Golang watcher.MustErr函数代码示例

func (w *RelationUnitsWatcher) loop() (err error) {
	sentInitial := false
	changes := RelationUnitsChange{}
	out := w.out
	out = nil
	for {
		select {
		case <-w.st.watcher.Dead():
			return watcher.MustErr(w.st.watcher)
		case <-w.tomb.Dying():
			return tomb.ErrDying
		case c, ok := <-w.sw.Changes():
			if !ok {
				return watcher.MustErr(w.sw)
			}
			if err = w.mergeScope(&changes, c); err != nil {
				return err
			}
			if !sentInitial || !changes.empty() {
				out = w.out
			} else {
				out = nil
			}
		case c := <-w.updates:
			if _, err = w.mergeSettings(&changes, c.Id.(string)); err != nil {
				return err
			}
			out = w.out
		case out <- changes:
			sentInitial = true
			changes = RelationUnitsChange{}
			out = nil
		}
	}
}

func (w *EnvironConfigWatcher) loop() (err error) {
	sw := w.st.watchSettings(environGlobalKey)
	defer sw.Stop()
	out := w.out
	out = nil
	cfg := &config.Config{}
	for {
		select {
		case <-w.st.watcher.Dead():
			return watcher.MustErr(w.st.watcher)
		case <-w.tomb.Dying():
			return tomb.ErrDying
		case settings, ok := <-sw.Changes():
			if !ok {
				return watcher.MustErr(sw)
			}
			cfg, err = config.New(settings.Map())
			if err == nil {
				out = w.out
			} else {
				out = nil
			}
		case out <- cfg:
			out = nil
		}
	}
	return nil
}

func (s *WatcherSuite) TestMustErr(c *C) {
	err := watcher.MustErr(&dummyWatcher{errors.New("POW")})
	c.Assert(err, ErrorMatches, "POW")

	stillAlive := func() { watcher.MustErr(&dummyWatcher{tomb.ErrStillAlive}) }
	c.Assert(stillAlive, PanicMatches, "watcher is still running")

	noErr := func() { watcher.MustErr(&dummyWatcher{nil}) }
	c.Assert(noErr, PanicMatches, "watcher was stopped cleanly")
}

func (q *AliveHookQueue) loop(initial *State) {
	defer q.tomb.Done()
	defer watcher.Stop(q.w, &q.tomb)

	// Consume initial event, and reconcile with initial state, by inserting
	// a new RelationUnitsChange before the initial event, which schedules
	// every missing unit for immediate departure before anything else happens
	// (apart from a single potential required post-joined changed event).
	ch1, ok := <-q.w.Changes()
	if !ok {
		q.tomb.Kill(watcher.MustErr(q.w))
		return
	}
	if len(ch1.Departed) != 0 {
		panic("AliveHookQueue must be started with a fresh RelationUnitsWatcher")
	}
	q.changedPending = initial.ChangedPending
	ch0 := state.RelationUnitsChange{}
	for unit, version := range initial.Members {
		q.info[unit] = &unitInfo{
			unit:    unit,
			version: version,
			joined:  true,
		}
		if _, found := ch1.Changed[unit]; !found {
			ch0.Departed = append(ch0.Departed, unit)
		}
	}
	q.update(ch0)
	q.update(ch1)

	var next hook.Info
	var out chan<- hook.Info
	for {
		if q.empty() {
			out = nil
		} else {
			out = q.out
			next = q.next()
		}
		select {
		case <-q.tomb.Dying():
			return
		case ch, ok := <-q.w.Changes():
			if !ok {
				q.tomb.Kill(watcher.MustErr(q.w))
				return
			}
			q.update(ch)
		case out <- next:
			q.pop()
		}
	}
}

func (p *Provisioner) loop() error {
	environWatcher := p.st.WatchEnvironConfig()
	defer watcher.Stop(environWatcher, &p.tomb)

	var err error
	p.environ, err = worker.WaitForEnviron(environWatcher, p.tomb.Dying())
	if err != nil {
		return err
	}

	// Get a new StateInfo from the environment: the one used to
	// launch the agent may refer to localhost, which will be
	// unhelpful when attempting to run an agent on a new machine.
	if p.stateInfo, p.apiInfo, err = p.environ.StateInfo(); err != nil {
		return err
	}

	// Call processMachines to stop any unknown instances before watching machines.
	if err := p.processMachines(nil); err != nil {
		return err
	}

	// Start responding to changes in machines, and to any further updates
	// to the environment config.
	machinesWatcher := p.st.WatchMachines()
	defer watcher.Stop(machinesWatcher, &p.tomb)
	// START OMIT
	// launchpad.net/juju-core/worker/provisioner/provisioner.go
	for {
		select {
		case <-p.tomb.Dying():
			return tomb.ErrDying
		case cfg, ok := <-environWatcher.Changes():
			if !ok {
				return watcher.MustErr(environWatcher)
			}
			if err := p.setConfig(cfg); err != nil {
				log.Errorf("worker/provisioner: loaded invalid environment configuration: %v", err)
			}
		case ids, ok := <-machinesWatcher.Changes():
			if !ok {
				return watcher.MustErr(machinesWatcher)
			}
			if err := p.processMachines(ids); err != nil {
				return err
			}
		}
	}
	// END OMIT
	panic("not reached")
}

func (task *provisionerTask) loop() error {
	logger.Infof("Starting up provisioner task %s", task.machineId)
	defer watcher.Stop(task.machineWatcher, &task.tomb)

	// When the watcher is started, it will have the initial changes be all
	// the machines that are relevant. Also, since this is available straight
	// away, we know there will be some changes right off the bat.
	for {
		select {
		case <-task.tomb.Dying():
			logger.Infof("Shutting down provisioner task %s", task.machineId)
			return tomb.ErrDying
		case ids, ok := <-task.machineWatcher.Changes():
			if !ok {
				return watcher.MustErr(task.machineWatcher)
			}
			// TODO(dfc; lp:1042717) fire process machines periodically to shut down unknown
			// instances.
			if err := task.processMachines(ids); err != nil {
				logger.Errorf("Process machines failed: %v", err)
				return err
			}
		}
	}
}

func (w *minUnitsWatcher) loop() (err error) {
	ch := make(chan watcher.Change)
	w.st.watcher.WatchCollection(w.st.minUnits.Name, ch)
	defer w.st.watcher.UnwatchCollection(w.st.minUnits.Name, ch)
	serviceNames, err := w.initial()
	if err != nil {
		return err
	}
	out := w.out
	for {
		select {
		case <-w.tomb.Dying():
			return tomb.ErrDying
		case change, ok := <-ch:
			if !ok {
				return watcher.MustErr(w.st.watcher)
			}
			if err = w.merge(serviceNames, change); err != nil {
				return err
			}
			if !serviceNames.IsEmpty() {
				out = w.out
			}
		case out <- serviceNames.Values():
			out = nil
			serviceNames = new(set.Strings)
		}
	}
	return nil
}

// Watch starts an NotifyWatcher for each given machine.
func (m *MachinerAPI) Watch(args params.Entities) (params.NotifyWatchResults, error) {
	result := params.NotifyWatchResults{
		Results: make([]params.NotifyWatchResult, len(args.Entities)),
	}
	if len(args.Entities) == 0 {
		return result, nil
	}
	for i, entity := range args.Entities {
		err := common.ErrPerm
		if m.auth.AuthOwner(entity.Tag) {
			var machine *state.Machine
			machine, err = m.st.Machine(state.MachineIdFromTag(entity.Tag))
			if err == nil {
				watch := machine.Watch()
				// Consume the initial event. Technically, API
				// calls to Watch 'transmit' the initial event
				// in the Watch response. But NotifyWatchers
				// have no state to transmit.
				if _, ok := <-watch.Changes(); ok {
					result.Results[i].NotifyWatcherId = m.resources.Register(watch)
				} else {
					err = watcher.MustErr(watch)
				}
			}
		}
		result.Results[i].Error = common.ServerError(err)
	}
	return result, nil
}

// addRelation causes the unit agent to join the supplied relation, and to
// store persistent state in the supplied dir.
func (u *Uniter) addRelation(rel *state.Relation, dir *relation.StateDir) error {
	log.Printf("worker/uniter: joining relation %q", rel)
	ru, err := rel.Unit(u.unit)
	if err != nil {
		return err
	}
	r := NewRelationer(ru, dir, u.relationHooks)
	w := u.unit.Watch()
	defer watcher.Stop(w, &u.tomb)
	for {
		select {
		case <-u.tomb.Dying():
			return tomb.ErrDying
		case _, ok := <-w.Changes():
			if !ok {
				return watcher.MustErr(w)
			}
			if err := r.Join(); err == state.ErrCannotEnterScopeYet {
				log.Printf("worker/uniter: cannot enter scope for relation %q; waiting for subordinate to be removed", rel)
				continue
			} else if err != nil {
				return err
			}
			log.Printf("worker/uniter: joined relation %q", rel)
			u.relationers[rel.Id()] = r
			return nil
		}
	}
	panic("unreachable")
}

func (d *Deployer) loop(w *state.UnitsWatcher) error {
	deployed, err := d.mgr.DeployedUnits()
	if err != nil {
		return err
	}
	for _, unitName := range deployed {
		d.deployed[unitName] = true
		if err := d.changed(unitName); err != nil {
			return err
		}
	}
	for {
		select {
		case <-d.tomb.Dying():
			return tomb.ErrDying
		case changes, ok := <-w.Changes():
			if !ok {
				return watcher.MustErr(w)
			}
			for _, unitName := range changes {
				if err := d.changed(unitName); err != nil {
					return err
				}
			}
		}
	}
	panic("unreachable")
}

func (d *Deployer) loop() error {
	machine, err := d.st.Machine(d.machineId)
	if err != nil {
		return err
	}
	machineUnitsWatcher := machine.WatchUnits()
	defer watcher.Stop(machineUnitsWatcher, &d.tomb)

	deployed, err := d.ctx.DeployedUnits()
	if err != nil {
		return err
	}
	for _, unitName := range deployed {
		d.deployed.Add(unitName)
		if err := d.changed(unitName); err != nil {
			return err
		}
	}
	for {
		select {
		case <-d.tomb.Dying():
			return tomb.ErrDying
		case changes, ok := <-machineUnitsWatcher.Changes():
			if !ok {
				return watcher.MustErr(machineUnitsWatcher)
			}
			for _, unitName := range changes {
				if err := d.changed(unitName); err != nil {
					return err
				}
			}
		}
	}
	panic("unreachable")
}

// startMachine creates a new data value for tracking details of the
// machine and starts watching the machine for units added or removed.
func (fw *Firewaller) startMachine(id string) error {
	machined := &machineData{
		fw:     fw,
		id:     id,
		unitds: make(map[string]*unitData),
		ports:  make([]instance.Port, 0),
	}
	m, err := machined.machine()
	if errors.IsNotFoundError(err) {
		return nil
	} else if err != nil {
		return fmt.Errorf("worker/firewaller: cannot watch machine units: %v", err)
	}
	unitw := m.WatchUnits()
	select {
	case <-fw.tomb.Dying():
		stop("units watcher", unitw)
		return tomb.ErrDying
	case change, ok := <-unitw.Changes():
		if !ok {
			stop("units watcher", unitw)
			return watcher.MustErr(unitw)
		}
		fw.machineds[id] = machined
		err = fw.unitsChanged(&unitsChange{machined, change})
		if err != nil {
			stop("units watcher", unitw)
			return fmt.Errorf("worker/firewaller: cannot respond to units changes for machine %q: %v", id, err)
		}
	}
	go machined.watchLoop(unitw)
	return nil
}

// watchLoop watches the unit for port changes.
func (ud *unitData) watchLoop(latestPorts []instance.Port) {
	defer ud.tomb.Done()
	w := ud.unit.Watch()
	defer watcher.Stop(w, &ud.tomb)
	for {
		select {
		case <-ud.tomb.Dying():
			return
		case _, ok := <-w.Changes():
			if !ok {
				ud.fw.tomb.Kill(watcher.MustErr(w))
				return
			}
			if err := ud.unit.Refresh(); err != nil {
				if !errors.IsNotFoundError(err) {
					ud.fw.tomb.Kill(err)
				}
				return
			}
			change := ud.unit.OpenedPorts()
			if samePorts(change, latestPorts) {
				continue
			}
			latestPorts = append(latestPorts[:0], change...)
			select {
			case ud.fw.portsChange <- &portsChange{ud, change}:
			case <-ud.tomb.Dying():
				return
			}
		}
	}
}

// ModeTerminating marks the unit dead and returns ErrTerminateAgent.
func ModeTerminating(u *Uniter) (next Mode, err error) {
	defer modeContext("ModeTerminating", &err)()
	if err = u.unit.SetStatus(params.StatusStopped, ""); err != nil {
		return nil, err
	}
	w := u.unit.Watch()
	defer watcher.Stop(w, &u.tomb)
	for {
		select {
		case <-u.tomb.Dying():
			return nil, tomb.ErrDying
		case _, ok := <-w.Changes():
			if !ok {
				return nil, watcher.MustErr(w)
			}
			if err := u.unit.Refresh(); err != nil {
				return nil, err
			}
			if len(u.unit.SubordinateNames()) > 0 {
				continue
			}
			// The unit is known to be Dying; so if it didn't have subordinates
			// just above, it can't acquire new ones before this call.
			if err := u.unit.EnsureDead(); err != nil {
				return nil, err
			}
			return nil, worker.ErrTerminateAgent
		}
	}
}

func (p *Provisioner) loop() error {
	environWatcher := p.st.WatchEnvironConfig()
	defer watcher.Stop(environWatcher, &p.tomb)

	var err error
	p.environ, err = worker.WaitForEnviron(environWatcher, p.tomb.Dying())
	if err != nil {
		return err
	}

	auth, err := NewSimpleAuthenticator(p.environ)
	if err != nil {
		return err
	}

	// Start a new worker for the environment provider.

	// Start responding to changes in machines, and to any further updates
	// to the environment config.
	instanceBroker, err := p.getBroker()
	if err != nil {
		return err
	}
	machineWatcher, err := p.getWatcher()
	if err != nil {
		return err
	}
	environmentProvisioner := NewProvisionerTask(
		p.machineId,
		p.st,
		machineWatcher,
		instanceBroker,
		auth)
	defer watcher.Stop(environmentProvisioner, &p.tomb)

	for {
		select {
		case <-p.tomb.Dying():
			return tomb.ErrDying
		case <-environmentProvisioner.Dying():
			err := environmentProvisioner.Err()
			logger.Errorf("environment provisioner died: %v", err)
			return err
		case cfg, ok := <-environWatcher.Changes():
			if !ok {
				return watcher.MustErr(environWatcher)
			}
			if err := p.setConfig(cfg); err != nil {
				logger.Errorf("loaded invalid environment configuration: %v", err)
			}
		}
	}
	panic("not reached")
}