Support proxy with dialer (#1098)

With this change, the default dialer checks environment variables to see if proxy is needed. If so, it dials to the proxy and does an HTTP CONNECT handshake.

clientconn.go

@@ -311,7 +311,14 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 	}
 	cc.mkp = cc.dopts.copts.KeepaliveParams
 
-	grpcUA := "grpc-go/" + Version
+	if cc.dopts.copts.Dialer == nil {
+		cc.dopts.copts.Dialer = newProxyDialer(
+			func(ctx context.Context, addr string) (net.Conn, error) {
+				return dialContext(ctx, "tcp", addr)
+			},
+		)
+	}
+
 	if cc.dopts.copts.UserAgent != "" {
 		cc.dopts.copts.UserAgent += " " + grpcUA
 	} else {

go16.go

@@ -0,0 +1,56 @@
+// +build go1.6,!go1.7
+
+/*
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+package grpc
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+
+	"golang.org/x/net/context"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{Cancel: ctx.Done()}).Dial(network, address)
+}
+
+func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error {
+	req.Cancel = ctx.Done()
+	if err := req.Write(conn); err != nil {
+		return fmt.Errorf("failed to write the HTTP request: %v", err)
+	}
+	return nil
+}

go17.go

@@ -0,0 +1,55 @@
+// +build go1.7
+
+/*
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+package grpc
+
+import (
+	"net"
+	"net/http"
+
+	"golang.org/x/net/context"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{}).DialContext(ctx, network, address)
+}
+
+func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error {
+	req = req.WithContext(ctx)
+	if err := req.Write(conn); err != nil {
+		return err
+	}
+	return nil
+}

proxy.go

@@ -0,0 +1,145 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+package grpc
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+
+	"golang.org/x/net/context"
+)
+
+var (
+	// errDisabled indicates that proxy is disabled for the address.
+	errDisabled = errors.New("proxy is disabled for the address")
+	// The following variable will be overwritten in the tests.
+	httpProxyFromEnvironment = http.ProxyFromEnvironment
+)
+
+func mapAddress(ctx context.Context, address string) (string, error) {
+	req := &http.Request{
+		URL: &url.URL{
+			Scheme: "https",
+			Host:   address,
+		},
+	}
+	url, err := httpProxyFromEnvironment(req)
+	if err != nil {
+		return "", err
+	}
+	if url == nil {
+		return "", errDisabled
+	}
+	return url.Host, nil
+}
+
+// To read a response from a net.Conn, http.ReadResponse() takes a bufio.Reader.
+// It's possible that this reader reads more than what's need for the response and stores
+// those bytes in the buffer.
+// bufConn wraps the original net.Conn and the bufio.Reader to make sure we don't lose the
+// bytes in the buffer.
+type bufConn struct {
+	net.Conn
+	r io.Reader
+}
+
+func (c *bufConn) Read(b []byte) (int, error) {
+	return c.r.Read(b)
+}
+
+func doHTTPConnectHandshake(ctx context.Context, conn net.Conn, addr string) (_ net.Conn, err error) {
+	defer func() {
+		if err != nil {
+			conn.Close()
+		}
+	}()
+
+	req := (&http.Request{
+		Method: http.MethodConnect,
+		URL:    &url.URL{Host: addr},
+		Header: map[string][]string{"User-Agent": {grpcUA}},
+	})
+
+	if err := sendHTTPRequest(ctx, req, conn); err != nil {
+		return nil, fmt.Errorf("failed to write the HTTP request: %v", err)
+	}
+
+	r := bufio.NewReader(conn)
+	resp, err := http.ReadResponse(r, req)
+	if err != nil {
+		return nil, fmt.Errorf("reading server HTTP response: %v", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		dump, err := httputil.DumpResponse(resp, true)
+		if err != nil {
+			return nil, fmt.Errorf("failed to do connect handshake, status code: %s", resp.Status)
+		}
+		return nil, fmt.Errorf("failed to do connect handshake, response: %q", dump)
+	}
+
+	return &bufConn{Conn: conn, r: r}, nil
+}
+
+// newProxyDialer returns a dialer that connects to proxy first if necessary.
+// The returned dialer checks if a proxy is necessary, dial to the proxy with the
+// provided dialer, does HTTP CONNECT handshake and returns the connection.
+func newProxyDialer(dialer func(context.Context, string) (net.Conn, error)) func(context.Context, string) (net.Conn, error) {
+	return func(ctx context.Context, addr string) (conn net.Conn, err error) {
+		var skipHandshake bool
+		newAddr, err := mapAddress(ctx, addr)
+		if err != nil {
+			if err != errDisabled {
+				return nil, err
+			}
+			skipHandshake = true
+			newAddr = addr
+		}
+
+		conn, err = dialer(ctx, newAddr)
+		if err != nil {
+			return
+		}
+		if !skipHandshake {
+			conn, err = doHTTPConnectHandshake(ctx, conn, addr)
+		}
+		return
+	}
+}

proxy_test.go

@@ -0,0 +1,192 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+package grpc
+
+import (
+	"bufio"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"testing"
+	"time"
+
+	"golang.org/x/net/context"
+)
+
+const (
+	envTestAddr  = "1.2.3.4:8080"
+	envProxyAddr = "2.3.4.5:7687"
+)
+
+// overwriteAndRestore overwrite function httpProxyFromEnvironment and
+// returns a function to restore the default values.
+func overwrite(hpfe func(req *http.Request) (*url.URL, error)) func() {
+	backHPFE := httpProxyFromEnvironment
+	httpProxyFromEnvironment = hpfe
+	return func() {
+		httpProxyFromEnvironment = backHPFE
+	}
+}
+
+func TestMapAddressEnv(t *testing.T) {
+	// Overwrite the function in the test and restore them in defer.
+	hpfe := func(req *http.Request) (*url.URL, error) {
+		if req.URL.Host == envTestAddr {
+			return &url.URL{
+				Scheme: "https",
+				Host:   envProxyAddr,
+			}, nil
+		}
+		return nil, nil
+	}
+	defer overwrite(hpfe)()
+
+	// envTestAddr should be handled by ProxyFromEnvironment.
+	got, err := mapAddress(context.Background(), envTestAddr)
+	if err != nil {
+		t.Error(err)
+	}
+	if got != envProxyAddr {
+		t.Errorf("want %v, got %v", envProxyAddr, got)
+	}
+}
+
+type proxyServer struct {
+	t   *testing.T
+	lis net.Listener
+	in  net.Conn
+	out net.Conn
+}
+
+func (p *proxyServer) run() {
+	in, err := p.lis.Accept()
+	if err != nil {
+		return
+	}
+	p.in = in
+
+	req, err := http.ReadRequest(bufio.NewReader(in))
+	if err != nil {
+		p.t.Errorf("failed to read CONNECT req: %v", err)
+		return
+	}
+	if req.Method != http.MethodConnect || req.UserAgent() != grpcUA {
+		resp := http.Response{StatusCode: http.StatusMethodNotAllowed}
+		resp.Write(p.in)
+		p.in.Close()
+		p.t.Errorf("get wrong CONNECT req: %+v", req)
+		return
+	}
+
+	out, err := net.Dial("tcp", req.URL.Host)
+	if err != nil {
+		p.t.Errorf("failed to dial to server: %v", err)
+		return
+	}
+	resp := http.Response{StatusCode: http.StatusOK, Proto: "HTTP/1.0"}
+	resp.Write(p.in)
+	p.out = out
+	go io.Copy(p.in, p.out)
+	go io.Copy(p.out, p.in)
+}
+
+func (p *proxyServer) stop() {
+	p.lis.Close()
+	if p.in != nil {
+		p.in.Close()
+	}
+	if p.out != nil {
+		p.out.Close()
+	}
+}
+
+func TestHTTPConnect(t *testing.T) {
+	plis, err := net.Listen("tcp", ":0")
+	if err != nil {
+		t.Fatalf("failed to listen: %v", err)
+	}
+	p := &proxyServer{t: t, lis: plis}
+	go p.run()
+	defer p.stop()
+
+	blis, err := net.Listen("tcp", ":0")
+	if err != nil {
+		t.Fatalf("failed to listen: %v", err)
+	}
+
+	msg := []byte{4, 3, 5, 2}
+	recvBuf := make([]byte, len(msg), len(msg))
+	done := make(chan struct{})
+	go func() {
+		in, err := blis.Accept()
+		if err != nil {
+			t.Errorf("failed to accept: %v", err)
+			return
+		}
+		defer in.Close()
+		in.Read(recvBuf)
+		close(done)
+	}()
+
+	// Overwrite the function in the test and restore them in defer.
+	hpfe := func(req *http.Request) (*url.URL, error) {
+		return &url.URL{Host: plis.Addr().String()}, nil
+	}
+	defer overwrite(hpfe)()
+
+	// Dial to proxy server.
+	dialer := newProxyDialer(func(ctx context.Context, addr string) (net.Conn, error) {
+		if deadline, ok := ctx.Deadline(); ok {
+			return net.DialTimeout("tcp", addr, deadline.Sub(time.Now()))
+		}
+		return net.Dial("tcp", addr)
+	})
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	c, err := dialer(ctx, blis.Addr().String())
+	if err != nil {
+		t.Fatalf("http connect Dial failed: %v", err)
+	}
+	defer c.Close()
+
+	// Send msg on the connection.
+	c.Write(msg)
+	<-done
+
+	// Check received msg.
+	if string(recvBuf) != string(msg) {
+		t.Fatalf("received msg: %v, want %v", recvBuf, msg)
+	}
+}

rpc_util.go

@@ -474,3 +474,5 @@ const SupportPackageIsVersion4 = true
 
 // Version is the current grpc version.
 const Version = "1.3.0-dev"
+
+const grpcUA = "grpc-go/" + Version