only use unknown_service as a fallback for job label

exporter/collector/googlemanagedprometheus/monitoredresource.go

@@ -15,6 +15,8 @@
 package googlemanagedprometheus
 
 import (
+	"strings"
+
 	"go.opentelemetry.io/collector/pdata/pcommon"
 	semconv "go.opentelemetry.io/collector/semconv/v1.18.0"
 	monitoredrespb "google.golang.org/genproto/googleapis/api/monitoredres"
@@ -32,6 +34,7 @@ const (
 	jobLabel              = "job"
 	serviceNamespaceLabel = "service_namespace"
 	instanceLabel         = "instance"
+	unknownServicePrefix  = "unknown_service"
 )
 
 // promTargetKeys are attribute keys which are used in the prometheus_target monitored resource.
@@ -40,9 +43,9 @@ var promTargetKeys = map[string][]string{
 	locationLabel:         {locationLabel, semconv.AttributeCloudAvailabilityZone, semconv.AttributeCloudRegion},
 	clusterLabel:          {clusterLabel, semconv.AttributeK8SClusterName},
 	namespaceLabel:        {namespaceLabel, semconv.AttributeK8SNamespaceName},
-	jobLabel:              {jobLabel, semconv.AttributeFaaSName, semconv.AttributeServiceName},
+	jobLabel:              {jobLabel, semconv.AttributeServiceName, semconv.AttributeFaaSName},
 	serviceNamespaceLabel: {semconv.AttributeServiceNamespace},
-	instanceLabel:         {instanceLabel, semconv.AttributeFaaSInstance, semconv.AttributeServiceInstanceID},
+	instanceLabel:         {instanceLabel, semconv.AttributeServiceInstanceID, semconv.AttributeFaaSInstance},
 }
 
 func (c Config) MapToPrometheusTarget(res pcommon.Resource) *monitoredrespb.MonitoredResource {
@@ -69,9 +72,24 @@ func (c Config) MapToPrometheusTarget(res pcommon.Resource) *monitoredrespb.Moni
 // getStringOrEmpty returns the value of the first key found, or the empty string.
 func getStringOrEmpty(attributes pcommon.Map, keys ...string) string {
 	for _, k := range keys {
-		if val, ok := attributes.Get(k); ok {
+		if val, ok := attributes.Get(k); ok && !strings.HasPrefix(val.Str(), unknownServicePrefix) {
+			return val.Str()
+		}
+	}
+	if contains(keys, string(semconv.AttributeServiceName)) {
+		// the service name started with unknown_service, and was ignored above
+		if val, ok := attributes.Get(semconv.AttributeServiceName); ok {
 			return val.Str()
 		}
 	}
 	return ""
 }
+
+func contains(list []string, element string) bool {
+	for _, item := range list {
+		if item == element {
+			return true
+		}
+	}
+	return false
+}

exporter/collector/googlemanagedprometheus/monitoredresource_test.go

@@ -150,7 +150,7 @@ func TestMapToPrometheusTarget(t *testing.T) {
 			desc: "Attributes from cloud run",
 			resourceLabels: map[string]string{
 				"cloud.region":  "us-central1",
-				"service.name":  "service:unknown",
+				"service.name":  "unknown_service:go",
 				"faas.name":     "my-cloud-run-service",
 				"faas.instance": "1234759430923053489543203",
 			},

exporter/collector/monitoredresource_test.go

@@ -517,6 +517,70 @@ func TestResourceMetricsToMonitoringMonitoredResource(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "Cloud Run Instance",
+			resourceLabels: map[string]string{
+				"cloud.provider": "gcp",
+				"cloud.platform": "gcp_cloud_run",
+				"cloud.region":   "my-region",
+				"faas.instance":  "myinstanceid",
+				"faas.name":      "myfaasname",
+				"faas.version":   "v1",
+			},
+			expectMr: &monitoredrespb.MonitoredResource{
+				Type: "generic_task",
+				Labels: map[string]string{
+					"job":       "myfaasname",
+					"location":  "my-region",
+					"namespace": "",
+					"task_id":   "myinstanceid",
+				},
+			},
+		},
+		{
+			name: "Cloud Run Instance with default service",
+			resourceLabels: map[string]string{
+				"cloud.provider": "gcp",
+				"cloud.platform": "gcp_cloud_run",
+				"cloud.region":   "my-region",
+				"service.name":   "unknown_service:go",
+				"faas.instance":  "myinstanceid",
+				"faas.name":      "myfaasname",
+				"faas.version":   "v1",
+			},
+			expectMr: &monitoredrespb.MonitoredResource{
+				Type: "generic_task",
+				Labels: map[string]string{
+					"job":       "myfaasname",
+					"location":  "my-region",
+					"namespace": "",
+					"task_id":   "myinstanceid",
+				},
+			},
+		},
+		{
+			name: "Cloud Run Instance with custom service",
+			resourceLabels: map[string]string{
+				"cloud.provider":      "gcp",
+				"cloud.platform":      "gcp_cloud_run",
+				"cloud.region":        "my-region",
+				"service.name":        "customservice",
+				"service.namespace":   "customnamespace",
+				"service.instance.id": "customserviceid",
+				"faas.instance":       "myinstanceid",
+				"faas.name":           "myfaasname",
+				"faas.version":        "v1",
+			},
+			expectMr: &monitoredrespb.MonitoredResource{
+				Type: "generic_task",
+				Labels: map[string]string{
+					"job":       "customservice",
+					"location":  "my-region",
+					"namespace": "customnamespace",
+					"task_id":   "customserviceid",
+				},
+			},
+		},
 	}
 
 	for _, test := range tests {

exporter/metric/metric_test.go

@@ -569,7 +569,7 @@ func TestResourceToMonitoredResourcepb(t *testing.T) {
 			},
 		},
 		{
-			desc: "Cloud Run From Detector",
+			desc: "Cloud Run From Detector with default service",
 			resource: resource.NewWithAttributes(
 				semconv.SchemaURL,
 				attribute.String("cloud.provider", "gcp"),
@@ -578,6 +578,7 @@ func TestResourceToMonitoredResourcepb(t *testing.T) {
 				attribute.String("faas.instance", "bar"),
 				attribute.String("faas.name", "x-service"),
 				attribute.String("faas.version", "v1"),
+				attribute.String("service.name", "unknown_service:go"),
 			),
 			expectedType: "generic_task",
 			expectedLabels: map[string]string{

internal/resourcemapping/resourcemapping.go

@@ -24,39 +24,40 @@ import (
 const (
 	ProjectIDAttributeKey = "gcp.project.id"
 
-	awsAccount        = "aws_account"
-	awsEc2Instance    = "aws_ec2_instance"
-	clusterName       = "cluster_name"
-	containerName     = "container_name"
-	gceInstance       = "gce_instance"
-	genericNode       = "generic_node"
-	genericTask       = "generic_task"
-	instanceID        = "instance_id"
-	job               = "job"
-	k8sCluster        = "k8s_cluster"
-	k8sContainer      = "k8s_container"
-	k8sNode           = "k8s_node"
-	k8sPod            = "k8s_pod"
-	location          = "location"
-	namespace         = "namespace"
-	namespaceName     = "namespace_name"
-	nodeID            = "node_id"
-	nodeName          = "node_name"
-	podName           = "pod_name"
-	region            = "region"
-	taskID            = "task_id"
-	zone              = "zone"
-	gaeInstance       = "gae_instance"
-	gaeApp            = "gae_app"
-	gaeModuleID       = "module_id"
-	gaeVersionID      = "version_id"
-	cloudRunRevision  = "cloud_run_revision"
-	cloudFunction     = "cloud_function"
-	cloudFunctionName = "function_name"
-	serviceName       = "service_name"
-	configurationName = "configuration_name"
-	revisionName      = "revision_name"
-	bmsInstance       = "baremetalsolution.googleapis.com/Instance"
+	awsAccount           = "aws_account"
+	awsEc2Instance       = "aws_ec2_instance"
+	clusterName          = "cluster_name"
+	containerName        = "container_name"
+	gceInstance          = "gce_instance"
+	genericNode          = "generic_node"
+	genericTask          = "generic_task"
+	instanceID           = "instance_id"
+	job                  = "job"
+	k8sCluster           = "k8s_cluster"
+	k8sContainer         = "k8s_container"
+	k8sNode              = "k8s_node"
+	k8sPod               = "k8s_pod"
+	location             = "location"
+	namespace            = "namespace"
+	namespaceName        = "namespace_name"
+	nodeID               = "node_id"
+	nodeName             = "node_name"
+	podName              = "pod_name"
+	region               = "region"
+	taskID               = "task_id"
+	zone                 = "zone"
+	gaeInstance          = "gae_instance"
+	gaeApp               = "gae_app"
+	gaeModuleID          = "module_id"
+	gaeVersionID         = "version_id"
+	cloudRunRevision     = "cloud_run_revision"
+	cloudFunction        = "cloud_function"
+	cloudFunctionName    = "function_name"
+	serviceName          = "service_name"
+	configurationName    = "configuration_name"
+	revisionName         = "revision_name"
+	bmsInstance          = "baremetalsolution.googleapis.com/Instance"
+	unknownServicePrefix = "unknown_service"
 )
 
 var (
@@ -252,10 +253,14 @@ func createMonitoredResource(
 		// Coalesce the possible keys in order
 		for _, otelKey := range mappingConfig.otelKeys {
 			mrValue, ok = resourceAttrs.GetString(otelKey)
-			if mrValue != "" {
+			if mrValue != "" && !strings.HasPrefix(mrValue, unknownServicePrefix) {
 				break
 			}
 		}
+		if mrValue == "" && contains(mappingConfig.otelKeys, string(semconv.ServiceNameKey)) {
+			// the service name started with unknown_service, and was ignored above
+			mrValue, ok = resourceAttrs.GetString(string(semconv.ServiceNameKey))
+		}
 		if !ok || mrValue == "" {
 			mrValue = mappingConfig.fallbackLiteral
 		}
@@ -267,6 +272,15 @@ func createMonitoredResource(
 	}
 }
 
+func contains(list []string, element string) bool {
+	for _, item := range list {
+		if item == element {
+			return true
+		}
+	}
+	return false
+}
+
 func sanitizeUTF8(s string) string {
 	return strings.ToValidUTF8(s, "�")
 }