ruanwenjun commented on code in PR #10981: URL: https://github.com/apache/dolphinscheduler/pull/10981#discussion_r926524325
########## dolphinscheduler-registry/dolphinscheduler-registry-plugins/dolphinscheduler-registry-etcd/src/main/java/org/apache/dolphinscheduler/plugin/registry/etcd/EtcdConnectionStateListener.java: ########## @@ -0,0 +1,119 @@ +/* + * 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.dolphinscheduler.plugin.registry.etcd; + +import org.apache.dolphinscheduler.registry.api.ConnectionListener; +import org.apache.dolphinscheduler.registry.api.ConnectionState; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.concurrent.Executors; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicReference; + +import com.google.common.util.concurrent.ThreadFactoryBuilder; + +import io.etcd.jetcd.Client; +import io.grpc.ManagedChannel; + +/** + * Get the connection status by listening to the Client's Channel + */ +public class EtcdConnectionStateListener implements AutoCloseable { + private final List<ConnectionListener> connectionListeners = Collections.synchronizedList(new ArrayList<>()); + // A thread pool that periodically obtains connection status + private final ScheduledExecutorService scheduledExecutorService; + // Client's Channel + private AtomicReference<ManagedChannel> channel; + // monitored client + private Client client; + // The state of the last monitor + private ConnectionState connectionState; + private long initialDelay = 500L; + private long delay = 500L; + public EtcdConnectionStateListener(Client client) { + this.client = client; + channel = new AtomicReference<>(); + this.scheduledExecutorService = Executors.newScheduledThreadPool( + 1, + new ThreadFactoryBuilder().setNameFormat("EtcdConnectionStateListenerThread").setDaemon(true).build()); + } + + public void addConnectionListener(ConnectionListener connectionListener) { + connectionListeners.add(connectionListener); + } + + @Override + public void close() throws Exception { + connectionListeners.clear(); + scheduledExecutorService.shutdownNow(); + } + + /** + * Apply for a lease through the client, if there is no exception, the connection is normal + * @return the current connection state + * @throws if there is a exception, return is DISCONNECTED + */ + private ConnectionState isConnected() { + try { + // Use Get() to ensure Future completes + client.getLeaseClient().grant(1).get().getID(); + return ConnectionState.CONNECTED; + } catch (Exception e) { + return ConnectionState.DISCONNECTED; + } + } + + /** + * Periodically execute thread to get connection status + */ + public void start() { + this.scheduledExecutorService.scheduleWithFixedDelay(() -> { + ConnectionState currentConnectionState = isConnected(); + if (currentConnectionState == connectionState) { + return; + } + if (connectionState == ConnectionState.CONNECTED) { + if (currentConnectionState == ConnectionState.DISCONNECTED) { + connectionState = ConnectionState.DISCONNECTED; + triggerListener(ConnectionState.DISCONNECTED); + } + } else if (connectionState == ConnectionState.DISCONNECTED) { + if (currentConnectionState == ConnectionState.CONNECTED) { + connectionState = ConnectionState.CONNECTED; + triggerListener(ConnectionState.RECONNECTED); + } + } else if (connectionState == null) { + connectionState = currentConnectionState; + triggerListener(connectionState); + } Review Comment: Yes, in fact, for all state changes, we need to notify the listener. I wrote these logic in MysqlRegistry, since we need to generate `ConnectionState.RECONNECTED` state :), but the state we story in memory is just `RECONNECTED` and `RECONNECTED`. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
