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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
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package org.apache.tinkerpop.gremlin.hadoop.process.computer.util;
import org.apache.commons.configuration.BaseConfiguration;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.OutputFormat;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
import org.apache.tinkerpop.gremlin.hadoop.Constants;
import org.apache.tinkerpop.gremlin.hadoop.process.computer.GraphFilterInputFormat;
import org.apache.tinkerpop.gremlin.hadoop.process.computer.HadoopCombine;
import org.apache.tinkerpop.gremlin.hadoop.process.computer.HadoopMap;
import org.apache.tinkerpop.gremlin.hadoop.process.computer.HadoopReduce;
import org.apache.tinkerpop.gremlin.hadoop.structure.HadoopGraph;
import org.apache.tinkerpop.gremlin.hadoop.structure.io.InputOutputHelper;
import org.apache.tinkerpop.gremlin.hadoop.structure.io.ObjectWritable;
import org.apache.tinkerpop.gremlin.hadoop.structure.io.ObjectWritableComparator;
import org.apache.tinkerpop.gremlin.hadoop.structure.io.ObjectWritableIterator;
import org.apache.tinkerpop.gremlin.hadoop.structure.util.ConfUtil;
import org.apache.tinkerpop.gremlin.process.computer.MapReduce;
import org.apache.tinkerpop.gremlin.process.computer.Memory;
import org.apache.tinkerpop.gremlin.process.computer.VertexProgram;
import java.io.IOException;
import java.util.Comparator;
import java.util.Optional;
/**
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public final class MapReduceHelper {
private MapReduceHelper() {
}
public static void executeMapReduceJob(final MapReduce mapReduce, final Memory.Admin memory, final Configuration configuration) throws IOException, ClassNotFoundException, InterruptedException {
final Configuration newConfiguration = new Configuration(configuration);
final boolean vertexProgramExists = newConfiguration.get(VertexProgram.VERTEX_PROGRAM, null) != null;
if (vertexProgramExists) {
newConfiguration.set(Constants.GREMLIN_HADOOP_GRAPH_READER, InputOutputHelper.getInputFormat((Class) newConfiguration.getClass(Constants.GREMLIN_HADOOP_GRAPH_WRITER, OutputFormat.class)).getCanonicalName());
newConfiguration.unset(Constants.GREMLIN_HADOOP_GRAPH_FILTER);
}
final BaseConfiguration apacheConfiguration = new BaseConfiguration();
apacheConfiguration.setDelimiterParsingDisabled(true);
mapReduce.storeState(apacheConfiguration);
ConfUtil.mergeApacheIntoHadoopConfiguration(apacheConfiguration, newConfiguration);
final Optional<Comparator<?>> mapSort = mapReduce.getMapKeySort();
final Optional<Comparator<?>> reduceSort = mapReduce.getReduceKeySort();
newConfiguration.setClass(Constants.GREMLIN_HADOOP_MAP_REDUCE_CLASS, mapReduce.getClass(), MapReduce.class);
final Job job = Job.getInstance(newConfiguration, mapReduce.toString());
HadoopGraph.LOGGER.info(Constants.GREMLIN_HADOOP_JOB_PREFIX + mapReduce.toString());
job.setJarByClass(HadoopGraph.class);
if (mapSort.isPresent())
job.setSortComparatorClass(ObjectWritableComparator.ObjectWritableMapComparator.class);
job.setMapperClass(HadoopMap.class);
if (mapReduce.doStage(MapReduce.Stage.REDUCE)) {
if (mapReduce.doStage(MapReduce.Stage.COMBINE))
job.setCombinerClass(HadoopCombine.class);
job.setReducerClass(HadoopReduce.class);
} else {
if (mapSort.isPresent()) {
job.setReducerClass(Reducer.class);
job.setNumReduceTasks(1); // todo: is this necessary to ensure sorted order?
} else {
job.setNumReduceTasks(0);
}
}
job.setMapOutputKeyClass(ObjectWritable.class);
job.setMapOutputValueClass(ObjectWritable.class);
job.setOutputKeyClass(ObjectWritable.class);
job.setOutputValueClass(ObjectWritable.class);
job.setInputFormatClass(GraphFilterInputFormat.class);
job.setOutputFormatClass(SequenceFileOutputFormat.class);
// if there is no vertex program, then grab the graph from the input location
final Path graphPath;
if (vertexProgramExists) {
graphPath = new Path(Constants.getGraphLocation(newConfiguration.get(Constants.GREMLIN_HADOOP_OUTPUT_LOCATION)));
} else {
graphPath = new Path(newConfiguration.get(Constants.GREMLIN_HADOOP_INPUT_LOCATION));
}
Path memoryPath = new Path(Constants.getMemoryLocation(newConfiguration.get(Constants.GREMLIN_HADOOP_OUTPUT_LOCATION), (reduceSort.isPresent() ? mapReduce.getMemoryKey() + "-temp" : mapReduce.getMemoryKey())));
if (FileSystem.get(newConfiguration).exists(memoryPath)) {
FileSystem.get(newConfiguration).delete(memoryPath, true);
}
FileInputFormat.setInputPaths(job, graphPath);
FileOutputFormat.setOutputPath(job, memoryPath);
job.waitForCompletion(true);
// if there is a reduce sort, we need to run another identity MapReduce job
if (reduceSort.isPresent()) {
final Job reduceSortJob = Job.getInstance(newConfiguration, "ReduceKeySort");
reduceSortJob.setSortComparatorClass(ObjectWritableComparator.ObjectWritableReduceComparator.class);
reduceSortJob.setMapperClass(Mapper.class);
reduceSortJob.setReducerClass(Reducer.class);
reduceSortJob.setMapOutputKeyClass(ObjectWritable.class);
reduceSortJob.setMapOutputValueClass(ObjectWritable.class);
reduceSortJob.setOutputKeyClass(ObjectWritable.class);
reduceSortJob.setOutputValueClass(ObjectWritable.class);
reduceSortJob.setInputFormatClass(SequenceFileInputFormat.class);
reduceSortJob.setOutputFormatClass(SequenceFileOutputFormat.class);
reduceSortJob.setNumReduceTasks(1); // todo: is this necessary to ensure sorted order?
FileInputFormat.setInputPaths(reduceSortJob, memoryPath);
final Path sortedMemoryPath = new Path(Constants.getMemoryLocation(newConfiguration.get(Constants.GREMLIN_HADOOP_OUTPUT_LOCATION), mapReduce.getMemoryKey()));
FileOutputFormat.setOutputPath(reduceSortJob, sortedMemoryPath);
reduceSortJob.waitForCompletion(true);
FileSystem.get(newConfiguration).delete(memoryPath, true); // delete the temporary memory path
memoryPath = sortedMemoryPath;
}
mapReduce.addResultToMemory(memory, new ObjectWritableIterator(newConfiguration, memoryPath));
}
}