ddtrace/tracer: add WithServiceNameMatch option (#1272)

* ddtrace/tracer: add WithServiceNameMatch option
Removed limitation of having service name match the name defined when starting the tracer for version tracking.

ddtrace/tracer/option.go

@@ -66,6 +66,10 @@ type config struct {
 	// serviceName specifies the name of this application.
 	serviceName string
 
+	// universalVersion, reports whether span service name and config service name
+	// should match to set application version tag. False by default
+	universalVersion bool
+
 	// version specifies the version of this application
 	version string
 
@@ -659,10 +663,22 @@ func WithSamplingRules(rules []SamplingRule) StartOption {
 }
 
 // WithServiceVersion specifies the version of the service that is running. This will
-// be included in spans from this service in the "version" tag.
+// be included in spans from this service in the "version" tag, provided that
+// span service name and config service name match. Do NOT use with WithUniversalVersion.
 func WithServiceVersion(version string) StartOption {
 	return func(cfg *config) {
 		cfg.version = version
+		cfg.universalVersion = false
+	}
+}
+
+// WithUniversalVersion specifies the version of the service that is running, and will be applied to all spans,
+// regardless of whether span service name and config service name match.
+// See: WithService, WithServiceVersion. Do NOT use with WithServiceVersion.
+func WithUniversalVersion(version string) StartOption {
+	return func(c *config) {
+		c.version = version
+		c.universalVersion = true
 	}
 }
 

ddtrace/tracer/tracer.go

@@ -421,8 +421,10 @@ func (t *tracer) StartSpan(operationName string, options ...ddtrace.StartSpanOpt
 		// all top level spans are measured. So the measured tag is redundant.
 		delete(span.Metrics, keyMeasured)
 	}
-	if t.config.version != "" && span.Service == t.config.serviceName {
-		span.setMeta(ext.Version, t.config.version)
+	if t.config.version != "" {
+		if t.config.universalVersion || (!t.config.universalVersion && span.Service == t.config.serviceName) {
+			span.setMeta(ext.Version, t.config.version)
+		}
 	}
 	if t.config.env != "" {
 		span.setMeta(ext.Environment, t.config.env)

ddtrace/tracer/tracer_test.go

@@ -1390,9 +1390,40 @@ func TestVersion(t *testing.T) {
 		v := sp.Meta[ext.Version]
 		assert.Equal("4.5.6", v)
 	})
+	t.Run("service", func(t *testing.T) {
+		tracer, _, _, stop := startTestTracer(t, WithServiceVersion("4.5.6"),
+			WithService("servenv"))
+		defer stop()
 
-	t.Run("unset", func(t *testing.T) {
-		tracer, _, _, stop := startTestTracer(t, WithServiceVersion("4.5.6"), WithService("servenv"))
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request", ServiceName("otherservenv")).(*span)
+		_, ok := sp.Meta[ext.Version]
+		assert.False(ok)
+	})
+	t.Run("universal", func(t *testing.T) {
+		tracer, _, _, stop := startTestTracer(t, WithService("servenv"), WithUniversalVersion("4.5.6"))
+		defer stop()
+
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request", ServiceName("otherservenv")).(*span)
+		v, ok := sp.Meta[ext.Version]
+		assert.True(ok)
+		assert.Equal("4.5.6", v)
+	})
+	t.Run("service/universal", func(t *testing.T) {
+		tracer, _, _, stop := startTestTracer(t, WithServiceVersion("4.5.6"),
+			WithService("servenv"), WithUniversalVersion("1.2.3"))
+		defer stop()
+
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request", ServiceName("otherservenv")).(*span)
+		v, ok := sp.Meta[ext.Version]
+		assert.True(ok)
+		assert.Equal("1.2.3", v)
+	})
+	t.Run("universal/service", func(t *testing.T) {
+		tracer, _, _, stop := startTestTracer(t, WithUniversalVersion("1.2.3"),
+			WithServiceVersion("4.5.6"), WithService("servenv"))
 		defer stop()
 
 		assert := assert.New(t)