Interactor class for dispatching change notifications to client wikis via the job queue. More...

Public Member Functions
	__construct (ChangeDispatchCoordinator $coordinator, ChangeNotificationSender $notificationSender, ChunkAccess $chunkedChangesAccess, SubscriptionLookup $subscriptionLookup)

	isVerbose ()

	setVerbose ( $verbose)

	getMessageReporter ()

	setMessageReporter (MessageReporter $messageReporter)

	getExceptionHandler ()

	setExceptionHandler (ExceptionHandler $exceptionHandler)

	getBatchSize ()

	setBatchSize ( $batchSize)

	getBatchChunkFactor ()

	setMaxChunks ( $maxChunks)

	getMaxChunks ()

	setBatchChunkFactor ( $batchChunkFactor)
	Sets the chunk factor. More...

	selectClient ()
	Selects a client wiki and locks it. More...

	getPendingChanges ( $siteID, $after)
	Returns a batch of changes for the given client wiki, starting from the given position in the wb_changes table. More...

	getDispatchCoordinator ()

Private Member Functions
	isRelevantChange (Change $change, $siteID)
	Checks whether the given Change is somehow relevant to the given wiki site. More...

	filterChanges ( $siteID, array $changes, $limit)
	Filters a list of changes, removing changes not relevant to the given client wiki. More...

	reIndexEntityIds (array $entityIds)

	trace ( $message)
	Log a message if verbose mode is enabled. More...

	log ( $message)

Private Attributes
	$batchSize = 1000

	$batchChunkFactor = 3

	$maxChunks = 15

	$verbose = false

	$notificationSender

	$coordinator

	$exceptionHandler

	$messageReporter

	$chunkedChangesAccess

	$subscriptionLookup

Detailed Description

Interactor class for dispatching change notifications to client wikis via the job queue.

See also: md_docs_topics_change-propagation for an overview of the change propagation mechanism.

Copyright: GPL-2.0-or-later

Author: Daniel Kinzler

Constructor & Destructor Documentation

◆ __construct()

Wikibase\Repo\ChangeDispatcher::__construct	(	ChangeDispatchCoordinator	$coordinator,
		ChangeNotificationSender	$notificationSender,
		ChunkAccess	$chunkedChangesAccess,
		SubscriptionLookup	$subscriptionLookup
	)

Parameters

ChangeDispatchCoordinator	$coordinator
ChangeNotificationSender	$notificationSender
ChunkAccess	$chunkedChangesAccess	Access to the changes table. Should only return Change objects from loadChunk.
SubscriptionLookup	$subscriptionLookup

Member Function Documentation

◆ filterChanges()

Wikibase\Repo\ChangeDispatcher::filterChanges	(		$siteID,
		array	$changes,
			$limit
	)

private

Filters a list of changes, removing changes not relevant to the given client wiki.

Currently, we keep EntityChanges for entities the client wiki is subscribed to, or that modify a sitelink to the client wiki.

Parameters

string	$siteID	The client wiki's global site identifier, as used by sitelinks.
Change[]	$changes	The list of changes to filter.
int	$limit	The max number of changes to return

Returns: array ( EntityChange[] $batch, int $seen ), where $batch is the filtered list of Change objects, and $seen is the ID of the last change considered for the batch (even if that was filtered out), for use as a continuation marker. -return array{0:EntityChange[],1:int}

◆ getBatchChunkFactor()

Wikibase\Repo\ChangeDispatcher::getBatchChunkFactor ( )

Returns: int

◆ getBatchSize()

Wikibase\Repo\ChangeDispatcher::getBatchSize ( )

Returns: int

◆ getDispatchCoordinator()

Wikibase\Repo\ChangeDispatcher::getDispatchCoordinator ( )

Returns: ChangeDispatchCoordinator

◆ getExceptionHandler()

Wikibase\Repo\ChangeDispatcher::getExceptionHandler ( )

Returns: ExceptionHandler

◆ getMaxChunks()

Wikibase\Repo\ChangeDispatcher::getMaxChunks ( )

Returns: int Maximum number of chunks or passes per wiki when selecting pending changes.

◆ getMessageReporter()

Wikibase\Repo\ChangeDispatcher::getMessageReporter ( )

Returns: MessageReporter

◆ getPendingChanges()

Wikibase\Repo\ChangeDispatcher::getPendingChanges	(	$siteID,
		$after
	)

Returns a batch of changes for the given client wiki, starting from the given position in the wb_changes table.

The changes may be filtered to only include those changes that are relevant to the given client wiki. The number of changes returned by this method is limited by $this->batchSize. Changes are returned with IDs in ascending order.

Note: due to programmatic filtering, this method may use multiple database queries to collect the changes for the next batch. The number of requests needed can be adjusted using $this->batchChunkFactor (via the 'dispatchBatchChunkFactor' setting).

Parameters

string	$siteID	The client wiki's global site identifier, as used by sitelinks.
int	$after	The last change ID processed by a previous run. All changes returned will have an ID greater than $after.

Returns: array ( Change[] $batch, int $seen ), where $batch is a list of Change objects, and $seen is the ID of the last change considered for the batch (even if that was filtered out), for use as a continuation marker. -return array{0:Change[],1:int}

◆ isRelevantChange()

Wikibase\Repo\ChangeDispatcher::isRelevantChange	(	Change	$change,
			$siteID
	)

private

Checks whether the given Change is somehow relevant to the given wiki site.

In particular this check whether the Change modifies any sitelink that refers to the given wiki site.

Note: this does not check whether the entity that was changes is or is not at all connected with (resp. used on) the target wiki.

Parameters

Change	$change	the change to examine.
string	$siteID	the site to consider.

Returns: bool

◆ isVerbose()

Wikibase\Repo\ChangeDispatcher::isVerbose ( )

Returns: bool

◆ log()

Wikibase\Repo\ChangeDispatcher::log ( $message )

private

◆ reIndexEntityIds()

Wikibase\Repo\ChangeDispatcher::reIndexEntityIds ( array $entityIds )

private

Parameters

EntityId[] $entityIds

Returns: EntityId[] $entityIds re-keyed by id string.

◆ selectClient()

Wikibase\Repo\ChangeDispatcher::selectClient ( )

Selects a client wiki and locks it.

If no suitable client wiki can be found, this method returns null.

Note: this implementation will try a wiki from the list returned by getCandidateClients() at random. If all have been tried and failed, it returns null.

Returns: array An associative array containing the state of the selected client wiki (or null, if no target could be locked). Fields are:

chd_site: the client wiki's global site ID
chd_db: the client wiki's logical database name
chd_seen: the last change ID processed for that client wiki
chd_touched: timestamp giving the last time that client wiki was updated
chd_lock: the name of a global lock currently active for that client wiki

Exceptions

MWException if no available client wiki could be found.

See also: releaseWiki()

◆ setBatchChunkFactor()

Wikibase\Repo\ChangeDispatcher::setBatchChunkFactor ( $batchChunkFactor )

Sets the chunk factor.

The governs how many changes getPendingChanges will load in one go: the number loaded is the batch size multiplied by the batch chunk factor. A chunk factor > 1 reduces the need to load more changes in case not all end up in the batch opf pending changes due to programmatic filtering (e.g. by whether the client site is subscribed to a given change).

For example: Consider loading a batch of 5 changes to dispatch to foowiki, but of the first 5 changes, only 3 are relevant to foowiki. A chunk factor of 1 means only 5 changes have been loaded for examination, meaning at least one more batch has to be loaded. A chunk factor of 2 means 10 changes have been loaded for examination, which makes it more likely to fine the desired 5 changes for foowiki without loading more changes.

Parameters

int $batchChunkFactor

◆ setBatchSize()

Wikibase\Repo\ChangeDispatcher::setBatchSize ( $batchSize )

Parameters

int $batchSize

◆ setExceptionHandler()

Wikibase\Repo\ChangeDispatcher::setExceptionHandler ( ExceptionHandler $exceptionHandler )

◆ setMaxChunks()

Wikibase\Repo\ChangeDispatcher::setMaxChunks ( $maxChunks )

Parameters

int $maxChunks Maximum number of chunks or passes per wiki when selecting pending changes.

◆ setMessageReporter()

Wikibase\Repo\ChangeDispatcher::setMessageReporter ( MessageReporter $messageReporter )

◆ setVerbose()

Wikibase\Repo\ChangeDispatcher::setVerbose ( $verbose )

Parameters

bool $verbose

◆ trace()

Wikibase\Repo\ChangeDispatcher::trace ( $message )

private

Log a message if verbose mode is enabled.

Parameters

string $message

Member Data Documentation

◆ $batchChunkFactor

Wikibase\Repo\ChangeDispatcher::$batchChunkFactor = 3

private

◆ $batchSize

Wikibase\Repo\ChangeDispatcher::$batchSize = 1000

private

◆ $chunkedChangesAccess

Wikibase\Repo\ChangeDispatcher::$chunkedChangesAccess

private

◆ $coordinator

Wikibase\Repo\ChangeDispatcher::$coordinator

private

◆ $exceptionHandler

Wikibase\Repo\ChangeDispatcher::$exceptionHandler

private

◆ $maxChunks

Wikibase\Repo\ChangeDispatcher::$maxChunks = 15

private

◆ $messageReporter

Wikibase\Repo\ChangeDispatcher::$messageReporter

private

◆ $notificationSender

Wikibase\Repo\ChangeDispatcher::$notificationSender

private

◆ $subscriptionLookup

Wikibase\Repo\ChangeDispatcher::$subscriptionLookup

private

◆ $verbose

Wikibase\Repo\ChangeDispatcher::$verbose = false

private

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

repo/includes/ChangeDispatcher.php

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ __construct()

Member Function Documentation

◆ filterChanges()

◆ getBatchChunkFactor()

◆ getBatchSize()

◆ getDispatchCoordinator()

◆ getExceptionHandler()

◆ getMaxChunks()

◆ getMessageReporter()

◆ getPendingChanges()

◆ isRelevantChange()

◆ isVerbose()

◆ log()

◆ reIndexEntityIds()

◆ selectClient()

◆ setBatchChunkFactor()

◆ setBatchSize()

◆ setExceptionHandler()

◆ setMaxChunks()

◆ setMessageReporter()

◆ setVerbose()

◆ trace()

Member Data Documentation

◆ $batchChunkFactor

◆ $batchSize

◆ $chunkedChangesAccess

◆ $coordinator

◆ $exceptionHandler

◆ $maxChunks

◆ $messageReporter

◆ $notificationSender

◆ $subscriptionLookup

◆ $verbose