dotcloud/docker

package daemon // import "github.com/docker/docker/daemon"

import (
    "context"
    "fmt"
    "io"

    "github.com/containerd/log"
    "github.com/docker/docker/api/types/backend"
    "github.com/docker/docker/api/types/events"
    "github.com/docker/docker/container"
    "github.com/docker/docker/container/stream"
    "github.com/docker/docker/daemon/logger"
    "github.com/docker/docker/errdefs"
    "github.com/docker/docker/pkg/stdcopy"
    "github.com/moby/term"
    "github.com/pkg/errors"
)

// ContainerAttach attaches to logs according to the config passed in. See ContainerAttachConfig.
func (daemon *Daemon) ContainerAttach(prefixOrName string, req *backend.ContainerAttachConfig) error {
    keys := []byte{}
    var err error
    if req.DetachKeys != "" {
        keys, err = term.ToBytes(req.DetachKeys)
        if err != nil {
            return errdefs.InvalidParameter(errors.Errorf("Invalid detach keys (%s) provided", req.DetachKeys))
        }
    }

    ctr, err := daemon.GetContainer(prefixOrName)
    if err != nil {
        return err
    }
    if ctr.IsPaused() {
        err := fmt.Errorf("container %s is paused, unpause the container before attach", prefixOrName)
        return errdefs.Conflict(err)
    }
    if ctr.IsRestarting() {
        err := fmt.Errorf("container %s is restarting, wait until the container is running", prefixOrName)
        return errdefs.Conflict(err)
    }

    cfg := stream.AttachConfig{
        UseStdin:   req.UseStdin,
        UseStdout:  req.UseStdout,
        UseStderr:  req.UseStderr,
        TTY:        ctr.Config.Tty,
        CloseStdin: ctr.Config.StdinOnce,
        DetachKeys: keys,
    }
    ctr.StreamConfig.AttachStreams(&cfg)

    multiplexed := !ctr.Config.Tty && req.MuxStreams

    clientCtx, closeNotify := context.WithCancel(context.Background())
    defer closeNotify()
    go func() {
        <-clientCtx.Done()
        // The client has disconnected
        // In this case we need to close the container's output streams so that the goroutines used to copy
        // to the client streams are unblocked and can exit.
        if cfg.CStdout != nil {
            cfg.CStdout.Close()
        }
        if cfg.CStderr != nil {
            cfg.CStderr.Close()
        }
    }()

    inStream, outStream, errStream, err := req.GetStreams(multiplexed, closeNotify)
    if err != nil {
        return err
    }

    defer inStream.Close()

    if multiplexed {
        errStream = stdcopy.NewStdWriter(errStream, stdcopy.Stderr)
        outStream = stdcopy.NewStdWriter(outStream, stdcopy.Stdout)
    }

    if cfg.UseStdin {
        cfg.Stdin = inStream
    }
    if cfg.UseStdout {
        cfg.Stdout = outStream
    }
    if cfg.UseStderr {
        cfg.Stderr = errStream
    }

    if err := daemon.containerAttach(ctr, &cfg, req.Logs, req.Stream); err != nil {
        fmt.Fprintf(outStream, "Error attaching: %s\n", err)
    }
    return nil
}

// ContainerAttachRaw attaches the provided streams to the container's stdio
func (daemon *Daemon) ContainerAttachRaw(prefixOrName string, stdin io.ReadCloser, stdout, stderr io.Writer, doStream bool, attached chan struct{}) error {
    ctr, err := daemon.GetContainer(prefixOrName)
    if err != nil {
        return err
    }
    cfg := stream.AttachConfig{
        UseStdin:   stdin != nil,
        UseStdout:  stdout != nil,
        UseStderr:  stderr != nil,
        TTY:        ctr.Config.Tty,
        CloseStdin: ctr.Config.StdinOnce,
    }
    ctr.StreamConfig.AttachStreams(&cfg)
    close(attached)
    if cfg.UseStdin {
        cfg.Stdin = stdin
    }
    if cfg.UseStdout {
        cfg.Stdout = stdout
    }
    if cfg.UseStderr {
        cfg.Stderr = stderr
    }

    return daemon.containerAttach(ctr, &cfg, false, doStream)
}

func (daemon *Daemon) containerAttach(c *container.Container, cfg *stream.AttachConfig, logs, doStream bool) error {
    if logs {
        logDriver, logCreated, err := daemon.getLogger(c)
        if err != nil {
            return err
        }
        if logCreated {
            defer func() {
                if err = logDriver.Close(); err != nil {
                    log.G(context.TODO()).Errorf("Error closing logger: %v", err)
                }
            }()
        }
        cLog, ok := logDriver.(logger.LogReader)
        if !ok {
            return logger.ErrReadLogsNotSupported{}
        }
        logs := cLog.ReadLogs(context.TODO(), logger.ReadConfig{Tail: -1})
        defer logs.ConsumerGone()

    LogLoop:
        for {
            select {
            case msg, ok := <-logs.Msg:
                if !ok {
                    break LogLoop
                }
                if msg.Source == "stdout" && cfg.Stdout != nil {
                    cfg.Stdout.Write(msg.Line)
                }
                if msg.Source == "stderr" && cfg.Stderr != nil {
                    cfg.Stderr.Write(msg.Line)
                }
            case err := <-logs.Err:
                log.G(context.TODO()).Errorf("Error streaming logs: %v", err)
                break LogLoop
            }
        }
    }

    daemon.LogContainerEvent(c, events.ActionAttach)

    if !doStream {
        return nil
    }

    if cfg.Stdin != nil {
        r, w := io.Pipe()
        go func(stdin io.ReadCloser) {
            defer w.Close()
            defer log.G(context.TODO()).Debug("Closing buffered stdin pipe")
            io.Copy(w, stdin)
        }(cfg.Stdin)
        cfg.Stdin = r
    }

    if !c.Config.OpenStdin {
        cfg.Stdin = nil
    }

    if c.Config.StdinOnce && !c.Config.Tty {
        // Wait for the container to stop before returning.
        waitChan := c.Wait(context.Background(), container.WaitConditionNotRunning)
        defer func() {
            <-waitChan // Ignore returned exit code.
        }()
    }

    ctx := c.AttachContext()
    err := <-c.StreamConfig.CopyStreams(ctx, cfg)
    if err != nil {
        var ierr term.EscapeError
        if errors.Is(err, context.Canceled) || errors.As(err, &ierr) {
            daemon.LogContainerEvent(c, events.ActionDetach)
        } else {
            log.G(ctx).Errorf("attach failed with error: %v", err)
        }
    }

    return nil
}