[metricbeat] gcp: check for nil metadata (#32281)

* add check for nil metadata

* add changelog entry

(cherry picked from commit fa8d17f)

CHANGELOG.next.asciidoc

@@ -53,6 +53,10 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 
 *Metricbeat*
 
+- update kubernetes apiserver metricset to not collect deprecated metrics and fix dashboard {pull}31973[31973]
+- Check for nil metadata in GCP. {pull}32281[32281]
+- update kubernetes controllermanager metricset to not collect deprecated metrics and fix dashboard {pull}32037[32037]
+- update elasticsearch node_stats metricset to use keyword for cgroup memory instead of long {pull}32197[32197]
 
 *Packetbeat*
 

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

@@ -314,14 +314,16 @@ func (m *MetricSet) getMetadata(out *metric.MetricDescriptor, metricsWithMeta ma
 		ingestDelay:  0 * time.Second,
 	}
 
-	if out.Metadata.SamplePeriod != nil {
-		m.Logger().Debugf("For metric type %s: sample period = %s", out.Type, out.Metadata.SamplePeriod)
-		meta.samplePeriod = time.Duration(out.Metadata.SamplePeriod.Seconds) * time.Second
-	}
+	if out.Metadata != nil {
+		if out.Metadata.SamplePeriod != nil {
+			m.Logger().Debugf("For metric type %s: sample period = %s", out.Type, out.Metadata.SamplePeriod)
+			meta.samplePeriod = time.Duration(out.Metadata.SamplePeriod.Seconds) * time.Second
+		}
 
-	if out.Metadata.IngestDelay != nil {
-		m.Logger().Debugf("For metric type %s: ingest delay = %s", out.Type, out.Metadata.IngestDelay)
-		meta.ingestDelay = time.Duration(out.Metadata.IngestDelay.Seconds) * time.Second
+		if out.Metadata.IngestDelay != nil {
+			m.Logger().Debugf("For metric type %s: ingest delay = %s", out.Type, out.Metadata.IngestDelay)
+			meta.ingestDelay = time.Duration(out.Metadata.IngestDelay.Seconds) * time.Second
+		}
 	}
 
 	metricsWithMeta[out.Type] = meta