From 7a84995b775b97f65477980c63aef8e59c98ef40 Mon Sep 17 00:00:00 2001
From: gabsn <gabin.marignier@datadoghq.com>
Date: Thu, 17 Aug 2017 17:02:37 -0400
Subject: [PATCH] wip

---
 libs/net/http/example_test.go |  5 ++---
 libs/net/http/http.go         |  4 +++-
 libs/net/http/http_test.go    | 20 +++++++++-----------
 3 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/libs/net/http/example_test.go b/libs/net/http/example_test.go
index 33f791f793..75ffca9c98 100644
--- a/libs/net/http/example_test.go
+++ b/libs/net/http/example_test.go
@@ -11,8 +11,7 @@ func handler(w http.ResponseWriter, r *http.Request) {
 }
 
 func Example() {
-	mux := http.NewServeMux()
+	mux := httptrace.NewServeMux("web-service", nil)
 	mux.HandleFunc("/", handler)
-
-	http.ListenAndServe(":8080", httptrace.NewDefaultHandler(mux, "web-service"))
+	http.ListenAndServe(":8080", mux)
 }
diff --git a/libs/net/http/http.go b/libs/net/http/http.go
index 836fd5988a..f8b20be03c 100644
--- a/libs/net/http/http.go
+++ b/libs/net/http/http.go
@@ -8,13 +8,14 @@ import (
 	"github.com/DataDog/dd-trace-go/tracer/ext"
 )
 
-// ServeMux is an HTTP request multiplexer.
+// ServeMux is an HTTP request multiplexer that traces all the incoming requests.
 type ServeMux struct {
 	*http.ServeMux
 	*tracer.Tracer
 	service string
 }
 
+// NewServeMux allocates and returns a new ServeMux.
 func NewServeMux(service string, t *tracer.Tracer) *ServeMux {
 	if t == nil {
 		t = tracer.DefaultTracer
@@ -25,6 +26,7 @@ func NewServeMux(service string, t *tracer.Tracer) *ServeMux {
 
 // ServeHTTP dispatches the request to the handler whose
 // pattern most closely matches the request URL.
+// We only needed to rewrite this method to be able to trace the multiplexer.
 func (mux *ServeMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	// bail out if tracing isn't enabled
 	if !mux.Tracer.Enabled() {
diff --git a/libs/net/http/http_test.go b/libs/net/http/http_test.go
index 5e1105f199..59622b7dbf 100644
--- a/libs/net/http/http_test.go
+++ b/libs/net/http/http_test.go
@@ -13,7 +13,10 @@ import (
 func TestHttpTracerDisabled(t *testing.T) {
 	assert := assert.New(t)
 
-	mux := http.NewServeMux()
+	testTracer, testTransport := tracertest.GetTestTracer()
+	testTracer.SetEnabled(false)
+
+	mux := NewServeMux("my-service", testTracer)
 	mux.HandleFunc("/disabled", func(w http.ResponseWriter, r *http.Request) {
 		_, err := w.Write([]byte("disabled!"))
 		assert.Nil(err)
@@ -24,14 +27,10 @@ func TestHttpTracerDisabled(t *testing.T) {
 		assert.False(ok)
 	})
 
-	testTracer, testTransport := tracertest.GetTestTracer()
-	testTracer.SetEnabled(false)
-	handler := NewHandler(mux, "service", "", testTracer)
-
 	// Make the request
 	r := httptest.NewRequest("GET", "/disabled", nil)
 	w := httptest.NewRecorder()
-	handler.ServeHTTP(w, r)
+	mux.ServeHTTP(w, r)
 	assert.Equal(200, w.Code)
 	assert.Equal("disabled!", w.Body.String())
 
@@ -102,14 +101,13 @@ func TestHttpTracer500(t *testing.T) {
 func setup(t *testing.T) (*tracer.Tracer, *tracertest.DummyTransport, http.Handler) {
 	h200 := handler200(t)
 	h500 := handler500(t)
-	mux := http.NewServeMux()
+	tracer, transport := tracertest.GetTestTracer()
+
+	mux := NewServeMux("my-service", tracer)
 	mux.HandleFunc("/200", h200)
 	mux.HandleFunc("/500", h500)
 
-	tracer, transport := tracertest.GetTestTracer()
-	traceHandler := NewHandler(mux, "my-service", "", tracer)
-
-	return tracer, transport, traceHandler
+	return tracer, transport, mux
 }
 
 func handler200(t *testing.T) http.HandlerFunc {