Accept scope attributes during Tracer creation (#3739)

* Accept scope attributes during Tracer creation

The OTel specification requires the instrumentation attributes are
accepted by the API for the Tracer. This adds a TracerOption to satisfy
that requirement.

CHANGELOG.md

@@ -31,6 +31,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
     - `OtelLibraryVersion` -> `OTelLibraryVersion`
     - `OtelStatusDescription` -> `OTelStatusDescription`
 - The `WithInstrumentationAttributes` option to `go.opentelemetry.io/otel/metric`. (#3738)
+- The `WithInstrumentationAttributes` option to `go.opentelemetry.io/otel/trace`. (#3739)
 
 ### Changed
 

trace/config.go

@@ -25,13 +25,20 @@ type TracerConfig struct {
 	instrumentationVersion string
 	// Schema URL of the telemetry emitted by the Tracer.
 	schemaURL string
+	attrs     attribute.Set
 }
 
 // InstrumentationVersion returns the version of the library providing instrumentation.
 func (t *TracerConfig) InstrumentationVersion() string {
 	return t.instrumentationVersion
 }
 
+// InstrumentationAttributes returns the attributes associated with the library
+// providing instrumentation.
+func (t *TracerConfig) InstrumentationAttributes() attribute.Set {
+	return t.attrs
+}
+
 // SchemaURL returns the Schema URL of the telemetry emitted by the Tracer.
 func (t *TracerConfig) SchemaURL() string {
 	return t.schemaURL
@@ -307,6 +314,16 @@ func WithInstrumentationVersion(version string) TracerOption {
 	})
 }
 
+// WithInstrumentationAttributes sets the instrumentation attributes.
+//
+// The passed attributes will be de-duplicated.
+func WithInstrumentationAttributes(attr ...attribute.KeyValue) TracerOption {
+	return tracerOptionFunc(func(config TracerConfig) TracerConfig {
+		config.attrs = attribute.NewSet(attr...)
+		return config
+	})
+}
+
 // WithSchemaURL sets the schema URL for the Tracer.
 func WithSchemaURL(schemaURL string) TracerOption {
 	return tracerOptionFunc(func(cfg TracerConfig) TracerConfig {

trace/config_test.go

@@ -211,46 +211,22 @@ func TestTracerConfig(t *testing.T) {
 	v1 := "semver:0.0.1"
 	v2 := "semver:1.0.0"
 	schemaURL := "https://opentelemetry.io/schemas/1.2.0"
-	tests := []struct {
-		options  []TracerOption
-		expected TracerConfig
-	}{
-		{
-			// No non-zero-values should be set.
-			[]TracerOption{},
-			TracerConfig{},
-		},
-		{
-			[]TracerOption{
-				WithInstrumentationVersion(v1),
-			},
-			TracerConfig{
-				instrumentationVersion: v1,
-			},
-		},
-		{
-			[]TracerOption{
-				// Multiple calls should overwrite.
-				WithInstrumentationVersion(v1),
-				WithInstrumentationVersion(v2),
-			},
-			TracerConfig{
-				instrumentationVersion: v2,
-			},
-		},
-		{
-			[]TracerOption{
-				WithSchemaURL(schemaURL),
-			},
-			TracerConfig{
-				schemaURL: schemaURL,
-			},
-		},
-	}
-	for _, test := range tests {
-		config := NewTracerConfig(test.options...)
-		assert.Equal(t, test.expected, config)
-	}
+	attrs := attribute.NewSet(
+		attribute.String("user", "alice"),
+		attribute.Bool("admin", true),
+	)
+
+	c := NewTracerConfig(
+		// Multiple calls should overwrite.
+		WithInstrumentationVersion(v1),
+		WithInstrumentationVersion(v2),
+		WithSchemaURL(schemaURL),
+		WithInstrumentationAttributes(attrs.ToSlice()...),
+	)
+
+	assert.Equal(t, v2, c.InstrumentationVersion(), "instrumentation version")
+	assert.Equal(t, schemaURL, c.SchemaURL(), "schema URL")
+	assert.Equal(t, attrs, c.InstrumentationAttributes(), "instrumentation attributes")
 }
 
 // Save benchmark results to a file level var to avoid the compiler optimizing