[fix] Correctly add Metric Labels as Metric Attributes in OTel, not as Resource Attributes (#42473)

#### Description

Fixes issue
#42232
By no longer adding Metric Labels from the source metric, to the target
Resource Attributes.
Instead for every metric, add the Labels as Metric Attributes (which was
happening for 'histograms' already)

#### Link to tracking issue
Fixes
#42232

#### Testing
As there was only a test for gauges, I extended it to validate
attributes are correctly converted.

---------

Co-authored-by: David Ashpole <[email protected]>

Author: mdonkers

.chloggen/fix-42232-receiver-googlecloudmonitor.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: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: receiver/googlecloudmonitoring
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add metric labels from Google Cloud metrics to all OTel metric attributes
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [42232]
+
+# (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/googlecloudmonitoringreceiver/internal/metrics_conversion.go

@@ -41,6 +41,7 @@ func (mb *MetricsBuilder) ConvertGaugeToMetrics(ts *monitoringpb.TimeSeries, m p
 	m.SetUnit(ts.GetUnit())
 	gauge := m.SetEmptyGauge()
 
+	metricAttributes := convertLabelsToMetricAttributes(ts.GetMetric().GetLabels())
 	for _, point := range ts.GetPoints() {
 		dp := gauge.DataPoints().AppendEmpty()
 
@@ -56,6 +57,8 @@ func (mb *MetricsBuilder) ConvertGaugeToMetrics(ts *monitoringpb.TimeSeries, m p
 			mb.logger.Warn("EndTime is invalid for metric:", zap.String("Metric", ts.GetMetric().GetType()))
 		}
 
+		metricAttributes.CopyTo(dp.Attributes())
+
 		switch v := point.Value.Value.(type) {
 		case *monitoringpb.TypedValue_DoubleValue:
 			dp.SetDoubleValue(v.DoubleValue)
@@ -75,6 +78,7 @@ func (mb *MetricsBuilder) ConvertSumToMetrics(ts *monitoringpb.TimeSeries, m pme
 	sum := m.SetEmptySum()
 	sum.SetAggregationTemporality(pmetric.AggregationTemporalityCumulative)
 
+	metricAttributes := convertLabelsToMetricAttributes(ts.GetMetric().GetLabels())
 	for _, point := range ts.GetPoints() {
 		dp := sum.DataPoints().AppendEmpty()
 
@@ -90,6 +94,8 @@ func (mb *MetricsBuilder) ConvertSumToMetrics(ts *monitoringpb.TimeSeries, m pme
 			mb.logger.Warn("EndTime is invalid for metric:", zap.String("Metric", ts.GetMetric().GetType()))
 		}
 
+		metricAttributes.CopyTo(dp.Attributes())
+
 		switch v := point.Value.Value.(type) {
 		case *monitoringpb.TypedValue_DoubleValue:
 			dp.SetDoubleValue(v.DoubleValue)
@@ -109,6 +115,7 @@ func (mb *MetricsBuilder) ConvertDeltaToMetrics(ts *monitoringpb.TimeSeries, m p
 	sum := m.SetEmptySum()
 	sum.SetAggregationTemporality(pmetric.AggregationTemporalityDelta)
 
+	metricAttributes := convertLabelsToMetricAttributes(ts.GetMetric().GetLabels())
 	for _, point := range ts.GetPoints() {
 		dp := sum.DataPoints().AppendEmpty()
 
@@ -124,6 +131,8 @@ func (mb *MetricsBuilder) ConvertDeltaToMetrics(ts *monitoringpb.TimeSeries, m p
 			mb.logger.Warn("EndTime is invalid for metric:", zap.String("Metric", ts.GetMetric().GetType()))
 		}
 
+		metricAttributes.CopyTo(dp.Attributes())
+
 		switch v := point.Value.Value.(type) {
 		case *monitoringpb.TypedValue_DoubleValue:
 			dp.SetDoubleValue(v.DoubleValue)
@@ -152,7 +161,7 @@ func (mb *MetricsBuilder) ConvertDistributionToMetrics(ts *monitoringpb.TimeSeri
 	// > Importers and exporters working with OpenTelemetry Metrics data are meant to disregard this specification when
 	// > translating to and from histogram formats that use inclusive lower bounds and exclusive upper bounds.
 
-	metricAttributes := convertDistributionLabels(ts.GetMetric().GetLabels())
+	metricAttributes := convertLabelsToMetricAttributes(ts.GetMetric().GetLabels())
 	for _, sourceDataPoint := range ts.GetPoints() {
 		sourceValue := sourceDataPoint.GetValue()
 		if sourceValue == nil {
@@ -271,7 +280,7 @@ func (mb *MetricsBuilder) ConvertDistributionToMetrics(ts *monitoringpb.TimeSeri
 	return m
 }
 
-func convertDistributionLabels(sourceLabels map[string]string) pcommon.Map {
+func convertLabelsToMetricAttributes(sourceLabels map[string]string) pcommon.Map {
 	metricAttributes := pcommon.NewMap()
 	metricAttributes.EnsureCapacity(len(sourceLabels))
 	for k, v := range sourceLabels {

receiver/googlecloudmonitoringreceiver/internal/metrics_conversion_test.go

@@ -43,6 +43,9 @@ func TestConvertGaugeToMetrics(t *testing.T) {
 						},
 					},
 				},
+				Metric: &metric.Metric{
+					Labels: map[string]string{"labelKey": "labelValue"},
+				},
 			},
 			fileNameExpected: "TestConvertGaugeToMetrics_ValidGaugePoints.yaml",
 		},

receiver/googlecloudmonitoringreceiver/internal/testdata/TestConvertGaugeToMetrics_ValidGaugePoints.yaml

@@ -7,4 +7,8 @@ resourceMetrics:
                 - asDouble: 42
                   startTimeUnixNano: "10000000000"
                   timeUnixNano: "20000000000"
+                  attributes:
+                    - key: labelKey
+                      value:
+                        stringValue: labelValue
         scope: {}

receiver/googlecloudmonitoringreceiver/receiver.go

@@ -279,13 +279,6 @@ func (mr *monitoringReceiver) convertGCPTimeSeriesToMetrics(metrics pmetric.Metr
 			}
 		}
 
-		// Add metric-specific labels if they are present
-		if len(timeSeries.GetMetric().Labels) > 0 {
-			for k, v := range timeSeries.GetMetric().GetLabels() {
-				resource.Attributes().PutStr(k, v)
-			}
-		}
-
 		// Store the newly created ResourceMetrics in the map
 		resourceMetricsMap[resourceKey] = rm
 	}