com.mellanox.r4h.R4HDatanodePlugin.java Source code

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Here is the source code for com.mellanox.r4h.R4HDatanodePlugin.java

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/*
 ** Copyright (C) 2014 Mellanox Technologies
 **
 ** Licensed 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.mellanox.r4h;

import java.io.IOException;
import java.net.URISyntaxException;

import org.accelio.jxio.EventQueueHandler;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hdfs.server.datanode.DataNode;
import org.apache.hadoop.hdfs.server.datanode.DataNodeBridge;
import org.apache.hadoop.util.Daemon;
import org.apache.hadoop.util.ServicePlugin;

/**
 * R4H implementation for a datanode service plugin to run a R4H serve side by side to HDFS server. Datanode starts
 * service plugins during initialization by going through the comma separated list of ServicePlugin implementation
 * classes configured on dfs.datanode.plugins parameter
 */
public class R4HDatanodePlugin implements ServicePlugin {
    private DataNode dn;
    private DataXceiverServer dxs;
    private Daemon daemon;
    private static Log LOG = LogFactory.getLog(R4HDatanodePlugin.class.getName());
    private DataNodeBridge dnExposer;

    // is not called on datanode
    public void close() throws IOException {
        stop();
    }

    /*
     * Starts a new thread of R4H server. Designed to be called by Datanode as a service.
     * 
     * @param service must be a Datanode instance or Object[] for standalone untitest
     * 
     * @see org.apache.hadoop.util.ServicePlugin#start(java.lang.Object)
     */
    public void start(Object service) {
        LOG.debug("Starting plugin");
        if (!(service instanceof DataNode)) {
            throw new IllegalArgumentException("Unexpected service object type");
        }
        LOG.debug("Service object is DataNode");
        dn = (DataNode) service;
        dnExposer = new DataNodeBridge(dn);

        try {
            DataNodeBridge dnBridge = new DataNodeBridge(dn);
            dxs = new DataXceiverServer(dnBridge);
        } catch (URISyntaxException e) {
            throw new IllegalArgumentException("Failed to create URI for DataXceriverServer", e);
        }
        daemon = new Daemon(dxs);
        daemon.setName(String.format("DataXceiverServer-JXIO-Listener-%d", daemon.getId()));
        daemon.start();

        LOG.info("Started");
        // JXIO version
        LOG.info("JXIO version :\t" + EventQueueHandler.class.getPackage().getImplementationVersion());
        // R4H version
        LOG.info("R4H verison :\t" + DataXceiver.class.getPackage().getImplementationVersion());
    }

    /*
     * Stop R4H server and wait until it closes all it's resources
     * 
     * @see org.apache.hadoop.util.ServicePlugin#stop()
     */
    public void stop() {
        stop(-1); // Infinite wait for daemon to stop
    }

    /**
     * Stop R4H server
     * 
     * @param waitForDaemon
     *            milliseconds to wait for resources to be closed or -1 for infinate wait
     */
    public void stop(int waitForDaemon) {
        if (waitForDaemon < -1) {
            throw new IllegalArgumentException(
                    "Illegal (begative) number of milliseconds argument to wait for deamon to stop");
        }

        LOG.debug("Stopping R4H Datanode plugin");
        Daemon dm = new Daemon(new Runnable() {

            @Override
            public void run() {
                dxs.stop();
            }
        });
        dm.start();

        try {
            if (waitForDaemon == -1) {
                daemon.join();
            } else {
                daemon.join(waitForDaemon);
            }
        } catch (InterruptedException e) {
            LOG.debug("daemon join interrupted. Exception: " + e.toString());
        }

        if (dm.isAlive()) {
            LOG.error("timeout waiting for R4H plugin to stop");
        } else {
            LOG.info("R4H Datanode plugin stopped");
        }
    }

    /**
     * @return true if server thread is still alive
     */
    public boolean isAlive() {
        if (daemon == null)
            return false;

        return daemon.isAlive();
    }

    @Override
    public String toString() {
        if (daemon == null) {
            return super.toString() + " is not started yet";
        } else {
            return String.format("R4HDatanodePlugin{DN='%s', DXS='%s', isAlive='%s'}",
                    (dn == null) ? "-" : dn.toString(), dxs.toString(), daemon.isAlive() ? "TRUE" : "FALSE");
        }
    }
}