func (task *managedTask) cleanupTask() {
	cleanupTime := ttime.After(task.KnownStatusTime.Add(taskStoppedDuration).Sub(ttime.Now()))
	cleanupTimeBool := make(chan bool)
	go func() {
		<-cleanupTime
		cleanupTimeBool <- true
		close(cleanupTimeBool)
	}()
	for !task.waitEvent(cleanupTimeBool) {
	}
	log.Debug("Cleaning up task's containers and data", "task", task.Task)

	// First make an attempt to cleanup resources
	task.engine.sweepTask(task.Task)
	task.engine.state.RemoveTask(task.Task)
	// Now remove ourselves from the global state and cleanup channels
	task.engine.processTasks.Lock()
	delete(task.engine.managedTasks, task.Arn)
	task.engine.processTasks.Unlock()
	task.engine.saver.Save()

	// Cleanup any leftover messages before closing their channels. No new
	// messages possible because we deleted ourselves from managedTasks, so this
	// removes all stale ones
	task.discardPendingMessages()

	close(task.dockerMessages)
	close(task.acsMessages)
}

// ListContainers returns a slice of container IDs.
func (dg *dockerGoClient) ListContainers(all bool) ListContainersResponse {
	timeout := ttime.After(listContainersTimeout)

	response := make(chan ListContainersResponse, 1)
	go func() { response <- dg.listContainers(all) }()
	select {
	case resp := <-response:
		return resp
	case <-timeout:
		return ListContainersResponse{Error: &DockerTimeoutError{listContainersTimeout, "listing"}}
	}
}

func (dg *dockerGoClient) RemoveContainer(dockerId string) error {
	timeout := ttime.After(removeContainerTimeout)

	response := make(chan error, 1)
	go func() { response <- dg.removeContainer(dockerId) }()
	select {
	case resp := <-response:
		return resp
	case <-timeout:
		return &DockerTimeoutError{removeContainerTimeout, "removing"}
	}
}

func (dg *DockerGoClient) PullImage(image string) DockerContainerMetadata {
	timeout := ttime.After(pullImageTimeout)

	response := make(chan DockerContainerMetadata, 1)
	go func() { response <- dg.pullImage(image) }()
	select {
	case resp := <-response:
		return resp
	case <-timeout:
		return DockerContainerMetadata{Error: &DockerTimeoutError{pullImageTimeout, "pulled"}}
	}
}

func (dg *dockerGoClient) StartContainer(id string) DockerContainerMetadata {
	timeout := ttime.After(startContainerTimeout)

	ctx, cancelFunc := context.WithCancel(context.TODO()) // Could pass one through from engine
	response := make(chan DockerContainerMetadata, 1)
	go func() { response <- dg.startContainer(ctx, id) }()
	select {
	case resp := <-response:
		return resp
	case <-timeout:
		cancelFunc()
		return DockerContainerMetadata{Error: &DockerTimeoutError{startContainerTimeout, "started"}}
	}
}

func (dg *dockerGoClient) CreateContainer(config *docker.Config, hostConfig *docker.HostConfig, name string) DockerContainerMetadata {
	timeout := ttime.After(createContainerTimeout)

	ctx, cancelFunc := context.WithCancel(context.TODO()) // Could pass one through from engine
	response := make(chan DockerContainerMetadata, 1)
	go func() { response <- dg.createContainer(ctx, config, hostConfig, name) }()
	select {
	case resp := <-response:
		return resp
	case <-timeout:
		cancelFunc()
		return DockerContainerMetadata{Error: &DockerTimeoutError{createContainerTimeout, "created"}}
	}
}

func (dg *dockerGoClient) StopContainer(dockerId string) DockerContainerMetadata {
	timeout := ttime.After(stopContainerTimeout)

	ctx, cancelFunc := context.WithCancel(context.TODO()) // Could pass one through from engine
	// Buffered channel so in the case of timeout it takes one write, never gets
	// read, and can still be GC'd
	response := make(chan DockerContainerMetadata, 1)
	go func() { response <- dg.stopContainer(ctx, dockerId) }()
	select {
	case resp := <-response:
		return resp
	case <-timeout:
		cancelFunc()
		return DockerContainerMetadata{Error: &DockerTimeoutError{stopContainerTimeout, "stopped"}}
	}
}

func (dg *dockerGoClient) PullImage(image string, authData *api.RegistryAuthenticationData) DockerContainerMetadata {
	timeout := ttime.After(pullImageTimeout)

	// Workaround for devicemapper bug. See:
	// https://github.com/docker/docker/issues/9718
	pullLock.Lock()
	defer pullLock.Unlock()

	response := make(chan DockerContainerMetadata, 1)
	go func() { response <- dg.pullImage(image, authData) }()
	select {
	case resp := <-response:
		return resp
	case <-timeout:
		return DockerContainerMetadata{Error: &DockerTimeoutError{pullImageTimeout, "pulled"}}
	}
}

func (dg *dockerGoClient) InspectContainer(dockerId string) (*docker.Container, error) {
	timeout := ttime.After(inspectContainerTimeout)

	type inspectResponse struct {
		container *docker.Container
		err       error
	}
	response := make(chan inspectResponse, 1)
	go func() {
		container, err := dg.inspectContainer(dockerId)
		response <- inspectResponse{container, err}
	}()
	select {
	case resp := <-response:
		return resp.container, resp.err
	case <-timeout:
		return nil, &DockerTimeoutError{inspectContainerTimeout, "inspecting"}
	}
}

func (task *managedTask) cleanupTask(taskStoppedDuration time.Duration) {
	cleanupTimeDuration := task.KnownStatusTime.Add(taskStoppedDuration).Sub(ttime.Now())
	// There is a potential deadlock here if cleanupTime is negative. Ignore the computed
	// value in this case in favor of the default config value.
	if cleanupTimeDuration < 0 {
		log.Debug("Task Cleanup Duration is too short. Resetting to " + config.DefaultTaskCleanupWaitDuration.String())
		cleanupTimeDuration = config.DefaultTaskCleanupWaitDuration
	}
	cleanupTime := ttime.After(cleanupTimeDuration)
	cleanupTimeBool := make(chan bool)
	go func() {
		<-cleanupTime
		cleanupTimeBool <- true
		close(cleanupTimeBool)
	}()
	for !task.waitEvent(cleanupTimeBool) {
	}
	log.Debug("Cleaning up task's containers and data", "task", task.Task)

	// For the duration of this, simply discard any task events; this ensures the
	// speedy processing of other events for other tasks
	handleCleanupDone := make(chan struct{})
	go func() {
		task.engine.sweepTask(task.Task)
		task.engine.state.RemoveTask(task.Task)
		handleCleanupDone <- struct{}{}
	}()
	task.discardEventsUntil(handleCleanupDone)
	log.Debug("Finished removing task data; removing from state no longer managing", "task", task.Task)
	// Now remove ourselves from the global state and cleanup channels
	task.engine.processTasks.Lock()
	delete(task.engine.managedTasks, task.Arn)
	task.engine.processTasks.Unlock()
	task.engine.saver.Save()

	// Cleanup any leftover messages before closing their channels. No new
	// messages possible because we deleted ourselves from managedTasks, so this
	// removes all stale ones
	task.discardPendingMessages()

	close(task.dockerMessages)
	close(task.acsMessages)
}

func (dg *dockerGoClient) pullImage(image string, authData *api.RegistryAuthenticationData) DockerContainerMetadata {
	log.Debug("Pulling image", "image", image)
	client, err := dg.dockerClient()
	if err != nil {
		return DockerContainerMetadata{Error: CannotGetDockerClientError{version: dg.version, err: err}}
	}

	// Special case; this image is not one that should be pulled, but rather
	// should be created locally if necessary
	if image == emptyvolume.Image+":"+emptyvolume.Tag {
		err := dg.createScratchImageIfNotExists()
		if err != nil {
			return DockerContainerMetadata{Error: &api.DefaultNamedError{Name: "CreateEmptyVolumeError", Err: "Could not create empty volume " + err.Error()}}
		}
		return DockerContainerMetadata{}
	}

	authConfig, err := dg.getAuthdata(image, authData)
	if err != nil {
		return DockerContainerMetadata{Error: err}
	}

	pullDebugOut, pullWriter := io.Pipe()
	defer pullWriter.Close()

	repository, tag := parsers.ParseRepositoryTag(image)
	if tag == "" {
		repository = repository + ":" + dockerDefaultTag
	} else {
		repository = image
	}

	opts := docker.PullImageOptions{
		Repository:   repository,
		OutputStream: pullWriter,
	}
	timeout := ttime.After(dockerPullBeginTimeout)
	// pullBegan is a channel indicating that we have seen at least one line of data on the 'OutputStream' above.
	// It is here to guard against a bug wherin docker never writes anything to that channel and hangs in pulling forever.
	pullBegan := make(chan bool, 1)
	// pullBeganOnce ensures we only indicate it began once (since our channel will only be read 0 or 1 times)
	pullBeganOnce := sync.Once{}

	go func() {
		reader := bufio.NewReader(pullDebugOut)
		var line string
		var err error
		for err == nil {
			line, err = reader.ReadString('\n')
			if err != nil {
				break
			}
			pullBeganOnce.Do(func() {
				pullBegan <- true
			})
			log.Debug("Pulling image", "image", image, "status", line)
			if strings.Contains(line, "already being pulled by another client. Waiting.") {
				// This can mean the deamon is 'hung' in pulling status for this image, but we can't be sure.
				log.Error("Image 'pull' status marked as already being pulled", "image", image, "status", line)
			}
		}
		if err != nil && err != io.EOF {
			log.Warn("Error reading pull image status", "image", image, "err", err)
		}
	}()
	pullFinished := make(chan error, 1)
	go func() {
		pullFinished <- client.PullImage(opts, authConfig)
		log.Debug("Pulling image complete", "image", image)
	}()

	select {
	case <-pullBegan:
		break
	case err := <-pullFinished:
		if err != nil {
			return DockerContainerMetadata{Error: CannotXContainerError{"Pull", err.Error()}}
		}
		return DockerContainerMetadata{}
	case <-timeout:
		return DockerContainerMetadata{Error: &DockerTimeoutError{dockerPullBeginTimeout, "pullBegin"}}
	}
	log.Debug("Pull began for image", "image", image)
	defer log.Debug("Pull completed for image", "image", image)

	err = <-pullFinished
	if err != nil {
		return DockerContainerMetadata{Error: CannotXContainerError{"Pull", err.Error()}}
	}
	return DockerContainerMetadata{}
}

func (task *managedTask) overseeTask() {
	llog := log.New("task", task)

	// Do a single updatestatus at the beginning to create the container
	// 'desiredstatus'es which are a construct of the engine used only here,
	// not present on the backend
	task.UpdateStatus()
	// If this was a 'state restore', send all unsent statuses
	task.emitCurrentStatus()

	if task.StartSequenceNumber != 0 && !task.DesiredStatus.Terminal() {
		llog.Debug("Waiting for any previous stops to complete", "seqnum", task.StartSequenceNumber)
		othersStopped := make(chan bool, 1)
		go func() {
			task.engine.taskStopGroup.Wait(task.StartSequenceNumber)
			othersStopped <- true
		}()
		for !task.waitEvent(othersStopped) {
			if task.DesiredStatus.Terminal() {
				// If we end up here, that means we recieved a start then stop for this
				// task before a task that was expected to stop before it could
				// actually stop
				break
			}
		}
		llog.Debug("Wait over; ready to move towards status: " + task.DesiredStatus.String())
	}
	for {
		// If it's steadyState, just spin until we need to do work
		for task.steadyState() {
			llog.Debug("Task at steady state", "state", task.KnownStatus.String())
			maxWait := make(chan bool, 1)
			timer := ttime.After(steadyStateTaskVerifyInterval)
			go func() {
				<-timer
				maxWait <- true
			}()
			timedOut := task.waitEvent(maxWait)

			if timedOut {
				llog.Debug("Checking task to make sure it's still at steadystate")
				go task.engine.CheckTaskState(task.Task)
			}
		}

		if !task.KnownStatus.Terminal() {
			// If we aren't terminal and we aren't steady state, we should be able to move some containers along
			llog.Debug("Task not steady state or terminal; progressing it")
			task.progressContainers()
		}

		// If we reach this point, we've changed the task in some way.
		// Conversely, for it to spin in steady state it will have to have been
		// loaded in steady state or progressed through here, so saving here should
		// be sufficient to capture state changes.
		err := task.engine.saver.Save()
		if err != nil {
			llog.Warn("Error checkpointing task's states to disk", "err", err)
		}
		if task.KnownStatus.Terminal() {
			break
		}
	}
	// We only break out of the above if this task is known to be stopped. Do
	// onetime cleanup here, including removing the task after a timeout
	llog.Debug("Task has reached stopped. We're just waiting and removing containers now")
	if task.StopSequenceNumber != 0 {
		llog.Debug("Marking done for this sequence", "seqnum", task.StopSequenceNumber)
		task.engine.taskStopGroup.Done(task.StopSequenceNumber)
	}
	task.cleanupTask(task.engine.cfg.TaskCleanupWaitDuration)
}