// 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)
}
}
}