org.apache.hadoop.mapred.TrackerClientCache.java Source code

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Here is the source code for org.apache.hadoop.mapred.TrackerClientCache.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.mapred;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.ipc.RPC;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.net.Node;
import org.apache.hadoop.net.TopologyCache;
import org.apache.hadoop.corona.Utilities;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.InetAddress;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * Cache of RPC clients to corona task trackers.
 */
class TrackerClientCache {
    /** Logger. */
    private static final Log LOG = LogFactory.getLog(TrackerClientCache.class);
    /** Map of host:port -> rpc client. */
    private ConcurrentMap<String, CoronaTaskTrackerProtocol> trackerClients = new ConcurrentHashMap<String, CoronaTaskTrackerProtocol>();
    /** Configuration. */
    private Configuration conf;

    /** The topology cache */
    private final TopologyCache topologyCache;

    /**
     * Constructor.
     * @param conf Configuration.
     */
    TrackerClientCache(Configuration conf, TopologyCache topologyCache) {
        this.conf = conf;
        this.topologyCache = topologyCache;
    }

    /**
     * API to get the RPC client.
     * @param host The host
     * @param port The port
     * @return The RPC client
     * @throws IOException
     */
    public CoronaTaskTrackerProtocol getClient(String host, int port) throws IOException {
        String key = makeKey(host, port);
        Node ttNode = topologyCache.getNode(host);
        CoronaTaskTrackerProtocol client = null;
        synchronized (ttNode) {
            client = trackerClients.get(key);
            if (client == null) {
                client = createClient(host, port);
                trackerClients.put(key, client);
            }
        }
        return client;
    }

    /**
     * Remove the RPC client form the cache.
     * @param host The host
     * @param port The port
     */
    public void resetClient(String host, int port) {
        trackerClients.remove(makeKey(host, port));
    }

    /**
     * Connect to the task tracker and get the RPC client.
     * @param host The host.
     * @param port the port.
     * @return The RPC client.
     * @throws IOException
     */
    private CoronaTaskTrackerProtocol createClient(String host, int port) throws IOException {
        String staticHost = NetUtils.getStaticResolution(host);
        InetSocketAddress s = null;
        InetAddress inetAddress = null;
        byte[] byteArr = null;
        if (staticHost != null) {
            inetAddress = InetAddress.getByName(staticHost);
        } else {
            byteArr = Utilities.asBytes(host);
            if (byteArr == null) {
                inetAddress = InetAddress.getByName(host);
            } else {
                inetAddress = InetAddress.getByAddress(byteArr);
            }
        }
        s = new InetSocketAddress(inetAddress, port);
        LOG.info("Creating client to " + (staticHost != null ? staticHost : host) + ":" + s.getPort());
        long connectTimeout = conf.getLong(CoronaJobTracker.TT_CONNECT_TIMEOUT_MSEC_KEY, 10000L);
        int rpcTimeout = conf.getInt(CoronaJobTracker.TT_RPC_TIMEOUT_MSEC_KEY, 60000);
        return RPC.waitForProxy(CoronaTaskTrackerProtocol.class, CoronaTaskTrackerProtocol.versionID, s, conf,
                connectTimeout, rpcTimeout);
    }

    /**
     * Creates a key from host and port
     * @param host The host
     * @param port The port
     * @return String in the form host:port
     */
    private static String makeKey(String host, int port) {
        return host + ":" + port;
    }
}