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exec.go
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exec.go
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package daemon
import (
"fmt"
"io"
"io/ioutil"
"strings"
"sync"
log "github.com/Sirupsen/logrus"
"github.com/docker/docker/daemon/execdriver"
"github.com/docker/docker/daemon/execdriver/lxc"
"github.com/docker/docker/engine"
"github.com/docker/docker/pkg/broadcastwriter"
"github.com/docker/docker/pkg/common"
"github.com/docker/docker/pkg/ioutils"
"github.com/docker/docker/pkg/promise"
"github.com/docker/docker/runconfig"
)
type execConfig struct {
sync.Mutex
ID string
Running bool
ExitCode int
ProcessConfig execdriver.ProcessConfig
StreamConfig
OpenStdin bool
OpenStderr bool
OpenStdout bool
Container *Container
}
type execStore struct {
s map[string]*execConfig
sync.RWMutex
}
func newExecStore() *execStore {
return &execStore{s: make(map[string]*execConfig, 0)}
}
func (e *execStore) Add(id string, execConfig *execConfig) {
e.Lock()
e.s[id] = execConfig
e.Unlock()
}
func (e *execStore) Get(id string) *execConfig {
e.RLock()
res := e.s[id]
e.RUnlock()
return res
}
func (e *execStore) Delete(id string) {
e.Lock()
delete(e.s, id)
e.Unlock()
}
func (e *execStore) List() []string {
var IDs []string
e.RLock()
for id := range e.s {
IDs = append(IDs, id)
}
e.RUnlock()
return IDs
}
func (execConfig *execConfig) Resize(h, w int) error {
return execConfig.ProcessConfig.Terminal.Resize(h, w)
}
func (d *Daemon) registerExecCommand(execConfig *execConfig) {
// Storing execs in container in order to kill them gracefully whenever the container is stopped or removed.
execConfig.Container.execCommands.Add(execConfig.ID, execConfig)
// Storing execs in daemon for easy access via remote API.
d.execCommands.Add(execConfig.ID, execConfig)
}
func (d *Daemon) getExecConfig(name string) (*execConfig, error) {
if execConfig := d.execCommands.Get(name); execConfig != nil {
if !execConfig.Container.IsRunning() {
return nil, fmt.Errorf("Container %s is not running", execConfig.Container.ID)
}
return execConfig, nil
}
return nil, fmt.Errorf("No such exec instance '%s' found in daemon", name)
}
func (d *Daemon) unregisterExecCommand(execConfig *execConfig) {
execConfig.Container.execCommands.Delete(execConfig.ID)
d.execCommands.Delete(execConfig.ID)
}
func (d *Daemon) getActiveContainer(name string) (*Container, error) {
container, err := d.Get(name)
if err != nil {
return nil, err
}
if !container.IsRunning() {
return nil, fmt.Errorf("Container %s is not running", name)
}
if container.IsPaused() {
return nil, fmt.Errorf("Container %s is paused, unpause the container before exec", name)
}
return container, nil
}
func (d *Daemon) ContainerExecCreate(job *engine.Job) engine.Status {
if len(job.Args) != 1 {
return job.Errorf("Usage: %s [options] container command [args]", job.Name)
}
if strings.HasPrefix(d.execDriver.Name(), lxc.DriverName) {
return job.Error(lxc.ErrExec)
}
var name = job.Args[0]
container, err := d.getActiveContainer(name)
if err != nil {
return job.Error(err)
}
config, err := runconfig.ExecConfigFromJob(job)
if err != nil {
return job.Error(err)
}
entrypoint, args := d.getEntrypointAndArgs(nil, config.Cmd)
processConfig := execdriver.ProcessConfig{
Tty: config.Tty,
Entrypoint: entrypoint,
Arguments: args,
}
execConfig := &execConfig{
ID: common.GenerateRandomID(),
OpenStdin: config.AttachStdin,
OpenStdout: config.AttachStdout,
OpenStderr: config.AttachStderr,
StreamConfig: StreamConfig{},
ProcessConfig: processConfig,
Container: container,
Running: false,
}
container.LogEvent("exec_create: " + execConfig.ProcessConfig.Entrypoint + " " + strings.Join(execConfig.ProcessConfig.Arguments, " "))
d.registerExecCommand(execConfig)
job.Printf("%s\n", execConfig.ID)
return engine.StatusOK
}
func (d *Daemon) ContainerExecStart(job *engine.Job) engine.Status {
if len(job.Args) != 1 {
return job.Errorf("Usage: %s [options] exec", job.Name)
}
var (
cStdin io.ReadCloser
cStdout, cStderr io.Writer
execName = job.Args[0]
)
execConfig, err := d.getExecConfig(execName)
if err != nil {
return job.Error(err)
}
func() {
execConfig.Lock()
defer execConfig.Unlock()
if execConfig.Running {
err = fmt.Errorf("Error: Exec command %s is already running", execName)
}
execConfig.Running = true
}()
if err != nil {
return job.Error(err)
}
log.Debugf("starting exec command %s in container %s", execConfig.ID, execConfig.Container.ID)
container := execConfig.Container
container.LogEvent("exec_start: " + execConfig.ProcessConfig.Entrypoint + " " + strings.Join(execConfig.ProcessConfig.Arguments, " "))
if execConfig.OpenStdin {
r, w := io.Pipe()
go func() {
defer w.Close()
defer log.Debugf("Closing buffered stdin pipe")
io.Copy(w, job.Stdin)
}()
cStdin = r
}
if execConfig.OpenStdout {
cStdout = job.Stdout
}
if execConfig.OpenStderr {
cStderr = job.Stderr
}
execConfig.StreamConfig.stderr = broadcastwriter.New()
execConfig.StreamConfig.stdout = broadcastwriter.New()
// Attach to stdin
if execConfig.OpenStdin {
execConfig.StreamConfig.stdin, execConfig.StreamConfig.stdinPipe = io.Pipe()
} else {
execConfig.StreamConfig.stdinPipe = ioutils.NopWriteCloser(ioutil.Discard) // Silently drop stdin
}
attachErr := d.Attach(&execConfig.StreamConfig, execConfig.OpenStdin, true, execConfig.ProcessConfig.Tty, cStdin, cStdout, cStderr)
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() {
err := container.Exec(execConfig)
if err != nil {
execErr <- fmt.Errorf("Cannot run exec command %s in container %s: %s", execName, container.ID, err)
}
}()
select {
case err := <-attachErr:
if err != nil {
return job.Errorf("attach failed with error: %s", err)
}
break
case err := <-execErr:
return job.Error(err)
}
return engine.StatusOK
}
func (d *Daemon) Exec(c *Container, execConfig *execConfig, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (int, error) {
exitStatus, err := d.execDriver.Exec(c.command, &execConfig.ProcessConfig, pipes, startCallback)
// 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
}
func (container *Container) GetExecIDs() []string {
return container.execCommands.List()
}
func (container *Container) Exec(execConfig *execConfig) error {
container.Lock()
defer container.Unlock()
waitStart := make(chan struct{})
callback := func(processConfig *execdriver.ProcessConfig, pid int) {
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()
}
}
close(waitStart)
}
// We use a callback here instead of a goroutine and an chan for
// syncronization purposes
cErr := promise.Go(func() error { return container.monitorExec(execConfig, callback) })
// Exec should not return until the process is actually running
select {
case <-waitStart:
case err := <-cErr:
return err
}
return nil
}
func (container *Container) monitorExec(execConfig *execConfig, callback execdriver.StartCallback) error {
var (
err error
exitCode int
)
pipes := execdriver.NewPipes(execConfig.StreamConfig.stdin, execConfig.StreamConfig.stdout, execConfig.StreamConfig.stderr, execConfig.OpenStdin)
exitCode, err = container.daemon.Exec(container, execConfig, pipes, callback)
if err != nil {
log.Errorf("Error running command in existing container %s: %s", container.ID, err)
}
log.Debugf("Exec task in container %s exited with code %d", container.ID, exitCode)
if execConfig.OpenStdin {
if err := execConfig.StreamConfig.stdin.Close(); err != nil {
log.Errorf("Error closing stdin while running in %s: %s", container.ID, err)
}
}
if err := execConfig.StreamConfig.stdout.Clean(); err != nil {
log.Errorf("Error closing stdout while running in %s: %s", container.ID, err)
}
if err := execConfig.StreamConfig.stderr.Clean(); err != nil {
log.Errorf("Error closing stderr while running in %s: %s", container.ID, err)
}
if execConfig.ProcessConfig.Terminal != nil {
if err := execConfig.ProcessConfig.Terminal.Close(); err != nil {
log.Errorf("Error closing terminal while running in container %s: %s", container.ID, err)
}
}
return err
}