Golang Manager.Cgroups方法代碼示例

func (e *LinuxExecutor) destroyCgroup() error {
	if e.groups == nil {
		return errors.New("Can't destroy: cgroup configuration empty")
	}

	manager := cgroupFs.Manager{}
	manager.Cgroups = e.groups
	pids, err := manager.GetPids()
	if err != nil {
		return fmt.Errorf("Failed to get pids in the cgroup %v: %v", e.groups.Name, err)
	}

	errs := new(multierror.Error)
	for _, pid := range pids {
		process, err := os.FindProcess(pid)
		if err != nil {
			multierror.Append(errs, fmt.Errorf("Failed to find Pid %v: %v", pid, err))
			continue
		}

		if err := process.Kill(); err != nil {
			multierror.Append(errs, fmt.Errorf("Failed to kill Pid %v: %v", pid, err))
			continue
		}

		if _, err := process.Wait(); err != nil {
			multierror.Append(errs, fmt.Errorf("Failed to wait Pid %v: %v", pid, err))
			continue
		}
	}

	// Remove the cgroup.
	if err := manager.Destroy(); err != nil {
		multierror.Append(errs, fmt.Errorf("Failed to delete the cgroup directories: %v", err))
	}

	if len(errs.Errors) != 0 {
		return fmt.Errorf("Failed to destroy cgroup: %v", errs)
	}

	return nil
}

// spawnDaemon executes a double fork to start the user command with proper
// isolation. Stores the child process for use in Wait.
func (e *LinuxExecutor) spawnDaemon() error {
	bin, err := discover.NomadExecutable()
	if err != nil {
		return fmt.Errorf("Failed to determine the nomad executable: %v", err)
	}

	// Serialize the cmd and the cgroup configuration so it can be passed to the
	// sub-process.
	var buffer bytes.Buffer
	enc := json.NewEncoder(&buffer)

	c := command.DaemonConfig{
		Cmd:        e.cmd.Cmd,
		Chroot:     e.taskDir,
		StdoutFile: filepath.Join(e.taskDir, allocdir.TaskLocal, fmt.Sprintf("%v.stdout", e.taskName)),
		StderrFile: filepath.Join(e.taskDir, allocdir.TaskLocal, fmt.Sprintf("%v.stderr", e.taskName)),
		StdinFile:  "/dev/null",
	}
	if err := enc.Encode(c); err != nil {
		return fmt.Errorf("Failed to serialize daemon configuration: %v", err)
	}

	// Create a pipe to capture Stdout.
	pr, pw, err := os.Pipe()
	if err != nil {
		return err
	}
	e.spawnOutputWriter = pw
	e.spawnOutputReader = pr

	// Call ourselves using a hidden flag. The new instance of nomad will join
	// the passed cgroup, forkExec the cmd, and output status codes through
	// Stdout.
	escaped := strconv.Quote(buffer.String())
	spawn := exec.Command(bin, "spawn-daemon", escaped)
	spawn.Stdout = e.spawnOutputWriter

	// Capture its Stdin.
	spawnStdIn, err := spawn.StdinPipe()
	if err != nil {
		return err
	}

	if err := spawn.Start(); err != nil {
		fmt.Errorf("Failed to call spawn-daemon on nomad executable: %v", err)
	}

	// Join the spawn-daemon to the cgroup.
	if e.groups != nil {
		manager := cgroupFs.Manager{}
		manager.Cgroups = e.groups

		// Apply will place the current pid into the tasks file for each of the
		// created cgroups:
		//  /sys/fs/cgroup/memory/user/1000.user/4.session/<uuid>/tasks
		//
		// Apply requires superuser permissions, and may fail if Nomad is not run with
		// the required permissions
		if err := manager.Apply(spawn.Process.Pid); err != nil {
			errs := new(multierror.Error)
			errs = multierror.Append(errs, fmt.Errorf("Failed to join spawn-daemon to the cgroup (config => %+v): %v", manager.Cgroups, err))

			if err := sendAbortCommand(spawnStdIn); err != nil {
				errs = multierror.Append(errs, err)
			}

			return errs
		}
	}

	// Tell it to start.
	if err := sendStartCommand(spawnStdIn); err != nil {
		return err
	}

	// Parse the response.
	dec := json.NewDecoder(e.spawnOutputReader)
	var resp command.SpawnStartStatus
	if err := dec.Decode(&resp); err != nil {
		return fmt.Errorf("Failed to parse spawn-daemon start response: %v", err)
	}

	if resp.ErrorMsg != "" {
		return fmt.Errorf("Failed to execute user command: %s", resp.ErrorMsg)
	}

	e.spawnChild = *spawn
	return nil
}