Package org.apache.hadoop.yarn.server.nodemanager.containermanager.localizer

Class LocalCacheDirectoryManager

java.lang.Object

org.apache.hadoop.yarn.server.nodemanager.containermanager.localizer.LocalCacheDirectoryManager

public class LocalCacheDirectoryManager
extends Object

LocalCacheDirectoryManager is used for managing hierarchical directories for local cache. It will allow to restrict the number of files in a directory to YarnConfiguration.NM_LOCAL_CACHE_MAX_FILES_PER_DIRECTORY which includes 36 sub-directories (named from 0 to 9 and a to z). Root directory is represented by an empty string. It internally maintains a vacant directory queue. As soon as the file count for the directory reaches its limit; new files will not be created in it until at least one file is deleted from it. New sub directories are not created unless a getRelativePathForLocalization() request is made and nonFullDirectories are empty. Note : this structure only returns relative localization path but doesn't create one on disk.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DIRECTORIES_PER_LEVEL

Constructor Summary

Constructors

Constructor	Description
LocalCacheDirectoryManager(org.apache.hadoop.conf.Configuration conf)

Method Summary

Modifier and Type	Method	Description
void	decrementFileCountForPath(String relPath)	This method will reduce the file count for the directory represented by path.
static org.apache.hadoop.fs.Path	getCacheDirectoryRoot(org.apache.hadoop.fs.Path path)	Given a path to a directory within a local cache tree return the root of the cache directory.
String	getRelativePathForLocalization()	This method will return relative path from the first available vacant directory.
void	incrementFileCountForPath(String relPath)	Increment the file count for a relative directory within the cache

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DIRECTORIES_PER_LEVEL

public static final int DIRECTORIES_PER_LEVEL

See Also:

• Constant Field Values

Constructor Details

LocalCacheDirectoryManager

public LocalCacheDirectoryManager(org.apache.hadoop.conf.Configuration conf)

Method Details

getRelativePathForLocalization

public String getRelativePathForLocalization()

This method will return relative path from the first available vacant directory.

Returns:

String relative path for localization

decrementFileCountForPath

public void decrementFileCountForPath(String relPath)

This method will reduce the file count for the directory represented by path. The root directory of this Local cache directory manager is represented by an empty string.

incrementFileCountForPath

public void incrementFileCountForPath(String relPath)

Increment the file count for a relative directory within the cache

Parameters:

relPath - the relative path

getCacheDirectoryRoot

public static org.apache.hadoop.fs.Path getCacheDirectoryRoot(org.apache.hadoop.fs.Path path)

Given a path to a directory within a local cache tree return the root of the cache directory.

Parameters:

path - the directory within a cache directory

Returns:

the local cache directory root or null if not found