Golang Conn.Set方法代碼示例

// Elect chooses a seed node, and returns a connection to a cal.
// If this process is the seed, returns nil.
func elect(name, id, laddr string, b *doozer.Conn) *doozer.Conn {
	// advertise our presence, since we might become a cal
	nspath := "/ctl/ns/" + name + "/" + id
	r, err := b.Set(nspath, 0, []byte(laddr))
	if err != nil {
		panic(err)
	}

	// fight to be the seed
	_, err = b.Set("/ctl/boot/"+name, 0, []byte(id))
	if err, ok := err.(*doozer.Error); ok && err.Err == doozer.ErrOldRev {
		// we lost, lookup addresses again
		cl := lookupAndAttach(b, name)
		if cl == nil {
			panic("failed to attach after losing election")
		}

		// also delete our entry, since we're not officially a cal yet.
		// it gets set again in peer.Main when we become a cal.
		err := b.Del(nspath, r)
		if err != nil {
			panic(err)
		}

		return cl
	} else if err != nil {
		panic(err)
	}

	return nil // we are the seed node -- don't attach
}

// watch updates the peer list of servers based on changes to the
// doozer configuration or signals from the OS.
func watch(d *doozer.Conn) {
	peerFile := "/peers"
	var peers []string
	var rev int64

	// Run the initial get.
	data, rev, err := d.Get(peerFile, nil)
	if err != nil {
		log.Println("initial peer list get:", err)
		log.Println("using empty set to start")
		peers = []string{}
	} else {
		peers = strings.Split(string(data), " ")
	}

	// Add myself to the list.
	peers = append(peers, "http://"+addr)
	rev, err = d.Set(peerFile, rev,
		[]byte(strings.Join(peers, " ")))
	if err != nil {
		log.Println("unable to add myself to the peer list (no longer watching).")
		return
	}
	pool.Set(peers...)
	log.Println("added myself to the peer list.")

	// Setup signal handling to deal with ^C and others.
	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, os.Interrupt, os.Kill)

	// Get the channel that's listening for changes.
	updates := wait(d, peerFile, &rev)

	for {
		select {
		case <-sigs:
			// Remove ourselves from the peer list and exit.
			for i, peer := range peers {
				if peer == "http://"+addr {
					peers = append(peers[:i], peers[i+1:]...)
					d.Set(peerFile, rev, []byte(strings.Join(peers, " ")))
					log.Println("removed myself from peer list before exiting.")
				}
			}
			os.Exit(1)

		case update, ok := <-updates:
			// If the channel was closed, we should stop selecting on it.
			if !ok {
				updates = nil
				continue
			}

			// Otherwise, update the peer list.
			peers = update
			log.Println("got new peer list:", strings.Join(peers, " "))
			pool.Set(peers...)
		}
	}
}

func set(cl *doozer.Conn, id, iter int, path string, value []byte, f cb) {
	for i := 0; i < iter; i++ {
		s := time.Nanoseconds()
		rev, err := cl.Set(path, math.MaxInt64, value)
		e := time.Nanoseconds()
		f(id, i, rev, s, e, err)
	}
}

func activate(st *store.Store, self string, c *doozer.Conn) int64 {
	rev, _ := st.Snap()

	entries := store.Getdir(st, calDir)
	base := entries[len(entries)-1]
	index, _ := strconv.ParseInt(base, 10, 32)
	index += 1
	p := calDir + "/" + strconv.Itoa(int(index))
	seqn, err := c.Set(p, rev, []byte(self))

	if err != nil {
		panic(err)
	}

	// for _, base := range store.Getdir(st, calDir) {
	// 	p := calDir + "/" + base
	// 	v, rev := st.Get(p)
	// 	if rev != store.Dir && v[0] == "" {
	// 		seqn, err := c.Set(p, rev, []byte(self))
	// 		if err != nil {
	// 			log.Println(err)
	// 			continue
	// 		}

	// 		return seqn
	// 	}
	// }

	// for {
	// 	ch, err := st.Wait(calGlob, rev+1)
	// 	if err != nil {
	// 		panic(err)
	// 	}
	// 	ev, ok := <-ch
	// 	if !ok {
	// 		panic(io.EOF)
	// 	}
	// 	rev = ev.Rev
	// 	// TODO ev.IsEmpty()
	// 	if ev.IsSet() && ev.Body == "" {
	// 		seqn, err := c.Set(ev.Path, ev.Rev, []byte(self))
	// 		if err != nil {
	// 			log.Println(err)
	// 			continue
	// 		}
	// 		return seqn
	// 	} else if ev.IsSet() && ev.Body == self {
	// 		return ev.Seqn
	// 	}
	// }

	return seqn
}

func activate(st *store.Store, self string, c *doozer.Conn) int64 {
	rev, _ := st.Snap()

	for _, base := range store.Getdir(st, calDir) {
		p := calDir + "/" + base
		v, rev := st.Get(p)
		if rev != store.Dir && v[0] == "" {
			seqn, err := c.Set(p, rev, []byte(self))
			if err != nil {
				log.Println(err)
				continue
			}

			return seqn
		}
	}

	for {
		ch, err := st.Wait(calGlob, rev+1)
		if err != nil {
			panic(err)
		}
		ev, ok := <-ch
		if !ok {
			panic(io.EOF)
		}
		rev = ev.Rev
		// TODO ev.IsEmpty()
		if ev.IsSet() && ev.Body == "" {
			seqn, err := c.Set(ev.Path, ev.Rev, []byte(self))
			if err != nil {
				log.Println(err)
				continue
			}
			return seqn
		} else if ev.IsSet() && ev.Body == self {
			return ev.Seqn
		}
	}

	return 0
}

func setC(cl *doozer.Conn, path, body string, rev int64) {
	_, err := cl.Set(path, rev, []byte(body))
	if err != nil {
		panic(err)
	}
}