org.apache.hadoop.hive.hwi.HWIServer.java Source code

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Here is the source code for org.apache.hadoop.hive.hwi.HWIServer.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.hive.hwi;

import java.io.File;
import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.shims.JettyShims;
import org.apache.hadoop.hive.shims.ShimLoader;

/**
 * This is the entry point for HWI. A web server is invoked in the same manner
 * as the hive CLI. Rather then opening a command line session a web server is
 * started and a web application to work with hive is started.
 */
public class HWIServer {
    protected static final Log l4j = LogFactory.getLog(HWIServer.class.getName());

    private JettyShims.Server webServer;
    private final String[] args;

    /**
     * 
     * @param args
     *            These are the command line arguments. Usually -hiveconf.
     * @throws java.io.IOException
     */
    public HWIServer(String[] args) throws IOException {
        this.args = args;
    }

    /**
     * This method initialized the internal Jetty Servlet Engine. It adds the
     * hwi context path.
     * 
     * @throws java.io.IOException
     *             Port already in use, bad bind etc.
     */
    public void start() throws IOException {

        HiveConf conf = new HiveConf(this.getClass());

        String listen = null;
        int port = -1;

        listen = conf.getVar(HiveConf.ConfVars.HIVEHWILISTENHOST);
        port = conf.getIntVar(HiveConf.ConfVars.HIVEHWILISTENPORT);

        if (listen.equals("")) {
            l4j.warn("hive.hwi.listen.host was not specified defaulting to 0.0.0.0");
            listen = "0.0.0.0";
        }
        if (port == -1) {
            l4j.warn("hive.hwi.listen.port was not specified defaulting to 9999");
            port = 9999;
        }

        String hwiWAR = conf.getVar(HiveConf.ConfVars.HIVEHWIWARFILE);
        String hivehome = System.getenv().get("HIVE_HOME");
        File hwiWARFile = new File(hivehome, hwiWAR);
        if (!hwiWARFile.exists()) {
            l4j.fatal("HWI WAR file not found at " + hwiWARFile.toString());
            System.exit(1);
        }

        webServer = ShimLoader.getJettyShims().startServer(listen, port);
        webServer.addWar(hwiWARFile.toString(), "/hwi");

        /*
         * The command line args may be used by multiple components. Rather by
         * setting these as a system property we avoid having to specifically
         * pass them
         */
        StringBuilder sb = new StringBuilder();
        for (String arg : args) {
            sb.append(arg + " ");
        }
        System.setProperty("hwi-args", sb.toString());

        try {
            while (true) {
                try {
                    webServer.start();
                    webServer.join();
                    l4j.debug(" HWI Web Server is started.");
                    break;
                } catch (org.mortbay.util.MultiException ex) {
                    throw ex;
                }
            }
        } catch (IOException ie) {
            throw ie;
        } catch (Exception e) {
            IOException ie = new IOException("Problem starting HWI server");
            ie.initCause(e);
            l4j.error("Parsing hwi.listen.port caused exception ", e);
            throw ie;
        }
    }

    /**
     * 
     * @param args
     *            as of now no arguments are supported
     * @throws java.lang.Exception
     *             Could be thrown if due to issues with Jetty or bad
     *             configuration options
     * 
     */
    public static void main(String[] args) throws Exception {
        HWIServer hwi = new HWIServer(args);
        l4j.info("HWI is starting up");
        hwi.start();
    }

    /**
     * Shut down the running HWI Server.
     * 
     * @throws Exception
     *             Running Thread.stop() can and probably will throw this
     */
    public void stop() throws Exception {
        l4j.info("HWI is shutting down");
        webServer.stop();
    }

}