✨ feat(etcd): 增强 etcd 服务注册功能

- 添加防抖机制，防止短时间内重复注册服务
- 引入 watcher 机制，支持动态监控服务续约状态
- 优化 watcher 的上下文管理，确保资源的正确释放
- 改进日志输出，提供更详细的注册和重试信息

etcd_registry.go

@@ -22,18 +22,23 @@ type EtcdRegistryConfig struct {
 
 // EtcdRegistry etcd 服务注册（带自动重连）
 type EtcdRegistry struct {
-	config      EtcdRegistryConfig
-	etcdClient  *EtcdClient
-	cli         *clientv3.Client
-	key         string
-	val         string
-	serviceName string
-	ttl         int64
-	leaseID     clientv3.LeaseID
-	keepAliveCh <-chan *clientv3.LeaseKeepAliveResponse
-	mu          sync.RWMutex
-	ctx         context.Context
-	cancel      context.CancelFunc
+	config           EtcdRegistryConfig
+	etcdClient       *EtcdClient
+	cli              *clientv3.Client
+	key              string
+	val              string
+	serviceName      string
+	ttl              int64
+	leaseID          clientv3.LeaseID
+	keepAliveCh      <-chan *clientv3.LeaseKeepAliveResponse
+	mu               sync.RWMutex
+	ctx              context.Context
+	cancel           context.CancelFunc
+	watcherCtx       context.Context
+	watcherCancel    context.CancelFunc
+	watcherMu        sync.Mutex
+	lastRegisterTime time.Time
+	registerMu       sync.Mutex
 }
 
 // NewEtcdRegistry 创建带重连功能的 etcd 服务注册器
@@ -53,12 +58,15 @@ func NewEtcdRegistry(cfg EtcdRegistryConfig) (*EtcdRegistry, error) {
 		return nil, err
 	}
 
+	watcherCtx, watcherCancel := context.WithCancel(context.Background())
 	return &EtcdRegistry{
-		config:     cfg,
-		etcdClient: etcdClient,
-		cli:        etcdClient.GetClient(),
-		ctx:        ctx,
-		cancel:     cancel,
+		config:        cfg,
+		etcdClient:    etcdClient,
+		cli:           etcdClient.GetClient(),
+		ctx:           ctx,
+		cancel:        cancel,
+		watcherCtx:    watcherCtx,
+		watcherCancel: watcherCancel,
 	}, nil
 }
 
@@ -75,15 +83,30 @@ func (r *EtcdRegistry) Register(serviceName, addr string, ttl int64) error {
 }
 
 func (r *EtcdRegistry) registerWithKV(ttl int64) error {
+	// 防抖：防止短时间内重复注册
+	r.registerMu.Lock()
+	now := time.Now()
+	if !r.lastRegisterTime.IsZero() && now.Sub(r.lastRegisterTime) < 2*time.Second {
+		r.registerMu.Unlock()
+		return fmt.Errorf("register too frequently, please wait")
+	}
+	r.lastRegisterTime = now
+	r.registerMu.Unlock()
+
 	r.mu.RLock()
 	cli := r.cli
 	key := r.key
 	val := r.val
 	r.mu.RUnlock()
 
+	// 如果 cli 为 nil 或连接已关闭，尝试重新获取客户端
 	if cli == nil {
-		// 尝试重新获取客户端
 		if r.etcdClient != nil {
+			// 检查连接状态
+			state := r.etcdClient.State()
+			if state != StateConnected {
+				return fmt.Errorf("etcd client is not connected, current state: %s", state)
+			}
 			r.mu.Lock()
 			r.cli = r.etcdClient.GetClient()
 			cli = r.cli
@@ -92,66 +115,174 @@ func (r *EtcdRegistry) registerWithKV(ttl int64) error {
 		if cli == nil {
 			return fmt.Errorf("etcd client is nil")
 		}
+	} else {
+		// 即使 cli 不为 nil，也要检查连接状态，因为可能连接已断开但 cli 引用还在
+		if r.etcdClient != nil {
+			state := r.etcdClient.State()
+			if state != StateConnected {
+				// 连接已断开，尝试更新 cli 引用
+				r.mu.Lock()
+				r.cli = r.etcdClient.GetClient()
+				cli = r.cli
+				r.mu.Unlock()
+				if cli == nil {
+					return fmt.Errorf("etcd client is not connected, current state: %s", state)
+				}
+			}
+		}
 	}
 
-	resp, err := cli.Grant(context.Background(), ttl)
+	// 使用带超时的 context 来避免长时间阻塞
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	resp, err := cli.Grant(ctx, ttl)
 	if err != nil {
-		return err
+		// 如果 Grant 失败，可能是连接已关闭，尝试更新 client 引用
+		if r.etcdClient != nil {
+			r.mu.Lock()
+			r.cli = r.etcdClient.GetClient()
+			cli = r.cli
+			r.mu.Unlock()
+			if cli != nil {
+				// 使用新的 client 重试
+				ctx2, cancel2 := context.WithTimeout(context.Background(), 5*time.Second)
+				defer cancel2()
+				resp, err = cli.Grant(ctx2, ttl)
+			}
+		}
+		if err != nil {
+			return fmt.Errorf("failed to grant lease: %w", err)
+		}
 	}
 
 	r.mu.Lock()
 	r.leaseID = resp.ID
 	r.mu.Unlock()
 
-	_, err = cli.Put(context.Background(), key, val, clientv3.WithLease(resp.ID))
+	ctx3, cancel3 := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel3()
+	_, err = cli.Put(ctx3, key, val, clientv3.WithLease(resp.ID))
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to put key: %w", err)
 	}
 
+	// KeepAlive 需要使用长期有效的 context，不能使用带超时的 context
 	keepAliveCh, err := cli.KeepAlive(context.Background(), resp.ID)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to start keep-alive: %w", err)
 	}
 
 	r.mu.Lock()
 	r.keepAliveCh = keepAliveCh
 	r.mu.Unlock()
 
-	go r.watcher(ttl)
+	// 停止旧的 watcher（如果存在）
+	r.watcherMu.Lock()
+	if r.watcherCancel != nil {
+		r.watcherCancel()
+	}
+	// 创建新的 watcher context
+	r.watcherCtx, r.watcherCancel = context.WithCancel(context.Background())
+	watcherCtx := r.watcherCtx
+	r.watcherMu.Unlock()
+
+	go r.watcher(ttl, watcherCtx)
 	log.Printf("[EtcdRegistry] 服务注册成功: %s", key)
 	return nil
 }
 
 // watcher 监听续约
-func (r *EtcdRegistry) watcher(ttl int64) {
+func (r *EtcdRegistry) watcher(ttl int64, watcherCtx context.Context) {
 	for {
 		select {
 		case <-r.ctx.Done():
 			log.Println("[EtcdRegistry] context done, watcher exiting.")
 			return
+		case <-watcherCtx.Done():
+			log.Println("[EtcdRegistry] watcher context done, exiting.")
+			return
 		case ka, ok := <-r.keepAliveCh:
 			if !ok {
-				log.Println("[EtcdRegistry] keep-alive channel closed, attempting to re-register...")
+				log.Println("[EtcdRegistry] keep-alive channel closed, waiting for connection recovery...")
 
-				// 更新 cli 引用
-				if r.etcdClient != nil {
-					r.mu.Lock()
-					r.cli = r.etcdClient.GetClient()
-					r.mu.Unlock()
+				// 等待连接恢复，而不是立即重试
+				maxWaitTime := 60 * time.Second
+				checkInterval := 500 * time.Millisecond
+				waited := time.Duration(0)
+
+				for waited < maxWaitTime {
+					select {
+					case <-r.ctx.Done():
+						return
+					case <-watcherCtx.Done():
+						return
+					default:
+					}
+
+					// 检查连接状态
+					if r.etcdClient != nil {
+						state := r.etcdClient.State()
+						if state == StateConnected {
+							// 连接已恢复，更新 cli 引用
+							r.mu.Lock()
+							r.cli = r.etcdClient.GetClient()
+							r.mu.Unlock()
+
+							// 等待一段时间确保连接稳定，避免立即重新注册
+							time.Sleep(1 * time.Second)
+
+							// 尝试重新注册
+							if err := r.registerWithKV(ttl); err == nil {
+								log.Println("[EtcdRegistry] 服务重新注册成功")
+								return // 退出当前 goroutine，让新的 watcher 启动
+							} else {
+								// 如果是防抖错误，继续等待
+								if err.Error() == "register too frequently, please wait" {
+									log.Println("[EtcdRegistry] 注册过于频繁，继续等待...")
+									time.Sleep(2 * time.Second)
+								} else {
+									log.Printf("[EtcdRegistry] 重新注册失败: %v, 继续等待连接恢复...", err)
+								}
+							}
+						}
+					}
+
+					time.Sleep(checkInterval)
+					waited += checkInterval
 				}
 
-				// 使用指数退避重试
-				delay := time.Second
+				// 如果等待超时，使用指数退避重试
+				log.Println("[EtcdRegistry] 等待连接恢复超时，使用重试机制...")
+				delay := 2 * time.Second
 				maxDelay := 30 * time.Second
 
 				for {
 					select {
 					case <-r.ctx.Done():
 						return
+					case <-watcherCtx.Done():
+						return
 					default:
 					}
 
+					// 再次检查连接状态
+					if r.etcdClient != nil {
+						state := r.etcdClient.State()
+						if state == StateConnected {
+							r.mu.Lock()
+							r.cli = r.etcdClient.GetClient()
+							r.mu.Unlock()
+						}
+					}
+
 					if err := r.registerWithKV(ttl); err != nil {
+						// 如果是防抖错误，等待更长时间
+						if err.Error() == "register too frequently, please wait" {
+							log.Println("[EtcdRegistry] 注册过于频繁，等待更长时间...")
+							time.Sleep(3 * time.Second)
+							continue
+						}
 						log.Printf("[EtcdRegistry] failed to re-register service: %v, retrying in %v...", err, delay)
 						time.Sleep(delay)
 						delay *= 2
@@ -159,6 +290,7 @@ func (r *EtcdRegistry) watcher(ttl int64) {
 							delay = maxDelay
 						}
 					} else {
+						log.Println("[EtcdRegistry] 服务重新注册成功")
 						return // 退出当前 goroutine，让新的 watcher 启动
 					}
 				}
@@ -171,7 +303,14 @@ func (r *EtcdRegistry) watcher(ttl int64) {
 
 // UnRegister 注销服务
 func (r *EtcdRegistry) UnRegister() {
-	r.cancel() // 停止 watcher
+	r.cancel() // 停止主 context
+
+	// 停止 watcher
+	r.watcherMu.Lock()
+	if r.watcherCancel != nil {
+		r.watcherCancel()
+	}
+	r.watcherMu.Unlock()
 
 	r.mu.RLock()
 	cli := r.cli
@@ -197,4 +336,3 @@ func (r *EtcdRegistry) State() ConnectionState {
 	}
 	return StateDisconnected
 }
-

manager.go

@@ -223,4 +223,3 @@ func (cm *ConnectionManager) Close() error {
 func (cm *ConnectionManager) TriggerReconnect() {
 	cm.reconnect()
 }
-