com.cloudera.flume.handlers.seqfile.SequenceFileOutputFormat.java Source code

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Here is the source code for com.cloudera.flume.handlers.seqfile.SequenceFileOutputFormat.java

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/**
 * Licensed to Cloudera, Inc. under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  Cloudera, Inc. 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.cloudera.flume.handlers.seqfile;

import com.cloudera.flume.conf.FlumeConfiguration;
import com.cloudera.flume.core.Event;
import com.cloudera.flume.handlers.hdfs.CustomDfsSink;
import com.cloudera.flume.handlers.hdfs.WriteableEvent;
import com.cloudera.flume.handlers.hdfs.WriteableEventKey;
import com.cloudera.flume.handlers.text.FormatFactory.OutputFormatBuilder;
import com.cloudera.flume.handlers.text.output.AbstractOutputFormat;
import com.cloudera.flume.handlers.text.output.OutputFormat;
import com.google.common.base.Preconditions;

import java.io.IOException;
import java.io.OutputStream;

import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.SequenceFile.CompressionType;
import org.apache.hadoop.io.SequenceFile.Writer;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.DefaultCodec;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * An {@link OutputFormat} for writing Flume events to Hadoop Sequence Files.
 * 
 * This class is not thread safe.
 */
public class SequenceFileOutputFormat extends AbstractOutputFormat {
    private static final Logger LOG = LoggerFactory.getLogger(SequenceFileOutputFormat.class);

    private static final String NAME = "seqfile";

    private CompressionType compressionType;
    private CompressionCodec codec;

    private OutputStream cachedOut;
    private Writer writer;

    public SequenceFileOutputFormat() {
        this(SequenceFile.getCompressionType(FlumeConfiguration.get()), new DefaultCodec());
    }

    public SequenceFileOutputFormat(CompressionType compressionType, CompressionCodec codec) {
        this.compressionType = compressionType;
        this.codec = codec;
    }

    @Override
    public void format(OutputStream o, Event e) throws IOException {
        if (writer == null) {
            cachedOut = o;
            FSDataOutputStream fsOut;
            if (o instanceof FSDataOutputStream) {
                fsOut = (FSDataOutputStream) o;
            } else {
                fsOut = new FSDataOutputStream(o, null);
            }
            writer = SequenceFile.createWriter(FlumeConfiguration.get(), fsOut, WriteableEventKey.class,
                    WriteableEvent.class, compressionType, codec);
        }
        if (cachedOut != o) {
            // different output than last time, fail here
            throw new IOException("OutputFormat instance can only write to the same OutputStream");
        }
        writer.append(new WriteableEventKey(e), new WriteableEvent(e));
    }

    public static OutputFormatBuilder builder() {
        return new OutputFormatBuilder() {

            @Override
            public OutputFormat build(String... args) {
                Preconditions.checkArgument(args.length <= 1, "usage: seqfile([codec])");

                OutputFormat format;

                String codecName = null;
                if (args.length > 0) {
                    codecName = args[0];
                    FlumeConfiguration conf = FlumeConfiguration.get();
                    CompressionType compressionType = SequenceFile.getCompressionType(conf);
                    CompressionCodec codec = CustomDfsSink.getCodec(conf, codecName);
                    format = new SequenceFileOutputFormat(compressionType, codec);
                } else {
                    format = new SequenceFileOutputFormat();
                }

                format.setBuilder(this);

                return format;
            }

            @Override
            public String getName() {
                return NAME;
            }

        };
    }
}