| /** |
| * 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.filecache; |
| |
| import java.io.*; |
| import java.util.*; |
| import org.apache.hadoop.conf.*; |
| import org.apache.hadoop.util.*; |
| import org.apache.hadoop.fs.*; |
| import org.apache.hadoop.fs.FileSystem; |
| |
| import java.net.URI; |
| |
| /** |
| * Distribute application-specific large, read-only files efficiently. |
| * |
| * <p><code>DistributedCache</code> is a facility provided by the Map-Reduce |
| * framework to cache files (text, archives, jars etc.) needed by applications. |
| * </p> |
| * |
| * <p>Applications specify the files, via urls (hdfs:// or http://) to be cached |
| * via the {@link org.apache.hadoop.mapred.JobConf}. |
| * The <code>DistributedCache</code> assumes that the |
| * files specified via hdfs:// urls are already present on the |
| * {@link FileSystem} at the path specified by the url.</p> |
| * |
| * <p>The framework will copy the necessary files on to the slave node before |
| * any tasks for the job are executed on that node. Its efficiency stems from |
| * the fact that the files are only copied once per job and the ability to |
| * cache archives which are un-archived on the slaves.</p> |
| * |
| * <p><code>DistributedCache</code> can be used to distribute simple, read-only |
| * data/text files and/or more complex types such as archives, jars etc. |
| * Archives (zip, tar and tgz/tar.gz files) are un-archived at the slave nodes. |
| * Jars may be optionally added to the classpath of the tasks, a rudimentary |
| * software distribution mechanism. Files have execution permissions. |
| * Optionally users can also direct it to symlink the distributed cache file(s) |
| * into the working directory of the task.</p> |
| * |
| * <p><code>DistributedCache</code> tracks modification timestamps of the cache |
| * files. Clearly the cache files should not be modified by the application |
| * or externally while the job is executing.</p> |
| * |
| * <p>Here is an illustrative example on how to use the |
| * <code>DistributedCache</code>:</p> |
| * <p><blockquote><pre> |
| * // Setting up the cache for the application |
| * |
| * 1. Copy the requisite files to the <code>FileSystem</code>: |
| * |
| * $ bin/hadoop fs -copyFromLocal lookup.dat /myapp/lookup.dat |
| * $ bin/hadoop fs -copyFromLocal map.zip /myapp/map.zip |
| * $ bin/hadoop fs -copyFromLocal mylib.jar /myapp/mylib.jar |
| * $ bin/hadoop fs -copyFromLocal mytar.tar /myapp/mytar.tar |
| * $ bin/hadoop fs -copyFromLocal mytgz.tgz /myapp/mytgz.tgz |
| * $ bin/hadoop fs -copyFromLocal mytargz.tar.gz /myapp/mytargz.tar.gz |
| * |
| * 2. Setup the application's <code>JobConf</code>: |
| * |
| * JobConf job = new JobConf(); |
| * DistributedCache.addCacheFile(new URI("/myapp/lookup.dat#lookup.dat"), |
| * job); |
| * DistributedCache.addCacheArchive(new URI("/myapp/map.zip", job); |
| * DistributedCache.addFileToClassPath(new Path("/myapp/mylib.jar"), job); |
| * DistributedCache.addCacheArchive(new URI("/myapp/mytar.tar", job); |
| * DistributedCache.addCacheArchive(new URI("/myapp/mytgz.tgz", job); |
| * DistributedCache.addCacheArchive(new URI("/myapp/mytargz.tar.gz", job); |
| * |
| * 3. Use the cached files in the {@link org.apache.hadoop.mapred.Mapper} |
| * or {@link org.apache.hadoop.mapred.Reducer}: |
| * |
| * public static class MapClass extends MapReduceBase |
| * implements Mapper<K, V, K, V> { |
| * |
| * private Path[] localArchives; |
| * private Path[] localFiles; |
| * |
| * public void configure(JobConf job) { |
| * // Get the cached archives/files |
| * localArchives = DistributedCache.getLocalCacheArchives(job); |
| * localFiles = DistributedCache.getLocalCacheFiles(job); |
| * } |
| * |
| * public void map(K key, V value, |
| * OutputCollector<K, V> output, Reporter reporter) |
| * throws IOException { |
| * // Use data from the cached archives/files here |
| * // ... |
| * // ... |
| * output.collect(k, v); |
| * } |
| * } |
| * |
| * </pre></blockquote></p> |
| * It is also very common to use the DistributedCache by using |
| * {@link org.apache.hadoop.util.GenericOptionsParser}. |
| * |
| * This class includes methods that should be used by users |
| * (specifically those mentioned in the example above, as well |
| * as {@link DistributedCache#addArchiveToClassPath(Path, Configuration)}), |
| * as well as methods intended for use by the MapReduce framework |
| * (e.g., {@link org.apache.hadoop.mapred.JobClient}). For implementation |
| * details, see {@link TrackerDistributedCacheManager} and |
| * {@link TaskDistributedCacheManager}. |
| * |
| * @see TrackerDistributedCacheManager |
| * @see TaskDistributedCacheManager |
| * @see org.apache.hadoop.mapred.JobConf |
| * @see org.apache.hadoop.mapred.JobClient |
| */ |
| public class DistributedCache { |
| /** |
| * Warning: {@link #CACHE_FILES_SIZES} is not a *public* constant. |
| */ |
| public static final String CACHE_FILES_SIZES = "mapred.cache.files.filesizes"; |
| |
| /** |
| * Warning: {@link #CACHE_ARCHIVES_SIZES} is not a *public* constant. |
| */ |
| public static final String CACHE_ARCHIVES_SIZES = |
| "mapred.cache.archives.filesizes"; |
| |
| /** |
| * Warning: {@link #CACHE_ARCHIVES_TIMESTAMPS} is not a *public* constant. |
| **/ |
| public static final String CACHE_ARCHIVES_TIMESTAMPS = "mapred.cache.archives.timestamps"; |
| |
| /** |
| * Warning: {@link #CACHE_FILES_TIMESTAMPS} is not a *public* constant. |
| **/ |
| public static final String CACHE_FILES_TIMESTAMPS = "mapred.cache.files.timestamps"; |
| |
| /** |
| * Warning: {@link #CACHE_ARCHIVES} is not a *public* constant. |
| **/ |
| public static final String CACHE_ARCHIVES = "mapred.cache.archives"; |
| |
| /** |
| * Warning: {@link #CACHE_FILES} is not a *public* constant. |
| **/ |
| public static final String CACHE_FILES = "mapred.cache.files"; |
| |
| /** |
| * Warning: {@link #CACHE_LOCALARCHIVES} is not a *public* constant. |
| **/ |
| public static final String CACHE_LOCALARCHIVES = "mapred.cache.localArchives"; |
| |
| /** |
| * Warning: {@link #CACHE_LOCALFILES} is not a *public* constant. |
| **/ |
| public static final String CACHE_LOCALFILES = "mapred.cache.localFiles"; |
| |
| /** |
| * Warning: {@link #CACHE_SYMLINK} is not a *public* constant. |
| **/ |
| public static final String CACHE_SYMLINK = "mapred.create.symlink"; |
| |
| /** |
| * Returns {@link FileStatus} of a given cache file on hdfs. Internal to |
| * MapReduce. |
| * @param conf configuration |
| * @param cache cache file |
| * @return <code>FileStatus</code> of a given cache file on hdfs |
| * @throws IOException |
| */ |
| public static FileStatus getFileStatus(Configuration conf, URI cache) |
| throws IOException { |
| FileSystem fileSystem = FileSystem.get(cache, conf); |
| return fileSystem.getFileStatus(new Path(cache.getPath())); |
| } |
| |
| /** |
| * Returns mtime of a given cache file on hdfs. Internal to MapReduce. |
| * @param conf configuration |
| * @param cache cache file |
| * @return mtime of a given cache file on hdfs |
| * @throws IOException |
| */ |
| public static long getTimestamp(Configuration conf, URI cache) |
| throws IOException { |
| return getFileStatus(conf, cache).getModificationTime(); |
| } |
| |
| /** |
| * This method create symlinks for all files in a given dir in another directory |
| * @param conf the configuration |
| * @param jobCacheDir the target directory for creating symlinks |
| * @param workDir the directory in which the symlinks are created |
| * @throws IOException |
| * @deprecated Internal to MapReduce framework. Use DistributedCacheManager |
| * instead. |
| */ |
| public static void createAllSymlink(Configuration conf, File jobCacheDir, File workDir) |
| throws IOException{ |
| TrackerDistributedCacheManager.createAllSymlink(conf, jobCacheDir, workDir); |
| } |
| |
| /** |
| * Set the configuration with the given set of archives. Intended |
| * to be used by user code. |
| * @param archives The list of archives that need to be localized |
| * @param conf Configuration which will be changed |
| */ |
| public static void setCacheArchives(URI[] archives, Configuration conf) { |
| String sarchives = StringUtils.uriToString(archives); |
| conf.set(CACHE_ARCHIVES, sarchives); |
| } |
| |
| /** |
| * Set the configuration with the given set of files. Intended to be |
| * used by user code. |
| * @param files The list of files that need to be localized |
| * @param conf Configuration which will be changed |
| */ |
| public static void setCacheFiles(URI[] files, Configuration conf) { |
| String sfiles = StringUtils.uriToString(files); |
| conf.set(CACHE_FILES, sfiles); |
| } |
| |
| private static Path[] parsePaths(String[] strs) { |
| if (strs == null) { |
| return null; |
| } |
| Path[] result = new Path[strs.length]; |
| for(int i=0; i < strs.length; ++i) { |
| result[i] = new Path(strs[i]); |
| } |
| return result; |
| } |
| |
| /** |
| * Get cache archives set in the Configuration. Used by |
| * internal DistributedCache and MapReduce code. |
| * @param conf The configuration which contains the archives |
| * @return An array of the caches set in the Configuration |
| * @throws IOException |
| */ |
| public static URI[] getCacheArchives(Configuration conf) throws IOException { |
| return StringUtils.stringToURI(conf.getStrings(CACHE_ARCHIVES)); |
| } |
| |
| /** |
| * Get cache files set in the Configuration. Used by internal |
| * DistributedCache and MapReduce code. |
| * @param conf The configuration which contains the files |
| * @return Am array of the files set in the Configuration |
| * @throws IOException |
| */ |
| public static URI[] getCacheFiles(Configuration conf) throws IOException { |
| return StringUtils.stringToURI(conf.getStrings(CACHE_FILES)); |
| } |
| |
| /** |
| * Return the path array of the localized caches. Intended to be used |
| * by user code. |
| * @param conf Configuration that contains the localized archives |
| * @return A path array of localized caches |
| * @throws IOException |
| */ |
| public static Path[] getLocalCacheArchives(Configuration conf) |
| throws IOException { |
| return StringUtils.stringToPath(conf |
| .getStrings(CACHE_LOCALARCHIVES)); |
| } |
| |
| /** |
| * Return the path array of the localized files. Intended to be used |
| * by user code. |
| * @param conf Configuration that contains the localized files |
| * @return A path array of localized files |
| * @throws IOException |
| */ |
| public static Path[] getLocalCacheFiles(Configuration conf) |
| throws IOException { |
| return StringUtils.stringToPath(conf.getStrings(CACHE_LOCALFILES)); |
| } |
| |
| /** |
| * Parse a list of strings into longs. |
| * @param strs the list of strings to parse |
| * @return a list of longs that were parsed. same length as strs. |
| */ |
| private static long[] parseTimestamps(String[] strs) { |
| if (strs == null) { |
| return null; |
| } |
| long[] result = new long[strs.length]; |
| for(int i=0; i < strs.length; ++i) { |
| result[i] = Long.parseLong(strs[i]); |
| } |
| return result; |
| } |
| |
| /** |
| * Get the timestamps of the archives. Used by internal |
| * DistributedCache and MapReduce code. |
| * @param conf The configuration which stored the timestamps |
| * @return a long array of timestamps |
| * @throws IOException |
| */ |
| public static long[] getArchiveTimestamps(Configuration conf) { |
| return parseTimestamps(conf.getStrings(CACHE_ARCHIVES_TIMESTAMPS)); |
| } |
| |
| /** |
| * Get the timestamps of the files. Used by internal |
| * DistributedCache and MapReduce code. |
| * @param conf The configuration which stored the timestamps |
| * @return a long array of timestamps |
| * @throws IOException |
| */ |
| public static long[] getFileTimestamps(Configuration conf) { |
| return parseTimestamps(conf.getStrings(CACHE_FILES_TIMESTAMPS)); |
| } |
| |
| /** |
| * This is to check the timestamp of the archives to be localized. |
| * Used by internal MapReduce code. |
| * @param conf Configuration which stores the timestamp's |
| * @param timestamps comma separated list of timestamps of archives. |
| * The order should be the same as the order in which the archives are added. |
| */ |
| public static void setArchiveTimestamps(Configuration conf, String timestamps) { |
| conf.set(CACHE_ARCHIVES_TIMESTAMPS, timestamps); |
| } |
| |
| /** |
| * This is to check the timestamp of the files to be localized. |
| * Used by internal MapReduce code. |
| * @param conf Configuration which stores the timestamp's |
| * @param timestamps comma separated list of timestamps of files. |
| * The order should be the same as the order in which the files are added. |
| */ |
| public static void setFileTimestamps(Configuration conf, String timestamps) { |
| conf.set(CACHE_FILES_TIMESTAMPS, timestamps); |
| } |
| |
| /** |
| * Set the conf to contain the location for localized archives. Used |
| * by internal DistributedCache code. |
| * @param conf The conf to modify to contain the localized caches |
| * @param str a comma separated list of local archives |
| */ |
| public static void setLocalArchives(Configuration conf, String str) { |
| conf.set(CACHE_LOCALARCHIVES, str); |
| } |
| |
| /** |
| * Set the conf to contain the location for localized files. Used |
| * by internal DistributedCache code. |
| * @param conf The conf to modify to contain the localized caches |
| * @param str a comma separated list of local files |
| */ |
| public static void setLocalFiles(Configuration conf, String str) { |
| conf.set(CACHE_LOCALFILES, str); |
| } |
| |
| /** |
| * Add a archive that has been localized to the conf. Used |
| * by internal DistributedCache code. |
| * @param conf The conf to modify to contain the localized caches |
| * @param str a comma separated list of local archives |
| */ |
| public static void addLocalArchives(Configuration conf, String str) { |
| String archives = conf.get(CACHE_LOCALARCHIVES); |
| conf.set(CACHE_LOCALARCHIVES, archives == null ? str |
| : archives + "," + str); |
| } |
| |
| /** |
| * Add a file that has been localized to the conf.. Used |
| * by internal DistributedCache code. |
| * @param conf The conf to modify to contain the localized caches |
| * @param str a comma separated list of local files |
| */ |
| public static void addLocalFiles(Configuration conf, String str) { |
| String files = conf.get(CACHE_LOCALFILES); |
| conf.set(CACHE_LOCALFILES, files == null ? str |
| : files + "," + str); |
| } |
| |
| /** |
| * Add a archives to be localized to the conf. Intended to |
| * be used by user code. |
| * @param uri The uri of the cache to be localized |
| * @param conf Configuration to add the cache to |
| */ |
| public static void addCacheArchive(URI uri, Configuration conf) { |
| String archives = conf.get(CACHE_ARCHIVES); |
| conf.set(CACHE_ARCHIVES, archives == null ? uri.toString() |
| : archives + "," + uri.toString()); |
| } |
| |
| /** |
| * Add a file to be localized to the conf. Intended |
| * to be used by user code. |
| * @param uri The uri of the cache to be localized |
| * @param conf Configuration to add the cache to |
| */ |
| public static void addCacheFile(URI uri, Configuration conf) { |
| String files = conf.get(CACHE_FILES); |
| conf.set(CACHE_FILES, files == null ? uri.toString() : files + "," |
| + uri.toString()); |
| } |
| |
| /** |
| * Add a file path to the current set of classpath entries. It adds the file |
| * to cache as well. Intended to be used by user code. |
| * |
| * @deprecated |
| * |
| * Please use {@link #addFileToClassPath(Path, Configuration, FileSystem)} |
| * instead. The {@code FileSystem} should be obtained within an |
| * appropriate {@code doAs}. |
| * |
| * @param file Path of the file to be added |
| * @param conf Configuration that contains the classpath setting |
| */ |
| @Deprecated |
| public static void addFileToClassPath(Path file, Configuration conf) |
| throws IOException { |
| addFileToClassPath(file, conf, file.getFileSystem(conf)); |
| } |
| |
| /** |
| * Add a file path to the current set of classpath entries. It adds the file |
| * to cache as well. Intended to be used by user code. |
| * |
| * @param file Path of the file to be added |
| * @param conf Configuration that contains the classpath setting |
| * @param fs FileSystem with respect to which {@code archivefile} should |
| * be interpreted. |
| */ |
| public static void addFileToClassPath |
| (Path file, Configuration conf, FileSystem fs) |
| throws IOException { |
| String filepath = file.toUri().getPath(); |
| String classpath = conf.get("mapred.job.classpath.files"); |
| conf.set("mapred.job.classpath.files", classpath == null |
| ? filepath |
| : classpath + System.getProperty("path.separator") + filepath); |
| URI uri = fs.makeQualified(file).toUri(); |
| addCacheFile(uri, conf); |
| } |
| |
| /** |
| * Get the file entries in classpath as an array of Path. |
| * Used by internal DistributedCache code. |
| * |
| * @param conf Configuration that contains the classpath setting |
| */ |
| public static Path[] getFileClassPaths(Configuration conf) { |
| String classpath = conf.get("mapred.job.classpath.files"); |
| if (classpath == null) |
| return null; |
| ArrayList<Object> list = Collections.list(new StringTokenizer(classpath, System |
| .getProperty("path.separator"))); |
| Path[] paths = new Path[list.size()]; |
| for (int i = 0; i < list.size(); i++) { |
| paths[i] = new Path((String) list.get(i)); |
| } |
| return paths; |
| } |
| |
| /** |
| * Add an archive path to the current set of classpath entries. It adds the |
| * archive to cache as well. Intended to be used by user code. |
| * |
| * @deprecated |
| * |
| * Please use {@link #addArchiveToClassPath(Path, Configuration, FileSystem)} |
| * instead. The {@code FileSystem} should be obtained within an |
| * appropriate {@code doAs}. |
| * |
| * @param archive Path of the archive to be added |
| * @param conf Configuration that contains the classpath setting |
| */ |
| @Deprecated |
| public static void addArchiveToClassPath |
| (Path archive, Configuration conf) |
| throws IOException { |
| addArchiveToClassPath(archive, conf, archive.getFileSystem(conf)); |
| } |
| |
| /** |
| * Add an archive path to the current set of classpath entries. It adds the |
| * archive to cache as well. Intended to be used by user code. |
| * |
| * @param archive Path of the archive to be added |
| * @param conf Configuration that contains the classpath setting |
| * @param fs FileSystem with respect to which {@code archive} should be interpreted. |
| */ |
| public static void addArchiveToClassPath |
| (Path archive, Configuration conf, FileSystem fs) |
| throws IOException { |
| String archivepath = archive.toUri().getPath(); |
| String classpath = conf.get("mapred.job.classpath.archives"); |
| conf.set("mapred.job.classpath.archives", classpath == null |
| ? archivepath |
| : classpath + System.getProperty("path.separator") + archivepath); |
| URI uri = fs.makeQualified(archive).toUri(); |
| |
| addCacheArchive(uri, conf); |
| } |
| |
| /** |
| * Get the archive entries in classpath as an array of Path. |
| * Used by internal DistributedCache code. |
| * |
| * @param conf Configuration that contains the classpath setting |
| */ |
| public static Path[] getArchiveClassPaths(Configuration conf) { |
| String classpath = conf.get("mapred.job.classpath.archives"); |
| if (classpath == null) |
| return null; |
| ArrayList<Object> list = Collections.list(new StringTokenizer(classpath, System |
| .getProperty("path.separator"))); |
| Path[] paths = new Path[list.size()]; |
| for (int i = 0; i < list.size(); i++) { |
| paths[i] = new Path((String) list.get(i)); |
| } |
| return paths; |
| } |
| |
| /** |
| * This method allows you to create symlinks in the current working directory |
| * of the task to all the cache files/archives. |
| * Intended to be used by user code. |
| * @param conf the jobconf |
| */ |
| public static void createSymlink(Configuration conf){ |
| conf.set(CACHE_SYMLINK, "yes"); |
| } |
| |
| /** |
| * This method checks to see if symlinks are to be create for the |
| * localized cache files in the current working directory |
| * Used by internal DistributedCache code. |
| * @param conf the jobconf |
| * @return true if symlinks are to be created- else return false |
| */ |
| public static boolean getSymlink(Configuration conf){ |
| String result = conf.get(CACHE_SYMLINK); |
| if ("yes".equals(result)){ |
| return true; |
| } |
| return false; |
| } |
| |
| /** |
| * This method checks if there is a conflict in the fragment names |
| * of the uris. Also makes sure that each uri has a fragment. It |
| * is only to be called if you want to create symlinks for |
| * the various archives and files. May be used by user code. |
| * @param uriFiles The uri array of urifiles |
| * @param uriArchives the uri array of uri archives |
| */ |
| public static boolean checkURIs(URI[] uriFiles, URI[] uriArchives) { |
| if ((uriFiles == null) && (uriArchives == null)){ |
| return true; |
| } |
| // check if fragment is null for any uri |
| // also check if there are any conflicts in fragment names |
| Set<String> fragments = new HashSet<String>(); |
| |
| // iterate over file uris |
| if (uriFiles != null) { |
| for (int i = 0; i < uriFiles.length; i++) { |
| String fragment = uriFiles[i].getFragment(); |
| if (fragment == null) { |
| return false; |
| } |
| String lowerCaseFragment = fragment.toLowerCase(); |
| if (fragments.contains(lowerCaseFragment)) { |
| return false; |
| } |
| fragments.add(lowerCaseFragment); |
| } |
| } |
| |
| // iterate over archive uris |
| if (uriArchives != null) { |
| for (int i = 0; i < uriArchives.length; i++) { |
| String fragment = uriArchives[i].getFragment(); |
| if (fragment == null) { |
| return false; |
| } |
| String lowerCaseFragment = fragment.toLowerCase(); |
| if (fragments.contains(lowerCaseFragment)) { |
| return false; |
| } |
| fragments.add(lowerCaseFragment); |
| } |
| } |
| return true; |
| } |
| |
| } |