com.datasalt.pangool.tuplemr.avro.AvroOutputFormat.java Source code

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Here is the source code for com.datasalt.pangool.tuplemr.avro.AvroOutputFormat.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.datasalt.pangool.tuplemr.avro;

import static org.apache.avro.file.DataFileConstants.DEFAULT_SYNC_INTERVAL;
import static org.apache.avro.file.DataFileConstants.DEFLATE_CODEC;

import java.io.IOException;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.Map;

import org.apache.avro.Schema;
import org.apache.avro.file.CodecFactory;
import org.apache.avro.file.DataFileWriter;
import org.apache.avro.mapred.AvroJob;
import org.apache.avro.mapred.AvroWrapper;
import org.apache.avro.reflect.ReflectDatumWriter;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

/**
 * This is the Pangool's version of {@link org.apache.avro.mapred.AvroOutputFormat}.
 * It implements the new Hadoop's api in package {@link org.apache.hadoop.mapreduce.lib.output}
 * Any {@link AvroOutputFormat} instance is stateful and is not configured 
 * via {@link Configuration}. Instead, it uses Java-serialization to store its state in 
 * a Distributed Cache file.  
 */
@SuppressWarnings("serial")
public class AvroOutputFormat<T> extends FileOutputFormat<AvroWrapper<T>, NullWritable> implements Serializable {

    /** The file name extension for avro data files. */
    public final static String EXT = ".avro";

    /** The configuration key for Avro deflate level. */
    public static final String DEFLATE_LEVEL_KEY = "avro.mapred.deflate.level";

    /** The configuration key for Avro sync interval. */
    public static final String SYNC_INTERVAL_KEY = "avro.mapred.sync.interval";

    /** The default deflate level. */
    public static final int DEFAULT_DEFLATE_LEVEL = 1;

    /** Enable output compression using the deflate codec and specify its level.*/
    public static void setDeflateLevel(Job job, int level) {
        FileOutputFormat.setCompressOutput(job, true);
        job.getConfiguration().setInt(DEFLATE_LEVEL_KEY, level);
    }

    /** Set the sync interval to be used by the underlying {@link DataFileWriter}.*/
    public static void setSyncInterval(Job job, int syncIntervalInBytes) {
        job.getConfiguration().setInt(SYNC_INTERVAL_KEY, syncIntervalInBytes);
    }

    static <T> void configureDataFileWriter(DataFileWriter<T> writer, TaskAttemptContext job, String codecName,
            int deflateLevel) throws UnsupportedEncodingException {
        Configuration conf = job.getConfiguration();
        if (FileOutputFormat.getCompressOutput(job)) {
            CodecFactory factory = codecName.equals(DEFLATE_CODEC) ? CodecFactory.deflateCodec(deflateLevel)
                    : CodecFactory.fromString(codecName);
            writer.setCodec(factory);
        }

        writer.setSyncInterval(conf.getInt(SYNC_INTERVAL_KEY, DEFAULT_SYNC_INTERVAL));

        // copy metadata from job
        for (Map.Entry<String, String> e : conf) {
            if (e.getKey().startsWith(AvroJob.TEXT_PREFIX))
                writer.setMeta(e.getKey().substring(AvroJob.TEXT_PREFIX.length()), e.getValue());
            if (e.getKey().startsWith(AvroJob.BINARY_PREFIX))
                writer.setMeta(e.getKey().substring(AvroJob.BINARY_PREFIX.length()),
                        URLDecoder.decode(e.getValue(), "ISO-8859-1").getBytes("ISO-8859-1"));
        }
    }

    private transient Schema schema;
    private String schemaStr;
    private int deflateLevel = DEFAULT_DEFLATE_LEVEL;
    private String codecName = DEFLATE_CODEC;

    public AvroOutputFormat(Schema schema) {
        this.schema = schema;
        this.schemaStr = schema.toString();
    }

    public AvroOutputFormat(Schema schema, String codecName) {
        this(schema);
        this.codecName = codecName;
    }

    public AvroOutputFormat(Schema schema, String codecName, int deflateLevel) {
        this(schema, codecName);
        this.deflateLevel = deflateLevel;
    }

    public Schema getSchema() {
        if (schema == null) {
            schema = new Schema.Parser().parse(schemaStr);
        }
        return schema;
    }

    @Override
    public RecordWriter<AvroWrapper<T>, NullWritable> getRecordWriter(TaskAttemptContext job)
            throws IOException, InterruptedException {

        final DataFileWriter<T> writer = new DataFileWriter<T>(new ReflectDatumWriter<T>());

        configureDataFileWriter(writer, job, codecName, deflateLevel);
        Path path = getDefaultWorkFile(job, EXT);
        writer.create(getSchema(), path.getFileSystem(job.getConfiguration()).create(path));

        return new RecordWriter<AvroWrapper<T>, NullWritable>() {
            @Override
            public void write(AvroWrapper<T> wrapper, NullWritable ignore) throws IOException {
                writer.append(wrapper.datum());
            }

            @Override
            public void close(TaskAttemptContext context) throws IOException {
                writer.close();
            }
        };
    }

}