com.ottogroup.bi.spqr.websocket.server.SPQRWebSocketServer.java Source code

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/**
 * Copyright 2015 Otto (GmbH & Co KG)
 *
 * 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.ottogroup.bi.spqr.websocket.server;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.apache.commons.cli.PosixParser;
import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.ottogroup.bi.spqr.websocket.server.cfg.SPQRWebSocketServerConfiguration;

/**
 * Ramps up the web socket server which provides access to pipelines results. As SPQR uses kafka by default
 * to interconnect pipelines and emit results the server currently supports to read content from 
 * kafka topics accordingly. <br/><br/>
 * In contrast to spqr node and resource management server this one is based on netty as it provides 
 * support for web sockets. 
 *  
 * @author mnxfst
 * @since Apr 17, 2015
 */
public class SPQRWebSocketServer {

    /** our faithful logging facility ... ;-) */
    private static final Logger logger = Logger.getLogger(SPQRWebSocketServer.class);

    public static final String CFG_HELP = "help";
    public static final String CFG_HELP_SHORT = "h";
    public static final String CFG_CONFIGURATION_FILE = "config";
    public static final String CFG_CONFIGURATION_FILE_SHORT = "c";

    /**
     * Initializes and executes the server components
     * @param configurationFile reference to configuration file
     * @throws IOException
     * @throws InterruptedException 
     */
    protected void run(final String configurationFile) throws IOException, InterruptedException {

        ///////////////////////////////////////////////////////////////////
        // lookup configuration file and create handle
        File cfgFile = new File(StringUtils.trim(configurationFile));
        if (!cfgFile.isFile())
            throw new FileNotFoundException("No configuration file found at '" + configurationFile + "'");
        //
        ///////////////////////////////////////////////////////////////////

        run(new FileInputStream(cfgFile));
    }

    /**
     * Initializes and executes the server components. Although the other {@link SPQRWebSocketServer#run(String)}
     * could do the same work this one allows better testing as the {@link InputStream} parameter allows
     * to inject a variable which may be controlled much better. In the case it would be necessary to 
     * provide a reference to a temporary file which is controlled by the use case ... somehow too much work ;-)
     * This one is easier.  
     * @param configurationFileStream stream holding configuration file content
     * @throws IOException
     * @throws InterruptedException 
     */
    protected void run(final InputStream configurationFileStream) throws IOException, InterruptedException {

        ///////////////////////////////////////////////////////////////////
        // parse out configuration from provided input stream
        ObjectMapper jsonMapper = new ObjectMapper();
        SPQRWebSocketServerConfiguration cfg = jsonMapper.readValue(configurationFileStream,
                SPQRWebSocketServerConfiguration.class);
        //
        ///////////////////////////////////////////////////////////////////

        PropertyConfigurator.configure(cfg.getLog4jConfigurationFile());

        EventLoopGroup bossGroup = new NioEventLoopGroup(cfg.getBossEventGroupThreads());
        EventLoopGroup workerGroup = new NioEventLoopGroup(cfg.getWorkerEventGroupThreads());

        logger.info(
                "websocket server [port=" + cfg.getPort() + ", bossGroupThreads=" + cfg.getBossEventGroupThreads()
                        + ", workerGroupThreads=" + cfg.getWorkerEventGroupThreads() + "]");

        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO)).childHandler(new SPQRWebSocketServerInitializer());

            Channel channel = bootstrap.bind(cfg.getPort()).sync().channel();
            channel.closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

    /**
     * Returns the available command-line options
     * @return
     */
    public static Options getOptions() {
        Options options = new Options();
        options.addOption(CFG_CONFIGURATION_FILE_SHORT, CFG_CONFIGURATION_FILE, true, "Configuration file");
        options.addOption(CFG_HELP_SHORT, CFG_HELP, false, "Help");
        return options;
    }

    /**
     * Checks the command-line settings and ramps up the server
     * @param args arguments passed from command-line
     * @throws ParseException indicates that parsing the command-line failed for any reason
     * @throws InterruptedException 
     * @throws IOException 
     */
    public static void main(String[] args) throws ParseException, IOException, InterruptedException {

        ////////////////////////////////////////////////////////////////////////
        // evaluate command-line and ensure that it provides valid input
        CommandLineParser parser = new PosixParser();
        CommandLine commandLine = parser.parse(getOptions(), args);

        if (commandLine.hasOption(CFG_HELP)) {
            new HelpFormatter().printHelp("spqr-websocket-server", getOptions());
            return;
        }

        if (!commandLine.hasOption(CFG_CONFIGURATION_FILE)) {
            new HelpFormatter().printHelp("spqr-websocket-server", "", getOptions(),
                    "Missing required configuration file");
            return;
        }
        //
        ////////////////////////////////////////////////////////////////////////

        new SPQRWebSocketServer().run(commandLine.getOptionValue(CFG_CONFIGURATION_FILE));
    }
}