Responded to Doug's comments

Author: zasweq

xds/internal/xdsclient/xdsresource/type_cds.go

@@ -85,7 +85,8 @@ type ClusterUpdate struct {
 
 	// Raw is the resource from the xds response.
 	Raw *anypb.Any
-	// All the string valued metadata of filter_metadata type
-	// "com.google.csm.telemetry_labels".
-	StringMD map[string]string
+	// TelemetryLabels are the string valued metadata of filter_metadata type
+	// "com.google.csm.telemetry_labels" with keys "service_name" or
+	// "service_namespace".
+	TelemetryLabels map[string]string
 }

xds/internal/xdsclient/xdsresource/unmarshal_cds.go

@@ -82,22 +82,18 @@ const (
 )
 
 func validateClusterAndConstructClusterUpdate(cluster *v3clusterpb.Cluster) (ClusterUpdate, error) {
-	stringMD := make(map[string]string)
+	telemetryLabels := make(map[string]string)
 	if fmd := cluster.GetMetadata().GetFilterMetadata(); fmd != nil {
 		if val, ok := fmd["com.google.csm.telemetry_labels"]; ok {
-			/*
-				"service_name" = "",
-				"service_namespace" = ""
-			*/
 			if fields := val.GetFields(); fields != nil {
 				if val, ok := fields["service_name"]; ok {
-					if _, isStringVal := val.GetKind().(*structpb.Value_StringValue); isStringVal {
-						stringMD["service_name"] = val.GetStringValue()
+					if _, ok := val.GetKind().(*structpb.Value_StringValue); ok {
+						telemetryLabels["service_name"] = val.GetStringValue()
 					}
 				}
 				if val, ok := fields["service_namespace"]; ok {
-					if _, isStringVal := val.GetKind().(*structpb.Value_StringValue); isStringVal {
-						stringMD["service_namespace"] = val.GetStringValue()
+					if _, ok := val.GetKind().(*structpb.Value_StringValue); ok {
+						telemetryLabels["service_namespace"] = val.GetStringValue()
 					}
 				}
 			}
@@ -183,7 +179,7 @@ func validateClusterAndConstructClusterUpdate(cluster *v3clusterpb.Cluster) (Clu
 		MaxRequests:      circuitBreakersFromCluster(cluster),
 		LBPolicy:         lbPolicy,
 		OutlierDetection: od,
-		StringMD:         stringMD,
+		TelemetryLabels:  telemetryLabels,
 	}
 
 	// Note that this is different from the gRFC (gRFC A47 says to include the

xds/internal/xdsclient/xdsresource/unmarshal_cds_test.go

@@ -1375,7 +1375,7 @@ func (s) TestUnmarshalCluster(t *testing.T) {
 				EDSServiceName:  v3Service,
 				LRSServerConfig: ClusterLRSServerSelf,
 				Raw:             v3ClusterAnyWithTelemetryLabels,
-				StringMD: map[string]string{
+				TelemetryLabels: map[string]string{
 					"service_name":      "grpc-service",
 					"service_namespace": "grpc-service-namespace",
 				},
@@ -1390,7 +1390,7 @@ func (s) TestUnmarshalCluster(t *testing.T) {
 				EDSServiceName:  v3Service,
 				LRSServerConfig: ClusterLRSServerSelf,
 				Raw:             v3ClusterAnyWithTelemetryLabelsIgnoreSome,
-				StringMD: map[string]string{
+				TelemetryLabels: map[string]string{
 					"service_name": "grpc-service",
 				},
 			},