DockerCLI/cli/command/container/attach.go

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package container
import (
"io"
"net/http/httputil"
"github.com/docker/cli/cli"
"github.com/docker/cli/cli/command"
"github.com/docker/docker/api/types"
"github.com/docker/docker/client"
"github.com/docker/docker/pkg/signal"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"github.com/spf13/cobra"
"golang.org/x/net/context"
)
type attachOptions struct {
noStdin bool
proxy bool
detachKeys string
container string
}
func inspectContainerAndCheckState(ctx context.Context, cli client.APIClient, args string) (*types.ContainerJSON, error) {
c, err := cli.ContainerInspect(ctx, args)
if err != nil {
return nil, err
}
if !c.State.Running {
return nil, errors.New("You cannot attach to a stopped container, start it first")
}
if c.State.Paused {
return nil, errors.New("You cannot attach to a paused container, unpause it first")
}
if c.State.Restarting {
return nil, errors.New("You cannot attach to a restarting container, wait until it is running")
}
return &c, nil
}
// NewAttachCommand creates a new cobra.Command for `docker attach`
func NewAttachCommand(dockerCli command.Cli) *cobra.Command {
var opts attachOptions
cmd := &cobra.Command{
Use: "attach [OPTIONS] CONTAINER",
Short: "Attach local standard input, output, and error streams to a running container",
Args: cli.ExactArgs(1),
RunE: func(cmd *cobra.Command, args []string) error {
opts.container = args[0]
return runAttach(dockerCli, &opts)
},
}
flags := cmd.Flags()
flags.BoolVar(&opts.noStdin, "no-stdin", false, "Do not attach STDIN")
flags.BoolVar(&opts.proxy, "sig-proxy", true, "Proxy all received signals to the process")
flags.StringVar(&opts.detachKeys, "detach-keys", "", "Override the key sequence for detaching a container")
return cmd
}
func runAttach(dockerCli command.Cli, opts *attachOptions) error {
ctx := context.Background()
client := dockerCli.Client()
c, err := inspectContainerAndCheckState(ctx, client, opts.container)
if err != nil {
return err
}
if err := dockerCli.In().CheckTty(!opts.noStdin, c.Config.Tty); err != nil {
return err
}
if opts.detachKeys != "" {
dockerCli.ConfigFile().DetachKeys = opts.detachKeys
}
options := types.ContainerAttachOptions{
Stream: true,
Stdin: !opts.noStdin && c.Config.OpenStdin,
Stdout: true,
Stderr: true,
DetachKeys: dockerCli.ConfigFile().DetachKeys,
}
var in io.ReadCloser
if options.Stdin {
in = dockerCli.In()
}
if opts.proxy && !c.Config.Tty {
sigc := ForwardAllSignals(ctx, dockerCli, opts.container)
defer signal.StopCatch(sigc)
}
resp, errAttach := client.ContainerAttach(ctx, opts.container, options)
if errAttach != nil && errAttach != httputil.ErrPersistEOF {
// ContainerAttach returns an ErrPersistEOF (connection closed)
// means server met an error and put it in Hijacked connection
// keep the error and read detailed error message from hijacked connection later
return errAttach
}
defer resp.Close()
// If use docker attach command to attach to a stop container, it will return
// "You cannot attach to a stopped container" error, it's ok, but when
// attach to a running container, it(docker attach) use inspect to check
// the container's state, if it pass the state check on the client side,
// and then the container is stopped, docker attach command still attach to
// the container and not exit.
//
// Recheck the container's state to avoid attach block.
_, err = inspectContainerAndCheckState(ctx, client, opts.container)
if err != nil {
return err
}
if c.Config.Tty && dockerCli.Out().IsTerminal() {
resizeTTY(ctx, dockerCli, opts.container)
}
streamer := hijackedIOStreamer{
streams: dockerCli,
inputStream: in,
outputStream: dockerCli.Out(),
errorStream: dockerCli.Err(),
resp: resp,
tty: c.Config.Tty,
detachKeys: options.DetachKeys,
}
if err := streamer.stream(ctx); err != nil {
return err
}
if errAttach != nil {
return errAttach
}
return getExitStatus(ctx, dockerCli.Client(), opts.container)
}
func resizeTTY(ctx context.Context, dockerCli command.Cli, containerID string) {
height, width := dockerCli.Out().GetTtySize()
// To handle the case where a user repeatedly attaches/detaches without resizing their
// terminal, the only way to get the shell prompt to display for attaches 2+ is to artificially
// resize it, then go back to normal. Without this, every attach after the first will
// require the user to manually resize or hit enter.
resizeTtyTo(ctx, dockerCli.Client(), containerID, height+1, width+1, false)
// After the above resizing occurs, the call to MonitorTtySize below will handle resetting back
// to the actual size.
if err := MonitorTtySize(ctx, dockerCli, containerID, false); err != nil {
logrus.Debugf("Error monitoring TTY size: %s", err)
}
}
func getExitStatus(ctx context.Context, apiclient client.ContainerAPIClient, containerID string) error {
container, err := apiclient.ContainerInspect(ctx, containerID)
if err != nil {
// If we can't connect, then the daemon probably died.
if !client.IsErrConnectionFailed(err) {
return err
}
return cli.StatusError{StatusCode: -1}
}
status := container.State.ExitCode
if status != 0 {
return cli.StatusError{StatusCode: status}
}
return nil
}