Add http proxy support for exec/port-forward

Add http proxy support for exec/port-forward in SpdyRoundTripper

pkg/util/httpstream/spdy/roundtripper.go

@@ -23,6 +23,8 @@ import (
 	"io/ioutil"
 	"net"
 	"net/http"
+	"net/http/httputil"
+	"net/url"
 	"strings"
 
 	"k8s.io/kubernetes/pkg/api"
@@ -53,21 +55,82 @@ type SpdyRoundTripper struct {
 	Dialer *net.Dialer
 }
 
-// NewSpdyRoundTripper creates a new SpdyRoundTripper that will use
+// NewRoundTripper creates a new SpdyRoundTripper that will use
 // the specified tlsConfig.
 func NewRoundTripper(tlsConfig *tls.Config) httpstream.UpgradeRoundTripper {
 	return NewSpdyRoundTripper(tlsConfig)
 }
 
+// NewSpdyRoundTripper creates a new SpdyRoundTripper that will use
+// the specified tlsConfig. This function is mostly meant for unit tests.
 func NewSpdyRoundTripper(tlsConfig *tls.Config) *SpdyRoundTripper {
 	return &SpdyRoundTripper{tlsConfig: tlsConfig}
 }
 
-// dial dials the host specified by req, using TLS if appropriate.
+// dial dials the host specified by req, using TLS if appropriate, optionally
+// using a proxy server if one is configured via environment variables.
 func (s *SpdyRoundTripper) dial(req *http.Request) (net.Conn, error) {
-	dialAddr := netutil.CanonicalAddr(req.URL)
+	proxyURL, err := http.ProxyFromEnvironment(req)
+	if err != nil {
+		return nil, err
+	}
 
-	if req.URL.Scheme == "http" {
+	if proxyURL == nil {
+		return s.dialWithoutProxy(req.URL)
+	}
+
+	// proxying logic adapted from http://blog.h6t.eu/post/74098062923/golang-websocket-with-http-proxy-support
+	proxyReq := http.Request{
+		Method: "CONNECT",
+		URL:    &url.URL{},
+		Host:   req.URL.Host,
+	}
+
+	proxyDialConn, err := s.dialWithoutProxy(proxyURL)
+	if err != nil {
+		return nil, err
+	}
+
+	proxyClientConn := httputil.NewProxyClientConn(proxyDialConn, nil)
+	_, err = proxyClientConn.Do(&proxyReq)
+	if err != nil && err != httputil.ErrPersistEOF {
+		return nil, err
+	}
+
+	rwc, _ := proxyClientConn.Hijack()
+
+	if req.URL.Scheme != "https" {
+		return rwc, nil
+	}
+
+	host, _, err := net.SplitHostPort(req.URL.Host)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(s.tlsConfig.ServerName) == 0 {
+		s.tlsConfig.ServerName = host
+	}
+
+	tlsConn := tls.Client(rwc, s.tlsConfig)
+
+	// need to manually call Handshake() so we can call VerifyHostname() below
+	if err := tlsConn.Handshake(); err != nil {
+		return nil, err
+	}
+
+	if err := tlsConn.VerifyHostname(host); err != nil {
+		return nil, err
+	}
+
+	return tlsConn, nil
+}
+
+// dialWithoutProxy dials the host specified by url, using TLS if appropriate.
+func (s *SpdyRoundTripper) dialWithoutProxy(url *url.URL) (net.Conn, error) {
+	dialAddr := netutil.CanonicalAddr(url)
+
+	if url.Scheme == "http" {
 		if s.Dialer == nil {
 			return net.Dial("tcp", dialAddr)
 		} else {