refactor listenDirEvent

config_center/zookeeper/impl.go

@@ -24,6 +24,7 @@ import (
 )
 
 import (
+	"github.com/dubbogo/go-zookeeper/zk"
 	gxset "github.com/dubbogo/gost/container/set"
 	gxzookeeper "github.com/dubbogo/gost/database/kv/zk"
 
@@ -80,15 +81,20 @@ func newZookeeperDynamicConfiguration(url *common.URL) (*zookeeperDynamicConfigu
 		logger.Errorf("zookeeper client start error ,error message is %v", err)
 		return nil, err
 	}
+	err = c.client.Create(c.rootPath)
+	if err != nil && err != zk.ErrNodeExists {
+		return nil, err
+	}
+
+	// Before handle client restart, we need to ensure that the zk dynamic configuration successfully start and create the configuration directory
 	c.wg.Add(1)
 	go zookeeper.HandleClientRestart(c)
 
+	// Start listener
 	c.listener = zookeeper.NewZkEventListener(c.client)
 	c.cacheListener = NewCacheListener(c.rootPath)
-
-	err = c.client.Create(c.rootPath)
 	c.listener.ListenServiceEvent(url, c.rootPath, c.cacheListener)
-	return c, err
+	return c, nil
 }
 
 func (c *zookeeperDynamicConfiguration) AddListener(key string, listener config_center.ConfigurationListener, opions ...config_center.Option) {

go.mod

@@ -12,7 +12,7 @@ require (
 	github.com/apache/dubbo-go-hessian2 v1.9.3
 	github.com/creasty/defaults v1.5.2
 	github.com/dubbogo/go-zookeeper v1.0.3
-	github.com/dubbogo/gost v1.11.19
+	github.com/dubbogo/gost v1.11.20-0.20211116110728-26777ca61b4a
 	github.com/dubbogo/grpc-go v1.42.5-triple
 	github.com/dubbogo/triple v1.1.3
 	github.com/emicklei/go-restful/v3 v3.7.1

go.sum

@@ -175,8 +175,8 @@ github.com/dubbogo/go-zookeeper v1.0.3/go.mod h1:fn6n2CAEer3novYgk9ULLwAjuV8/g4D
 github.com/dubbogo/gost v1.9.0/go.mod h1:pPTjVyoJan3aPxBPNUX0ADkXjPibLo+/Ib0/fADXSG8=
 github.com/dubbogo/gost v1.11.12/go.mod h1:vIcP9rqz2KsXHPjsAwIUtfJIJjppQLQDcYaZTy/61jI=
 github.com/dubbogo/gost v1.11.18/go.mod h1:vIcP9rqz2KsXHPjsAwIUtfJIJjppQLQDcYaZTy/61jI=
-github.com/dubbogo/gost v1.11.19 h1:R1rZ3TNJKV9W5XHLMv+GDO2Wy6UDnwGQtVWbsWYvo0A=
-github.com/dubbogo/gost v1.11.19/go.mod h1:vIcP9rqz2KsXHPjsAwIUtfJIJjppQLQDcYaZTy/61jI=
+github.com/dubbogo/gost v1.11.20-0.20211116110728-26777ca61b4a h1:RLUCy1Rftro4EmUmqWQCdofwgo9mzPbrZ6d6xWgZNwo=
+github.com/dubbogo/gost v1.11.20-0.20211116110728-26777ca61b4a/go.mod h1:vIcP9rqz2KsXHPjsAwIUtfJIJjppQLQDcYaZTy/61jI=
 github.com/dubbogo/grpc-go v1.42.5-triple h1:Ed5z/ikkpdZHBMA4mTEthQFTQeKlHtkdAsQrZjTbFk8=
 github.com/dubbogo/grpc-go v1.42.5-triple/go.mod h1:F1T9hnUvYGW4JLK1QNriavpOkhusU677ovPzLkk6zHM=
 github.com/dubbogo/jsonparser v1.0.1/go.mod h1:tYAtpctvSP/tWw4MeelsowSPgXQRVHHWbqL6ynps8jU=

registry/zookeeper/registry.go

@@ -150,7 +150,11 @@ func (r *zkRegistry) InitListeners() {
 
 // CreatePath creates the path in the registry center of zookeeper
 func (r *zkRegistry) CreatePath(path string) error {
-	return r.ZkClient().Create(path)
+	err := r.ZkClient().Create(path)
+	if err != nil && err != zk.ErrNodeExists {
+		return err
+	}
+	return nil
 }
 
 // DoRegister actually do the register job in the registry center of zookeeper
@@ -218,17 +222,18 @@ func (r *zkRegistry) registerTempZookeeperNode(root string, node string) error {
 	}
 	logger.Infof("[Zookeeper Registry] Registry instance with root = %s, node = %s", root, node)
 	err = r.client.Create(root)
-	if err != nil {
+	if err != nil && err != zk.ErrNodeExists {
 		logger.Errorf("zk.Create(root{%s}) = err{%v}", root, perrors.WithStack(err))
 		return perrors.WithStack(err)
 	}
 
-	// try to register the node
+	// Try to register the node
 	zkPath, err = r.client.RegisterTemp(root, node)
 	if err == nil {
 		return nil
 	}
 
+	// Maybe the node did exist, then we need to delete it first and recreate it
 	if perrors.Cause(err) == zk.ErrNodeExists {
 		if err = r.client.Delete(zkPath); err == nil {
 			_, err = r.client.RegisterTemp(root, node)

remoting/zookeeper/listener.go

@@ -228,52 +228,32 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkRootPath string, li
 		if err == nil {
 			ttl = timeout
 		} else {
-			logger.Warnf("wrong configuration for registry ttl, error:=%+v, using default value %v instead", err, defaultTTL)
+			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 for a zkPath
+		// Get current children with watcher for the zkRootPath
 		children, childEventCh, err := l.client.GetChildrenW(zkRootPath)
 		if err != nil {
 			failTimes++
 			if MaxFailTimes <= failTimes {
 				failTimes = MaxFailTimes
 			}
-			logger.Debugf("listenDirEvent(path{%s}) = error{%v}", zkRootPath, err)
-			// clear the event channel
-		CLEAR:
-			for {
-				select {
-				case <-event:
-				default:
-					break CLEAR
-				}
-			}
-			l.client.RegisterEvent(zkRootPath, &event)
-			if err == errNilNode {
-				logger.Warnf("listenDirEvent(path{%s}) got errNilNode,so exit listen", zkRootPath)
-				l.client.UnregisterEvent(zkRootPath, &event)
-				return
-			}
+			logger.Errorf("[Zookeeper EventListener][listenDirEvent] Get children of path {%s} with watcher failed, the error is %+v", zkRootPath, err)
 
+			// May be the provider does not ready yet, sleep failTimes * ConnDelay senconds to wait
 			after := time.After(timeSecondDuration(failTimes * ConnDelay))
 			select {
 			case <-after:
-				l.client.UnregisterEvent(zkRootPath, &event)
-				continue
-			case <-l.exit:
-				l.client.UnregisterEvent(zkRootPath, &event)
-				logger.Debugf("listen(path{%s}) goroutine exit now...", zkRootPath)
-				return
-			case <-event:
-				logger.Debugf("get zk.EventNodeDataChange notify event")
-				l.client.UnregisterEvent(zkRootPath, &event)
-				l.handleZkNodeEvent(zkRootPath, nil, listener)
 				continue
 			}
 		}
 		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.")
+			continue
+		}
 		for _, c := range children {
 			// Only need to compare Path when subscribing to provider
 			if strings.LastIndex(zkRootPath, constant.ProviderCategory) != -1 {
@@ -283,7 +263,7 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkRootPath string, li
 				}
 			}
 
-			// listen l service node
+			// Build the children path
 			zkNodePath := path.Join(zkRootPath, c)
 
 			// Save the path to avoid listen repeatedly
@@ -294,7 +274,7 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkRootPath string, li
 			}
 			l.pathMapLock.Unlock()
 			if ok {
-				logger.Warnf("@zkPath %s has already been listened.", zkNodePath)
+				logger.Warnf("[Zookeeper EventListener][listenDirEvent] The child with zk path {%s} has already been listened.", zkNodePath)
 				continue
 			}
 
@@ -308,13 +288,13 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkRootPath string, li
 
 			l.client.RUnlock()
 			if err != nil {
-				logger.Errorf("Get new node path {%v} 's content error,message is  {%v}", zkNodePath, perrors.WithStack(err))
+				logger.Errorf("[Zookeeper EventListener][listenDirEvent] Get content of the child node {%v} failed, the error is %+v", zkNodePath, perrors.WithStack(err))
 			}
-			logger.Debugf("Get children!{%s}", zkNodePath)
+			logger.Debugf("[Zookeeper EventListener][listenDirEvent] Get children!{%s}", zkNodePath)
 			if !listener.DataChange(remoting.Event{Path: zkNodePath, Action: remoting.EventTypeAdd, Content: string(content)}) {
 				continue
 			}
-			logger.Infof("[Zookeeper Listener] listen dubbo service key{%s}", zkNodePath)
+			logger.Debugf("[Zookeeper EventListener][listenDirEvent] listen dubbo service key{%s}", zkNodePath)
 			l.wg.Add(1)
 			go func(zkPath string, listener remoting.DataListener) {
 				// invoker l.wg.Done() in l.listenServiceNodeEvent
@@ -366,7 +346,7 @@ func (l *ZkEventListener) startScheduleWatchTask(
 				ticker = time.NewTicker(tickerTTL)
 			}
 		case zkEvent := <-childEventCh:
-			logger.Warnf("get a zookeeper childEventCh{type:%s, server:%s, path:%s, state:%d-%s, err:%v}",
+			logger.Debugf("Get a zookeeper childEventCh{type:%s, server:%s, path:%s, state:%d-%s, err:%v}",
 				zkEvent.Type.String(), zkEvent.Server, zkEvent.Path, zkEvent.State, gxzookeeper.StateToString(zkEvent.State), zkEvent.Err)
 			ticker.Stop()
 			if zkEvent.Type == zk.EventNodeChildrenChanged {