mediawiki-extensions-Echo/includes/EchoDbFactory.php

191 lines
4.9 KiB
PHP
Raw Normal View History

<?php
use MediaWiki\MediaWikiServices;
use Wikimedia\Rdbms\LoadBalancer;
/**
* Database factory class, this will determine whether to use the main database
* or an external database defined in configuration file
*/
class MWEchoDbFactory {
/**
* The cluster for the database
* @var string|bool
*/
private $cluster;
private $shared;
private $sharedCluster;
/**
* @param string|bool $cluster
* @param string|bool $shared
* @param string|bool $sharedCluster
*/
public function __construct( $cluster = false, $shared = false, $sharedCluster = false ) {
$this->cluster = $cluster;
$this->shared = $shared;
$this->sharedCluster = $sharedCluster;
}
/**
* Create a db factory instance from default Echo configuration
* A singleton is not necessary because it's actually handled
* inside core database object
*
* @return MWEchoDbFactory
*/
public static function newFromDefault() {
global $wgEchoCluster, $wgEchoSharedTrackingDB, $wgEchoSharedTrackingCluster;
return new self( $wgEchoCluster, $wgEchoSharedTrackingDB, $wgEchoSharedTrackingCluster );
}
/**
* @return bool
*/
public function isReadOnly() {
return ( $this->getLB()->getReadOnlyReason() !== false );
}
/**
* Get the database load balancer
* @return LoadBalancer
*/
protected function getLB() {
// Use the external db defined for Echo
if ( $this->cluster ) {
$lb = MediaWikiServices::getInstance()->getDBLoadBalancerFactory()->getExternalLB( $this->cluster );
} else {
$lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
}
return $lb;
}
/**
* @return LoadBalancer
*/
protected function getSharedLB() {
if ( $this->sharedCluster ) {
$lb = MediaWikiServices::getInstance()->getDBLoadBalancerFactory()->getExternalLB( $this->sharedCluster );
} else {
$lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
}
return $lb;
}
/**
* Get the database connection for Echo
* @param int $db Index of the connection to get
* @param mixed $groups Query groups.
* @return \Wikimedia\Rdbms\IDatabase
*/
public function getEchoDb( $db, $groups = [] ) {
return $this->getLB()->getConnection( $db, $groups );
}
/**
* @param int $db Index of the connection to get
* @param array $groups Query groups
* @return bool|\Wikimedia\Rdbms\IDatabase false if no shared db is configured
*/
public function getSharedDb( $db, $groups = [] ) {
if ( !$this->shared ) {
return false;
}
return $this->getSharedLB()->getConnection( $db, $groups, $this->shared );
}
/**
* Wrapper function for wfGetDB, some extensions like MobileFrontend is
* using this to issue sql queries against Echo database directly. This
* is totally not accepted and should be updated to use Echo database access
* objects
*
* @deprecated Use newFromDefault() instead to create a db factory
* @param int $db Index of the connection to get
* @param mixed $groups Query groups.
* @param string|bool $wiki The wiki ID, or false for the current wiki
* @return \Wikimedia\Rdbms\IDatabase
*/
public static function getDB( $db, $groups = [], $wiki = false ) {
global $wgEchoCluster;
$services = MediaWikiServices::getInstance();
// Use the external db defined for Echo
if ( $wgEchoCluster ) {
$lb = $services->getDBLoadBalancerFactory()->getExternalLB( $wgEchoCluster );
} else {
if ( $wiki === false ) {
$lb = $services->getDBLoadBalancer();
} else {
$lb = $services->getDBLoadBalancerFactory()->getMainLB( $wiki );
}
}
return $lb->getConnection( $db, $groups, $wiki );
}
/**
* Wait for the slaves of the database
*/
public function waitForSlaves() {
$this->waitFor( $this->getMasterPosition() );
}
/**
* Get the current master position for the wiki and echo
* db when they have at least one slave in their cluster.
*
* @return array
*/
public function getMasterPosition() {
$position = [
'wikiDb' => false,
'echoDb' => false,
];
$lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
if ( $lb->getServerCount() > 1 ) {
$position['wikiDb'] = $lb->getMasterPos();
};
if ( $this->cluster ) {
$lb = $this->getLB();
if ( $lb->getServerCount() > 1 ) {
$position['echoDb'] = $lb->getMasterPos();
}
}
return $position;
}
/**
* Receives the output of self::getMasterPosition. Waits
* for slaves to catch up to the master position at that
* point.
*
* @param array $position
*/
public function waitFor( array $position ) {
if ( $position['wikiDb'] ) {
MediaWikiServices::getInstance()->getDBLoadBalancer()->waitFor( $position['wikiDb'] );
}
if ( $position['echoDb'] ) {
$this->getLB()->waitFor( $position['echoDb'] );
}
}
/**
* Check whether it makes sense to retry a failed lookup on the master.
* @return bool True if there are multiple servers and changes were made in this request; false otherwise
*/
public function canRetryMaster() {
return $this->getLB()->getServerCount() > 1 && $this->getLB()->hasOrMadeRecentMasterChanges();
}
}