com.cloudera.cdk.maven.plugins.RunToolMojo.java Source code

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Here is the source code for com.cloudera.cdk.maven.plugins.RunToolMojo.java

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/**
 * Copyright 2013 Cloudera Inc.
 *
 * 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.cloudera.cdk.maven.plugins;

import com.google.common.base.Joiner;
import java.io.File;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import org.apache.maven.artifact.Artifact;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.apache.maven.plugins.annotations.Mojo;
import org.apache.maven.plugins.annotations.Parameter;
import org.apache.maven.plugins.annotations.ResolutionScope;

/**
 * Run a Hadoop tool on the local machine.
 */
@Mojo(name = "run-tool", requiresDependencyResolution = ResolutionScope.RUNTIME)
public class RunToolMojo extends AbstractHadoopMojo {

    /**
     * The tool class to run. The specified class must have a standard Java
     * <code>main</code> method.
     */
    @Parameter(property = "cdk.toolClass", required = true)
    private String toolClass;

    /**
     * Arguments to pass to the tool, in addition to those generated by
     * <code>addDependenciesToDistributedCache</code> and <code>hadoopConfiguration</code>.
     */
    @Parameter(property = "cdk.args")
    private String[] args;

    /**
     * Whether to add dependencies in the <i>runtime</i> classpath to Hadoop's distributed
     * cache so that they are added to the classpath for MapReduce tasks
     * (via <code>-libjars</code>).
     */
    @Parameter(property = "cdk.addDependenciesToDistributedCache", defaultValue = "true")
    private boolean addDependenciesToDistributedCache;

    /**
     * Hadoop configuration properties.
     *
     * WARNING: This configuration setting is not compatible with the factory
     * methods in {@link com.cloudera.cdk.data.DatasetRepositories} because it
     * does not alter the environment configuration. For example, if using
     * this to modify the environment's "fs.defaultFS" property in the tool that
     * is run by this Mojo, opening a repo by URI will continue to use the
     * environment's default FS.
     *
     * Configuration properties set using this option will only affect the
     * {@link org.apache.hadoop.conf.Configuration} objects passed by
     * {@link org.apache.hadoop.util.ToolRunner} or created by
     * {@link org.apache.hadoop.util.GenericOptionsParser}.
     */
    @Parameter(property = "cdk.hadoopConfiguration")
    private Properties hadoopConfiguration;

    public void execute() throws MojoExecutionException, MojoFailureException {
        List<String> libJars = new ArrayList<String>();
        List<URL> classpath = new ArrayList<URL>();

        File mainArtifactFile = new File(mavenProject.getBuild().getDirectory(),
                mavenProject.getBuild().getFinalName() + ".jar");
        if (!mainArtifactFile.exists()) {
            throw new MojoExecutionException("Main artifact missing: " + mainArtifactFile);
        }
        libJars.add(mainArtifactFile.toString());
        classpath.add(toURL(mainArtifactFile));
        for (Object a : mavenProject.getRuntimeArtifacts()) {
            File file = ((Artifact) a).getFile();
            classpath.add(toURL(file));
            libJars.add(file.toString());
        }

        final List<String> commandArgs = new ArrayList<String>();
        for (String key : hadoopConfiguration.stringPropertyNames()) {
            String value = hadoopConfiguration.getProperty(key);
            commandArgs.add("-D");
            commandArgs.add(key + "=" + value);
        }
        if (addDependenciesToDistributedCache) {
            commandArgs.add("-libjars");
            commandArgs.add(Joiner.on(',').join(libJars));
        }
        if (args != null) {
            for (String arg : args) {
                commandArgs.add(arg);
            }
        }

        getLog().debug("Running tool with args: " + commandArgs);
        getLog().debug("Running tool with classpath: " + classpath);

        Thread executionThread = new Thread() {
            @Override
            public void run() {
                try {
                    Method main = Thread.currentThread().getContextClassLoader().loadClass(toolClass)
                            .getMethod("main", new Class[] { String[].class });
                    main.invoke(null, new Object[] { commandArgs.toArray(new String[commandArgs.size()]) });
                } catch (Exception e) {
                    Thread.currentThread().getThreadGroup().uncaughtException(Thread.currentThread(), e);
                }
            }
        };
        ClassLoader parentClassLoader = getClass().getClassLoader(); // use Maven's classloader, not the system one
        ClassLoader classLoader = new URLClassLoader(classpath.toArray(new URL[classpath.size()]),
                parentClassLoader);
        executionThread.setContextClassLoader(classLoader);
        executionThread.start();
        try {
            executionThread.join();
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            getLog().warn("interrupted while joining against thread " + executionThread, e);
        }
    }

    private URL toURL(File file) throws MojoExecutionException {
        try {
            return file.toURI().toURL();
        } catch (MalformedURLException e) {
            throw new MojoExecutionException("Can't convert file  to URL: " + file, e);
        }
    }
}