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listener.go
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/
listener.go
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/*
* 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 zookeeper
import (
"strings"
"sync"
)
import (
gxchan "github.com/dubbogo/gost/container/chan"
gxzookeeper "github.com/dubbogo/gost/database/kv/zk"
perrors "github.com/pkg/errors"
)
import (
"github.com/xd-luqiang/dubbo-go/v3/common"
"github.com/xd-luqiang/dubbo-go/v3/common/constant"
"github.com/xd-luqiang/dubbo-go/v3/common/logger"
"github.com/xd-luqiang/dubbo-go/v3/config_center"
"github.com/xd-luqiang/dubbo-go/v3/registry"
"github.com/xd-luqiang/dubbo-go/v3/remoting"
)
// RegistryDataListener contains all URL information subscribed by zookeeper registry
type RegistryDataListener struct {
subscribed map[string]config_center.ConfigurationListener
mutex sync.Mutex
closed bool
}
// NewRegistryDataListener constructs a new RegistryDataListener
func NewRegistryDataListener() *RegistryDataListener {
return &RegistryDataListener{
subscribed: make(map[string]config_center.ConfigurationListener),
}
}
// SubscribeURL is used to set a watch listener for url
func (l *RegistryDataListener) SubscribeURL(url *common.URL, listener config_center.ConfigurationListener) {
if l.closed {
return
}
l.subscribed[url.ServiceKey()] = listener
}
// UnSubscribeURL is used to unset a watch listener for url
func (l *RegistryDataListener) UnSubscribeURL(url *common.URL) config_center.ConfigurationListener {
if l.closed {
return nil
}
listener := l.subscribed[url.ServiceKey()]
listener.(*RegistryConfigurationListener).Close()
delete(l.subscribed, url.ServiceKey())
return listener
}
// DataChange accepts all events sent from the zookeeper server and trigger the corresponding listener for processing
func (l *RegistryDataListener) DataChange(event remoting.Event) bool {
providersPath := constant.PathSeparator + constant.ProviderCategory + constant.PathSeparator
// Intercept the last bit
index := strings.Index(event.Path, providersPath)
if index == -1 {
logger.Warnf("[RegistryDataListener][DataChange]Listen error zk node path {%s}, "+
"this listener is used to listen services which under the directory of providers/", event.Path)
return false
}
url := event.Path[index+len(providersPath):]
serviceURL, err := common.NewURL(url)
if err != nil {
logger.Errorf("[RegistryDataListener][DataChange]Listen NewURL({%s}) = error{%+v} event.Path={%s}", url, err, event.Path)
return false
}
l.mutex.Lock()
defer l.mutex.Unlock()
if l.closed {
return false
}
for serviceKey, listener := range l.subscribed {
if serviceURL.ServiceKey() == serviceKey {
listener.Process(
&config_center.ConfigChangeEvent{
Key: event.Path,
Value: serviceURL,
ConfigType: event.Action,
},
)
return true
}
}
return false
}
// Close all RegistryConfigurationListener in subscribed
func (l *RegistryDataListener) Close() {
l.mutex.Lock()
defer l.mutex.Unlock()
l.closed = true
for _, listener := range l.subscribed {
listener.(*RegistryConfigurationListener).Close()
}
}
// RegistryConfigurationListener represent the processor of zookeeper watcher
type RegistryConfigurationListener struct {
client *gxzookeeper.ZookeeperClient
registry *zkRegistry
events *gxchan.UnboundedChan
isClosed bool
close chan struct{}
closeOnce sync.Once
subscribeURL *common.URL
}
// NewRegistryConfigurationListener for listening the event of zk.
func NewRegistryConfigurationListener(client *gxzookeeper.ZookeeperClient, reg *zkRegistry, conf *common.URL) *RegistryConfigurationListener {
reg.WaitGroup().Add(1)
return &RegistryConfigurationListener{
client: client,
registry: reg,
events: gxchan.NewUnboundedChan(32),
isClosed: false,
close: make(chan struct{}, 1),
subscribeURL: conf,
}
}
// Process submit the ConfigChangeEvent to the event chan to notify all observer
func (l *RegistryConfigurationListener) Process(configType *config_center.ConfigChangeEvent) {
l.events.In() <- configType
}
// Next will observe the registry state and events chan
func (l *RegistryConfigurationListener) Next() (*registry.ServiceEvent, error) {
for {
select {
case <-l.close:
return nil, perrors.New("listener have been closed")
case <-l.registry.Done():
logger.Warnf("zk consumer register has quit, so zk event listener exit now. (registry url {%v}", l.registry.BaseRegistry.URL)
return nil, perrors.New("zookeeper registry, (registry url{%v}) stopped")
case val := <-l.events.Out():
e, _ := val.(*config_center.ConfigChangeEvent)
logger.Debugf("got zk event %s", e)
if e.ConfigType == remoting.EventTypeDel && !l.valid() {
logger.Warnf("update @result{%s}. But its connection to registry is invalid", e.Value)
continue
}
return ®istry.ServiceEvent{Action: e.ConfigType, Service: e.Value.(*common.URL)}, nil
}
}
}
// Close RegistryConfigurationListener only once
func (l *RegistryConfigurationListener) Close() {
// ensure that the listener will be closed at most once.
l.closeOnce.Do(func() {
l.isClosed = true
l.close <- struct{}{}
l.registry.WaitGroup().Done()
})
}
// valid return the true if the client conn isn't nil
func (l *RegistryConfigurationListener) valid() bool {
return l.client.ZkConnValid()
}