-7da6b618a7ee
 	go.opentelemetry.io/collector/pdata v1.14.2-0.20240829190554-7da6b618a7ee
 	go.opentelemetry.io/collector/semconv v0.108.2-0.20240829190554-7da6b618a7ee
 	go.uber.org/goleak v1.3.0
@@ -31,6 +32,7 @@ require (
 	github.com/go-viper/mapstructure/v2 v2.1.0 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/google/uuid v1.6.0 // indirect
+	github.com/hashicorp/go-version v1.7.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/compress v1.17.9 // indirect
 	github.com/knadh/koanf/maps v0.1.1 // indirect