func newRegionLeader(lockNode string) *regionLeader {
rl := ®ionLeader{
active: true,
lockNode: lockNode,
rescinded: make(chan struct{}),
}
// establish a watch to cleanup
go func() {
_, _, watch, err := zookeeper.GetW(rl.lockNode)
if err != nil {
rl.Rescind()
return
}
<-watch
log.Debugf("[Sync:RegionLeader] Watch triggered on '%v', will rescind leadership", rl.lockNode)
inst.Counter(1.0, "sync.regionleader.remotely-rescinded")
rl.Rescind()
return
}()
// Register region leader
mu.Lock()
rls = append(rls, rl)
mu.Unlock()
return rl
}
func waitForWinner(path, ourNode string) error {
seq, err := parseSeq(ourNode)
if err != nil {
return err
}
for {
lowestSeq, prevSeqPath, err := findLowestSequenceNode(path, seq)
if err != nil {
return err
}
if seq == lowestSeq {
// we are now the leader!
break
}
// wait on the node next in line for the lock
_, _, ch, err := zookeeper.GetW(path + "/" + prevSeqPath)
if err != nil && err != gozk.ErrNoNode {
return err
} else if err != nil && err == gozk.ErrNoNode {
// try again
continue
}
ev := <-ch
if ev.Err != nil {
return ev.Err
}
}
return nil
}