avoid the problem of cpu idling & fix wrong definition of error

registry/zookeeper/listener.go

@@ -71,17 +71,18 @@ func (l *RegistryDataListener) UnSubscribeURL(url *common.URL) config_center.Con
 }
 
 // DataChange accepts all events sent from the zookeeper server and trigger the corresponding listener for processing
-func (l *RegistryDataListener) DataChange(eventType remoting.Event) bool {
+func (l *RegistryDataListener) DataChange(event remoting.Event) bool {
 	// Intercept the last bit
-	index := strings.Index(eventType.Path, "/providers/")
+	index := strings.Index(event.Path, "/providers/")
 	if index == -1 {
-		logger.Warnf("Listen with no url, event.path={%v}", eventType.Path)
+		logger.Warnf("[RegistryDataListener][DataChange]Listen error zk node path {%s}, "+
+			"this listener is used to listen services which under the directory of providers/", event.Path)
 		return false
 	}
-	url := eventType.Path[index+len("/providers/"):]
+	url := event.Path[index+len("/providers/"):]
 	serviceURL, err := common.NewURL(url)
 	if err != nil {
-		logger.Errorf("Listen NewURL(r{%s}) = error{%v} eventType.Path={%v}", url, err, eventType.Path)
+		logger.Errorf("[RegistryDataListener][DataChange]Listen NewURL({%s}) = error{%+v} event.Path={%s}", url, err, event.Path)
 		return false
 	}
 	l.mutex.Lock()
@@ -93,9 +94,9 @@ func (l *RegistryDataListener) DataChange(eventType remoting.Event) bool {
 		if serviceURL.ServiceKey() == serviceKey {
 			listener.Process(
 				&config_center.ConfigChangeEvent{
-					Key:        eventType.Path,
+					Key:        event.Path,
 					Value:      serviceURL,
-					ConfigType: eventType.Action,
+					ConfigType: event.Action,
 				},
 			)
 			return true

remoting/zookeeper/client.go

@@ -39,12 +39,6 @@ const (
 	MaxFailTimes = 3
 )
 
-var (
-	errNilZkClientConn = perrors.New("zookeeper client{conn} is nil")
-	errNilChildren     = perrors.Errorf("has none children")
-	errNilNode         = perrors.Errorf("node does not exist")
-)
-
 // ValidateZookeeperClient validates client and sets options
 func ValidateZookeeperClient(container ZkClientFacade, zkName string) error {
 	lock := container.ZkClientLock()

remoting/zookeeper/listener.go

@@ -152,16 +152,16 @@ func (l *ZkEventListener) handleZkNodeEvent(zkPath string, children []string, li
 
 	newChildren, err := l.client.GetChildren(zkPath)
 	if err != nil {
-		// FIXME always false
-		if err == errNilChildren {
+		// TODO need to ignore this error in gost
+		if err == gxzookeeper.ErrNilChildren {
 			content, _, connErr := l.client.Conn.Get(zkPath)
 			if connErr != nil {
 				logger.Errorf("Get new node path {%v} 's content error,message is  {%v}",
 					zkPath, perrors.WithStack(connErr))
 			} else {
+				// TODO this if for config center listener, and will be removed when we refactor config center listener
 				listener.DataChange(remoting.Event{Path: zkPath, Action: remoting.EventTypeUpdate, Content: string(content)})
 			}
-
 		} else {
 			logger.Errorf("path{%s} child nodes changed, zk.Children() = error{%v}", zkPath, perrors.WithStack(err))
 		}
@@ -219,9 +219,7 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkRootPath string, li
 	var (
 		failTimes int
 		ttl       time.Duration
-		event     chan struct{}
 	)
-	event = make(chan struct{}, 4)
 	ttl = defaultTTL
 	if conf != nil {
 		timeout, err := time.ParseDuration(conf.GetParam(constant.RegistryTTLKey, constant.DefaultRegTTL))
@@ -231,7 +229,6 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkRootPath string, li
 			logger.Warnf("[Zookeeper EventListener][listenDirEvent] Wrong configuration for registry.ttl, error=%+v, using default value %v instead", err, defaultTTL)
 		}
 	}
-	defer close(event)
 	for {
 		// Get current children with watcher for the zkRootPath
 		children, childEventCh, err := l.client.GetChildrenW(zkRootPath)
@@ -251,8 +248,7 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkRootPath string, li
 		}
 		failTimes = 0
 		if len(children) == 0 {
-			logger.Warnf("[Zookeeper EventListener][listenDirEvent] Can not gey any children for the path {%s}, please check if the provider does ready.", zkRootPath)
-			continue
+			logger.Debugf("[Zookeeper EventListener][listenDirEvent] Can not gey any children for the path {%s}, please check if the provider does ready.", zkRootPath)
 		}
 		for _, c := range children {
 			// Only need to compare Path when subscribing to provider
@@ -324,10 +320,10 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkRootPath string, li
 	}
 }
 
+// startScheduleWatchTask periodically update provider information, return true when receive exit signal
 func (l *ZkEventListener) startScheduleWatchTask(
 	zkRootPath string, children []string, ttl time.Duration,
 	listener remoting.DataListener, childEventCh <-chan zk.Event) bool {
-	// Periodically update provider information
 	tickerTTL := ttl
 	if tickerTTL > 20e9 {
 		tickerTTL = 20e9