Golang State.NewTask方法代码示例

// Disconnect returns a set of tasks for  disconnecting an interface.
func Disconnect(s *state.State, plugSnap, plugName, slotSnap, slotName string) (*state.TaskSet, error) {
	// TODO: Remove the intent-to-connect from the state so that we no longer
	// automatically try to reconnect on reboot.
	summary := fmt.Sprintf(i18n.G("Disconnect %s:%s from %s:%s"),
		plugSnap, plugName, slotSnap, slotName)
	task := s.NewTask("disconnect", summary)
	task.Set("slot", interfaces.SlotRef{Snap: slotSnap, Name: slotName})
	task.Set("plug", interfaces.PlugRef{Snap: plugSnap, Name: plugName})
	return state.NewTaskSet(task), nil
}

// Connect returns a set of tasks for connecting an interface.
//
func Connect(s *state.State, plugSnap, plugName, slotSnap, slotName string) (*state.TaskSet, error) {
	// TODO: Store the intent-to-connect in the state so that we automatically
	// try to reconnect on reboot (reconnection can fail or can connect with
	// different parameters so we cannot store the actual connection details).
	summary := fmt.Sprintf(i18n.G("Connect %s:%s to %s:%s"),
		plugSnap, plugName, slotSnap, slotName)
	task := s.NewTask("connect", summary)
	task.Set("slot", interfaces.SlotRef{Snap: slotSnap, Name: slotName})
	task.Set("plug", interfaces.PlugRef{Snap: plugSnap, Name: plugName})
	return state.NewTaskSet(task), nil
}

func doInstall(s *state.State, curActive bool, snapName, snapPath, channel string, userID int, flags snappy.InstallFlags) (*state.TaskSet, error) {
	if err := checkChangeConflict(s, snapName); err != nil {
		return nil, err
	}

	if snapPath == "" && channel == "" {
		channel = "stable"
	}

	var prepare *state.Task
	ss := SnapSetup{
		Channel: channel,
		UserID:  userID,
		Flags:   int(flags),
	}
	ss.Name = snapName
	ss.SnapPath = snapPath
	if snapPath != "" {
		prepare = s.NewTask("prepare-snap", fmt.Sprintf(i18n.G("Prepare snap %q"), snapPath))
	} else {
		prepare = s.NewTask("download-snap", fmt.Sprintf(i18n.G("Download snap %q from channel %q"), snapName, channel))
	}
	prepare.Set("snap-setup", ss)

	tasks := []*state.Task{prepare}
	addTask := func(t *state.Task) {
		t.Set("snap-setup-task", prepare.ID())
		tasks = append(tasks, t)
	}

	// mount
	mount := s.NewTask("mount-snap", fmt.Sprintf(i18n.G("Mount snap %q"), snapName))
	addTask(mount)
	mount.WaitFor(prepare)
	precopy := mount

	if curActive {
		// unlink-current-snap (will stop services for copy-data)
		unlink := s.NewTask("unlink-current-snap", fmt.Sprintf(i18n.G("Make current revision for snap %q unavailable"), snapName))
		addTask(unlink)
		unlink.WaitFor(mount)
		precopy = unlink
	}

	// copy-data (needs stopped services by unlink)
	copyData := s.NewTask("copy-snap-data", fmt.Sprintf(i18n.G("Copy snap %q data"), snapName))
	addTask(copyData)
	copyData.WaitFor(precopy)

	// security
	setupSecurity := s.NewTask("setup-profiles", fmt.Sprintf(i18n.G("Setup snap %q security profiles"), snapName))
	addTask(setupSecurity)
	setupSecurity.WaitFor(copyData)

	// finalize (wrappers+current symlink)
	linkSnap := s.NewTask("link-snap", fmt.Sprintf(i18n.G("Make snap %q available to the system"), snapName))
	addTask(linkSnap)
	linkSnap.WaitFor(setupSecurity)

	return state.NewTaskSet(tasks...), nil
}

// Remove returns a set of tasks for removing snap.
// Note that the state must be locked by the caller.
func Remove(s *state.State, name string, flags snappy.RemoveFlags) (*state.TaskSet, error) {
	if err := checkChangeConflict(s, name); err != nil {
		return nil, err
	}

	var snapst SnapState
	err := Get(s, name, &snapst)
	if err != nil && err != state.ErrNoState {
		return nil, err
	}

	cur := snapst.Current()
	if cur == nil {
		return nil, fmt.Errorf("cannot find snap %q", name)
	}

	revision := snapst.Current().Revision
	active := snapst.Active

	info, err := Info(s, name, revision)
	if err != nil {
		return nil, err
	}

	ss := SnapSetup{
		Name:     name,
		Revision: revision,
		Flags:    int(flags),
	}

	// check if this is something that can be removed
	if !backend.CanRemove(info, active) {
		return nil, fmt.Errorf("snap %q is not removable", ss.Name)
	}

	// trigger remove

	discardSnap := s.NewTask("discard-snap", fmt.Sprintf(i18n.G("Remove snap %q from the system"), name))
	discardSnap.Set("snap-setup", ss)

	discardSnapID := discardSnap.ID()
	tasks := ([]*state.Task)(nil)
	var chain *state.Task
	addNext := func(t *state.Task) {
		if chain != nil {
			t.WaitFor(chain)
		}
		if t.ID() != discardSnapID {
			t.Set("snap-setup-task", discardSnapID)
		}
		tasks = append(tasks, t)
		chain = t
	}

	if active {
		unlink := s.NewTask("unlink-snap", fmt.Sprintf(i18n.G("Make snap %q unavailable to the system"), name))

		addNext(unlink)
	}

	removeSecurity := s.NewTask("remove-profiles", fmt.Sprintf(i18n.G("Remove security profile for snap %q"), name))
	addNext(removeSecurity)

	clearData := s.NewTask("clear-snap", fmt.Sprintf(i18n.G("Remove data for snap %q"), name))
	addNext(clearData)

	addNext(discardSnap)

	if len(snapst.Sequence) == 1 {
		discardConns := s.NewTask("discard-conns", fmt.Sprintf(i18n.G("Discard interface connections for snap %q"), name))
		addNext(discardConns)
	}

	return state.NewTaskSet(tasks...), nil
}