// RegisterTmp create a ephemeral node, and watch it, if node droped then send a SIGQUIT to self.
func RegisterTemp(conn *zk.Conn, fpath, data string) error {
tpath, err := conn.Create(path.Join(fpath)+"/", []byte(data), zk.FlagEphemeral|zk.FlagSequence, zk.WorldACL(zk.PermAll))
if err != nil {
glog.Errorf("conn.Create(\"%s\", \"%s\", zk.FlagEphemeral|zk.FlagSequence) error(%v)", fpath, data, err)
return err
}
glog.V(1).Infof("create a zookeeper node:%s", tpath)
// watch self
go func() {
for {
glog.Infof("zk path: \"%s\" set a watch", tpath)
exist, _, watch, err := conn.ExistsW(tpath)
if err != nil {
glog.Errorf("zk.ExistsW(\"%s\") error(%v)", tpath, err)
glog.Warningf("zk path: \"%s\" set watch failed, kill itself", tpath)
killSelf()
return
}
if !exist {
glog.Warningf("zk path: \"%s\" not exist, kill itself", tpath)
killSelf()
return
}
event := <-watch
glog.Infof("zk path: \"%s\" receive a event %v", tpath, event)
}
}()
return nil
}
// 创建一个临时节点，并监听自己
func CreateTempW(conn *zk.Conn, fpath, data string, watchFunc func(bool, zk.Event)) error {
tpath, err := conn.Create(path.Join(fpath)+"/", []byte(data), zk.FlagEphemeral|zk.FlagSequence, zk.WorldACL(zk.PermAll))
if err != nil {
glog.Errorf("conn.Create(\"%s\", \"%s\", zk.FlagEphemeral|zk.FlagSequence) error(%v)", fpath, data, err)
return err
}
glog.V(1).Infof("create a zookeeper node:%s", tpath)
// watch self
if watchFunc != nil {
go func() {
for {
glog.Infof("zk path: \"%s\" set a watch", tpath)
exist, _, watch, err := conn.ExistsW(tpath)
if err != nil {
glog.Errorf("zk.ExistsW(%s) error(%v)", tpath, err)
return
}
event := <-watch
watchFunc(exist, event)
glog.Infof("zk path: \"%s\" receive a event %v", tpath, event)
}
}()
}
return nil
}
// The lexically lowest node is the lock holder - verify that this
// path holds the lock. Call this queue-lock because the semantics are
// a hybrid. Normal zookeeper locks make assumptions about sequential
// numbering that don't hold when the data in a lock is modified.
// if the provided 'interrupted' chan is closed, we'll just stop waiting
// and return an interruption error
func ObtainQueueLock(zconn zookeeper.Conn, zkPath string, wait time.Duration, interrupted chan struct{}) error {
queueNode := path.Dir(zkPath)
lockNode := path.Base(zkPath)
timer := time.NewTimer(wait)
trylock:
children, _, err := zconn.Children(queueNode)
if err != nil {
return fmt.Errorf("zkutil: trylock failed %v", err)
}
sort.Strings(children)
if len(children) > 0 {
if children[0] == lockNode {
return nil
}
if wait > 0 {
prevLock := ""
for i := 1; i < len(children); i++ {
if children[i] == lockNode {
prevLock = children[i-1]
break
}
}
if prevLock == "" {
return fmt.Errorf("zkutil: no previous queue node found: %v", zkPath)
}
zkPrevLock := path.Join(queueNode, prevLock)
_, stat, watch, err := zconn.ExistsW(zkPrevLock)
if err != nil {
return fmt.Errorf("zkutil: unable to watch queued node %v %v", zkPrevLock, err)
}
if stat == nil {
goto trylock
}
select {
case <-timer.C:
break
case <-interrupted:
return ErrInterrupted
case <-watch:
// The precise event doesn't matter - try to read again regardless.
goto trylock
}
}
return ErrTimeout
}
return fmt.Errorf("zkutil: empty queue node: %v", queueNode)
}
func ZkCreateRoot(zkConn *zk.Conn, root string) {
flags := int32(0)
acl := zk.WorldACL(zk.PermAll)
found, _, _, err := zkConn.ExistsW(root)
if err != nil {
panic(err.Error())
}
if !found {
fmt.Printf("create %s\n", root)
path, err := zkConn.Create(root, []byte(""), flags, acl)
if err != nil {
panic(err.Error())
}
fmt.Printf("created %s\n", path)
}
}
