Service interface for a inter-process locking service intended to coordinate message dispatching between multiple processes. More...
Inheritance diagram for Wikibase\Repo\Store\ChangeDispatchCoordinator:
Public Member Functions | |
| selectClient () | |
| Selects a client wiki and locks it. More... | |
| initState (array $clientWikiDBs) | |
| Initializes the dispatch table by injecting dummy records for all target wikis that are in the configuration but not yet in the dispatch table. More... | |
| lockClient (string $siteID) | |
| Attempt to lock the given target wiki. More... | |
| releaseClient (array $state) | |
| Updates the given client wiki's entry in the dispatch table and releases the global lock on that wiki. More... | |
Detailed Description
Service interface for a inter-process locking service intended to coordinate message dispatching between multiple processes.
The purpose of a ChangeDispatchCoordinator is to determine which client wiki to dispatch to next in a fair manner, and to prevent multiple processes to try and dispatch to the same wiki at once.
- Copyright
- GPL-2.0-or-later
Member Function Documentation
◆ initState()
| Wikibase\Repo\Store\ChangeDispatchCoordinator::initState | ( | array | $clientWikiDBs | ) |
Initializes the dispatch table by injecting dummy records for all target wikis that are in the configuration but not yet in the dispatch table.
- Parameters
-
string[] $clientWikiDBs Associative array mapping client wiki IDs to client wiki (logical) database names.
Implemented in Wikibase\Repo\Store\Sql\SqlChangeDispatchCoordinator.
◆ lockClient()
| Wikibase\Repo\Store\ChangeDispatchCoordinator::lockClient | ( | string | $siteID | ) |
Attempt to lock the given target wiki.
If it can't be locked because another dispatch process is working on it, this method returns false.
- Parameters
-
string $siteID The ID of the client wiki to lock.
- Exceptions
-
Exception
- Returns
- array|false An associative array containing the state of the selected client wiki (see selectClient()) or false if the client wiki could not be locked.
- See also
- selectClient()
Implemented in Wikibase\Repo\Store\Sql\SqlChangeDispatchCoordinator.
◆ releaseClient()
| Wikibase\Repo\Store\ChangeDispatchCoordinator::releaseClient | ( | array | $state | ) |
Updates the given client wiki's entry in the dispatch table and releases the global lock on that wiki.
The $state parameter represents the client wiki's state after the update pass. Its structure must be the one returned by selectClient(), with the chd_seen and field updated to reflect any dispatch activity.
- Parameters
-
array $state Associative array representing the client wiki's state after the update pass.
- Exceptions
-
Exception
- See also
- selectWiki()
Implemented in Wikibase\Repo\Store\Sql\SqlChangeDispatchCoordinator.
◆ selectClient()
| Wikibase\Repo\Store\ChangeDispatchCoordinator::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|null 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()
Implemented in Wikibase\Repo\Store\Sql\SqlChangeDispatchCoordinator.
The documentation for this interface was generated from the following file:
- repo/includes/Store/ChangeDispatchCoordinator.php
