/
websocket-proxy.go
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/
websocket-proxy.go
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/*
* Tencent is pleased to support the open source community by making Blueking Container Service available.
* Copyright (C) 2019 THL A29 Limited, a Tencent company. All rights reserved.
* Licensed under the MIT License (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
* http://opensource.org/licenses/MIT
* Unless required by applicable law or agreed to in writing, software distributed under
* the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied. See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package webconsole
import (
"fmt"
"io"
"net"
"net/http"
"net/url"
"strings"
"github.com/Tencent/bk-bcs/bcs-common/common"
"github.com/Tencent/bk-bcs/bcs-common/common/blog"
"github.com/Tencent/bk-bcs/bcs-common/common/ssl"
"github.com/Tencent/bk-bcs/bcs-runtime/bcs-mesos/bcs-mesos-driver/mesosdriver/config"
"github.com/gorilla/websocket"
)
var (
// DefaultUpgrader specifies the parameters for upgrading an HTTP
// connection to a WebSocket connection.
DefaultUpgrader = &websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
}
)
// WebsocketProxy is an HTTP Handler that takes an incoming WebSocket
// connection and proxies it to another server.
type WebsocketProxy struct {
// Director, if non-nil, is a function that may copy additional request
// headers from the incoming WebSocket connection into the output headers
// which will be forwarded to another server.
Director func(incoming *http.Request, out http.Header)
BackendUrl *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
}
// NewWebsocketProxy returns a new Websocket reverse proxy that rewrites the
// URL's to the scheme, host and base path provider in target.
func NewWebsocketProxy(certConfig *config.CertConfig, backendUrl *url.URL) *WebsocketProxy {
if certConfig.IsSSL {
backendUrl.Scheme = "wss"
} else {
backendUrl.Scheme = "ws"
}
// DefaultDialer is a dialer with all fields set to the default zero values.
defaultDialer := websocket.DefaultDialer
if certConfig.IsSSL {
cliTls, err := ssl.ClientTslConfVerity(certConfig.CAFile, certConfig.CertFile, certConfig.KeyFile, certConfig.CertPasswd)
if err != nil {
blog.Errorf("set client tls config error %s", err.Error())
return nil
}
defaultDialer.TLSClientConfig = cliTls
blog.Infof("set client tls config success")
}
return &WebsocketProxy{
BackendUrl: backendUrl,
Dialer: defaultDialer,
Upgrader: DefaultUpgrader,
}
}
// ServeHTTP implements the http.Handler that proxies WebSocket connections.
func (w *WebsocketProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
backendURL := w.BackendUrl
// Pass headers from the incoming request to the dialer to forward them to
// the final destinations.
requestHeader := http.Header{}
if origin := req.Header.Get("Origin"); origin != "" {
requestHeader.Add("Origin", 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)
}
if req.Host != "" {
requestHeader.Set("Host", req.Host)
}
if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
if prior, ok := req.Header["X-Forwarded-For"]; ok {
clientIP = strings.Join(prior, ", ") + ", " + clientIP
}
requestHeader.Set("X-Forwarded-For", clientIP)
}
requestHeader.Set("X-Forwarded-Proto", "http")
if req.TLS != nil {
requestHeader.Set("X-Forwarded-Proto", "https")
}
if w.Director != nil {
w.Director(req, requestHeader)
}
connBackend, resp, err := w.Dialer.Dial(backendURL.String(), requestHeader)
if err != nil {
blog.Errorf("websocketproxy: couldn't dial to remote backend url %s", err)
message := fmt.Sprintf("errcode: %d, couldn't dial to remote backend url %s", common.BcsErrApiWebConsoleFailedCode, err.Error())
if resp != nil {
if err := copyResponse(rw, resp); err != nil {
blog.Errorf("websocketproxy: couldn't write response after failed remote backend handshake: %s", err)
}
} else {
http.Error(rw, message, http.StatusServiceUnavailable)
}
return
}
defer connBackend.Close()
// Only pass those headers to the upgrader.
upgradeHeader := http.Header{}
if hdr := resp.Header.Get("Sec-Websocket-Protocol"); hdr != "" {
upgradeHeader.Set("Sec-Websocket-Protocol", hdr)
}
if hdr := resp.Header.Get("Set-Cookie"); hdr != "" {
upgradeHeader.Set("Set-Cookie", hdr)
}
w.Upgrader.CheckOrigin = func(r *http.Request) bool {
return true
}
// Now upgrade the existing incoming request to a WebSocket connection.
// Also pass the header that we gathered from the Dial handshake.
connPub, err := w.Upgrader.Upgrade(rw, req, upgradeHeader)
if err != nil {
blog.Errorf("websocketproxy: couldn't upgrade %s", err)
return
}
defer connPub.Close()
errClient := make(chan error, 1)
errBackend := make(chan error, 1)
go replicateWebsocketConn(connPub, connBackend, errClient)
go replicateWebsocketConn(connBackend, connPub, errBackend)
var message string
select {
case err = <-errClient:
message = "websocketproxy: Error when copying from backend to client: %v"
case err = <-errBackend:
message = "websocketproxy: Error when copying from client to backend: %v"
}
if e, ok := err.(*websocket.CloseError); !ok || e.Code == websocket.CloseAbnormalClosure {
blog.Errorf(message, err)
}
}
func replicateWebsocketConn(dst, src *websocket.Conn, errc chan error) {
for {
msgType, msg, err1 := src.ReadMessage()
if err1 != nil {
m := websocket.FormatCloseMessage(websocket.CloseNormalClosure, fmt.Sprintf("%v", err1))
if e, ok := err1.(*websocket.CloseError); ok {
if e.Code != websocket.CloseNoStatusReceived {
m = websocket.FormatCloseMessage(e.Code, e.Text)
}
}
errc <- err1
dst.WriteMessage(websocket.CloseMessage, m)
break
}
err := dst.WriteMessage(msgType, msg)
if err != nil {
errc <- err
break
}
}
}
func copyHeader(dst, src http.Header) {
for k, vv := range src {
for _, v := range vv {
dst.Add(k, v)
}
}
}
func copyResponse(rw http.ResponseWriter, resp *http.Response) error {
copyHeader(rw.Header(), resp.Header)
rw.WriteHeader(resp.StatusCode)
defer resp.Body.Close()
_, err := io.Copy(rw, resp.Body)
return err
}