Java tutorial
/** * 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 org.apache.tez.mapreduce.task.impl; import java.io.IOException; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.classification.InterfaceStability; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.LocalDirAllocator; import org.apache.hadoop.fs.Path; import org.apache.hadoop.mapred.JobConf; import org.apache.hadoop.mapred.MapOutputFile; import org.apache.hadoop.mapreduce.JobContext; import org.apache.hadoop.mapreduce.MRConfig; import org.apache.tez.common.Constants; /** * Manipulate the working area for the transient store for maps and reduces. * * This class is used by map and reduce tasks to identify the directories that * they need to write to/read from for intermediate files. The callers of * these methods are from child space. */ @InterfaceAudience.Private @InterfaceStability.Unstable public class YarnOutputFiles extends MapOutputFile { private JobConf conf; private static final String JOB_OUTPUT_DIR = "output"; private static final String SPILL_FILE_PATTERN = "%s_spill_%d.out"; private static final String SPILL_INDEX_FILE_PATTERN = SPILL_FILE_PATTERN + ".index"; public YarnOutputFiles() { } // assume configured to $localdir/usercache/$user/appcache/$appId private LocalDirAllocator lDirAlloc = new LocalDirAllocator(MRConfig.LOCAL_DIR); private Path getAttemptOutputDir() { return new Path(JOB_OUTPUT_DIR, conf.get(JobContext.TASK_ATTEMPT_ID)); } /** * Return the path to local map output file created earlier * * @return path * @throws IOException */ public Path getOutputFile() throws IOException { Path attemptOutput = new Path(getAttemptOutputDir(), Constants.MAP_OUTPUT_FILENAME_STRING); return lDirAlloc.getLocalPathToRead(attemptOutput.toString(), conf); } /** * Create a local map output file name. * * @param size the size of the file * @return path * @throws IOException */ public Path getOutputFileForWrite(long size) throws IOException { Path attemptOutput = new Path(getAttemptOutputDir(), Constants.MAP_OUTPUT_FILENAME_STRING); return lDirAlloc.getLocalPathForWrite(attemptOutput.toString(), size, conf); } /** * Create a local map output file name on the same volume. */ public Path getOutputFileForWriteInVolume(Path existing) { Path outputDir = new Path(existing.getParent(), JOB_OUTPUT_DIR); Path attemptOutputDir = new Path(outputDir, conf.get(JobContext.TASK_ATTEMPT_ID)); return new Path(attemptOutputDir, Constants.MAP_OUTPUT_FILENAME_STRING); } /** * Return the path to a local map output index file created earlier * * @return path * @throws IOException */ public Path getOutputIndexFile() throws IOException { Path attemptIndexOutput = new Path(getAttemptOutputDir(), Constants.MAP_OUTPUT_FILENAME_STRING + Constants.MAP_OUTPUT_INDEX_SUFFIX_STRING); return lDirAlloc.getLocalPathToRead(attemptIndexOutput.toString(), conf); } /** * Create a local map output index file name. * * @param size the size of the file * @return path * @throws IOException */ public Path getOutputIndexFileForWrite(long size) throws IOException { Path attemptIndexOutput = new Path(getAttemptOutputDir(), Constants.MAP_OUTPUT_FILENAME_STRING + Constants.MAP_OUTPUT_INDEX_SUFFIX_STRING); return lDirAlloc.getLocalPathForWrite(attemptIndexOutput.toString(), size, conf); } /** * Create a local map output index file name on the same volume. */ public Path getOutputIndexFileForWriteInVolume(Path existing) { Path outputDir = new Path(existing.getParent(), JOB_OUTPUT_DIR); Path attemptOutputDir = new Path(outputDir, conf.get(JobContext.TASK_ATTEMPT_ID)); return new Path(attemptOutputDir, Constants.MAP_OUTPUT_FILENAME_STRING + Constants.MAP_OUTPUT_INDEX_SUFFIX_STRING); } /** * Return a local map spill file created earlier. * * @param spillNumber the number * @return path * @throws IOException */ public Path getSpillFile(int spillNumber) throws IOException { return lDirAlloc.getLocalPathToRead( String.format(SPILL_FILE_PATTERN, conf.get(JobContext.TASK_ATTEMPT_ID), spillNumber), conf); } /** * Create a local map spill file name. * * @param spillNumber the number * @param size the size of the file * @return path * @throws IOException */ public Path getSpillFileForWrite(int spillNumber, long size) throws IOException { return lDirAlloc.getLocalPathForWrite( String.format(String.format(SPILL_FILE_PATTERN, conf.get(JobContext.TASK_ATTEMPT_ID), spillNumber)), size, conf); } /** * Return a local map spill index file created earlier * * @param spillNumber the number * @return path * @throws IOException */ public Path getSpillIndexFile(int spillNumber) throws IOException { return lDirAlloc.getLocalPathToRead( String.format(SPILL_INDEX_FILE_PATTERN, conf.get(JobContext.TASK_ATTEMPT_ID), spillNumber), conf); } /** * Create a local map spill index file name. * * @param spillNumber the number * @param size the size of the file * @return path * @throws IOException */ public Path getSpillIndexFileForWrite(int spillNumber, long size) throws IOException { return lDirAlloc.getLocalPathForWrite( String.format(SPILL_INDEX_FILE_PATTERN, conf.get(JobContext.TASK_ATTEMPT_ID), spillNumber), size, conf); } /** * Return a local reduce input file created earlier * * @param mapId a map task id * @return path * @throws IOException */ public Path getInputFile(int mapId) throws IOException { throw new UnsupportedOperationException("Incompatible with LocalRunner"); } /** * Create a local reduce input file name. * * @param mapId a map task id * @param size the size of the file * @return path * @throws IOException */ public Path getInputFileForWrite(org.apache.hadoop.mapreduce.TaskID mapId, long size) throws IOException { return lDirAlloc.getLocalPathForWrite(String.format(Constants.REDUCE_INPUT_FILE_FORMAT_STRING, getAttemptOutputDir().toString(), mapId.getId()), size, conf); } /** Removes all of the files related to a task. */ public void removeAll() throws IOException { throw new UnsupportedOperationException("Incompatible with LocalRunner"); } @Override public void setConf(Configuration conf) { if (conf instanceof JobConf) { this.conf = (JobConf) conf; } else { this.conf = new JobConf(conf); } } @Override public Configuration getConf() { return conf; } }