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The etcd3 registry module of Dubbo project
/*
* 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 org.apache.dubbo.registry.etcd;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.extension.ExtensionLoader;
import org.apache.dubbo.common.logger.Logger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.common.utils.ConcurrentHashSet;
import org.apache.dubbo.event.EventDispatcher;
import org.apache.dubbo.event.EventListener;
import org.apache.dubbo.registry.client.AbstractServiceDiscovery;
import org.apache.dubbo.registry.client.DefaultServiceInstance;
import org.apache.dubbo.registry.client.ServiceInstance;
import org.apache.dubbo.registry.client.event.ServiceInstancesChangedEvent;
import org.apache.dubbo.registry.client.event.listener.ServiceInstancesChangedListener;
import org.apache.dubbo.remoting.etcd.ChildListener;
import org.apache.dubbo.remoting.etcd.EtcdClient;
import org.apache.dubbo.remoting.etcd.EtcdTransporter;
import org.apache.dubbo.remoting.etcd.StateListener;
import org.apache.dubbo.remoting.etcd.option.OptionUtil;
import org.apache.dubbo.rpc.RpcException;
import com.google.gson.Gson;
import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
/**
* 2019-07-08
*/
public class EtcdServiceDiscovery extends AbstractServiceDiscovery implements EventListener {
private static final Logger logger = LoggerFactory.getLogger(EtcdServiceDiscovery.class);
private final String root = "/services";
private final Set services = new ConcurrentHashSet<>();
private final Map childListenerMap = new ConcurrentHashMap<>();
EtcdClient etcdClient;
EventDispatcher dispatcher;
private URL registryURL;
@Override
public void onEvent(ServiceInstancesChangedEvent event) {
registerServiceWatcher(event.getServiceName());
}
@Override
public void initialize(URL registryURL) throws Exception {
EtcdTransporter etcdTransporter = ExtensionLoader.getExtensionLoader(EtcdTransporter.class).getAdaptiveExtension();
if (registryURL.isAnyHost()) {
throw new IllegalStateException("Service discovery address is invalid, actual: '" + registryURL.getHost() + "'");
}
etcdClient = etcdTransporter.connect(registryURL);
etcdClient.addStateListener(state -> {
if (state == StateListener.CONNECTED) {
try {
recover();
} catch (Exception e) {
logger.error(e.getMessage(), e);
}
}
});
this.dispatcher = EventDispatcher.getDefaultExtension();
this.dispatcher.addEventListener(this);
this.registryURL = registryURL;
}
@Override
public void destroy() {
if (etcdClient != null && etcdClient.isConnected()) {
etcdClient.close();
}
}
@Override
public void doRegister(ServiceInstance serviceInstance) {
try {
String path = toPath(serviceInstance);
// etcdClient.createEphemeral(path);
etcdClient.putEphemeral(path, new Gson().toJson(serviceInstance));
services.add(serviceInstance.getServiceName());
} catch (Throwable e) {
throw new RpcException("Failed to register " + serviceInstance + " to etcd " + etcdClient.getUrl()
+ ", cause: " + (OptionUtil.isProtocolError(e)
? "etcd3 registry may not be supported yet or etcd3 registry is not available."
: e.getMessage()), e);
}
}
String toPath(ServiceInstance serviceInstance) {
return root + File.separator + serviceInstance.getServiceName() + File.separator + serviceInstance.getHost()
+ ":" + serviceInstance.getPort();
}
String toParentPath(String serviceName) {
return root + File.separator + serviceName;
}
@Override
public void doUpdate(ServiceInstance serviceInstance) {
try {
String path = toPath(serviceInstance);
etcdClient.putEphemeral(path, new Gson().toJson(serviceInstance));
services.add(serviceInstance.getServiceName());
} catch (Throwable e) {
throw new RpcException("Failed to register " + serviceInstance + " to etcd " + etcdClient.getUrl()
+ ", cause: " + (OptionUtil.isProtocolError(e)
? "etcd3 registry may not be supported yet or etcd3 registry is not available."
: e.getMessage()), e);
}
}
@Override
public void unregister(ServiceInstance serviceInstance) throws RuntimeException {
try {
String path = toPath(serviceInstance);
etcdClient.delete(path);
services.remove(serviceInstance.getServiceName());
this.serviceInstance = null;
} catch (Throwable e) {
throw new RpcException("Failed to unregister " + serviceInstance + " to etcd " + etcdClient.getUrl() + ", cause: " + e.getMessage(), e);
}
}
@Override
public Set getServices() {
return Collections.unmodifiableSet(services);
}
@Override
public void addServiceInstancesChangedListener(ServiceInstancesChangedListener listener) throws NullPointerException, IllegalArgumentException {
listener.getServiceNames().forEach(serviceName -> registerServiceWatcher(serviceName));
}
@Override
public List getInstances(String serviceName) {
List children = etcdClient.getChildren(toParentPath(serviceName));
if (CollectionUtils.isEmpty(children)) {
return Collections.EMPTY_LIST;
}
List list = new ArrayList<>(children.size());
for (String child : children) {
ServiceInstance serviceInstance = new Gson().fromJson(etcdClient.getKVValue(child), DefaultServiceInstance.class);
list.add(serviceInstance);
}
return list;
}
protected void registerServiceWatcher(String serviceName) {
String path = root + File.separator + serviceName;
/*
* if we have no category watcher listener,
* we find out the current listener or create one for the current category, put or get only once.
*/
ChildListener childListener =
Optional.ofNullable(childListenerMap.get(serviceName))
.orElseGet(() -> {
ChildListener watchListener, prev;
prev = childListenerMap.putIfAbsent(serviceName, watchListener = (parentPath, currentChildren) ->
dispatchServiceInstancesChangedEvent(serviceName));
return prev != null ? prev : watchListener;
});
etcdClient.create(path);
etcdClient.addChildListener(path, childListener);
}
private void recover() throws Exception {
// register
if (serviceInstance != null) {
if (logger.isInfoEnabled()) {
logger.info("Recover application register: " + serviceInstance);
}
register(serviceInstance);
}
}
@Override
public URL getUrl() {
return registryURL;
}
}