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

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Here is the source code for org.apache.hadoop.mapred.ClusterMapReduceTestCase.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.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.junit.After;
import org.junit.Before;

import java.io.IOException;
import java.util.Map;
import java.util.Properties;

/**
 * Test case to run a MapReduce job.
 * <p/>
 * It runs a 2 node cluster Hadoop with a 2 node DFS.
 * <p/>
 * The JobConf to use must be obtained via the creatJobConf() method.
 * <p/>
 * It creates a temporary directory -accessible via getTestRootDir()-
 * for both input and output.
 * <p/>
 * The input directory is accesible via getInputDir() and the output
 * directory via getOutputDir()
 * <p/>
 * The DFS filesystem is formated before the testcase starts and after it ends.
 */
public abstract class ClusterMapReduceTestCase {
    private MiniDFSCluster dfsCluster = null;
    private MiniMRCluster mrCluster = null;

    /**
     * Creates Hadoop Cluster and DFS before a test case is run.
     *
     * @throws Exception
     */
    @Before
    public void setUp() throws Exception {
        startCluster(true, null);
    }

    /**
     * Starts the cluster within a testcase.
     * <p/>
     * Note that the cluster is already started when the testcase method
     * is invoked. This method is useful if as part of the testcase the
     * cluster has to be shutdown and restarted again.
     * <p/>
     * If the cluster is already running this method does nothing.
     *
     * @param reformatDFS indicates if DFS has to be reformated
     * @param props configuration properties to inject to the mini cluster
     * @throws Exception if the cluster could not be started
     */
    protected synchronized void startCluster(boolean reformatDFS, Properties props) throws Exception {
        if (dfsCluster == null) {
            JobConf conf = new JobConf();
            if (props != null) {
                for (Map.Entry entry : props.entrySet()) {
                    conf.set((String) entry.getKey(), (String) entry.getValue());
                }
            }
            dfsCluster = new MiniDFSCluster.Builder(conf).numDataNodes(2).format(reformatDFS).racks(null).build();

            ConfigurableMiniMRCluster.setConfiguration(props);
            //noinspection deprecation
            mrCluster = new ConfigurableMiniMRCluster(2, getFileSystem().getUri().toString(), 1, conf);
        }
    }

    private static class ConfigurableMiniMRCluster extends MiniMRCluster {
        private static Properties config;

        public static void setConfiguration(Properties props) {
            config = props;
        }

        public ConfigurableMiniMRCluster(int numTaskTrackers, String namenode, int numDir, JobConf conf)
                throws Exception {
            super(0, 0, numTaskTrackers, namenode, numDir, null, null, null, conf);
        }

        public JobConf createJobConf() {
            JobConf conf = super.createJobConf();
            if (config != null) {
                for (Map.Entry entry : config.entrySet()) {
                    conf.set((String) entry.getKey(), (String) entry.getValue());
                }
            }
            return conf;
        }
    }

    /**
     * Stops the cluster within a testcase.
     * <p/>
     * Note that the cluster is already started when the testcase method
     * is invoked. This method is useful if as part of the testcase the
     * cluster has to be shutdown.
     * <p/>
     * If the cluster is already stopped this method does nothing.
     *
     * @throws Exception if the cluster could not be stopped
     */
    protected void stopCluster() throws Exception {
        if (mrCluster != null) {
            mrCluster.shutdown();
            mrCluster = null;
        }
        if (dfsCluster != null) {
            dfsCluster.shutdown();
            dfsCluster = null;
        }
    }

    /**
     * Destroys Hadoop Cluster and DFS after a test case is run.
     *
     * @throws Exception
     */
    @After
    public void tearDown() throws Exception {
        stopCluster();
    }

    /**
     * Returns a preconfigured Filesystem instance for test cases to read and
     * write files to it.
     * <p/>
     * TestCases should use this Filesystem instance.
     *
     * @return the filesystem used by Hadoop.
     * @throws IOException 
     */
    protected FileSystem getFileSystem() throws IOException {
        return dfsCluster.getFileSystem();
    }

    protected MiniMRCluster getMRCluster() {
        return mrCluster;
    }

    /**
     * Returns the path to the root directory for the testcase.
     *
     * @return path to the root directory for the testcase.
     */
    protected Path getTestRootDir() {
        return new Path("x").getParent();
    }

    /**
     * Returns a path to the input directory for the testcase.
     *
     * @return path to the input directory for the tescase.
     */
    protected Path getInputDir() {
        return new Path("target/input");
    }

    /**
     * Returns a path to the output directory for the testcase.
     *
     * @return path to the output directory for the tescase.
     */
    protected Path getOutputDir() {
        return new Path("target/output");
    }

    /**
     * Returns a job configuration preconfigured to run against the Hadoop
     * managed by the testcase.
     *
     * @return configuration that works on the testcase Hadoop instance
     */
    protected JobConf createJobConf() {
        return mrCluster.createJobConf();
    }

}