com.inmobi.conduit.distcp.tools.FileBasedCopyListing.java Source code

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Here is the source code for com.inmobi.conduit.distcp.tools.FileBasedCopyListing.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 com.inmobi.conduit.distcp.tools;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.security.Credentials;

/**
 * FileBasedCopyListing implements the CopyListing interface,
 * to create the copy-listing for DistCp,
 * by iterating over all source paths mentioned in a specified input-file.
 */
public class FileBasedCopyListing extends CopyListing {

    private final CopyListing globbedListing;

    /**
     * Constructor, to initialize base-class.
     * @param configuration: The input Configuration object.
     * @param credentials - Credentials object on which the FS delegation tokens are cached. If null
     * delegation token caching is skipped
     */
    public FileBasedCopyListing(Configuration configuration, Credentials credentials) {
        super(configuration, credentials);
        globbedListing = new GlobbedCopyListing(getConf(), credentials);
    }

    /** {@inheritDoc} */
    @Override
    protected void validatePaths(DistCpOptions options) throws IOException, InvalidInputException {
    }

    /**
     * Implementation of CopyListing::buildListing().
     *   Iterates over all source paths mentioned in the input-file.
     * @param pathToListFile: Path on HDFS where the listing file is written.
     * @param options: Input Options for DistCp (indicating source/target paths.)
     * @throws IOException
     */
    @Override
    public void doBuildListing(Path pathToListFile, DistCpOptions options) throws IOException {
        List<Path> sourcePaths = fetchFileList(options.getSourceFileListing(), getConf());
        DistCpOptions newOption = new DistCpOptions(sourcePaths, options.getTargetPath());
        newOption.setSyncFolder(options.shouldSyncFolder());
        newOption.setOverwrite(options.shouldOverwrite());
        newOption.setDeleteMissing(options.shouldDeleteMissing());
        newOption.setPreserveSrcPath(options.shouldPreserveSrcPath());
        newOption.setSkipPathValidation(options.isSkipPathValidation());
        newOption.setUseSimpleFileListing(options.isUseSimpleFileListing());

        globbedListing.buildListing(pathToListFile, newOption);
    }

    protected static List<Path> fetchFileList(Path sourceListing, Configuration conf) throws IOException {
        List<Path> result = new ArrayList<Path>();
        FileSystem fs = sourceListing.getFileSystem(conf);
        BufferedReader input = null;
        try {
            input = new BufferedReader(new InputStreamReader(fs.open(sourceListing)));
            String line = input.readLine();
            while (line != null) {
                result.add(new Path(line));
                line = input.readLine();
            }
        } finally {
            IOUtils.closeStream(input);
        }
        return result;
    }

    /** {@inheritDoc} */
    @Override
    protected long getBytesToCopy() {
        return globbedListing.getBytesToCopy();
    }

    /** {@inheritDoc} */
    @Override
    protected long getNumberOfPaths() {
        return globbedListing.getNumberOfPaths();
    }
}