Golang Store.Watch方法代碼示例

// This thing keeps track of who is supposed to be in the cluster for every
// seqn. It also remembers the network address of every member.
// TODO remove the `start` param when store.Get provides a version
func NewRegistrar(st *store.Store, start uint64, alpha int) *Registrar {
	rg := &Registrar{
		alpha:    alpha,
		st:       st,
		evs:      st.Watch("**"), // watch absolutely everything
		lookupCh: make(chan *lookup),
		lookups:  new(lookupQueue),
	}
	go rg.process(start, readdirMap(st, membersKey), readdirMap(st, slotKey))
	return rg
}

func Clean(st *store.Store) {
	cl := &cleaner{
		st:     st,
		table:  make(map[string]uint64),
		logger: util.NewLogger("clean"),
	}

	for ev := range st.Watch("/doozer/info/*/applied") {
		cl.update(ev)
		cl.check()
	}
}

func Clean(st *store.Store, p paxos.Proposer) {
	logger := util.NewLogger("member")
	for ev := range st.Watch("/session/*") {
		if !ev.IsDel() {
			continue
		}

		parts := strings.Split(ev.Path, "/", 3)
		name := parts[2]
		logger.Printf("lost session %s", name)

		clearSlot(p, ev, name)
		removeMember(p, ev, name)
		removeInfo(p, ev, name)
	}
}

func Clean(st *store.Store, pp paxos.Proposer) {
	logger := util.NewLogger("lock")
	for ev := range st.Watch("/session/*") {
		if !ev.IsDel() {
			continue
		}

		parts := strings.Split(ev.Path, "/", 3)
		name := parts[2]
		logger.Printf("lost session %s", name)

		ch, err := store.Walk(ev, "/lock/**")
		if err != nil {
			continue
		}

		for ev := range ch {
			if ev.Body == name {
				paxos.Del(pp, ev.Path, ev.Cas)
			}
		}
	}
}

func Monitor(self string, st *store.Store, cl SetDeler) os.Error {

	mon := &monitor{
		self:    self,
		st:      st,
		cl:      cl,
		clock:   make(chan ticker),
		units:   make(map[string]unit),
		refs:    make(map[string]int),
		exitCh:  make(chan exit),
		readyCh: make(chan ready),
		logger:  util.NewLogger("monitor"),
	}

	mon.logger.Println("reading units")
	evs := make(chan store.Event)
	st.GetDirAndWatch(ctlKey, evs)
	go func(c <-chan store.Event) {
		for e := range c {
			evs <- e
		}
		close(evs)
	}(st.Watch(lockKey + "/*"))

	for {
		select {
		case t := <-mon.clock:
			t.tick()
		case ev := <-evs:
			prefix, id := path.Split(ev.Path)
			switch prefix {
			case ctlDir:
				if ev.IsDel() {
					mon.logger.Println("\n\n\ndel", id)
					mon.decrefUnit(id)
					break
				}

				ut := mon.increfUnit(id)
				if ut == nil {
					break
				}

				switch ev.Body {
				case "start":
					ut.start()
				case "stop":
					ut.stop()
				case "auto", "":
					fallthrough
				default:
					// nothing
				}

			case lockDir:
				ut := mon.units[id]
				if ut == nil {
					break
				}

				ut.dispatchLockEvent(ev)
			}
		case e := <-mon.exitCh:
			e.e.exited(e.w)
		case r := <-mon.readyCh:
			r.r.ready(r.f)
		}
	}
	panic("unreachable")
}