| /** |
| * 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.hadoop.mapreduce.lib.output; |
| |
| import java.io.IOException; |
| import java.net.URI; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.fs.FileStatus; |
| import org.apache.hadoop.fs.FileSystem; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.mapreduce.JobContext; |
| import org.apache.hadoop.mapreduce.OutputCommitter; |
| import org.apache.hadoop.mapreduce.TaskAttemptContext; |
| import org.apache.hadoop.mapreduce.TaskAttemptID; |
| import org.apache.hadoop.util.StringUtils; |
| |
| /** An {@link OutputCommitter} that commits files specified |
| * in job output directory i.e. ${mapreduce.output.fileoutputformat.outputdir}. |
| **/ |
| public class FileOutputCommitter extends OutputCommitter { |
| |
| private static final Log LOG = LogFactory.getLog(FileOutputCommitter.class); |
| |
| /** |
| * Temporary directory name |
| */ |
| protected static final String TEMP_DIR_NAME = "_temporary"; |
| private FileSystem outputFileSystem = null; |
| private Path outputPath = null; |
| private Path workPath = null; |
| |
| /** |
| * Create a file output committer |
| * @param outputPath the job's output path |
| * @param context the task's context |
| * @throws IOException |
| */ |
| public FileOutputCommitter(Path outputPath, |
| TaskAttemptContext context) throws IOException { |
| if (outputPath != null) { |
| this.outputPath = outputPath; |
| outputFileSystem = outputPath.getFileSystem(context.getConfiguration()); |
| workPath = new Path(outputPath, |
| (FileOutputCommitter.TEMP_DIR_NAME + Path.SEPARATOR + |
| "_" + context.getTaskAttemptID().toString() |
| )).makeQualified(outputFileSystem); |
| } |
| } |
| |
| /** |
| * Create the temporary directory that is the root of all of the task |
| * work directories. |
| * @param context the job's context |
| */ |
| public void setupJob(JobContext context) throws IOException { |
| if (outputPath != null) { |
| Path tmpDir = new Path(outputPath, FileOutputCommitter.TEMP_DIR_NAME); |
| FileSystem fileSys = tmpDir.getFileSystem(context.getConfiguration()); |
| if (!fileSys.mkdirs(tmpDir)) { |
| LOG.error("Mkdirs failed to create " + tmpDir.toString()); |
| } |
| } |
| } |
| |
| /** |
| * Delete the temporary directory, including all of the work directories. |
| * @param context the job's context |
| */ |
| public void cleanupJob(JobContext context) throws IOException { |
| if (outputPath != null) { |
| Path tmpDir = new Path(outputPath, FileOutputCommitter.TEMP_DIR_NAME); |
| FileSystem fileSys = tmpDir.getFileSystem(context.getConfiguration()); |
| if (fileSys.exists(tmpDir)) { |
| fileSys.delete(tmpDir, true); |
| } |
| } |
| } |
| |
| /** |
| * No task setup required. |
| */ |
| @Override |
| public void setupTask(TaskAttemptContext context) throws IOException { |
| // FileOutputCommitter's setupTask doesn't do anything. Because the |
| // temporary task directory is created on demand when the |
| // task is writing. |
| } |
| |
| /** |
| * Move the files from the work directory to the job output directory |
| * @param context the task context |
| */ |
| public void commitTask(TaskAttemptContext context) |
| throws IOException { |
| TaskAttemptID attemptId = context.getTaskAttemptID(); |
| if (workPath != null) { |
| context.progress(); |
| if (outputFileSystem.exists(workPath)) { |
| // Move the task outputs to their final place |
| moveTaskOutputs(context, outputFileSystem, outputPath, workPath); |
| // Delete the temporary task-specific output directory |
| if (!outputFileSystem.delete(workPath, true)) { |
| LOG.warn("Failed to delete the temporary output" + |
| " directory of task: " + attemptId + " - " + workPath); |
| } |
| LOG.info("Saved output of task '" + attemptId + "' to " + |
| outputPath); |
| } |
| } |
| } |
| |
| /** |
| * Move all of the files from the work directory to the final output |
| * @param context the task context |
| * @param fs the output file system |
| * @param jobOutputDir the final output direcotry |
| * @param taskOutput the work path |
| * @throws IOException |
| */ |
| private void moveTaskOutputs(TaskAttemptContext context, |
| FileSystem fs, |
| Path jobOutputDir, |
| Path taskOutput) |
| throws IOException { |
| TaskAttemptID attemptId = context.getTaskAttemptID(); |
| context.progress(); |
| if (fs.isFile(taskOutput)) { |
| Path finalOutputPath = getFinalPath(jobOutputDir, taskOutput, |
| workPath); |
| if (!fs.rename(taskOutput, finalOutputPath)) { |
| if (!fs.delete(finalOutputPath, true)) { |
| throw new IOException("Failed to delete earlier output of task: " + |
| attemptId); |
| } |
| if (!fs.rename(taskOutput, finalOutputPath)) { |
| throw new IOException("Failed to save output of task: " + |
| attemptId); |
| } |
| } |
| LOG.debug("Moved " + taskOutput + " to " + finalOutputPath); |
| } else if(fs.getFileStatus(taskOutput).isDir()) { |
| FileStatus[] paths = fs.listStatus(taskOutput); |
| Path finalOutputPath = getFinalPath(jobOutputDir, taskOutput, workPath); |
| fs.mkdirs(finalOutputPath); |
| if (paths != null) { |
| for (FileStatus path : paths) { |
| moveTaskOutputs(context, fs, jobOutputDir, path.getPath()); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Delete the work directory |
| */ |
| @Override |
| public void abortTask(TaskAttemptContext context) { |
| try { |
| if (workPath != null) { |
| context.progress(); |
| outputFileSystem.delete(workPath, true); |
| } |
| } catch (IOException ie) { |
| LOG.warn("Error discarding output" + StringUtils.stringifyException(ie)); |
| } |
| } |
| |
| /** |
| * Find the final name of a given output file, given the job output directory |
| * and the work directory. |
| * @param jobOutputDir the job's output directory |
| * @param taskOutput the specific task output file |
| * @param taskOutputPath the job's work directory |
| * @return the final path for the specific output file |
| * @throws IOException |
| */ |
| private Path getFinalPath(Path jobOutputDir, Path taskOutput, |
| Path taskOutputPath) throws IOException { |
| URI taskOutputUri = taskOutput.toUri(); |
| URI relativePath = taskOutputPath.toUri().relativize(taskOutputUri); |
| if (taskOutputUri == relativePath) { |
| throw new IOException("Can not get the relative path: base = " + |
| taskOutputPath + " child = " + taskOutput); |
| } |
| if (relativePath.getPath().length() > 0) { |
| return new Path(jobOutputDir, relativePath.getPath()); |
| } else { |
| return jobOutputDir; |
| } |
| } |
| |
| /** |
| * Did this task write any files in the work directory? |
| * @param context the task's context |
| */ |
| @Override |
| public boolean needsTaskCommit(TaskAttemptContext context |
| ) throws IOException { |
| return workPath != null && outputFileSystem.exists(workPath); |
| } |
| |
| /** |
| * Get the directory that the task should write results into |
| * @return the work directory |
| * @throws IOException |
| */ |
| public Path getWorkPath() throws IOException { |
| return workPath; |
| } |
| } |