package client import ( "encoding/json" "fmt" "io" "github.com/Sirupsen/logrus" "github.com/docker/docker/api/types" "github.com/docker/docker/pkg/promise" "github.com/docker/docker/runconfig" ) // CmdExec runs a command in a running container. // // Usage: docker exec [OPTIONS] CONTAINER COMMAND [ARG...] func (cli *DockerCli) CmdExec(args ...string) error { cmd := cli.Subcmd("exec", "CONTAINER COMMAND [ARG...]", "Run a command in a running container", true) execConfig, err := runconfig.ParseExec(cmd, args) // just in case the ParseExec does not exit if execConfig.Container == "" || err != nil { return StatusError{StatusCode: 1} } stream, _, err := cli.call("POST", "/containers/"+execConfig.Container+"/exec", execConfig, nil) if err != nil { return err } var response types.ContainerExecCreateResponse if err := json.NewDecoder(stream).Decode(&response); err != nil { return err } for _, warning := range response.Warnings { fmt.Fprintf(cli.err, "WARNING: %s\n", warning) } execID := response.ID if execID == "" { fmt.Fprintf(cli.out, "exec ID empty") return nil } if !execConfig.Detach { if err := cli.CheckTtyInput(execConfig.AttachStdin, execConfig.Tty); err != nil { return err } } else { if _, _, err := readBody(cli.call("POST", "/exec/"+execID+"/start", execConfig, nil)); err != nil { return err } // For now don't print this - wait for when we support exec wait() // fmt.Fprintf(cli.out, "%s\n", execID) return nil } // Interactive exec requested. var ( out, stderr io.Writer in io.ReadCloser hijacked = make(chan io.Closer) errCh chan error ) // Block the return until the chan gets closed defer func() { logrus.Debugf("End of CmdExec(), Waiting for hijack to finish.") if _, ok := <-hijacked; ok { logrus.Errorf("Hijack did not finish (chan still open)") } }() if execConfig.AttachStdin { in = cli.in } if execConfig.AttachStdout { out = cli.out } if execConfig.AttachStderr { if execConfig.Tty { stderr = cli.out } else { stderr = cli.err } } errCh = promise.Go(func() error { return cli.hijack("POST", "/exec/"+execID+"/start", execConfig.Tty, in, out, stderr, hijacked, execConfig) }) // Acknowledge the hijack before starting select { case closer := <-hijacked: // Make sure that hijack gets closed when returning. (result // in closing hijack chan and freeing server's goroutines. if closer != nil { defer closer.Close() } case err := <-errCh: if err != nil { logrus.Debugf("Error hijack: %s", err) return err } } if execConfig.Tty && cli.isTerminalIn { if err := cli.monitorTtySize(execID, true); err != nil { logrus.Errorf("Error monitoring TTY size: %s", err) } } if err := <-errCh; err != nil { logrus.Debugf("Error hijack: %s", err) return err } var status int if _, status, err = getExecExitCode(cli, execID); err != nil { return err } if status != 0 { return StatusError{StatusCode: status} } return nil }