com.ery.estorm.cluster.tracker.BackMasterTracker.java Source code

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Here is the source code for com.ery.estorm.cluster.tracker.BackMasterTracker.java

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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 com.ery.estorm.cluster.tracker;

import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.zookeeper.KeeperException;

import com.ery.estorm.ServerInfo;
import com.ery.estorm.daemon.DaemonMaster;
import com.ery.estorm.daemon.ServerManager;
import com.ery.estorm.zk.ZKUtil;
import com.ery.estorm.zk.ZooKeeperListener;
import com.ery.estorm.zk.ZooKeeperWatcher;

//Master
public class BackMasterTracker extends ZooKeeperListener {
    private static final Log LOG = LogFactory.getLog(BackMasterTracker.class);
    private final Map<String, ServerInfo> masterServers = new ConcurrentHashMap<String, ServerInfo>();
    private ServerManager serverManager;
    private DaemonMaster master;

    public BackMasterTracker(ZooKeeperWatcher watcher, DaemonMaster abortable, ServerManager serverManager) {
        super(watcher);
        this.master = abortable;
        this.serverManager = serverManager;
    }

    /**
     * Starts the tracking of online RegionServers.
     * 
     * <p>
     * All RSs will be tracked after this method is called.
     * 
     * @throws KeeperException
     * @throws IOException
     */
    public void start() throws KeeperException, IOException {
        watcher.registerListener(this);
        List<String> servers = ZKUtil.listChildrenAndWatchThem(watcher, watcher.estormBackupMasterAddressesZNode);
        add(servers);
    }

    private void add(final List<String> servers) throws IOException, KeeperException {
        synchronized (this.masterServers) {
            this.masterServers.clear();
            for (String n : servers) {
                byte[] data = ZKUtil.getDataAndWatch(watcher, watcher.estormBackupMasterAddressesZNode + "/" + n);
                ServerInfo master = ServerInfo.parseFrom(data);
                this.masterServers.put(master.getHostname(), master);
                serverManager.recordNewServer(master);
            }
        }
    }

    @Override
    public void nodeDeleted(String path) {
        if (path.startsWith(watcher.estormBackupMasterAddressesZNode + "/")) {
            String serverName = ZKUtil.getNodeName(path);
            LOG.info("MasterServer ephemeral node deleted, processing expiration [" + serverName + "]");
            ServerInfo sn = this.masterServers.remove(serverName);
            if (!serverManager.isMasterServerOnline(sn)) {
                LOG.warn(serverName.toString() + " is not online or isn't known to the master."
                        + "The latter could be caused by a DNS misconfiguration.");
                return;
            }
            if (!sn.equals(master.getActiveMaster())) {
                this.serverManager.expireServer(sn);
            }
        }
    }

    @Override
    public void nodeChildrenChanged(String path) {
        if (path.equals(watcher.estormBackupMasterAddressesZNode)) {
            try {
                List<String> servers = ZKUtil.listChildrenAndWatchThem(watcher,
                        watcher.estormBackupMasterAddressesZNode);
                add(servers);
            } catch (IOException e) {
                master.abort("Unexpected zk exception getting RS nodes", e);
            } catch (KeeperException e) {
                master.abort("Unexpected zk exception getting RS nodes", e);
            }
        }
    }

    /**
     * Called when a new node has been created.
     * 
     * @param path
     *            full path of the new node
     */
    public void nodeCreated(String path) {
        // no-op
    }

    /**
     * Gets the online servers.
     * 
     * @return list of online servers
     */
    public List<ServerInfo> getOnlineServers() {
        return serverManager.getOnlineServers();
    }
}