x-pack/metricbeat/module/gcp: Fix missing ECS labels when using exclu…

…de_labels: true (#40467)

* Issue fix

* Change.log

* resolved comments

* fix

CHANGELOG.next.asciidoc

@@ -182,6 +182,7 @@ https://github.com/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 - Update beat module with apm-server monitoring metrics fields {pull}40127[40127]
 - Fix Azure Monitor metric timespan to restore Storage Account PT1H metrics {issue}40376[40376] {pull}40367[40367]
 - Remove excessive info-level logs in cgroups setup {pull}40491[40491]
+- Add missing ECS Cloud fields in GCP `metrics` metricset when using `exclude_labels: true` {issue}40437[40437] {pull}40467[40467]
 
 *Osquerybeat*
 

x-pack/metricbeat/module/gcp/metrics/metricset.go

@@ -215,7 +215,7 @@ func (m *MetricSet) Fetch(ctx context.Context, reporter mb.ReporterV2) (err erro
 func (m *MetricSet) mapToEvents(ctx context.Context, timeSeries []timeSeriesWithAligner, sdc metricsConfig) ([]mb.Event, error) {
 	mapper := newIncomingFieldMapper(m.Logger(), sdc)
 
-	var metadataService = gcp.NewStackdriverMetadataServiceForTimeSeries(nil)
+	var metadataService gcp.MetadataService
 	var err error
 
 	if !m.config.ExcludeLabels {