com.huayu.metis.flume.sink.hdfs.HDFSSequenceFile.java Source code

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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.huayu.metis.flume.sink.hdfs;

import java.io.IOException;
import org.apache.flume.Context;
import org.apache.flume.Event;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.SequenceFile;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class HDFSSequenceFile extends AbstractHDFSWriter {

    private static final Logger logger = LoggerFactory.getLogger(HDFSSequenceFile.class);
    private SequenceFile.Writer writer;
    private String writeFormat;
    private Context serializerContext;
    private SequenceFileSerializer serializer;
    private FSDataOutputStream outStream = null;

    public HDFSSequenceFile() {
        writer = null;
    }

    @Override
    public void configure(Context context) {
        super.configure(context);
        //?
        writeFormat = context.getString("hdfs.writeFormat", SequenceFileSerializerType.Text.name());
        serializerContext = new Context(context.getSubProperties(SequenceFileSerializerFactory.CTX_PREFIX));
        serializer = SequenceFileSerializerFactory.getSerializer(writeFormat, serializerContext);
        logger.info("writeFormat = " + writeFormat);
    }

    @Override
    public void open(String filePath) throws IOException {
        Configuration conf = new Configuration();
        Path dstPath = new Path(filePath);

        FileSystem fileSystem = dstPath.getFileSystem(conf);
        //2.2Hadoop, dfs.append.support ???
        if (fileSystem.exists(dstPath) && fileSystem.isFile(dstPath)) {
            outStream = fileSystem.append(dstPath);
        } else {
            outStream = fileSystem.create(dstPath);
        }

        writer = SequenceFile.createWriter(conf, SequenceFile.Writer.stream(outStream),
                SequenceFile.Writer.keyClass(serializer.getKeyClass()),
                SequenceFile.Writer.valueClass(serializer.getValueClass()));
        registerCurrentStream(outStream, fileSystem, dstPath);
    }

    @Override
    public void append(Event e) throws IOException {
        for (SequenceFileSerializer.Record record : serializer.serialize(e)) {
            writer.append(record.getKey(), record.getValue());
        }
    }

    @Override
    public void sync() throws IOException {
        writer.hsync();
    }

    @Override
    public void close() throws IOException {
        writer.close();
        closeHDFSOutputStream(outStream);
        unregisterCurrentStream();
    }
}