org.apache.flink.streaming.util.HDFSCopyToLocal.java Source code

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Here is the source code for org.apache.flink.streaming.util.HDFSCopyToLocal.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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * 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.flink.streaming.util;

import org.apache.flink.api.java.tuple.Tuple1;
import org.apache.flink.runtime.fs.hdfs.HadoopFileSystem;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

import java.io.File;
import java.net.URI;

/**
 * Utility for copying from a HDFS {@link FileSystem} to the local file system.
 */
public class HDFSCopyToLocal {

    public static void copyToLocal(final URI remotePath, final File localPath) throws Exception {
        // Do it in another Thread because HDFS can deadlock if being interrupted while copying
        String threadName = "HDFS Copy from " + remotePath + " to " + localPath;

        final Tuple1<Exception> asyncException = Tuple1.of(null);

        Thread copyThread = new Thread(threadName) {
            @Override
            public void run() {
                try {
                    Configuration hadoopConf = HadoopFileSystem.getHadoopConfiguration();

                    FileSystem fs = FileSystem.get(remotePath, hadoopConf);
                    fs.copyToLocalFile(new Path(remotePath), new Path(localPath.getAbsolutePath()));
                } catch (Exception t) {
                    asyncException.f0 = t;
                }
            }
        };

        copyThread.setDaemon(true);
        copyThread.start();
        copyThread.join();

        if (asyncException.f0 != null) {
            throw asyncException.f0;
        }
    }
}