Added websocket support https://github.com/EmileVauge/traefik/issues/8

middlewares/websocket.go

@@ -0,0 +1,52 @@
+/*
+Copyright
+*/
+package middlewares
+
+import (
+	log "github.com/Sirupsen/logrus"
+	"github.com/mailgun/oxy/roundrobin"
+	"net/http"
+	"strings"
+	"time"
+)
+
+type WebsocketUpgrader struct {
+	rr *roundrobin.RoundRobin
+}
+
+func NewWebsocketUpgrader(rr *roundrobin.RoundRobin) *WebsocketUpgrader {
+	wu := WebsocketUpgrader{
+		rr: rr,
+	}
+	return &wu
+}
+
+func (u *WebsocketUpgrader) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	// If request is websocket, serve with golang websocket server to do protocol handshake
+	if strings.Join(req.Header["Upgrade"], "") == "websocket" {
+		start := time.Now().UTC()
+		url, err := u.rr.NextServer()
+		if err != nil {
+			log.Errorf("Can't round robin in websocket middleware")
+			return
+		}
+		log.Debugf("Websocket forward to %s", url.String())
+		NewProxy(url).ServeHTTP(w, req)
+
+		if req.TLS != nil {
+			log.Debugf("Round trip: %v, duration: %v tls:version: %x, tls:resume:%t, tls:csuite:%x, tls:server:%v",
+				req.URL, time.Now().UTC().Sub(start),
+				req.TLS.Version,
+				req.TLS.DidResume,
+				req.TLS.CipherSuite,
+				req.TLS.ServerName)
+		} else {
+			log.Debugf("Round trip: %v, duration: %v",
+				req.URL, time.Now().UTC().Sub(start))
+		}
+
+		return
+	}
+	u.rr.ServeHTTP(w, req)
+}

middlewares/websocketproxy.go

@@ -0,0 +1,170 @@
+package middlewares
+
+import (
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+
+	log "github.com/Sirupsen/logrus"
+	"github.com/gorilla/websocket"
+)
+
+// Original developpement made by https://github.com/koding/websocketproxy
+var (
+	// DefaultUpgrader specifies the parameters for upgrading an HTTP
+	// connection to a WebSocket connection.
+	DefaultUpgrader = &websocket.Upgrader{
+		ReadBufferSize:  1024,
+		WriteBufferSize: 1024,
+	}
+
+	// DefaultDialer is a dialer with all fields set to the default zero values.
+	DefaultDialer = websocket.DefaultDialer
+)
+
+// WebsocketProxy is an HTTP Handler that takes an incoming WebSocket
+// connection and proxies it to another server.
+type WebsocketProxy struct {
+	// Backend returns the backend URL which the proxy uses to reverse proxy
+	// the incoming WebSocket connection. Request is the initial incoming and
+	// unmodified request.
+	Backend func(*http.Request) *url.URL
+
+	// Upgrader specifies the parameters for upgrading a incoming HTTP
+	// connection to a WebSocket connection. If nil, DefaultUpgrader is used.
+	Upgrader *websocket.Upgrader
+
+	//  Dialer contains options for connecting to the backend WebSocket server.
+	//  If nil, DefaultDialer is used.
+	Dialer *websocket.Dialer
+}
+
+// ProxyHandler returns a new http.Handler interface that reverse proxies the
+// request to the given target.
+func ProxyHandler(target *url.URL) http.Handler {
+	return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		NewProxy(target).ServeHTTP(rw, req)
+	})
+}
+
+// NewProxy returns a new Websocket reverse proxy that rewrites the
+// URL's to the scheme, host and base path provider in target.
+func NewProxy(target *url.URL) *WebsocketProxy {
+	backend := func(r *http.Request) *url.URL {
+		// Shallow copy
+		u := *target
+		u.Fragment = r.URL.Fragment
+		u.Path = r.URL.Path
+		u.RawQuery = r.URL.RawQuery
+		rurl := u.String()
+		if strings.HasPrefix(rurl, "http") {
+			u.Scheme = "ws"
+		}
+		if strings.HasPrefix(rurl, "https") {
+			u.Scheme = "wss"
+		}
+		return &u
+	}
+	return &WebsocketProxy{Backend: backend}
+}
+
+// ServeHTTP implements the http.Handler that proxies WebSocket connections.
+func (w *WebsocketProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	if w.Backend == nil {
+		log.Println("websocketproxy: backend function is not defined")
+		http.Error(rw, "internal server error (code: 1)", http.StatusInternalServerError)
+		return
+	}
+
+	backendURL := w.Backend(req)
+	if backendURL == nil {
+		log.Println("websocketproxy: backend URL is nil")
+		http.Error(rw, "internal server error (code: 2)", http.StatusInternalServerError)
+		return
+	}
+
+	dialer := w.Dialer
+	if w.Dialer == nil {
+		dialer = DefaultDialer
+	}
+
+	// Pass headers from the incoming request to the dialer to forward them to
+	// the final destinations.
+	requestHeader := http.Header{}
+	requestHeader.Add("Origin", req.Header.Get("Origin"))
+	for _, prot := range req.Header[http.CanonicalHeaderKey("Sec-WebSocket-Protocol")] {
+		requestHeader.Add("Sec-WebSocket-Protocol", prot)
+	}
+	for _, cookie := range req.Header[http.CanonicalHeaderKey("Cookie")] {
+		requestHeader.Add("Cookie", cookie)
+	}
+
+	// Pass X-Forwarded-For headers too, code below is a part of
+	// httputil.ReverseProxy. See http://en.wikipedia.org/wiki/X-Forwarded-For
+	// for more information
+	// TODO: use RFC7239 http://tools.ietf.org/html/rfc7239
+	if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
+		// If we aren't the first proxy retain prior
+		// X-Forwarded-For information as a comma+space
+		// separated list and fold multiple headers into one.
+		if prior, ok := req.Header["X-Forwarded-For"]; ok {
+			clientIP = strings.Join(prior, ", ") + ", " + clientIP
+		}
+		requestHeader.Set("X-Forwarded-For", clientIP)
+	}
+
+	// Set the originating protocol of the incoming HTTP request. The SSL might
+	// be terminated on our site and because we doing proxy adding this would
+	// be helpful for applications on the backend.
+	requestHeader.Set("X-Forwarded-Proto", "http")
+	if req.TLS != nil {
+		requestHeader.Set("X-Forwarded-Proto", "https")
+	}
+
+	// Connect to the backend URL, also pass the headers we get from the requst
+	// together with the Forwarded headers we prepared above.
+	// TODO: support multiplexing on the same backend connection instead of
+	// opening a new TCP connection time for each request. This should be
+	// optional:
+	// http://tools.ietf.org/html/draft-ietf-hybi-websocket-multiplexing-01
+	connBackend, resp, err := dialer.Dial(backendURL.String(), nil)
+	if err != nil {
+		log.Printf("websocketproxy: couldn't dial to remote backend url %s, %s, %+v", backendURL.String(), err, resp)
+		return
+	}
+	defer connBackend.Close()
+
+	upgrader := w.Upgrader
+	if w.Upgrader == nil {
+		upgrader = DefaultUpgrader
+	}
+
+	// Only pass those headers to the upgrader.
+	upgradeHeader := http.Header{}
+	upgradeHeader.Set("Sec-WebSocket-Protocol",
+		resp.Header.Get(http.CanonicalHeaderKey("Sec-WebSocket-Protocol")))
+	upgradeHeader.Set("Set-Cookie",
+		resp.Header.Get(http.CanonicalHeaderKey("Set-Cookie")))
+
+	// Now upgrade the existing incoming request to a WebSocket connection.
+	// Also pass the header that we gathered from the Dial handshake.
+	connPub, err := upgrader.Upgrade(rw, req, upgradeHeader)
+	if err != nil {
+		log.Printf("websocketproxy: couldn't upgrade %s\n", err)
+		return
+	}
+	defer connPub.Close()
+
+	errc := make(chan error, 2)
+	cp := func(dst io.Writer, src io.Reader) {
+		_, err := io.Copy(dst, src)
+		errc <- err
+	}
+
+	// Start our proxy now, everything is ready...
+	go cp(connBackend.UnderlyingConn(), connPub.UnderlyingConn())
+	go cp(connPub.UnderlyingConn(), connBackend.UnderlyingConn())
+	<-errc
+}

traefik.go

@@ -278,7 +278,7 @@ func LoadConfig(configurations configs, globalConfiguration *GlobalConfiguration
 					}
 				case wrr:
 					log.Infof("Creating load-balancer wrr")
-					lb = rr
+					lb = middlewares.NewWebsocketUpgrader(rr)
 					for serverName, server := range configuration.Backends[frontend.Backend].Servers {
 						url, err := url.Parse(server.URL)
 						if err != nil {