Use Host from Request instead of Request.URL (#1036)

Request.URL contains the value sent in the HTTP request and not in the Host header.

plugin/ochttp/client_stats.go

@@ -34,8 +34,8 @@ type statsTransport struct {
 // RoundTrip implements http.RoundTripper, delegating to Base and recording stats for the request.
 func (t statsTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 	ctx, _ := tag.New(req.Context(),
-		tag.Upsert(KeyClientHost, req.URL.Host),
-		tag.Upsert(Host, req.URL.Host),
+		tag.Upsert(KeyClientHost, req.Host),
+		tag.Upsert(Host, req.Host),
 		tag.Upsert(KeyClientPath, req.URL.Path),
 		tag.Upsert(Path, req.URL.Path),
 		tag.Upsert(KeyClientMethod, req.Method),

plugin/ochttp/server.go

@@ -136,7 +136,7 @@ func (h *Handler) extractSpanContext(r *http.Request) (trace.SpanContext, bool)
 
 func (h *Handler) startStats(w http.ResponseWriter, r *http.Request) (http.ResponseWriter, func(tags *addedTags)) {
 	ctx, _ := tag.New(r.Context(),
-		tag.Upsert(Host, r.URL.Host),
+		tag.Upsert(Host, r.Host),
 		tag.Upsert(Path, r.URL.Path),
 		tag.Upsert(Method, r.Method))
 	track := &trackingResponseWriter{

plugin/ochttp/trace.go

@@ -151,7 +151,7 @@ func spanNameFromURL(req *http.Request) string {
 func requestAttrs(r *http.Request) []trace.Attribute {
 	return []trace.Attribute{
 		trace.StringAttribute(PathAttribute, r.URL.Path),
-		trace.StringAttribute(HostAttribute, r.URL.Host),
+		trace.StringAttribute(HostAttribute, r.Host),
 		trace.StringAttribute(MethodAttribute, r.Method),
 		trace.StringAttribute(UserAgentAttribute, r.UserAgent()),
 	}