com.marklogic.mapreduce.examples.BinaryReader Maven / Gradle / Ivy
/*
* Copyright (c) 2020 MarkLogic Corporation
*
* Licensed 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.marklogic.mapreduce.examples;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
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.BytesWritable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
import com.marklogic.mapreduce.DocumentInputFormat;
import com.marklogic.mapreduce.DocumentURI;
/**
* Read binary documents from MarkLogic Server and write the content out to
* HDFS. Can be used with config file conf/marklogic-subbinary.xml, which
* demonstrates how to use advanced mode with split range binding.
*/
public class BinaryReader {
public static class DocMapper
extends Mapper {
public static final Log LOG =
LogFactory.getLog(DocMapper.class);
public void map(DocumentURI key, BytesWritable value, Context context)
throws IOException, InterruptedException {
if (key != null && value != null) {
LOG.debug("value length: " + value.getLength());
context.write(key, value);
} else {
LOG.error("key: " + key + ", value: " + value);
}
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
if (args.length < 2) {
System.err.println("Usage: BinaryReader configFile outputDir");
System.exit(2);
}
String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
Job job = Job.getInstance(conf, "binary reader");
job.setJarByClass(BinaryReader.class);
job.setInputFormatClass(DocumentInputFormat.class);
job.setMapperClass(DocMapper.class);
job.setMapOutputKeyClass(DocumentURI.class);
job.setMapOutputValueClass(BytesWritable.class);
job.setOutputFormatClass(BinaryOutputFormat.class);
job.setOutputKeyClass(DocumentURI.class);
job.setOutputValueClass(BytesWritable.class);
FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
conf = job.getConfiguration();
conf.addResource(otherArgs[0]);
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
class BinaryOutputFormat extends FileOutputFormat {
@Override
public RecordWriter getRecordWriter(
TaskAttemptContext context)
throws IOException, InterruptedException {
return new BinaryWriter(getOutputPath(context),
context.getConfiguration());
}
}
class BinaryWriter extends RecordWriter {
Path dir;
Configuration conf;
public BinaryWriter(Path path, Configuration conf) {
dir = path;
this.conf = conf;
}
@Override
public void close(TaskAttemptContext arg0) throws IOException,
InterruptedException {
}
@Override
public void write(DocumentURI uri, BytesWritable content)
throws IOException, InterruptedException {
String pathStr = dir.getName() + uri.getUri();
Path path = new Path(pathStr);
FileSystem fs = path.getFileSystem(conf);
FSDataOutputStream out = fs.create(path, false);
System.out.println("writing to: " + path);
out.write(content.getBytes(), 0, content.getLength());
out.flush();
out.close();
}
}