Using upstream hostname for request (fabiolb#294)

proxy/http_integration_test.go

@@ -117,6 +117,63 @@ func TestProxyStripsPath(t *testing.T) {
 	}
 }
 
+//	TestProxyUseUpstreamHostname
+func TestProxyUseUpstreamHostname(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprint(w, r.Host)
+	}))
+
+	proxy := httptest.NewServer(&HTTPProxy{
+		Transport: &http.Transport{
+			Dial: func(network, addr string) (net.Conn, error) {
+				addr = server.URL[len("http://"):]
+				return net.Dial(network, addr)
+			},
+		},
+		Lookup: func(r *http.Request) *route.Target {
+			tbl, _ := route.NewTable(`route add mock / http://a.com/ opts "useupstreamhostname=true"`)
+			return tbl.Lookup(r, "", route.Picker["rr"], route.Matcher["prefix"])
+		},
+	})
+	defer proxy.Close()
+
+	resp, body := mustGet(proxy.URL + "/")
+	if got, want := resp.StatusCode, http.StatusOK; got != want {
+		t.Fatalf("got status %d want %d", got, want)
+	}
+	if got, want := string(body), "a.com"; got != want {
+		t.Fatalf("got body %q want %q", got, want)
+	}
+}
+
+func TestProxyDoNotUseUpstreamHostname(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprint(w, r.Host)
+	}))
+
+	proxy := httptest.NewServer(&HTTPProxy{
+		Transport: &http.Transport{
+			Dial: func(network, addr string) (net.Conn, error) {
+				addr = server.URL[len("http://"):]
+				return net.Dial(network, addr)
+			},
+		},
+		Lookup: func(r *http.Request) *route.Target {
+			tbl, _ := route.NewTable(`route add mock / http://a.com/ opts "useupstreamhostname=false"`)
+			return tbl.Lookup(r, "", route.Picker["rr"], route.Matcher["prefix"])
+		},
+	})
+	defer proxy.Close()
+
+	resp, body := mustGet(proxy.URL + "/")
+	if got, want := resp.StatusCode, http.StatusOK; got != want {
+		t.Fatalf("got status %d want %d", got, want)
+	}
+	if got, want := string(body), proxy.URL[len("http://"):]; got != want {
+		t.Fatalf("got body %q want %q", got, want)
+	}
+}
+
 func TestProxyLogOutput(t *testing.T) {
 	// build a format string from all log fields and one header field
 	fields := []string{"header.X-Foo:$header.X-Foo"}

proxy/http_proxy.go

@@ -100,6 +100,10 @@ func (p *HTTPProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		targetURL.RawQuery = t.URL.RawQuery + "&" + r.URL.RawQuery
 	}
 
+	if t.UseUpstreamHostname {
+		r.Host = targetURL.Host
+	}
+
 	// TODO(fs): The HasPrefix check seems redundant since the lookup function should
 	// TODO(fs): have found the target based on the prefix but there may be other
 	// TODO(fs): matchers which may have different rules. I'll keep this for

route/route.go

@@ -71,6 +71,7 @@ func (r *Route) addTarget(service string, targetURL *url.URL, fixedWeight float6
 	if r.Opts != nil {
 		t.StripPath = r.Opts["strip"]
 		t.TLSSkipVerify = r.Opts["tlsskipverify"] == "true"
+		t.UseUpstreamHostname = r.Opts["useupstreamhostname"] == "true"
 	}
 
 	r.Targets = append(r.Targets, t)

route/target.go

@@ -21,6 +21,11 @@ type Target struct {
 	// TLS connections.
 	TLSSkipVerify bool
 
+	// UseUpstreamHostname causes the origin host header to be
+	// replaced by the upstream host header as its moving
+	// through the proxy.
+	UseUpstreamHostname bool
+
 	// URL is the endpoint the service instance listens on
 	URL *url.URL