org.commoncrawl.hadoop.io.mapreduce.ARCFileRecordReader.java Source code

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Here is the source code for org.commoncrawl.hadoop.io.mapreduce.ARCFileRecordReader.java

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package org.commoncrawl.hadoop.io.mapreduce;

/**
 * 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.
 * 
 */

import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.s3native.NativeS3FileSystem;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.commoncrawl.util.shared.ARCFileReader;
import org.commoncrawl.util.shared.CCStringUtils;
import org.commoncrawl.util.shared.S3InputStream;
import org.jets3t.service.Jets3tProperties;

/** 
 * Reads an ARCFile whose location is spcified via a FileInputSplit
 * 
 * @author rana
 *
 */
public class ARCFileRecordReader extends RecordReader<Text, BytesWritable> {

    /** logging **/
    private static final Log LOG = LogFactory.getLog(ARCFileRecordReader.class);

    protected Configuration conf;
    ARCFileReader reader;
    private Text key = new Text();
    private BytesWritable value = new BytesWritable();
    private long start;
    private long end;

    @Override
    public void initialize(InputSplit split, TaskAttemptContext context) throws IOException, InterruptedException {
        FileSplit fileSplit = (FileSplit) split;
        conf = context.getConfiguration();
        Path path = fileSplit.getPath();
        FileSystem fs = path.getFileSystem(conf);
        InputStream in = null;
        if (fs instanceof NativeS3FileSystem) {
            if (conf.getBoolean(ARCFileInputFormat.USE_S3_INPUTSTREAM, false)) {
                in = new S3InputStream(path.toUri(), conf.get("fs.s3n.awsAccessKeyId"),
                        conf.get("fs.s3n.awsSecretAccessKey"), 1048576);
            } else {
                Jets3tProperties properties = Jets3tProperties
                        .getInstance(org.jets3t.service.Constants.JETS3T_PROPERTIES_FILENAME);
                properties.setProperty("s3service.https-only", "false");
            }
        }
        if (in == null) {
            in = fs.open(path);
        }
        try {
            reader = new ARCFileReader(in);
        } catch (IOException e) {
            LOG.error(CCStringUtils.stringifyException(e));
            in.close();
            throw e;
        }
        start = fileSplit.getStart();
        end = fileSplit.getLength();
        if (start != 0 || fs.getFileStatus(path).getLen() != end) {
            throw new IOException("Invalid FileSplit encountered! Split Details:" + split.toString());
        }
    }

    @Override
    public boolean nextKeyValue() throws IOException, InterruptedException {
        if (reader.hasMoreItems()) {
            reader.nextKeyValue(key, value);
            return true;
        }
        return false;
    }

    @Override
    public Text getCurrentKey() throws IOException, InterruptedException {
        return key;
    }

    @Override
    public BytesWritable getCurrentValue() throws IOException, InterruptedException {
        return value;
    }

    @Override
    public float getProgress() throws IOException, InterruptedException {
        return Math.min(1.0f, (reader.getPosition() - start) / (float) (end - start));
    }

    @Override
    public void close() throws IOException {
        reader.close();
    }
}