robocanic commented on code in PR #1371: URL: https://github.com/apache/dubbo-admin/pull/1371#discussion_r2636692569
########## pkg/discovery/zk/zkwatcher/watcher.go: ########## @@ -0,0 +1,243 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package zkwatcher + +import ( + "sync" + "time" + + "github.com/dubbogo/go-zookeeper/zk" + set "github.com/duke-git/lancet/v2/datastructure/set" + + "github.com/apache/dubbo-admin/pkg/core/logger" +) + +type EventType string + +const ( + NodeCreated EventType = "NodeCreated" + NodeDeleted EventType = "NodeDeleted" + NodeChanged EventType = "NodeChanged" +) + +// ZookeeperEvent represents a zookeeper event +type ZookeeperEvent struct { + Type EventType + // node path + Path string + // node data + Data string + // whether it is a leaf node + leafNode bool +} + +// RecursiveWatcher recursive watcher +type RecursiveWatcher struct { + conn *zk.Conn + basePath string + eventChan chan ZookeeperEvent + stopChan chan struct{} + mu sync.Mutex +} + +// NewRecursiveWatcher create a new recursive watcher +func NewRecursiveWatcher(conn *zk.Conn, basePath string) *RecursiveWatcher { + return &RecursiveWatcher{ + conn: conn, + basePath: basePath, + eventChan: make(chan ZookeeperEvent, 1000), + stopChan: make(chan struct{}), + } +} + +// Start begin watching +func (rw *RecursiveWatcher) Start() error { + logger.Infof("Start watching path: %s", rw.basePath) + // Recursively watch the initial path + return rw.watchPathRecursively(rw.basePath) +} + +// Stop watching +func (rw *RecursiveWatcher) Stop() { + close(rw.stopChan) + rw.conn.Close() + close(rw.eventChan) +} + +// EventChan return event channel +func (rw *RecursiveWatcher) EventChan() <-chan ZookeeperEvent { + return rw.eventChan +} + +// watchPathRecursively watch path recursively +func (rw *RecursiveWatcher) watchPathRecursively(path string) error { + // Watch data changes for the current path + go rw.watchDataChanges(path) + + // Get children of current path and watch + children, _, err := rw.conn.Children(path) + if err != nil { + logger.Errorf("Failed to get children of path: %s, cause: %v", path, err) + return err + } + // Watch children list changes + go rw.watchChildrenChanges(path) + + // Recursively watch child nodes + for _, child := range children { + childPath := path + "/" + child + if err := rw.watchPathRecursively(childPath); err != nil { + logger.Errorf("Failed to watch subpath %s: %v", childPath, err) + } + } + return nil +} + +// watchDataChanges watch node data changes +func (rw *RecursiveWatcher) watchDataChanges(path string) { + logger.Debugf("Watching data changes for path: %s", path) + for { + + select { + case <-rw.stopChan: + return + default: + } + + // Get data and set up watch + data, stat, watcher, err := rw.conn.GetW(path) + if err != nil { + logger.Errorf("Failed to watch data changes for path %s, cause: %v", path, err) + time.Sleep(time.Second) + continue + } + rw.eventChan <- ZookeeperEvent{ + Type: NodeCreated, + Path: path, + Data: string(data), + leafNode: stat.NumChildren == 0, + } + + select { + case event := <-watcher.EvtCh: + if event.Type == zk.EventNodeDataChanged { + logger.Debugf("node data changed: %s", path) + + // Re-watch data changes + go rw.watchDataChanges(path) + return + } else if event.Type == zk.EventNodeDeleted { + // Node deleted, stop watching + logger.Debugf("node deleted: %s", path) + rw.eventChan <- ZookeeperEvent{ + Type: NodeDeleted, + Path: path, + leafNode: stat.NumChildren == 0, + } + return + } + case <-rw.stopChan: + return + } + + // If node exists but no changes, continue watching + if stat != nil { + continue + } + } +} + +// watchChildrenChanges watch child node changes +func (rw *RecursiveWatcher) watchChildrenChanges(path string) { + logger.Debugf("Watching child node changes for path: %s", path) + for { + // Check if stopped + select { + case <-rw.stopChan: + return + default: + } + + // Get child nodes and set up watch + children, stat, watcher, err := rw.conn.ChildrenW(path) + if err != nil { + logger.Errorf("Failed to watch child node changes for path %s: %v", path, err) + time.Sleep(time.Second) + continue + } + + select { + case event := <-watcher.EvtCh: + if event.Type == zk.EventNodeChildrenChanged { + logger.Debugf("Child node list changed: %s", path) + + // Get current child nodes + newChildren, _, err := rw.conn.Children(path) + if err != nil { + logger.Debugf("Failed to get new child nodes: %v", err) + continue + } + // Calculate added and deleted child nodes + newChildSet := set.FromSlice(newChildren) + oldChildSet := set.FromSlice(children) + addedChildren := newChildSet.Minus(oldChildSet) + deletedChildren := oldChildSet.Minus(newChildSet) + + // watch newly added child nodes + for _, c := range addedChildren.ToSlice() { + childPath := path + "/" + c + logger.Debugf("New child node added: %s", childPath) + // Recursively watch new node + go func() { + err := rw.watchPathRecursively(childPath) + if err != nil { + logger.Errorf("Failed to watch subpath %s: %v", childPath, err) + } + }() + } + + // Check for deleted child nodes + for _, c := range deletedChildren.ToSlice() { + logger.Debugf("child node %s of %s deleted", c, path) + } + + // Re-watch child node changes + go rw.watchChildrenChanges(path) + return + } else if event.Type == zk.EventNodeDeleted { + // Parent node deleted, stop watching + logger.Debugf("parent node %s deleted, stop watching children changes", path) + return + } + case <-rw.stopChan: + return + } + + // If node exists but no changes, continue watching + if stat != nil { + continue + } + } +} + +// handleEvents handle events +func (rw *RecursiveWatcher) handleEvents() { + for event := range rw.eventChan { + logger.Infof("Event type: %s, Path: %s, leafNode: %v, Data: %s", event.Type, event.Path, event.leafNode, event.Data) + } +} Review Comment: removed -- This is an automated message from the Apache Git Service. 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