| /** |
| * 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.s4.comm.topology; |
| |
| import java.net.InetAddress; |
| import java.net.UnknownHostException; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.locks.Lock; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| import org.I0Itec.zkclient.IZkStateListener; |
| import org.I0Itec.zkclient.serialize.ZkSerializer; |
| import org.apache.zookeeper.Watcher.Event.KeeperState; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.google.inject.Inject; |
| import com.google.inject.name.Named; |
| |
| /** |
| * Monitors all clusters |
| * |
| */ |
| public class ClustersFromZK implements Clusters, IZkStateListener { |
| private static final Logger logger = LoggerFactory.getLogger(ClustersFromZK.class); |
| private KeeperState state; |
| private final ZkClient zkClient; |
| private final Lock lock; |
| private String machineId; |
| private final Map<String, ClusterFromZK> clusters = new HashMap<String, ClusterFromZK>(); |
| private final int connectionTimeout; |
| private final String clusterName; |
| |
| @Inject |
| public ClustersFromZK(@Named("s4.cluster.name") String clusterName, |
| @Named("s4.cluster.zk_connection_timeout") int connectionTimeout, ZkClient zkClient) throws Exception { |
| this.clusterName = clusterName; |
| this.connectionTimeout = connectionTimeout; |
| lock = new ReentrantLock(); |
| this.zkClient = zkClient; |
| zkClient.subscribeStateChanges(this); |
| zkClient.waitUntilConnected(connectionTimeout, TimeUnit.MILLISECONDS); |
| try { |
| machineId = InetAddress.getLocalHost().getCanonicalHostName(); |
| } catch (UnknownHostException e) { |
| logger.warn("Unable to get hostname", e); |
| machineId = "UNKNOWN"; |
| } |
| // bug in zkClient, it does not invoke handleNewSession the first time |
| // it connects |
| this.handleStateChanged(KeeperState.SyncConnected); |
| |
| this.handleNewSession(); |
| |
| } |
| |
| /** |
| * One method to do any processing if there is a change in ZK, all callbacks will be processed sequentially |
| */ |
| private void doProcess() { |
| lock.lock(); |
| try { |
| for (Map.Entry<String, ClusterFromZK> cluster : clusters.entrySet()) { |
| cluster.getValue().doProcess(); |
| } |
| } catch (Exception e) { |
| logger.warn("Exception in tryToAcquireTask", e); |
| } finally { |
| lock.unlock(); |
| } |
| } |
| |
| @Override |
| public void handleStateChanged(KeeperState state) throws Exception { |
| this.state = state; |
| if (state.equals(KeeperState.Expired)) { |
| logger.error( |
| "Zookeeper session expired, possibly due to a network partition for cluster [{}]. This node is considered as dead by Zookeeper. Proceeding to stop this node.", |
| clusterName); |
| System.exit(1); |
| } |
| } |
| |
| @Override |
| public void handleNewSession() throws Exception { |
| logger.info("New session:" + zkClient.getSessionId()); |
| List<String> clusterNames = zkClient.getChildren("/s4/clusters"); |
| for (String clusterName : clusterNames) { |
| ClusterFromZK cluster = new ClusterFromZK(clusterName, zkClient, machineId); |
| clusters.put(clusterName, cluster); |
| } |
| doProcess(); |
| } |
| |
| @Override |
| public Cluster getCluster(String clusterName) { |
| return clusters.get(clusterName); |
| } |
| |
| } |