From 3907104629d85aa788fe6c5ad61476f125782ec0 Mon Sep 17 00:00:00 2001
From: watermelon <80680489@qq.com>
Date: Sat, 23 Jan 2021 23:33:50 +0800
Subject: [PATCH] Fix: issue #951 etcd exit panic

---
 registry/etcdv3/listener.go | 11 ++++++++---
 registry/etcdv3/registry.go | 19 +++++--------------
 remoting/etcdv3/listener.go |  6 +++---
 3 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/registry/etcdv3/listener.go b/registry/etcdv3/listener.go
index 4bc387cafa..e1b1e8dc80 100644
--- a/registry/etcdv3/listener.go
+++ b/registry/etcdv3/listener.go
@@ -19,6 +19,7 @@ package etcdv3
 
 import (
 	"strings"
+	"sync"
 )
 
 import (
@@ -79,8 +80,9 @@ func (l *dataListener) DataChange(eventType remoting.Event) bool {
 }
 
 type configurationListener struct {
-	registry *etcdV3Registry
-	events   chan *config_center.ConfigChangeEvent
+	registry  *etcdV3Registry
+	events    chan *config_center.ConfigChangeEvent
+	closeOnce sync.Once
 }
 
 // NewConfigurationListener for listening the event of etcdv3.
@@ -119,6 +121,9 @@ func (l *configurationListener) Next() (*registry.ServiceEvent, error) {
 }
 
 // Close etcd registry center
+// BugFix why no real close
 func (l *configurationListener) Close() {
-	l.registry.WaitGroup().Done()
+	l.closeOnce.Do(func() {
+		l.registry.WaitGroup().Done()
+	})
 }
diff --git a/registry/etcdv3/registry.go b/registry/etcdv3/registry.go
index f3cc379bd8..7ccf32661c 100644
--- a/registry/etcdv3/registry.go
+++ b/registry/etcdv3/registry.go
@@ -51,7 +51,7 @@ type etcdV3Registry struct {
 	registry.BaseRegistry
 	cltLock        sync.Mutex
 	client         *etcdv3.Client
-	listenerLock   sync.Mutex
+	listenerLock   sync.RWMutex
 	listener       *etcdv3.EventListener
 	dataListener   *dataListener
 	configListener *configurationListener
@@ -150,14 +150,9 @@ func (r *etcdV3Registry) CreatePath(k string) error {
 
 // DoSubscribe actually subscribe the provider URL
 func (r *etcdV3Registry) DoSubscribe(svc *common.URL) (registry.Listener, error) {
-
-	var (
-		configListener *configurationListener
-	)
-
-	r.listenerLock.Lock()
-	configListener = r.configListener
-	r.listenerLock.Unlock()
+	r.listenerLock.RLock()
+	configListener := r.configListener
+	r.listenerLock.RUnlock()
 	if r.listener == nil {
 		r.cltLock.Lock()
 		client := r.client
@@ -165,12 +160,8 @@ func (r *etcdV3Registry) DoSubscribe(svc *common.URL) (registry.Listener, error)
 		if client == nil {
 			return nil, perrors.New("etcd client broken")
 		}
-
-		// new client & listener
-		listener := etcdv3.NewEventListener(r.client)
-
 		r.listenerLock.Lock()
-		r.listener = listener
+		r.listener = etcdv3.NewEventListener(r.client) // new client & listener
 		r.listenerLock.Unlock()
 	}
 
diff --git a/remoting/etcdv3/listener.go b/remoting/etcdv3/listener.go
index c66928a636..fd6f958597 100644
--- a/remoting/etcdv3/listener.go
+++ b/remoting/etcdv3/listener.go
@@ -36,7 +36,7 @@ import (
 // nolint
 type EventListener struct {
 	client     *Client
-	keyMapLock sync.Mutex
+	keyMapLock sync.RWMutex
 	keyMap     map[string]struct{}
 	wg         sync.WaitGroup
 }
@@ -181,9 +181,9 @@ func timeSecondDuration(sec int) time.Duration {
 //                            --------> listenServiceNodeEvent
 func (l *EventListener) ListenServiceEvent(key string, listener remoting.DataListener) {
 
-	l.keyMapLock.Lock()
+	l.keyMapLock.RLock()
 	_, ok := l.keyMap[key]
-	l.keyMapLock.Unlock()
+	l.keyMapLock.RUnlock()
 	if ok {
 		logger.Warnf("etcdv3 key %s has already been listened.", key)
 		return