/**
* Clear the entire contents of the cache and delete the backing files. This should only be used
* when the server is reinitializing, because the users are going to lose their files.
*/
public static void purgeCache(Configuration conf, MRAsyncDiskService service) throws IOException {
synchronized (cachedArchives) {
LocalFileSystem localFs = FileSystem.getLocal(conf);
for (Map.Entry<String, CacheStatus> f : cachedArchives.entrySet()) {
try {
deleteLocalPath(service, localFs, f.getValue().localizedLoadPath);
} catch (IOException ie) {
LOG.debug("Error cleaning up cache", ie);
}
}
cachedArchives.clear();
}
}
/**
* Get the locally cached file or archive; it could either be previously cached (and valid) or
* copy it from the {@link FileSystem} now.
*
* @param cache the cache to be localized, this should be specified as new
* URI(hdfs://hostname:port/absolute_path_to_file#LINKNAME). If no schema or hostname:port is
* provided the file is assumed to be in the filesystem being used in the Configuration
* @param conf The Confguration file which contains the filesystem
* @param subDir The sub cache Dir where you want to localize the files/archives
* @param fileStatus The file status on the dfs.
* @param isArchive if the cache is an archive or a file. In case it is an archive with a .zip or
* .jar or .tar or .tgz or .tar.gz extension it will be unzipped/unjarred/untarred
* automatically and the directory where the archive is unzipped/unjarred/untarred is returned
* as the Path. In case of a file, the path to the file is returned
* @param confFileStamp this is the hdfs file modification timestamp to verify that the file to be
* cached hasn't changed since the job started
* @param fileLength this is the length of the cache file
* @param currentWorkDir this is the directory where you would want to create symlinks for the
* locally cached files/archives
* @param honorSymLinkConf if this is false, then the symlinks are not created even if conf says
* so (this is required for an optimization in task launches
* @param lDirAllocator LocalDirAllocator of the tracker
* @return the path to directory where the archives are unjarred in case of archives, the path to
* the file where the file is copied locally
* @throws IOException
*/
private static Path getLocalCache(
URI cache,
Configuration conf,
Path subDir,
FileStatus fileStatus,
boolean isArchive,
long confFileStamp,
long fileLength,
Path currentWorkDir,
boolean honorSymLinkConf,
MRAsyncDiskService asyncDiskService,
LocalDirAllocator lDirAllocator)
throws IOException {
String key = getKey(cache, conf, confFileStamp);
CacheStatus lcacheStatus;
Path localizedPath;
synchronized (cachedArchives) {
lcacheStatus = cachedArchives.get(key);
if (lcacheStatus == null) {
// was never localized
Path uniqueParentDir = new Path(subDir, String.valueOf(random.nextLong()));
String cachePath = new Path(uniqueParentDir, makeRelative(cache, conf)).toString();
Path localPath = lDirAllocator.getLocalPathForWrite(cachePath, fileLength, conf);
lcacheStatus =
new CacheStatus(
new Path(localPath.toString().replace(cachePath, "")), localPath, uniqueParentDir);
cachedArchives.put(key, lcacheStatus);
}
lcacheStatus.refcount++;
}
boolean initSuccessful = false;
try {
synchronized (lcacheStatus) {
if (!lcacheStatus.isInited()) {
localizedPath = localizeCache(conf, cache, confFileStamp, lcacheStatus, isArchive);
lcacheStatus.initComplete();
} else {
if (fileStatus != null) {
localizedPath =
checkCacheStatusValidity(
conf, cache, confFileStamp, lcacheStatus, fileStatus, isArchive);
} else {
// if fileStatus is null, then the md5 must be correct
// so there is no need to check for cache validity
localizedPath = lcacheStatus.localizedLoadPath;
}
}
createSymlink(conf, cache, lcacheStatus, isArchive, currentWorkDir, honorSymLinkConf);
}
// try deleting stuff if you can
long size = 0;
int numberSubDir = 0;
synchronized (lcacheStatus) {
synchronized (baseDirSize) {
Long get = baseDirSize.get(lcacheStatus.getBaseDir());
if (get != null) {
size = get.longValue();
} else {
LOG.warn("Cannot find size of baseDir: " + lcacheStatus.getBaseDir());
}
}
synchronized (baseDirNumberSubDir) {
Integer get = baseDirNumberSubDir.get(lcacheStatus.getBaseDir());
if (get != null) {
numberSubDir = get.intValue();
} else {
LOG.warn("Cannot find subdirectories limit of baseDir: " + lcacheStatus.getBaseDir());
}
}
}
// setting the cache size to a default of 10GB
long allowedSize = conf.getLong("local.cache.size", DEFAULT_CACHE_SIZE);
long allowedNumberSubDir =
conf.getLong("local.cache.numbersubdir", DEFAULT_CACHE_SUBDIR_LIMIT);
if (allowedSize < size || allowedNumberSubDir < numberSubDir) {
// try some cache deletions
LOG.debug(
"Start deleting released cache because"
+ " [size, allowedSize, numberSubDir, allowedNumberSubDir] ="
+ " ["
+ size
+ ", "
+ allowedSize
+ ", "
+ numberSubDir
+ ", "
+ allowedNumberSubDir
+ "]");
deleteCache(conf, asyncDiskService);
}
initSuccessful = true;
return localizedPath;
} finally {
if (!initSuccessful) {
synchronized (cachedArchives) {
lcacheStatus.refcount--;
}
}
}
}