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moby--moby/daemon/exec.go

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package daemon
import (
"io"
"strings"
"time"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/container"
"github.com/docker/docker/daemon/exec"
"github.com/docker/docker/daemon/execdriver"
derr "github.com/docker/docker/errors"
"github.com/docker/docker/pkg/pools"
"github.com/docker/docker/pkg/promise"
"github.com/docker/docker/pkg/term"
"github.com/docker/engine-api/types"
"github.com/docker/engine-api/types/strslice"
)
func (d *Daemon) registerExecCommand(container *container.Container, config *exec.Config) {
// Storing execs in container in order to kill them gracefully whenever the container is stopped or removed.
container.ExecCommands.Add(config.ID, config)
// Storing execs in daemon for easy access via remote API.
d.execCommands.Add(config.ID, config)
}
// ExecExists looks up the exec instance and returns a bool if it exists or not.
// It will also return the error produced by `getConfig`
func (d *Daemon) ExecExists(name string) (bool, error) {
if _, err := d.getExecConfig(name); err != nil {
return false, err
}
return true, nil
}
// getExecConfig looks up the exec instance by name. If the container associated
// with the exec instance is stopped or paused, it will return an error.
func (d *Daemon) getExecConfig(name string) (*exec.Config, error) {
ec := d.execCommands.Get(name)
// If the exec is found but its container is not in the daemon's list of
// containers then it must have been deleted, in which case instead of
// saying the container isn't running, we should return a 404 so that
// the user sees the same error now that they will after the
// 5 minute clean-up loop is run which erases old/dead execs.
if ec != nil {
if container := d.containers.Get(ec.ContainerID); container != nil {
if !container.IsRunning() {
return nil, derr.ErrorCodeContainerNotRunning.WithArgs(container.ID, container.State.String())
}
if container.IsPaused() {
return nil, derr.ErrorCodeExecPaused.WithArgs(container.ID)
}
if container.IsRestarting() {
return nil, derr.ErrorCodeContainerRestarting.WithArgs(container.ID)
}
return ec, nil
}
}
return nil, derr.ErrorCodeNoExecID.WithArgs(name)
}
func (d *Daemon) unregisterExecCommand(container *container.Container, execConfig *exec.Config) {
container.ExecCommands.Delete(execConfig.ID)
d.execCommands.Delete(execConfig.ID)
}
func (d *Daemon) getActiveContainer(name string) (*container.Container, error) {
container, err := d.GetContainer(name)
if err != nil {
return nil, err
}
if !container.IsRunning() {
return nil, derr.ErrorCodeNotRunning.WithArgs(name)
}
if container.IsPaused() {
return nil, derr.ErrorCodeExecPaused.WithArgs(name)
}
if container.IsRestarting() {
return nil, derr.ErrorCodeContainerRestarting.WithArgs(name)
}
return container, nil
}
// ContainerExecCreate sets up an exec in a running container.
func (d *Daemon) ContainerExecCreate(config *types.ExecConfig) (string, error) {
container, err := d.getActiveContainer(config.Container)
if err != nil {
return "", err
}
cmd := strslice.New(config.Cmd...)
entrypoint, args := d.getEntrypointAndArgs(strslice.New(), cmd)
keys := []byte{}
if config.DetachKeys != "" {
keys, err = term.ToBytes(config.DetachKeys)
if err != nil {
logrus.Warnf("Wrong escape keys provided (%s, error: %s) using default : ctrl-p ctrl-q", config.DetachKeys, err.Error())
}
}
processConfig := &execdriver.ProcessConfig{
CommonProcessConfig: execdriver.CommonProcessConfig{
Tty: config.Tty,
Entrypoint: entrypoint,
Arguments: args,
},
}
setPlatformSpecificExecProcessConfig(config, container, processConfig)
execConfig := exec.NewConfig()
execConfig.OpenStdin = config.AttachStdin
execConfig.OpenStdout = config.AttachStdout
execConfig.OpenStderr = config.AttachStderr
execConfig.ProcessConfig = processConfig
execConfig.ContainerID = container.ID
execConfig.DetachKeys = keys
d.registerExecCommand(container, execConfig)
d.LogContainerEvent(container, "exec_create: "+execConfig.ProcessConfig.Entrypoint+" "+strings.Join(execConfig.ProcessConfig.Arguments, " "))
return execConfig.ID, nil
}
// ContainerExecStart starts a previously set up exec instance. The
// std streams are set up.
func (d *Daemon) ContainerExecStart(name string, stdin io.ReadCloser, stdout io.Writer, stderr io.Writer) error {
var (
cStdin io.ReadCloser
cStdout, cStderr io.Writer
)
ec, err := d.getExecConfig(name)
if err != nil {
return derr.ErrorCodeNoExecID.WithArgs(name)
}
ec.Lock()
if ec.ExitCode != nil {
ec.Unlock()
return derr.ErrorCodeExecExited.WithArgs(ec.ID)
}
if ec.Running {
ec.Unlock()
return derr.ErrorCodeExecRunning.WithArgs(ec.ID)
}
ec.Running = true
ec.Unlock()
c := d.containers.Get(ec.ContainerID)
logrus.Debugf("starting exec command %s in container %s", ec.ID, c.ID)
d.LogContainerEvent(c, "exec_start: "+ec.ProcessConfig.Entrypoint+" "+strings.Join(ec.ProcessConfig.Arguments, " "))
if ec.OpenStdin {
r, w := io.Pipe()
go func() {
defer w.Close()
defer logrus.Debugf("Closing buffered stdin pipe")
pools.Copy(w, stdin)
}()
cStdin = r
}
if ec.OpenStdout {
cStdout = stdout
}
if ec.OpenStderr {
cStderr = stderr
}
if ec.OpenStdin {
ec.NewInputPipes()
} else {
ec.NewNopInputPipe()
}
attachErr := container.AttachStreams(ec.StreamConfig, ec.OpenStdin, true, ec.ProcessConfig.Tty, cStdin, cStdout, cStderr, ec.DetachKeys)
execErr := make(chan error)
// Note, the ExecConfig data will be removed when the container
// itself is deleted. This allows us to query it (for things like
// the exitStatus) even after the cmd is done running.
go func() {
execErr <- d.containerExec(c, ec)
}()
select {
case err := <-attachErr:
if err != nil {
return derr.ErrorCodeExecAttach.WithArgs(err)
}
return nil
case err := <-execErr:
if aErr := <-attachErr; aErr != nil && err == nil {
return derr.ErrorCodeExecAttach.WithArgs(aErr)
}
if err == nil {
return nil
}
// Maybe the container stopped while we were trying to exec
if !c.IsRunning() {
return derr.ErrorCodeExecContainerStopped
}
return derr.ErrorCodeExecCantRun.WithArgs(ec.ID, c.ID, err)
}
}
// Exec calls the underlying exec driver to run
func (d *Daemon) Exec(c *container.Container, execConfig *exec.Config, pipes *execdriver.Pipes, startCallback execdriver.DriverCallback) (int, error) {
hooks := execdriver.Hooks{
Start: startCallback,
}
exitStatus, err := d.execDriver.Exec(c.Command, execConfig.ProcessConfig, pipes, hooks)
// On err, make sure we don't leave ExitCode at zero
if err != nil && exitStatus == 0 {
exitStatus = 128
}
execConfig.ExitCode = &exitStatus
execConfig.Running = false
return exitStatus, err
}
// execCommandGC runs a ticker to clean up the daemon references
// of exec configs that are no longer part of the container.
func (d *Daemon) execCommandGC() {
for range time.Tick(5 * time.Minute) {
var (
cleaned int
liveExecCommands = d.containerExecIds()
)
for id, config := range d.execCommands.Commands() {
if config.CanRemove {
cleaned++
d.execCommands.Delete(id)
} else {
if _, exists := liveExecCommands[id]; !exists {
config.CanRemove = true
}
}
}
if cleaned > 0 {
logrus.Debugf("clean %d unused exec commands", cleaned)
}
}
}
// containerExecIds returns a list of all the current exec ids that are in use
// and running inside a container.
func (d *Daemon) containerExecIds() map[string]struct{} {
ids := map[string]struct{}{}
for _, c := range d.containers.List() {
for _, id := range c.ExecCommands.List() {
ids[id] = struct{}{}
}
}
return ids
}
func (d *Daemon) containerExec(container *container.Container, ec *exec.Config) error {
container.Lock()
defer container.Unlock()
callback := func(processConfig *execdriver.ProcessConfig, pid int, chOOM <-chan struct{}) error {
if processConfig.Tty {
// The callback is called after the process Start()
// so we are in the parent process. In TTY mode, stdin/out/err is the PtySlave
// which we close here.
if c, ok := processConfig.Stdout.(io.Closer); ok {
c.Close()
}
}
ec.Close()
return nil
}
// We use a callback here instead of a goroutine and an chan for
// synchronization purposes
cErr := promise.Go(func() error { return d.monitorExec(container, ec, callback) })
return ec.Wait(cErr)
}
func (d *Daemon) monitorExec(container *container.Container, execConfig *exec.Config, callback execdriver.DriverCallback) error {
pipes := execdriver.NewPipes(execConfig.Stdin(), execConfig.Stdout(), execConfig.Stderr(), execConfig.OpenStdin)
exitCode, err := d.Exec(container, execConfig, pipes, callback)
if err != nil {
logrus.Errorf("Error running command in existing container %s: %s", container.ID, err)
}
logrus.Debugf("Exec task in container %s exited with code %d", container.ID, exitCode)
if err := execConfig.CloseStreams(); err != nil {
logrus.Errorf("%s: %s", container.ID, err)
}
if execConfig.ProcessConfig.Terminal != nil {
if err := execConfig.ProcessConfig.Terminal.Close(); err != nil {
logrus.Errorf("Error closing terminal while running in container %s: %s", container.ID, err)
}
}
// remove the exec command from the container's store only and not the
// daemon's store so that the exec command can be inspected.
container.ExecCommands.Delete(execConfig.ID)
return err
}