yarn.demo.InteractableYarnApplicationContainersClusterDemo.java Source code

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Here is the source code for yarn.demo.InteractableYarnApplicationContainersClusterDemo.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * 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 yarn.demo;

import java.io.File;
import java.nio.ByteBuffer;
import java.util.Random;

import org.apache.hadoop.yarn.conf.YarnConfiguration;

import demo.utils.MiniClusterUtils;

import oz.hadoop.yarn.api.ApplicationContainerProcessor;
import oz.hadoop.yarn.api.ContainerReplyListener;
import oz.hadoop.yarn.api.DataProcessor;
import oz.hadoop.yarn.api.YarnApplication;
import oz.hadoop.yarn.api.YarnAssembly;
import oz.hadoop.yarn.api.utils.ConfigUtils;

/**
 * This demo showcases long-running reusable containers you can interact with
 * by exchanging messages. This one (while trivial) demonstrates a simple YARN
 * application which echoes back the message. If you want to print the reply 
 * that was echoed back simply register {@link ContainerReplyListener} with
 * {@link DataProcessor}
 * 
 * This demo requires a valid YARN cluster (mini-cluster or full cluster) provided
 * through YarnConfiguration. 
 * 
 * There is an identical demo that runs in YARN Emulator. Please see 
 * InteractableYarnApplicationContainersEmulatorDemo.java in this package.
 * 
 * @author Oleg Zhurakousky
 * 
 */
public class InteractableYarnApplicationContainersClusterDemo {

    /**
     * Ensure valid YarnConfiguration is available in the classpath, then run.
     */
    public static void main(String[] args) throws Exception {
        MiniClusterUtils.startMiniCluster();

        ConfigUtils.addToClasspath(new File("mini-cluster-config"));

        YarnApplication<DataProcessor> yarnApplication = YarnAssembly
                .forApplicationContainer(DemoEchoContainer.class).containerCount(4)
                .withApplicationMaster(new YarnConfiguration()).maxAttempts(2)
                .build("InteractableYarnApplicationContainersClusterDemo");

        yarnApplication.registerReplyListener(new ContainerReplyListener() {
            @Override
            public void onReply(ByteBuffer replyData) {
                byte[] replyBytes = new byte[replyData.limit()];
                replyData.rewind();
                replyData.get(replyBytes);
                replyData.rewind();
                String reply = new String(replyBytes);
                System.out.println("REPLY: " + reply);
            }
        });
        /*
         * DataProcessor essentially is a proxy over all Application Containers defined by this 
         * application and running in YARN (8 in this case).
         * It is aware of which Application Containers are available and will 
         * delegate its process(..) invocation to the first available Application Container.
         * So essentially DataProcessor is a gateway to the YARN Distributed Computing Grid.
         * 
         * Additionally you can register oz.hadoop.yarn.api.DataProcessorReplyListener with 
         * DataProcessor if interested in receiving a reply from the distributed process.
         */
        final DataProcessor dataProcessor = yarnApplication.launch();

        for (int i = 0; i < 30; i++) {
            /*
             * Actual processing will be delegated to the first available (out of 8 deployed) 
             * remote Application Containers.
             */
            dataProcessor.process(ByteBuffer.wrap(("Hello Yarn Grid! - " + i).getBytes()));
        }

        yarnApplication.shutDown();
        System.out.println("Processes completed since launch: " + dataProcessor.completedSinceStart());

        MiniClusterUtils.stoptMiniCluster();
    }

    /**
     * 
     */
    public static class DemoEchoContainer implements ApplicationContainerProcessor {
        @Override
        public ByteBuffer process(ByteBuffer inputMessage) {
            try {
                Thread.sleep(new Random().nextInt(3000));
                System.out.println("Echoing. . .");
            } catch (Exception e) {
                // TODO: handle exception
            }
            return inputMessage;
        }
    }
}