Use null value to suppress built-in resource attributes

open-telemetry · May 24, 2022 · 4638360 · 4638360
1 parent 9c4bc84
commit 4638360
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Showing 3 changed files with 29 additions and 23 deletions.
diff --git a/config/moved_service.go b/config/moved_service.go
@@ -43,8 +43,8 @@ type ServiceTelemetry struct {
 	// For metrics the attributes become Prometheus labels.
 	// Note that some attributes are added automatically (e.g. service.version) even
 	// if they are not specified here. In order to suppress such attributes the
-	// attribute must be specified in this map with empty string value.
-	Resource map[string]string `mapstructure:"resource"`
+	// attribute must be specified in this map with null YAML value (nil string pointer).
+	Resource map[string]*string `mapstructure:"resource"`
 }
 
 // ServiceTelemetryLogs defines the configurable settings for service telemetry logs.

diff --git a/service/collector_test.go b/service/collector_test.go
@@ -180,7 +180,7 @@ func TestCollectorFailedShutdown(t *testing.T) {
 
 // mapConverter applies extraMap of config settings. Useful for overriding the config
 // for testing purposes. Keys must use "::" delimiter between levels.
-func mapConverter(extraMap map[string]string) config.MapConverterFunc {
+func mapConverter(extraMap map[string]*string) config.MapConverterFunc {
 	return func(ctx context.Context, cfgMap *config.Map) error {
 		for k, v := range extraMap {
 			cfgMap.Set(k, v)
@@ -204,10 +204,14 @@ type labelValue struct {
 
 type ownMetricsTestCase struct {
 	name                string
-	userDefinedResource map[string]string
+	userDefinedResource map[string]*string
 	expectedLabels      map[string]labelValue
 }
 
+var testResourceAttrValue = "resource_attr_test_value"
+var testInstanceId = "test_instance_id"
+var testServiceVersion = "2022-05-20"
+
 var ownMetricsTestCases = []ownMetricsTestCase{
 	{
 		name:                "no resource",
@@ -225,8 +229,8 @@ var ownMetricsTestCases = []ownMetricsTestCase{
 	},
 	{
 		name: "resource with custom attr",
-		userDefinedResource: map[string]string{
-			"custom_resource_attr": "resource_attr_test_value",
+		userDefinedResource: map[string]*string{
+			"custom_resource_attr": &testResourceAttrValue,
 		},
 		expectedLabels: map[string]labelValue{
 			"service_instance_id":  {state: labelAnyValue},
@@ -236,18 +240,18 @@ var ownMetricsTestCases = []ownMetricsTestCase{
 	},
 	{
 		name: "override service.instance.id",
-		userDefinedResource: map[string]string{
-			"service.instance.id": "my_instance_id",
+		userDefinedResource: map[string]*string{
+			"service.instance.id": &testInstanceId,
 		},
 		expectedLabels: map[string]labelValue{
-			"service_instance_id": {label: "my_instance_id", state: labelSpecificValue},
+			"service_instance_id": {label: "test_instance_id", state: labelSpecificValue},
 			"service_version":     {label: version.Version, state: labelSpecificValue},
 		},
 	},
 	{
 		name: "suppress service.instance.id",
-		userDefinedResource: map[string]string{
-			"service.instance.id": "",
+		userDefinedResource: map[string]*string{
+			"service.instance.id": nil, // nil value in config is used to suppress attributes.
 		},
 		expectedLabels: map[string]labelValue{
 			"service_instance_id": {state: labelNotPresent},
@@ -256,8 +260,8 @@ var ownMetricsTestCases = []ownMetricsTestCase{
 	},
 	{
 		name: "override service.version",
-		userDefinedResource: map[string]string{
-			"service.version": "2022-05-20",
+		userDefinedResource: map[string]*string{
+			"service.version": &testServiceVersion,
 		},
 		expectedLabels: map[string]labelValue{
 			"service_instance_id": {state: labelAnyValue},
@@ -266,8 +270,8 @@ var ownMetricsTestCases = []ownMetricsTestCase{
 	},
 	{
 		name: "suppress service.version",
-		userDefinedResource: map[string]string{
-			"service.version": "",
+		userDefinedResource: map[string]*string{
+			"service.version": nil, // nil value in config is used to suppress attributes.
 		},
 		expectedLabels: map[string]labelValue{
 			"service_instance_id": {state: labelAnyValue},
@@ -294,9 +298,9 @@ func testCollectorStartHelper(t *testing.T, telemetry collectorTelemetryExporter
 	})
 
 	// Prepare config properties to be merged with the main config.
-	extraCfgAsProps := map[string]string{
+	extraCfgAsProps := map[string]*string{
 		// Set the metrics address to expose own metrics on.
-		"service::telemetry::metrics::address": metricsAddr,
+		"service::telemetry::metrics::address": &metricsAddr,
 	}
 	// Also include resource attributes under the service.telemetry.resource key.
 	for k, v := range tc.userDefinedResource {

diff --git a/service/telemetry.go b/service/telemetry.go
@@ -111,28 +111,28 @@ func (tel *colTelemetry) initOnce(col *Collector) error {
 	logger.Info("Setting up own telemetry...")
 
 	if resource == nil {
-		resource = map[string]string{}
+		resource = map[string]*string{}
 	}
 
 	if _, ok := resource[semconv.AttributeServiceInstanceID]; !ok {
 		// AttributeServiceInstanceID is not specified in the config. Auto-generate one.
 		instanceUUID, _ := uuid.NewRandom()
 		instanceID := instanceUUID.String()
-		resource[semconv.AttributeServiceInstanceID] = instanceID
+		resource[semconv.AttributeServiceInstanceID] = &instanceID
 	}
 
 	if AddCollectorVersionTag {
 		if _, ok := resource[semconv.AttributeServiceVersion]; !ok {
 			// AttributeServiceVersion is not specified in the config. Use the actual
 			// build version.
-			resource[semconv.AttributeServiceVersion] = version.Version
+			resource[semconv.AttributeServiceVersion] = &version.Version
 		}
 	}
 
 	// Empty Resource attributes are an indication by the user to suppress and stop
 	// emitting the particular attribute.
 	for k, v := range resource {
-		if v == "" {
+		if v == nil {
 			delete(resource, k)
 		}
 	}
@@ -176,7 +176,7 @@ func (tel *colTelemetry) initOnce(col *Collector) error {
 	return nil
 }
 
-func (tel *colTelemetry) initOpenCensus(col *Collector, labels map[string]string) (http.Handler, error) {
+func (tel *colTelemetry) initOpenCensus(col *Collector, labels map[string]*string) (http.Handler, error) {
 	processMetricsViews, err := telemetry2.NewProcessMetricsViews(getBallastSize(col.service.host))
 	if err != nil {
 		return nil, err
@@ -203,7 +203,9 @@ func (tel *colTelemetry) initOpenCensus(col *Collector, labels map[string]string
 	opts.ConstLabels = make(map[string]string)
 
 	for k, v := range labels {
-		opts.ConstLabels[sanitizePrometheusKey(k)] = v
+		if v != nil {
+			opts.ConstLabels[sanitizePrometheusKey(k)] = *v
+		}
 	}
 
 	pe, err := prometheus.NewExporter(opts)