Golang Client.TestAndSet方法代码示例

// This will attempt to Acquire a lock for a given amount of time.
// If the lock is acquired, goChan will be unblocked
// If the lock is lost, stopChan will be unblocked
// TODO: Handle non-expected errors
func Acquire(cli *etcd.Client, lock string, timeout uint64) (goChan chan int, stopChan chan int) {
	me := uuid.NewV1().String()
	goChan = make(chan int)
	stopChan = make(chan int)

	go func() {
		log.Println("Hello, I am:", me)

		for {
			resp, acq, err := cli.TestAndSet(lock, "", me, timeout)

			if debug {
				log.Println("Lock Resp:", acq, resp, err)
			}

			if !acq {
				// We want to watch for a change in the lock, and we'll repeat
				var watcherCh = make(chan *store.Response)
				var endCh = make(chan bool)

				go cli.Watch(lock, 0, watcherCh, endCh)
				<-watcherCh

				// Now, we'll try to acquire the lock, again
			} else {

				// We got a lock, we want to keep it
				go func() {
					for {
						resp, acq, err := cli.TestAndSet(lock, me, me, timeout) // Keep the lock alive

						if debug {
							log.Println("Reset Resp:", acq, resp, err)
						}

						if !acq {

							if debug {
								log.Println("Demoted:", me)
							}
							stopChan <- 1 // Let's boot ourselves, we're no longer the leader
						}

						time.Sleep(time.Duration(timeout*500) * time.Millisecond) // We'll re-up after 50% fo the lock period
					}
				}()

				if debug {
					log.Println("King:", me)
				}
				goChan <- 1
			}
		}
	}()

	return
}

// A stupid spin lock
func lock(c *etcd.Client) bool {
	for {
		_, success, _ := c.TestAndSet("lock", "unlock", "lock", 0)

		if success != true {
			fmt.Println("tried lock failed!")
		} else {
			return true
		}
	}
}

func inspectAndSet(c chan string, etcdClient *etcd.Client, dockerClient *docker.Client, keyname *string, ttl *uint64) {
	for {
		id := <-c
		container, err := dockerClient.InspectContainer(id)
		if err != nil {
			log.Fatal(err)
		} else {

			var addr string

			//if the container config contains ports then set the IP as the host IP
			if len(container.Config.PortSpecs) > 0 {
				addr = localIp()
			} else {
				addr = container.NetworkSettings.IPAddress
			}

			etcdClient.TestAndSet(*keyname+"/"+container.Config.Hostname, addr, addr, *ttl)
			log.Print(container.Config.Hostname)

		}

	}
}