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package client // import "github.com/docker/docker/client"
import (
"bufio"
"context"
"crypto/tls"
"fmt"
"net"
"net/http"
"net/http/httputil"
"net/url"
"time"
"github.com/docker/docker/api/types"
"github.com/docker/go-connections/sockets"
"github.com/pkg/errors"
)
// postHijacked sends a POST request and hijacks the connection.
func (cli *Client) postHijacked(ctx context.Context, path string, query url.Values, body interface{}, headers map[string][]string) (types.HijackedResponse, error) {
bodyEncoded, err := encodeData(body)
if err != nil {
return types.HijackedResponse{}, err
}
apiPath := cli.getAPIPath(path, query)
req, err := http.NewRequest("POST", apiPath, bodyEncoded)
if err != nil {
return types.HijackedResponse{}, err
}
req = cli.addHeaders(req, headers)
conn, err := cli.setupHijackConn(ctx, req, "tcp")
if err != nil {
return types.HijackedResponse{}, err
}
return types.HijackedResponse{Conn: conn, Reader: bufio.NewReader(conn)}, err
}
// fallbackDial is used when WithDialer() was not called.
// See cli.Dialer().
func fallbackDial(proto, addr string, tlsConfig *tls.Config) (net.Conn, error) {
if tlsConfig != nil && proto != "unix" && proto != "npipe" {
return tls.Dial(proto, addr, tlsConfig)
}
if proto == "npipe" {
return sockets.DialPipe(addr, 32*time.Second)
}
return net.Dial(proto, addr)
}
func (cli *Client) setupHijackConn(ctx context.Context, req *http.Request, proto string) (net.Conn, error) {
req.Host = cli.addr
req.Header.Set("Connection", "Upgrade")
req.Header.Set("Upgrade", proto)
dialer := cli.Dialer()
conn, err := dialer(ctx)
if err != nil {
return nil, errors.Wrap(err, "cannot connect to the Docker daemon. Is 'docker daemon' running on this host?")
}
// When we set up a TCP connection for hijack, there could be long periods
// of inactivity (a long running command with no output) that in certain
// network setups may cause ECONNTIMEOUT, leaving the client in an unknown
// state. Setting TCP KeepAlive on the socket connection will prohibit
// ECONNTIMEOUT unless the socket connection truly is broken
if tcpConn, ok := conn.(*net.TCPConn); ok {
tcpConn.SetKeepAlive(true)
tcpConn.SetKeepAlivePeriod(30 * time.Second)
}
clientconn := httputil.NewClientConn(conn, nil)
defer clientconn.Close()
// Server hijacks the connection, error 'connection closed' expected
resp, err := clientconn.Do(req)
if err != httputil.ErrPersistEOF {
if err != nil {
return nil, err
}
if resp.StatusCode != http.StatusSwitchingProtocols {
resp.Body.Close()
return nil, fmt.Errorf("unable to upgrade to %s, received %d", proto, resp.StatusCode)
}
}
c, br := clientconn.Hijack()
if br.Buffered() > 0 {
// If there is buffered content, wrap the connection. We return an
// object that implements CloseWrite iff the underlying connection
// implements it.
if _, ok := c.(types.CloseWriter); ok {
c = &hijackedConnCloseWriter{&hijackedConn{c, br}}
} else {
c = &hijackedConn{c, br}
}
} else {
br.Reset(nil)
}
return c, nil
}
// hijackedConn wraps a net.Conn and is returned by setupHijackConn in the case
// that a) there was already buffered data in the http layer when Hijack() was
// called, and b) the underlying net.Conn does *not* implement CloseWrite().
// hijackedConn does not implement CloseWrite() either.
type hijackedConn struct {
net.Conn
r *bufio.Reader
}
func (c *hijackedConn) Read(b []byte) (int, error) {
return c.r.Read(b)
}
// hijackedConnCloseWriter is a hijackedConn which additionally implements
// CloseWrite(). It is returned by setupHijackConn in the case that a) there
// was already buffered data in the http layer when Hijack() was called, and b)
// the underlying net.Conn *does* implement CloseWrite().
type hijackedConnCloseWriter struct {
*hijackedConn
}
var _ types.CloseWriter = &hijackedConnCloseWriter{}
func (c *hijackedConnCloseWriter) CloseWrite() error {
conn := c.Conn.(types.CloseWriter)
return conn.CloseWrite()
}