org.apache.hadoop.hbase.zookeeper.RegionServerTracker.java Source code

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Here is the source code for org.apache.hadoop.hbase.zookeeper.RegionServerTracker.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 org.apache.hadoop.hbase.zookeeper;

import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.ArrayList;
import java.util.List;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.TreeMap;
import java.util.TreeSet;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hbase.Abortable;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.master.ServerManager;
import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.RegionServerInfo;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.zookeeper.KeeperException;

/**
 * Tracks the online region servers via ZK.
 *
 * <p>Handling of new RSs checking in is done via RPC.  This class
 * is only responsible for watching for expired nodes.  It handles
 * listening for changes in the RS node list and watching each node.
 *
 * <p>If an RS node gets deleted, this automatically handles calling of
 * {@link ServerManager#expireServer(ServerName)}
 */
@InterfaceAudience.Private
public class RegionServerTracker extends ZooKeeperListener {
    private static final Log LOG = LogFactory.getLog(RegionServerTracker.class);
    private NavigableMap<ServerName, RegionServerInfo> regionServers = new TreeMap<ServerName, RegionServerInfo>();
    private ServerManager serverManager;
    private Abortable abortable;

    public RegionServerTracker(ZooKeeperWatcher watcher, Abortable abortable, ServerManager serverManager) {
        super(watcher);
        this.abortable = 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.rsZNode);
        add(servers);
    }

    private void add(final List<String> servers) throws IOException {
        synchronized (this.regionServers) {
            this.regionServers.clear();
            for (String n : servers) {
                ServerName sn = ServerName.parseServerName(ZKUtil.getNodeName(n));
                if (regionServers.get(sn) == null) {
                    RegionServerInfo.Builder rsInfoBuilder = RegionServerInfo.newBuilder();
                    try {
                        String nodePath = ZKUtil.joinZNode(watcher.rsZNode, n);
                        byte[] data = ZKUtil.getData(watcher, nodePath);
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("RS node: " + nodePath + " data: " + Bytes.toString(data));
                        }
                        if (data != null && data.length > 0 && ProtobufUtil.isPBMagicPrefix(data)) {
                            int magicLen = ProtobufUtil.lengthOfPBMagic();
                            rsInfoBuilder.mergeFrom(data, magicLen, data.length - magicLen);
                        }
                    } catch (KeeperException e) {
                        LOG.warn("Get Rs info port from ephemeral node", e);
                    } catch (IOException e) {
                        LOG.warn("Illegal data from ephemeral node", e);
                    } catch (InterruptedException e) {
                        throw new InterruptedIOException();
                    }
                    this.regionServers.put(sn, rsInfoBuilder.build());
                }
            }
        }
    }

    private void remove(final ServerName sn) {
        synchronized (this.regionServers) {
            this.regionServers.remove(sn);
        }
    }

    @Override
    public void nodeDeleted(String path) {
        if (path.startsWith(watcher.rsZNode)) {
            String serverName = ZKUtil.getNodeName(path);
            LOG.info("RegionServer ephemeral node deleted, processing expiration [" + serverName + "]");
            ServerName sn = ServerName.parseServerName(serverName);
            if (!serverManager.isServerOnline(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;
            }
            remove(sn);
            this.serverManager.expireServer(sn);
        }
    }

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

    public RegionServerInfo getRegionServerInfo(final ServerName sn) {
        return regionServers.get(sn);
    }

    /**
     * Gets the online servers.
     * @return list of online servers
     */
    public List<ServerName> getOnlineServers() {
        synchronized (this.regionServers) {
            return new ArrayList<ServerName>(this.regionServers.keySet());
        }
    }
}