Add service.name resource attribute to the collector's own telemetry

Resolves open-telemetry#6136

- The default service.name is set to "io.opentelemetry.collector". I think this
  is a good choice since it is unambiguous and is still short enough to be readable.
  This also matches the OpAMP recommendations: https://github.com/open-telemetry/opamp-spec/blob/main/specification.md#agentdescriptionidentifying_attributes
- The service.name can be overridden by the end user via telemetry config setting.

CHANGELOG.md

@@ -39,6 +39,7 @@
 
 - Add AppendEmpty and EnsureCapacity method to primitive pdata slices (#6060)
 - Expose `AsRaw` and `FromRaw` `pcommon.Value` methods (#6090)
+- service.name Resource attribute is added to Collector's own telemetry and defaults to "io.opentelemetry.collector" (#6152) 
 
 ## v0.60.0 Beta
 

service/telemetry.go

@@ -60,6 +60,11 @@ const (
 	// supported trace propagators
 	traceContextPropagator = "tracecontext"
 	b3Propagator           = "b3"
+
+	// Default value of "service.name" attribute in the telemetry
+	// that the Collector produces about itself. This can be overridden
+	// by the end user via telemetry.Config.Resource setting.
+	defaultServiceName = "io.opentelemetry.collector"
 )
 
 var (
@@ -112,27 +117,8 @@ func (tel *telemetryInitializer) initOnce(buildInfo component.BuildInfo, logger
 
 	logger.Info("Setting up own telemetry...")
 
-	// Construct telemetry attributes from resource attributes.
-	telAttrs := map[string]string{}
-	for k, v := range cfg.Resource {
-		// nil value indicates that the attribute should not be included in the telemetry.
-		if v != nil {
-			telAttrs[k] = *v
-		}
-	}
-
-	if _, ok := cfg.Resource[semconv.AttributeServiceInstanceID]; !ok {
-		// AttributeServiceInstanceID is not specified in the config. Auto-generate one.
-		instanceUUID, _ := uuid.NewRandom()
-		instanceID := instanceUUID.String()
-		telAttrs[semconv.AttributeServiceInstanceID] = instanceID
-	}
-
-	if _, ok := cfg.Resource[semconv.AttributeServiceVersion]; !ok {
-		// AttributeServiceVersion is not specified in the config. Use the actual
-		// build version.
-		telAttrs[semconv.AttributeServiceVersion] = buildInfo.Version
-	}
+	// Construct telemetry attributes from build info and config's resource attributes.
+	telAttrs := buildTelAttrs(buildInfo, cfg)
 
 	if tp, err := textMapPropagatorFromConfig(cfg.Traces.Propagators); err == nil {
 		otel.SetTextMapPropagator(tp)
@@ -174,6 +160,37 @@ func (tel *telemetryInitializer) initOnce(buildInfo component.BuildInfo, logger
 	return nil
 }
 
+func buildTelAttrs(buildInfo component.BuildInfo, cfg telemetry.Config) map[string]string {
+	telAttrs := map[string]string{}
+
+	for k, v := range cfg.Resource {
+		// nil value indicates that the attribute should not be included in the telemetry.
+		if v != nil {
+			telAttrs[k] = *v
+		}
+	}
+
+	if _, ok := cfg.Resource[semconv.AttributeServiceName]; !ok {
+		// AttributeServiceName is not specified in the config. Use the Service name.
+		telAttrs[semconv.AttributeServiceName] = defaultServiceName
+	}
+
+	if _, ok := cfg.Resource[semconv.AttributeServiceInstanceID]; !ok {
+		// AttributeServiceInstanceID is not specified in the config. Auto-generate one.
+		instanceUUID, _ := uuid.NewRandom()
+		instanceID := instanceUUID.String()
+		telAttrs[semconv.AttributeServiceInstanceID] = instanceID
+	}
+
+	if _, ok := cfg.Resource[semconv.AttributeServiceVersion]; !ok {
+		// AttributeServiceVersion is not specified in the config. Use the actual
+		// build version.
+		telAttrs[semconv.AttributeServiceVersion] = buildInfo.Version
+	}
+
+	return telAttrs
+}
+
 func (tel *telemetryInitializer) initOpenCensus(cfg telemetry.Config, telAttrs map[string]string) (http.Handler, error) {
 	tel.ocRegistry = ocmetric.NewRegistry()
 	metricproducer.GlobalManager().AddProducer(tel.ocRegistry)

service/telemetry_test.go

@@ -0,0 +1,69 @@
+// Copyright  The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.opentelemetry.io/collector/component"
+	semconv "go.opentelemetry.io/collector/semconv/v1.5.0"
+	"go.opentelemetry.io/collector/service/telemetry"
+)
+
+func TestBuildTelAttrs(t *testing.T) {
+	buildInfo := component.NewDefaultBuildInfo()
+
+	// Check default config
+	cfg := telemetry.Config{}
+	telAttrs := buildTelAttrs(buildInfo, cfg)
+
+	assert.Len(t, telAttrs, 3)
+	assert.Equal(t, defaultServiceName, telAttrs[semconv.AttributeServiceName])
+	assert.Equal(t, buildInfo.Version, telAttrs[semconv.AttributeServiceVersion])
+
+	_, exists := telAttrs[semconv.AttributeServiceInstanceID]
+	assert.True(t, exists)
+
+	// Check override by nil
+	cfg = telemetry.Config{
+		Resource: map[string]*string{
+			semconv.AttributeServiceName:       nil,
+			semconv.AttributeServiceVersion:    nil,
+			semconv.AttributeServiceInstanceID: nil,
+		},
+	}
+	telAttrs = buildTelAttrs(buildInfo, cfg)
+
+	// Attributes should not exist since we nil-ified all.
+	assert.Len(t, telAttrs, 0)
+
+	// Check override values
+	strPtr := func(v string) *string { return &v }
+	cfg = telemetry.Config{
+		Resource: map[string]*string{
+			semconv.AttributeServiceName:       strPtr("a"),
+			semconv.AttributeServiceVersion:    strPtr("b"),
+			semconv.AttributeServiceInstanceID: strPtr("c"),
+		},
+	}
+	telAttrs = buildTelAttrs(buildInfo, cfg)
+
+	assert.Len(t, telAttrs, 3)
+	assert.Equal(t, "a", telAttrs[semconv.AttributeServiceName])
+	assert.Equal(t, "b", telAttrs[semconv.AttributeServiceVersion])
+	assert.Equal(t, "c", telAttrs[semconv.AttributeServiceInstanceID])
+}