Fix: zk lost event

README.md

@@ -117,6 +117,7 @@ Finished List:
     * [Nacos](https://github.com/apache/dubbo-go/pull/522)
     * [Zookeeper](https://github.com/apache/dubbo-go/pull/633)
     * [Etcd](https://github.com/apache/dubbo-go/blob/9a5990d9a9c3d5e6633c0d7d926c156416bcb931/metadata/report/etcd/report.go)
+    * [Consul](https://github.com/apache/dubbo-go/pull/633)
 
 - Service discovery
     * [Nacos](https://github.com/apache/dubbo-go/blob/9a5990d9a9c3d5e6633c0d7d926c156416bcb931/registry/nacos/service_discovery.go)

README_CN.md

@@ -115,6 +115,7 @@ Apache License, Version 2.0
     * [Nacos](https://github.com/apache/dubbo-go/pull/522)
     * [Zookeeper](https://github.com/apache/dubbo-go/pull/633)
     * [Etcd](https://github.com/apache/dubbo-go/blob/9a5990d9a9c3d5e6633c0d7d926c156416bcb931/metadata/report/etcd/report.go)
+    * [Consul](https://github.com/apache/dubbo-go/pull/633)
 
 - 服务发现
     * [Nacos](https://github.com/apache/dubbo-go/blob/9a5990d9a9c3d5e6633c0d7d926c156416bcb931/registry/nacos/service_discovery.go)
@@ -179,7 +180,7 @@ go test ./... -coverprofile=coverage.txt -covermode=atomic
 
 ## [User List](https://github.com/apache/dubbo-go/issues/2)
 
-若你正在使用 [apache/dubbo-go](github.com/apache/dubbo-go) 且认为其有用或者向对其做改进，请忝列贵司信息于 [用户列表](https://github.com/apache/dubbo-go/issues/2)，以便我们知晓之。
+若你正在使用 [apache/dubbo-go](github.com/apache/dubbo-go) 且认为其有用或者想对其做改进，请添列贵司信息于 [用户列表](https://github.com/apache/dubbo-go/issues/2)，以便我们知晓。
 
 <div>
 <table>

common/constant/default.go

@@ -37,6 +37,7 @@ const (
 	DEFAULT_RETRIES_INT        = 2
 	DEFAULT_PROTOCOL           = "dubbo"
 	DEFAULT_REG_TIMEOUT        = "10s"
+	DEFAULT_REG_TTL            = "15m"
 	DEFAULT_CLUSTER            = "failover"
 	DEFAULT_FAILBACK_TIMES     = "3"
 	DEFAULT_FAILBACK_TIMES_INT = 3

common/constant/key.go

@@ -97,6 +97,7 @@ const (
 	ROLE_KEY             = "registry.role"
 	REGISTRY_DEFAULT_KEY = "registry.default"
 	REGISTRY_TIMEOUT_KEY = "registry.timeout"
+	REGISTRY_TTL_KEY     = "registry.ttl"
 )
 
 const (

config/registry_config.go

@@ -39,6 +39,7 @@ type RegistryConfig struct {
 	// I changed "type" to "protocol" ,the same as "protocol" field in java class RegistryConfig
 	TimeoutStr string `yaml:"timeout" default:"5s" json:"timeout,omitempty" property:"timeout"` // unit: second
 	Group      string `yaml:"group" json:"group,omitempty" property:"group"`
+	TTL        string `yaml:"ttl" default:"10m" json:"ttl,omitempty" property:"ttl"` // unit: minute
 	// for registry
 	Address    string            `yaml:"address" json:"address,omitempty" property:"address"`
 	Username   string            `yaml:"username" json:"username,omitempty" property:"username"`
@@ -118,6 +119,7 @@ func (c *RegistryConfig) getUrlMap(roleType common.RoleType) url.Values {
 	urlMap.Set(constant.ROLE_KEY, strconv.Itoa(int(roleType)))
 	urlMap.Set(constant.REGISTRY_KEY, c.Protocol)
 	urlMap.Set(constant.REGISTRY_TIMEOUT_KEY, c.TimeoutStr)
+	urlMap.Set(constant.REGISTRY_TTL_KEY, c.TTL)
 	for k, v := range c.Params {
 		urlMap.Set(k, v)
 	}

registry/zookeeper/registry.go

@@ -243,6 +243,8 @@ func (r *zkRegistry) getListener(conf *common.URL) (*RegistryConfigurationListen
 
 	var zkListener *RegistryConfigurationListener
 	dataListener := r.dataListener
+	ttl := r.GetParam(constant.REGISTRY_TTL_KEY, constant.DEFAULT_REG_TTL)
+	conf.SetParam(constant.REGISTRY_TTL_KEY, ttl)
 	dataListener.mutex.Lock()
 	defer dataListener.mutex.Unlock()
 	if r.dataListener.subscribed[conf.ServiceKey()] != nil {

remoting/zookeeper/listener.go

@@ -37,6 +37,10 @@ import (
 	"github.com/apache/dubbo-go/remoting"
 )
 
+var (
+	DefaultTTL = 15 * time.Minute
+)
+
 // nolint
 type ZkEventListener struct {
 	client      *ZookeeperClient
@@ -197,10 +201,20 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkPath string, listen
 
 	var (
 		failTimes int
+		ttl       time.Duration
 		event     chan struct{}
 		zkEvent   zk.Event
 	)
 	event = make(chan struct{}, 4)
+	ttl = DefaultTTL
+	if conf != nil {
+		timeout, err := time.ParseDuration(conf.GetParam(constant.REGISTRY_TTL_KEY, constant.DEFAULT_REG_TTL))
+		if err == nil {
+			ttl = timeout
+		} else {
+			logger.Warnf("wrong configuration for registry ttl, error:=%+v", err)
+		}
+	}
 	defer close(event)
 	for {
 		// get current children for a zkPath
@@ -302,18 +316,29 @@ func (l *ZkEventListener) listenDirEvent(conf *common.URL, zkPath string, listen
 				}(dubboPath, listener)
 			}
 		}
-		select {
-		case zkEvent = <-childEventCh:
-			logger.Warnf("get a zookeeper zkEvent{type:%s, server:%s, path:%s, state:%d-%s, err:%s}",
-				zkEvent.Type.String(), zkEvent.Server, zkEvent.Path, zkEvent.State, StateToString(zkEvent.State), zkEvent.Err)
-			if zkEvent.Type != zk.EventNodeChildrenChanged {
-				continue
+		// Periodically update provider information
+		ticker := time.NewTicker(ttl)
+	WATCH:
+		for {
+			select {
+			case <-ticker.C:
+				l.handleZkNodeEvent(zkEvent.Path, children, listener)
+			case zkEvent = <-childEventCh:
+				logger.Warnf("get a zookeeper zkEvent{type:%s, server:%s, path:%s, state:%d-%s, err:%s}",
+					zkEvent.Type.String(), zkEvent.Server, zkEvent.Path, zkEvent.State, StateToString(zkEvent.State), zkEvent.Err)
+				ticker.Stop()
+				if zkEvent.Type != zk.EventNodeChildrenChanged {
+					break WATCH
+				}
+				l.handleZkNodeEvent(zkEvent.Path, children, listener)
+				break WATCH
+			case <-l.client.Done():
+				logger.Warnf("client.done(), listen(path{%s}) goroutine exit now...", zkPath)
+				ticker.Stop()
+				return
 			}
-			l.handleZkNodeEvent(zkEvent.Path, children, listener)
-		case <-l.client.Done():
-			logger.Warnf("client.done(), listen(path{%s}) goroutine exit now...", zkPath)
-			return
 		}
+
 	}
 }