feat(global): add container exec support

api/hijack.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"bytes"
+	"crypto/tls"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"time"
+)
+
+type execConfig struct {
+	Tty    bool
+	Detach bool
+}
+
+// hijack allows to upgrade an HTTP connection to a TCP connection
+// It redirects IO streams for stdin, stdout and stderr to a websocket
+func hijack(addr, scheme, method, path string, tlsConfig *tls.Config, setRawTerminal bool, in io.ReadCloser, stdout, stderr io.Writer, started chan io.Closer, data interface{}) error {
+	execConfig := &execConfig{
+		Tty:    true,
+		Detach: false,
+	}
+
+	buf, err := json.Marshal(execConfig)
+	if err != nil {
+		return fmt.Errorf("error marshaling exec config: %s", err)
+	}
+
+	rdr := bytes.NewReader(buf)
+
+	req, err := http.NewRequest(method, path, rdr)
+	if err != nil {
+		return fmt.Errorf("error during hijack request: %s", err)
+	}
+
+	req.Header.Set("User-Agent", "Docker-Client")
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Connection", "Upgrade")
+	req.Header.Set("Upgrade", "tcp")
+	req.Host = addr
+
+	var (
+		dial    net.Conn
+		dialErr error
+	)
+
+	if tlsConfig == nil {
+		dial, dialErr = net.Dial(scheme, addr)
+	} else {
+		dial, dialErr = tls.Dial(scheme, addr, tlsConfig)
+	}
+
+	if dialErr != nil {
+		return dialErr
+	}
+
+	// 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 := dial.(*net.TCPConn); ok {
+		tcpConn.SetKeepAlive(true)
+		tcpConn.SetKeepAlivePeriod(30 * time.Second)
+	}
+	if err != nil {
+		return err
+	}
+	clientconn := httputil.NewClientConn(dial, nil)
+	defer clientconn.Close()
+
+	// Server hijacks the connection, error 'connection closed' expected
+	clientconn.Do(req)
+
+	rwc, br := clientconn.Hijack()
+	defer rwc.Close()
+
+	if started != nil {
+		started <- rwc
+	}
+
+	var receiveStdout chan error
+
+	if stdout != nil || stderr != nil {
+		go func() (err error) {
+			if setRawTerminal && stdout != nil {
+				_, err = io.Copy(stdout, br)
+			}
+			return err
+		}()
+	}
+
+	go func() error {
+		if in != nil {
+			io.Copy(rwc, in)
+		}
+
+		if conn, ok := rwc.(interface {
+			CloseWrite() error
+		}); ok {
+			if err := conn.CloseWrite(); err != nil {
+			}
+		}
+		return nil
+	}()
+
+	if stdout != nil || stderr != nil {
+		if err := <-receiveStdout; err != nil {
+			return err
+		}
+	}
+	go func() {
+		for {
+			fmt.Println(br)
+		}
+	}()
+
+	return nil
+}