From 4e82b6fafe5f2e1392fd112a2a80f145bee83ce4 Mon Sep 17 00:00:00 2001
From: "vito.he" <hxmhlt@163.com>
Date: Fri, 7 Feb 2020 17:14:16 +0800
Subject: [PATCH] Add: more comment of registry module
---
registry/base_registry.go | 27 ++++++++++++++++++---------
registry/etcdv3/listener.go | 2 +-
registry/etcdv3/registry.go | 1 +
registry/zookeeper/listener.go | 2 +-
registry/zookeeper/registry.go | 2 ++
5 files changed, 23 insertions(+), 11 deletions(-)
diff --git a/registry/base_registry.go b/registry/base_registry.go
index 74ec6b410..bd3a14bb5 100644
--- a/registry/base_registry.go
+++ b/registry/base_registry.go
@@ -84,12 +84,11 @@ type BaseRegistry struct {
context context.Context
facadeBasedRegistry FacadeBasedRegistry
*common.URL
- birth int64 // time of file birth, seconds since Epoch; 0 if unknown
- wg sync.WaitGroup // wg+done for zk restart
- done chan struct{}
-
- cltLock sync.Mutex
- services map[string]common.URL // service name + protocol -> service config
+ birth int64 // time of file birth, seconds since Epoch; 0 if unknown
+ wg sync.WaitGroup // wg+done for zk restart
+ done chan struct{}
+ cltLock sync.Mutex //ctl lock is a lock for services map
+ services map[string]common.URL // service name + protocol -> service config, for store the service registered
}
func (r *BaseRegistry) InitBaseRegistry(url *common.URL, facadeRegistry FacadeBasedRegistry) Registry {
@@ -98,17 +97,22 @@ func (r *BaseRegistry) InitBaseRegistry(url *common.URL, facadeRegistry FacadeBa
r.done = make(chan struct{})
r.services = make(map[string]common.URL)
r.facadeBasedRegistry = facadeRegistry
- r.wg.Add(1)
return r
}
func (r *BaseRegistry) GetUrl() common.URL {
return *r.URL
}
+
+//for graceful down
func (r *BaseRegistry) Destroy() {
+ //first step close registry's all listeners
r.facadeBasedRegistry.CloseListener()
+ // then close r.done to notify other program who listen to it
close(r.done)
+ // wait waitgroup done (wait listeners outside close over)
r.wg.Wait()
+ //close registry client
r.closeRegisters()
}
@@ -165,6 +169,7 @@ func (r *BaseRegistry) Register(conf common.URL) error {
return nil
}
+//get service path stored in url
func (r *BaseRegistry) service(c common.URL) string {
return url.QueryEscape(c.Service())
}
@@ -322,7 +327,7 @@ func sleepWait(n int) {
time.Sleep(wait)
}
-//subscribe from registry
+//Subscribe from registry
func (r *BaseRegistry) Subscribe(url *common.URL, notifyListener NotifyListener) {
n := 0
for {
@@ -362,11 +367,13 @@ func (r *BaseRegistry) closeRegisters() {
r.cltLock.Lock()
defer r.cltLock.Unlock()
logger.Infof("begin to close provider client")
- // Close the old client first to close the tmp node.
+ // Close and remove(set to nil) the registry client
r.facadeBasedRegistry.CloseAndNilClient()
+ // reset the services map
r.services = nil
}
+//judge to is registry not closed by chan r.done
func (r *BaseRegistry) IsAvailable() bool {
select {
case <-r.done:
@@ -376,10 +383,12 @@ func (r *BaseRegistry) IsAvailable() bool {
}
}
+//open for outside add the waitgroup to add some logic before registry destroyed over(graceful down)
func (r *BaseRegistry) WaitGroup() *sync.WaitGroup {
return &r.wg
}
+//open for outside to listen the event of registry Destroy() called.
func (r *BaseRegistry) Done() chan struct{} {
return r.done
}
diff --git a/registry/etcdv3/listener.go b/registry/etcdv3/listener.go
index de769e8ad..5ed56f6cc 100644
--- a/registry/etcdv3/listener.go
+++ b/registry/etcdv3/listener.go
@@ -78,7 +78,7 @@ type configurationListener struct {
events chan *config_center.ConfigChangeEvent
}
-// NewConfigurationListener ...
+// NewConfigurationListener for listening the event of etcdv3.
func NewConfigurationListener(reg *etcdV3Registry) *configurationListener {
// add a new waiter
reg.WaitGroup().Add(1)
diff --git a/registry/etcdv3/registry.go b/registry/etcdv3/registry.go
index f66abe3ef..e1c257681 100644
--- a/registry/etcdv3/registry.go
+++ b/registry/etcdv3/registry.go
@@ -95,6 +95,7 @@ func newETCDV3Registry(url *common.URL) (registry.Registry, error) {
); err != nil {
return nil, err
}
+ r.WaitGroup().Add(1) //etcdv3 client start successful, then wg +1
go etcdv3.HandleClientRestart(r)
diff --git a/registry/zookeeper/listener.go b/registry/zookeeper/listener.go
index 6dbf588ca..e89524326 100644
--- a/registry/zookeeper/listener.go
+++ b/registry/zookeeper/listener.go
@@ -85,7 +85,7 @@ type RegistryConfigurationListener struct {
closeOnce sync.Once
}
-// NewRegistryConfigurationListener ...
+// NewRegistryConfigurationListener for listening the event of zk.
func NewRegistryConfigurationListener(client *zk.ZookeeperClient, reg *zkRegistry) *RegistryConfigurationListener {
reg.WaitGroup().Add(1)
return &RegistryConfigurationListener{client: client, registry: reg, events: make(chan *config_center.ConfigChangeEvent, 32), isClosed: false}
diff --git a/registry/zookeeper/registry.go b/registry/zookeeper/registry.go
index 877c4e3f2..f4e53dcc4 100644
--- a/registry/zookeeper/registry.go
+++ b/registry/zookeeper/registry.go
@@ -78,6 +78,7 @@ func newZkRegistry(url *common.URL) (registry.Registry, error) {
if err != nil {
return nil, err
}
+ r.WaitGroup().Add(1) //zk client start successful, then wg +1
go zookeeper.HandleClientRestart(r)
@@ -112,6 +113,7 @@ func newMockZkRegistry(url *common.URL, opts ...zookeeper.Option) (*zk.TestClust
if err != nil {
return nil, nil, err
}
+ r.WaitGroup().Add(1) //zk client start successful, then wg +1
go zookeeper.HandleClientRestart(r)
r.InitListeners()
return c, r, nil
--
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