tillrohrmann commented on a change in pull request #17485: URL: https://github.com/apache/flink/pull/17485#discussion_r791560202
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/leaderelection/ZooKeeperMultipleComponentLeaderElectionDriver.java ########## @@ -0,0 +1,250 @@ +/* + * 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.flink.runtime.leaderelection; + +import org.apache.flink.runtime.util.ZooKeeperUtils; +import org.apache.flink.util.ExceptionUtils; +import org.apache.flink.util.Preconditions; +import org.apache.flink.util.concurrent.Executors; + +import org.apache.flink.shaded.curator4.org.apache.curator.framework.CuratorFramework; +import org.apache.flink.shaded.curator4.org.apache.curator.framework.recipes.cache.ChildData; +import org.apache.flink.shaded.curator4.org.apache.curator.framework.recipes.cache.TreeCache; +import org.apache.flink.shaded.curator4.org.apache.curator.framework.recipes.cache.TreeCacheSelector; +import org.apache.flink.shaded.curator4.org.apache.curator.framework.recipes.leader.LeaderLatch; +import org.apache.flink.shaded.curator4.org.apache.curator.framework.recipes.leader.LeaderLatchListener; +import org.apache.flink.shaded.curator4.org.apache.curator.framework.state.ConnectionState; +import org.apache.flink.shaded.curator4.org.apache.curator.framework.state.ConnectionStateListener; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.concurrent.atomic.AtomicBoolean; + +/** ZooKeeper based {@link MultipleComponentLeaderElectionDriver} implementation. */ +public class ZooKeeperMultipleComponentLeaderElectionDriver + implements MultipleComponentLeaderElectionDriver, LeaderLatchListener { + + private static final Logger LOG = + LoggerFactory.getLogger(ZooKeeperMultipleComponentLeaderElectionDriver.class); + + private final CuratorFramework curatorFramework; + + private final String leaderContenderDescription; + + private final MultipleComponentLeaderElectionDriver.Listener leaderElectionListener; + + private final LeaderLatch leaderLatch; + + private final TreeCache treeCache; + + private final ConnectionStateListener listener = + (client, newState) -> handleStateChange(newState); + + private AtomicBoolean running = new AtomicBoolean(true); + + public ZooKeeperMultipleComponentLeaderElectionDriver( + CuratorFramework curatorFramework, + String leaderContenderDescription, + MultipleComponentLeaderElectionDriver.Listener leaderElectionListener) + throws Exception { + this.curatorFramework = curatorFramework; + this.leaderContenderDescription = leaderContenderDescription; + this.leaderElectionListener = leaderElectionListener; + + this.leaderLatch = new LeaderLatch(curatorFramework, ZooKeeperUtils.getLeaderLatchNode()); + this.treeCache = + TreeCache.newBuilder(curatorFramework, "/") + .setCacheData(true) + .setCreateParentNodes(false) + .setSelector( + new ZooKeeperMultipleComponentLeaderElectionDriver + .ConnectionInfoNodeSelector()) + .setExecutor(Executors.newDirectExecutorService()) + .build(); + treeCache + .getListenable() + .addListener( + (client, event) -> { + switch (event.getType()) { + case NODE_ADDED: + case NODE_REMOVED: + case NODE_UPDATED: + if (event.getData() != null) { Review comment: Yes, I think you are right that this should be a `checkState` for the `event.getData() != null`. Moreover, I think that I am handling the `NODE_REMOVED` event wrongly. In this case, the leader information should be marked as `LeaderInformation.empty` because the event will be created with the old node data. I will correct the code. -- 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]
