ddtrace/tracer: add service version to tracer.

contrib/google.golang.org/grpc/stats_client_test.go

@@ -52,6 +52,7 @@ func TestClientStatsHandler(t *testing.T) {
 		"span.type":     ext.AppTypeRPC,
 		"grpc.code":     codes.OK.String(),
 		"service.name":  serviceName,
+		"service":       serviceName,
 		"resource.name": "/grpc.Fixture/Ping",
 		tagMethodName:   "/grpc.Fixture/Ping",
 		ext.TargetHost:  "127.0.0.1",

contrib/google.golang.org/grpc/stats_server_test.go

@@ -48,6 +48,7 @@ func TestServerStatsHandler(t *testing.T) {
 		"span.type":     ext.AppTypeRPC,
 		"grpc.code":     codes.OK.String(),
 		"service.name":  serviceName,
+		"service":       serviceName,
 		"resource.name": "/grpc.Fixture/Ping",
 		tagMethodName:   "/grpc.Fixture/Ping",
 	}, span.Tags())

ddtrace/ext/tags.go

@@ -43,6 +43,12 @@ const (
 	// ServiceName defines the Service name for this Span.
 	ServiceName = "service.name"
 
+	// Service defines the Service tag for this Span.
+	Service = "service"
+
+	// Version is a tag that specifies the current application version.
+	Version = "version"
+
 	// ResourceName defines the Resource name for the Span.
 	ResourceName = "resource.name"
 

ddtrace/tracer/option.go

@@ -30,6 +30,12 @@ type config struct {
 	// serviceName specifies the name of this application.
 	serviceName string
 
+	// service specifies the service tag set with DD_SERVICE that will be sent with all traces.
+	service string
+
+	// version specifies the version of this application
+	version string
+
 	// sampler specifies the sampler that will be used for sampling traces.
 	sampler Sampler
 
@@ -107,6 +113,10 @@ func defaults(c *config) {
 	}
 	if v := os.Getenv("DD_SERVICE"); v != "" {
 		c.serviceName = v
+		c.service = v
+		if ver := os.Getenv("DD_VERSION"); ver != "" {
+			c.version = ver
+		}
 	} else {
 		c.serviceName = filepath.Base(os.Args[0])
 	}
@@ -190,6 +200,7 @@ func WithServiceName(name string) StartOption {
 func WithService(name string) StartOption {
 	return func(c *config) {
 		c.serviceName = name
+		WithGlobalTag(ext.Service, name)(c)
 	}
 }
 
@@ -300,7 +311,10 @@ func Tag(k string, v interface{}) StartSpanOption {
 
 // ServiceName sets the given service name on the started span. For example "http.server".
 func ServiceName(name string) StartSpanOption {
-	return Tag(ext.ServiceName, name)
+	return func(cfg *ddtrace.StartSpanConfig) {
+		Tag(ext.ServiceName, name)(cfg)
+		Tag(ext.Service, name)(cfg)
+	}
 }
 
 // ResourceName sets the given resource name on the started span. A resource could

ddtrace/tracer/tracer.go

@@ -313,6 +313,9 @@ func (t *tracer) StartSpan(operationName string, options ...ddtrace.StartSpanOpt
 			span.setMeta("language", "go")
 		}
 	}
+	if t.config.service != "" {
+		span.SetTag(ext.Service, t.config.service)
+	}
 	// add tags from options
 	for k, v := range opts.Tags {
 		span.SetTag(k, v)
@@ -321,6 +324,9 @@ func (t *tracer) StartSpan(operationName string, options ...ddtrace.StartSpanOpt
 	for k, v := range t.config.globalTags {
 		span.SetTag(k, v)
 	}
+	if t.config.version != "" && span.Meta[ext.Service] == t.config.service {
+		span.SetTag(ext.Version, t.config.version)
+	}
 	if context == nil {
 		// this is a brand new trace, sample it
 		t.sample(span)

ddtrace/tracer/tracer_test.go

@@ -1014,6 +1014,108 @@ func TestTracerReportsHostname(t *testing.T) {
 	})
 }
 
+func TestEnvTags(t *testing.T) {
+	t.Run("service", func(t *testing.T) {
+		os.Setenv("DD_SERVICE", "servenv")
+		defer os.Unsetenv("DD_SERVICE")
+
+		tracer, _, _, stop := startTestTracer(t)
+		defer stop()
+
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request").(*span)
+		assert.Equal("servenv", sp.Meta[ext.Service])
+	})
+	t.Run("version", func(t *testing.T) {
+		os.Setenv("DD_SERVICE", "servenv")
+		os.Setenv("DD_VERSION", "1.2.3")
+		defer os.Unsetenv("DD_VERSION")
+		defer os.Unsetenv("DD_SERVICE")
+
+		tracer, _, _, stop := startTestTracer(t)
+		defer stop()
+
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request").(*span)
+		assert.Equal("1.2.3", sp.Meta[ext.Version])
+	})
+	t.Run("noversion", func(t *testing.T) {
+		os.Setenv("DD_VERSION", "1.2.3")
+		defer os.Unsetenv("DD_VERSION")
+
+		tracer, _, _, stop := startTestTracer(t)
+		defer stop()
+
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request").(*span)
+		_, ok := sp.Meta[ext.Version]
+		assert.False(ok)
+	})
+	t.Run("noversion2", func(t *testing.T) {
+		os.Setenv("DD_VERSION", "1.2.3")
+		defer os.Unsetenv("DD_VERSION")
+
+		tracer, _, _, stop := startTestTracer(t, WithGlobalTag(ext.Service, "otherservenv"))
+		defer stop()
+
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request", ServiceName("otherservenv")).(*span)
+		_, ok := sp.Meta[ext.Version]
+		assert.False(ok)
+	})
+	t.Run("serviceOverride", func(t *testing.T) {
+		os.Setenv("DD_SERVICE", "servenv")
+		os.Setenv("DD_VERSION", "1.2.3")
+		defer os.Unsetenv("DD_VERSION")
+		defer os.Unsetenv("DD_SERVICE")
+
+		tracer, _, _, stop := startTestTracer(t, WithGlobalTag(ext.Service, "otherservenv"))
+		defer stop()
+
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request").(*span)
+		assert.Equal("otherservenv", sp.Meta[ext.Service])
+		_, ok := sp.Meta[ext.Version]
+		assert.False(ok)
+	})
+	t.Run("serviceOverride2", func(t *testing.T) {
+		os.Setenv("DD_SERVICE", "servenv")
+		os.Setenv("DD_VERSION", "1.2.3")
+		defer os.Unsetenv("DD_VERSION")
+		defer os.Unsetenv("DD_SERVICE")
+
+		tracer, _, _, stop := startTestTracer(t, WithService("otherservenv"))
+		defer stop()
+
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request").(*span)
+		assert.Equal("otherservenv", sp.Meta[ext.Service])
+		_, ok := sp.Meta[ext.Version]
+		assert.False(ok)
+	})
+	t.Run("serviceOverride3", func(t *testing.T) {
+		os.Setenv("DD_SERVICE", "servenv")
+		os.Setenv("DD_VERSION", "1.2.3")
+		defer os.Unsetenv("DD_VERSION")
+		defer os.Unsetenv("DD_SERVICE")
+
+		tracer, _, _, stop := startTestTracer(t)
+		defer stop()
+
+		assert := assert.New(t)
+		sp := tracer.StartSpan("http.request", ServiceName("otherservenv")).(*span)
+		sp2 := tracer.StartSpan("http.request", Tag(ext.Service, "otherservenv")).(*span)
+
+		assert.Equal("otherservenv", sp.Meta[ext.Service])
+		_, ok := sp.Meta[ext.Version]
+		assert.False(ok)
+
+		assert.Equal("otherservenv", sp2.Meta[ext.Service])
+		_, ok = sp2.Meta[ext.Version]
+		assert.False(ok)
+	})
+}
+
 // BenchmarkConcurrentTracing tests the performance of spawning a lot of
 // goroutines where each one creates a trace with a parent and a child.
 func BenchmarkConcurrentTracing(b *testing.B) {