Manage locks using memcached servers. More...

Collaboration diagram for MemcLockManager:

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Public Member Functions
	__construct (array $config)
	Construct a new instance from configuration.

	__destruct ()
	Make sure remaining locks get cleared.

Public Member Functions inherited from LockManager
	lock (array $paths, $type=self::LOCK_EX, $timeout=0)
	Lock the resources at the given abstract paths.

	lockByType (array $pathsByType, $timeout=0)
	Lock the resources at the given abstract paths.

	unlock (array $paths, $type=self::LOCK_EX)
	Unlock the resources at the given abstract paths.

	unlockByType (array $pathsByType)
	Unlock the resources at the given abstract paths.

Protected Member Functions

acquireMutexes (MemcachedBagOStuff $memc, array $keys)

freeLocksOnServer ( $lockSrv, array $pathsByType)

Get a connection to a lock server and release locks on $paths.Subclasses must effectively implement this or releaseAllLocks().

Parameters

string	$lockSrv
array	$pathsByType	Map of LockManager::LOCK_* constants to lists of paths

Returns: StatusValue

getCache ( $lockSrv)

Get the MemcachedBagOStuff object for a $lockSrv.

getLocksOnServer ( $lockSrv, array $pathsByType)

Get a connection to a lock server and acquire locks.

Parameters

string	$lockSrv
array	$pathsByType	Map of LockManager::LOCK_* constants to lists of paths

Returns: StatusValue

isServerUp ( $lockSrv)

newLockArray ()

recordKeyForPath ( $path)

releaseAllLocks ()

releaseMutexes (MemcachedBagOStuff $memc, array $keys)

sanitizeLockArray ( $a)

Protected Member Functions inherited from QuorumLockManager

collectPledgeQuorum ( $bucket, callable $callback)

Attempt to acquire pledges with the peers for a bucket.

doLock (array $paths, $type)

Lock resources with the given keys and lock type.

Parameters

array	$paths	List of paths
int	$type	LockManager::LOCK_* constant

Returns: StatusValue

doLockByType (array $pathsByType)

See also: LockManager::lockByType()

Stability: stable: to override

Parameters

array $pathsByType Map of LockManager::LOCK_* constants to lists of paths

Returns: StatusValue

Since: 1.22

doLockingRequestBucket ( $bucket, array $pathsByType)

Attempt to acquire locks with the peers for a bucket.

doUnlock (array $paths, $type)

Unlock resources with the given keys and lock type.

Parameters

array	$paths	List of paths
int	$type	LockManager::LOCK_* constant

Returns: StatusValue

doUnlockByType (array $pathsByType)

doUnlockingRequestBucket ( $bucket, array $pathsByType)

Attempt to release locks with the peers for a bucket.

getBucketFromPath ( $path)

Get the bucket for resource path.

releasePledges ( $bucket, callable $callback)

Attempt to release pledges with the peers for a bucket.

Protected Member Functions inherited from LockManager

normalizePathsByType (array $pathsByType)

Normalize the $paths array by converting LOCK_UW locks into the appropriate type and removing any duplicated paths for each lock type.

sha1Base36Absolute ( $path)

Get the base 36 SHA-1 of a string, padded to 31 digits.

Protected Attributes
MemcachedBagOStuff[]	$cacheServers = []
	Map of (server name => MemcachedBagOStuff)

array	$lockTypeMap
	Mapping of lock types to the type actually used.

MapCacheLRU	$statusCache
	Server status cache.

Protected Attributes inherited from QuorumLockManager
array	$degradedBuckets = []
	Map of degraded buckets.

array	$srvsByBucket = []
	Map of bucket indexes to peer server lists.

Protected Attributes inherited from LockManager
string	$domain
	domain (usually wiki ID)

array	$locksHeld = []
	Map of (resource path => lock type => count)

int	$lockTTL
	maximum time locks can be held

array	$lockTypeMap
	Mapping of lock types to the type actually used.

LoggerInterface	$logger

string	$session
	Random 32-char hex number.

const	MAX_LOCK_TTL = 2 * 3600
	Max expected lock expiry in any context.

const	MIN_LOCK_TTL = 5
	Minimum lock TTL.

Additional Inherited Members
Public Attributes inherited from LockManager
const	LOCK_EX = 3

const	LOCK_SH = 1
	Lock types; stronger locks have higher values.

const	LOCK_UW = 2

Detailed Description

Manage locks using memcached servers.

Version of LockManager based on using memcached servers. This is meant for multi-wiki systems that may share files. All locks are non-blocking, which avoids deadlocks.

All lock requests for a resource, identified by a hash string, will map to one bucket. Each bucket maps to one or several peer servers, each running memcached. A majority of peers must agree for a lock to be acquired.

Since: 1.20

Definition at line 26 of file MemcLockManager.php.

Constructor & Destructor Documentation

◆ __construct()

MemcLockManager::__construct ( array $config )

Construct a new instance from configuration.

Parameters

array

$config

Parameters include:

lockServers : Associative array of server names to "<IP>:<port>" strings.
srvsByBucket : [optional] An array of up to 16 arrays, each containing the server names in a bucket. Each bucket should have an odd number of servers. If omitted, all servers will be in one bucket.
memcConfig : [optional] Configuration array for MemcachedBagOStuff::construct() with an additional 'class' parameter specifying which MemcachedBagOStuff subclass to use. The server names will be injected.

Exceptions

Exception

Reimplemented from LockManager.

Definition at line 52 of file MemcLockManager.php.

◆ __destruct()

MemcLockManager::__destruct ( )

Make sure remaining locks get cleared.

Definition at line 339 of file MemcLockManager.php.

References $path, and LockManager\unlockByType().

Member Function Documentation

◆ acquireMutexes()

MemcLockManager::acquireMutexes	(	MemcachedBagOStuff	$memc,
		array	$keys )

protected

Parameters

MemcachedBagOStuff	$memc
array	$keys	List of keys to acquire

Returns: bool

Definition at line 292 of file MemcLockManager.php.

References Wikimedia\ObjectCache\MediumSpecificBagOStuff\add(), and releaseMutexes().

Referenced by freeLocksOnServer(), and getLocksOnServer().

◆ freeLocksOnServer()

MemcLockManager::freeLocksOnServer	(		$lockSrv,
		array	$pathsByType )

protected

Get a connection to a lock server and release locks on $paths.Subclasses must effectively implement this or releaseAllLocks().

Parameters

string	$lockSrv
array	$pathsByType	Map of LockManager::LOCK_* constants to lists of paths

Returns: StatusValue

Reimplemented from QuorumLockManager.

Definition at line 153 of file MemcLockManager.php.

References LockManager\$locksHeld, $path, acquireMutexes(), getCache(), newLockArray(), recordKeyForPath(), releaseMutexes(), and sanitizeLockArray().

◆ getCache()

MemcLockManager::getCache ( $lockSrv )

protected

Get the MemcachedBagOStuff object for a $lockSrv.

Parameters

string $lockSrv Server name

Returns: MemcachedBagOStuff|null

Definition at line 241 of file MemcLockManager.php.

Referenced by freeLocksOnServer(), getLocksOnServer(), and isServerUp().

◆ getLocksOnServer()

MemcLockManager::getLocksOnServer	(		$lockSrv,
		array	$pathsByType )

protected

Get a connection to a lock server and acquire locks.

Parameters

string	$lockSrv
array	$pathsByType	Map of LockManager::LOCK_* constants to lists of paths

Returns: StatusValue

Reimplemented from QuorumLockManager.

Definition at line 80 of file MemcLockManager.php.

References LockManager\$locksHeld, LockManager\$lockTTL, $path, LockManager\$session, acquireMutexes(), getCache(), newLockArray(), recordKeyForPath(), releaseMutexes(), and sanitizeLockArray().

◆ isServerUp()

MemcLockManager::isServerUp ( $lockSrv )

protected

See also: QuorumLockManager::isServerUp()

Parameters

string $lockSrv

Returns: bool

Reimplemented from QuorumLockManager.

Definition at line 231 of file MemcLockManager.php.

References getCache().

◆ newLockArray()

MemcLockManager::newLockArray ( )

protected

Returns: array An empty lock structure for a key

Definition at line 269 of file MemcLockManager.php.

Referenced by freeLocksOnServer(), getLocksOnServer(), and sanitizeLockArray().

◆ recordKeyForPath()

MemcLockManager::recordKeyForPath ( $path )

protected

Parameters

string $path

Returns: string

Definition at line 262 of file MemcLockManager.php.

References $path, and LockManager\sha1Base36Absolute().

Referenced by freeLocksOnServer(), and getLocksOnServer().

◆ releaseAllLocks()

MemcLockManager::releaseAllLocks ( )

protected

See also: QuorumLockManager::releaseAllLocks()

Returns: StatusValue

Reimplemented from QuorumLockManager.

Definition at line 222 of file MemcLockManager.php.

◆ releaseMutexes()

MemcLockManager::releaseMutexes	(	MemcachedBagOStuff	$memc,
		array	$keys )

protected

Parameters

MemcachedBagOStuff	$memc
array	$keys	List of acquired keys

Definition at line 330 of file MemcLockManager.php.

References Wikimedia\ObjectCache\MediumSpecificBagOStuff\delete().

Referenced by acquireMutexes(), freeLocksOnServer(), and getLocksOnServer().

◆ sanitizeLockArray()

MemcLockManager::sanitizeLockArray ( $a )

protected

Parameters

array $a

Returns: array An empty lock structure for a key

Definition at line 277 of file MemcLockManager.php.

References newLockArray().

Referenced by freeLocksOnServer(), and getLocksOnServer().

Member Data Documentation

◆ $cacheServers

MemcachedBagOStuff [] MemcLockManager::$cacheServers = []

protected

Map of (server name => MemcachedBagOStuff)

Definition at line 35 of file MemcLockManager.php.

◆ $lockTypeMap

array MemcLockManager::$lockTypeMap

protected

Initial value:

= [
        self::LOCK_SH => self::LOCK_SH,
        self::LOCK_UW => self::LOCK_SH,
        self::LOCK_EX => self::LOCK_EX
    ]

Mapping of lock types to the type actually used.

Definition at line 28 of file MemcLockManager.php.

◆ $statusCache

MapCacheLRU MemcLockManager::$statusCache

protected

Server status cache.

Definition at line 37 of file MemcLockManager.php.

The documentation for this class was generated from the following file:

includes/libs/LockManager/MemcLockManager.php

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ __construct()

◆ __destruct()

Member Function Documentation

◆ acquireMutexes()

◆ freeLocksOnServer()

◆ getCache()

◆ getLocksOnServer()

◆ isServerUp()

◆ newLockArray()

◆ recordKeyForPath()

◆ releaseAllLocks()

◆ releaseMutexes()

◆ sanitizeLockArray()

Member Data Documentation

◆ $cacheServers

◆ $lockTypeMap

◆ $statusCache