github.com/olljanat/moby@v1.13.1/cli/command/container/attach.go (about)

     1  package container
     2  
     3  import (
     4  	"fmt"
     5  	"io"
     6  	"net/http/httputil"
     7  
     8  	"golang.org/x/net/context"
     9  
    10  	"github.com/Sirupsen/logrus"
    11  	"github.com/docker/docker/api/types"
    12  	"github.com/docker/docker/cli"
    13  	"github.com/docker/docker/cli/command"
    14  	"github.com/docker/docker/pkg/signal"
    15  	"github.com/spf13/cobra"
    16  )
    17  
    18  type attachOptions struct {
    19  	noStdin    bool
    20  	proxy      bool
    21  	detachKeys string
    22  
    23  	container string
    24  }
    25  
    26  // NewAttachCommand creates a new cobra.Command for `docker attach`
    27  func NewAttachCommand(dockerCli *command.DockerCli) *cobra.Command {
    28  	var opts attachOptions
    29  
    30  	cmd := &cobra.Command{
    31  		Use:   "attach [OPTIONS] CONTAINER",
    32  		Short: "Attach to a running container",
    33  		Args:  cli.ExactArgs(1),
    34  		RunE: func(cmd *cobra.Command, args []string) error {
    35  			opts.container = args[0]
    36  			return runAttach(dockerCli, &opts)
    37  		},
    38  	}
    39  
    40  	flags := cmd.Flags()
    41  	flags.BoolVar(&opts.noStdin, "no-stdin", false, "Do not attach STDIN")
    42  	flags.BoolVar(&opts.proxy, "sig-proxy", true, "Proxy all received signals to the process")
    43  	flags.StringVar(&opts.detachKeys, "detach-keys", "", "Override the key sequence for detaching a container")
    44  	return cmd
    45  }
    46  
    47  func runAttach(dockerCli *command.DockerCli, opts *attachOptions) error {
    48  	ctx := context.Background()
    49  	client := dockerCli.Client()
    50  
    51  	c, err := client.ContainerInspect(ctx, opts.container)
    52  	if err != nil {
    53  		return err
    54  	}
    55  
    56  	if !c.State.Running {
    57  		return fmt.Errorf("You cannot attach to a stopped container, start it first")
    58  	}
    59  
    60  	if c.State.Paused {
    61  		return fmt.Errorf("You cannot attach to a paused container, unpause it first")
    62  	}
    63  
    64  	if err := dockerCli.In().CheckTty(!opts.noStdin, c.Config.Tty); err != nil {
    65  		return err
    66  	}
    67  
    68  	if opts.detachKeys != "" {
    69  		dockerCli.ConfigFile().DetachKeys = opts.detachKeys
    70  	}
    71  
    72  	options := types.ContainerAttachOptions{
    73  		Stream:     true,
    74  		Stdin:      !opts.noStdin && c.Config.OpenStdin,
    75  		Stdout:     true,
    76  		Stderr:     true,
    77  		DetachKeys: dockerCli.ConfigFile().DetachKeys,
    78  	}
    79  
    80  	var in io.ReadCloser
    81  	if options.Stdin {
    82  		in = dockerCli.In()
    83  	}
    84  
    85  	if opts.proxy && !c.Config.Tty {
    86  		sigc := ForwardAllSignals(ctx, dockerCli, opts.container)
    87  		defer signal.StopCatch(sigc)
    88  	}
    89  
    90  	resp, errAttach := client.ContainerAttach(ctx, opts.container, options)
    91  	if errAttach != nil && errAttach != httputil.ErrPersistEOF {
    92  		// ContainerAttach returns an ErrPersistEOF (connection closed)
    93  		// means server met an error and put it in Hijacked connection
    94  		// keep the error and read detailed error message from hijacked connection later
    95  		return errAttach
    96  	}
    97  	defer resp.Close()
    98  
    99  	if c.Config.Tty && dockerCli.Out().IsTerminal() {
   100  		height, width := dockerCli.Out().GetTtySize()
   101  		// To handle the case where a user repeatedly attaches/detaches without resizing their
   102  		// terminal, the only way to get the shell prompt to display for attaches 2+ is to artificially
   103  		// resize it, then go back to normal. Without this, every attach after the first will
   104  		// require the user to manually resize or hit enter.
   105  		resizeTtyTo(ctx, client, opts.container, height+1, width+1, false)
   106  
   107  		// After the above resizing occurs, the call to MonitorTtySize below will handle resetting back
   108  		// to the actual size.
   109  		if err := MonitorTtySize(ctx, dockerCli, opts.container, false); err != nil {
   110  			logrus.Debugf("Error monitoring TTY size: %s", err)
   111  		}
   112  	}
   113  	if err := holdHijackedConnection(ctx, dockerCli, c.Config.Tty, in, dockerCli.Out(), dockerCli.Err(), resp); err != nil {
   114  		return err
   115  	}
   116  
   117  	if errAttach != nil {
   118  		return errAttach
   119  	}
   120  
   121  	_, status, err := getExitCode(ctx, dockerCli, opts.container)
   122  	if err != nil {
   123  		return err
   124  	}
   125  	if status != 0 {
   126  		return cli.StatusError{StatusCode: status}
   127  	}
   128  
   129  	return nil
   130  }