Add service tag to metrics and traces (#261)

* Set service name tag on metrics

* Add service tag to tracing config

Author: Mike Heffner

metriks/metriks.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/url"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/armon/go-metrics"
@@ -92,15 +93,30 @@ func createDatadogSink(url, hostname, serviceName string, tags map[string]string
 		return nil, err
 	}
 
+	// Don't override a setting from the user
+	var serviceTagSet bool
 	var ddTags []string
 	for k, v := range tags {
+		if strings.ToLower(k) == "service" {
+			serviceTagSet = true
+		}
+
 		ddTags = append(ddTags, fmt.Sprintf("%s:%s", k, v))
 	}
 
 	for _, t := range extraTags {
+		sp := strings.Split(t, ":")
+		if len(sp) > 0 && strings.ToLower(sp[0]) == "service" {
+			serviceTagSet = true
+		}
+
 		ddTags = append(ddTags, t)
 	}
 
+	if !serviceTagSet {
+		ddTags = append(ddTags, fmt.Sprintf("service:%s", serviceName))
+	}
+
 	sink.SetTags(ddTags)
 	if err := initDistribution(url, serviceName, ddTags); err != nil {
 		return nil, errors.Wrap(err, "failed to initialize the datadog statsd client")

metriks/metriks_test.go

@@ -38,11 +38,15 @@ func TestDatadogSink(t *testing.T) {
 
 	Inc("test_counter", 1)
 
-	expectedMsg := "test.test_counter:1|c|#app:edge-state,env:test"
-	buf := make([]byte, len(expectedMsg))
-	_, _, err = l.ReadFrom(buf)
+	expectedMsg := "test.test_counter:1|c|#app:edge-state,env:test,service:test"
+
+	var readBytes int
+	buf := make([]byte, 512)
+	readBytes, _, err = l.ReadFrom(buf)
 	require.NoError(t, err)
-	bytes.Contains(buf, []byte(expectedMsg))
+	require.True(t, readBytes > 0)
+
+	require.True(t, bytes.Equal(buf[0:readBytes], []byte(expectedMsg)))
 }
 
 func TestDiscardSink(t *testing.T) {

tracing/config.go

@@ -2,6 +2,7 @@ package tracing
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/opentracing/opentracing-go"
 	"github.com/sirupsen/logrus"
@@ -40,10 +41,19 @@ func Configure(tc *Config, log logrus.FieldLogger, svcName string) {
 			tracerOps = append(tracerOps, tracer.WithLogger(debugLogger{log.WithField("component", "opentracing")}))
 		}
 
+		var serviceTagSet bool
 		for k, v := range tc.Tags {
+			if strings.ToLower(k) == "service" {
+				serviceTagSet = true
+			}
+
 			tracerOps = append(tracerOps, tracer.WithGlobalTag(k, v))
 		}
 
+		if !serviceTagSet {
+			tracerOps = append(tracerOps, tracer.WithGlobalTag("service", svcName))
+		}
+
 		if tc.UseDatadog {
 			tracer.Start(tracerOps...)
 		} else {