includes/objectcache/ObjectCacheFactory.php
<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
use MediaWiki\Config\ServiceOptions;
use MediaWiki\Http\Telemetry;
use MediaWiki\Logger\Spi;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use Wikimedia\Stats\StatsFactory;
/**
* Factory for cache objects as configured in the ObjectCaches setting.
*
* The word "cache" has two main dictionary meanings, and both
* are used in this factory class. They are:
*
* - a) Cache (the computer science definition).
* A place to store copies or computations on existing data for
* higher access speeds.
* - b) Storage.
* A place to store lightweight data that is not canonically
* stored anywhere else (e.g. a "hoard" of objects).
*
* Primary entry points:
*
* - ObjectCacheFactory::getLocalServerInstance( $fallbackType )
* Purpose: Memory cache for very hot keys.
* Stored only on the individual web server (typically APC or APCu for web requests,
* and EmptyBagOStuff in CLI mode).
* Not replicated to the other servers.
*
* - ObjectCacheFactory::getLocalClusterInstance()
* Purpose: Memory storage for per-cluster coordination and tracking.
* A typical use case would be a rate limit counter or cache regeneration mutex.
* Stored centrally within the local data-center. Not replicated to other DCs.
* Configured by $wgMainCacheType.
*
* - ObjectCacheFactory::getInstance( $cacheType )
* Purpose: Special cases (like tiered memory/disk caches).
* Get a specific cache type by key in $wgObjectCaches.
*
* All the above BagOStuff cache instances have their makeKey()
* method scoped to the *current* wiki ID. Use makeGlobalKey() to avoid this scoping
* when using keys that need to be shared amongst wikis.
*
* @ingroup Cache
* @since 1.42
*/
class ObjectCacheFactory {
/**
* @internal For use by ServiceWiring.php
* @var array
*/
public const CONSTRUCTOR_OPTIONS = [
MainConfigNames::SQLiteDataDir,
MainConfigNames::UpdateRowsPerQuery,
MainConfigNames::MemCachedServers,
MainConfigNames::MemCachedPersistent,
MainConfigNames::MemCachedTimeout,
MainConfigNames::CachePrefix,
MainConfigNames::ObjectCaches,
MainConfigNames::MainCacheType,
MainConfigNames::MessageCacheType,
MainConfigNames::ParserCacheType,
];
private ServiceOptions $options;
private StatsFactory $stats;
private Spi $logger;
/** @var BagOStuff[] */
private $instances = [];
private string $domainId;
/** @var callable */
private $dbLoadBalancerFactory;
/**
* @internal ObjectCacheTest only
* @var string
*/
public static $localServerCacheClass;
public function __construct(
ServiceOptions $options,
StatsFactory $stats,
Spi $loggerSpi,
callable $dbLoadBalancerFactory,
string $domainId
) {
$options->assertRequiredOptions( self::CONSTRUCTOR_OPTIONS );
$this->options = $options;
$this->stats = $stats;
$this->logger = $loggerSpi;
$this->dbLoadBalancerFactory = $dbLoadBalancerFactory;
$this->domainId = $domainId;
}
/**
* Get the default keyspace for this wiki.
*
* This is either the value of the MainConfigNames::CachePrefix setting
* or (if the former is unset) the MainConfigNames::DBname setting, with
* MainConfigNames::DBprefix (if defined).
*
* @return string
*/
private function getDefaultKeyspace(): string {
$cachePrefix = $this->options->get( MainConfigNames::CachePrefix );
if ( is_string( $cachePrefix ) && $cachePrefix !== '' ) {
return $cachePrefix;
}
return $this->domainId;
}
/**
* Create a new cache object of the specified type.
*
* @param string|int $id A key in $wgObjectCaches.
* @return BagOStuff
*/
private function newFromId( $id ): BagOStuff {
if ( $id === CACHE_ANYTHING ) {
$id = $this->getAnythingId();
}
if ( !isset( $this->options->get( MainConfigNames::ObjectCaches )[$id] ) ) {
// Always recognize these
if ( $id === CACHE_NONE ) {
return new EmptyBagOStuff();
} elseif ( $id === CACHE_HASH ) {
return new HashBagOStuff();
} elseif ( $id === CACHE_ACCEL ) {
return self::makeLocalServerCache( $this->getDefaultKeyspace() );
}
throw new InvalidArgumentException( "Invalid object cache type \"$id\" requested. " .
"It is not present in \$wgObjectCaches." );
}
return $this->newFromParams( $this->options->get( MainConfigNames::ObjectCaches )[$id] );
}
/**
* Get a cached instance of the specified type of cache object.
*
* @param string|int $id A key in $wgObjectCaches.
* @return BagOStuff
*/
public function getInstance( $id ): BagOStuff {
if ( !isset( $this->instances[$id] ) ) {
$this->instances[$id] = $this->newFromId( $id );
}
return $this->instances[$id];
}
/**
* Create a new cache object from parameters specification supplied.
*
* @internal Using this method directly outside of MediaWiki core
* is discouraged. Use getInstance() instead and supply the ID
* of the cache instance to be looked up.
*
* @param array $params Must have 'factory' or 'class' property.
* - factory: Callback passed $params that returns BagOStuff.
* - class: BagOStuff subclass constructed with $params.
* - loggroup: Alias to set 'logger' key with LoggerFactory group.
* - .. Other parameters passed to factory or class.
*
* @return BagOStuff
*/
public function newFromParams( array $params ): BagOStuff {
$logger = $this->logger->getLogger( $params['loggroup'] ?? 'objectcache' );
// Apply default parameters and resolve the logger instance
$params += [
'logger' => $logger,
'keyspace' => $this->getDefaultKeyspace(),
'asyncHandler' => [ DeferredUpdates::class, 'addCallableUpdate' ],
'reportDupes' => true,
'stats' => $this->stats,
];
if ( isset( $params['factory'] ) ) {
$args = $params['args'] ?? [ $params ];
return call_user_func( $params['factory'], ...$args );
}
if ( !isset( $params['class'] ) ) {
throw new InvalidArgumentException(
'No "factory" nor "class" provided; got "' . print_r( $params, true ) . '"'
);
}
$class = $params['class'];
// Normalization and DI for SqlBagOStuff
if ( is_a( $class, SqlBagOStuff::class, true ) ) {
$this->prepareSqlBagOStuffFromParams( $params );
}
// Normalization and DI for MemcachedBagOStuff
if ( is_subclass_of( $class, MemcachedBagOStuff::class ) ) {
$this->prepareMemcachedBagOStuffFromParams( $params );
}
// Normalization and DI for MultiWriteBagOStuff
if ( is_a( $class, MultiWriteBagOStuff::class, true ) ) {
$this->prepareMultiWriteBagOStuffFromParams( $params );
}
if ( is_a( $class, RESTBagOStuff::class, true ) ) {
$this->prepareRESTBagOStuffFromParams( $params );
}
return new $class( $params );
}
private function prepareSqlBagOStuffFromParams( array &$params ): void {
if ( isset( $params['globalKeyLB'] ) ) {
throw new InvalidArgumentException(
'globalKeyLB in $wgObjectCaches is no longer supported' );
}
if ( isset( $params['server'] ) && !isset( $params['servers'] ) ) {
$params['servers'] = [ $params['server'] ];
unset( $params['server'] );
}
if ( isset( $params['servers'] ) ) {
// In the past it was not required to set 'dbDirectory' in $wgObjectCaches
foreach ( $params['servers'] as &$server ) {
if ( $server['type'] === 'sqlite' && !isset( $server['dbDirectory'] ) ) {
$server['dbDirectory'] = $this->options->get( MainConfigNames::SQLiteDataDir );
}
}
} elseif ( isset( $params['cluster'] ) ) {
$cluster = $params['cluster'];
$dbLbFactory = $this->dbLoadBalancerFactory;
$params['loadBalancerCallback'] = static function () use ( $cluster, $dbLbFactory ) {
return $dbLbFactory()->getExternalLB( $cluster );
};
$params += [ 'dbDomain' => false ];
} else {
$dbLbFactory = $this->dbLoadBalancerFactory;
$params['loadBalancerCallback'] = static function () use ( $dbLbFactory ) {
return $dbLbFactory()->getMainLb();
};
$params += [ 'dbDomain' => false ];
}
$params += [ 'writeBatchSize' => $this->options->get( MainConfigNames::UpdateRowsPerQuery ) ];
}
private function prepareMemcachedBagOStuffFromParams( array &$params ): void {
$params += [
'servers' => $this->options->get( MainConfigNames::MemCachedServers ),
'persistent' => $this->options->get( MainConfigNames::MemCachedPersistent ),
'timeout' => $this->options->get( MainConfigNames::MemCachedTimeout ),
];
}
private function prepareMultiWriteBagOStuffFromParams( array &$params ): void {
// Phan warns about foreach with non-array because it
// thinks any key can be Closure|IBufferingStatsdDataFactory
'@phan-var array{caches:array[]} $params';
foreach ( $params['caches'] ?? [] as $i => $cacheInfo ) {
// Ensure logger, keyspace, asyncHandler, etc are injected just as if
// one of these was configured without MultiWriteBagOStuff.
$params['caches'][$i] = $this->newFromParams( $cacheInfo );
}
}
private function prepareRESTBagOStuffFromParams( array &$params ): void {
$params['telemetry'] = Telemetry::getInstance();
}
/**
* Factory function for CACHE_ACCEL (referenced from configuration)
*
* This will look for any APC or APCu style server-local cache.
* A fallback cache can be specified if none is found.
*
* // Direct calls
* ObjectCache::getLocalServerInstance( $fallbackType );
*
* // From $wgObjectCaches via newFromParams()
* ObjectCache::getLocalServerInstance( [ 'fallback' => $fallbackType ] );
*
* @param int|string|array $fallback Fallback cache or parameter map with 'fallback'
* @return BagOStuff
* @throws InvalidArgumentException
*/
public function getLocalServerInstance( $fallback = CACHE_NONE ): BagOStuff {
$cache = $this->getInstance( CACHE_ACCEL );
if ( $cache instanceof EmptyBagOStuff ) {
if ( is_array( $fallback ) ) {
$fallback = $fallback['fallback'] ?? CACHE_NONE;
}
$cache = $this->getInstance( $fallback );
}
return $cache;
}
/**
* Clear all the cached instances.
*/
public function clear(): void {
$this->instances = [];
}
/**
* Get the class which will be used for the local server cache
* @return string
*/
private static function getLocalServerCacheClass() {
if ( self::$localServerCacheClass !== null ) {
return self::$localServerCacheClass;
}
if ( function_exists( 'apcu_fetch' ) ) {
// Make sure the APCu methods actually store anything
if ( PHP_SAPI !== 'cli' || ini_get( 'apc.enable_cli' ) ) {
return APCUBagOStuff::class;
}
} elseif ( function_exists( 'wincache_ucache_get' ) ) {
return WinCacheBagOStuff::class;
}
return EmptyBagOStuff::class;
}
/**
* Get the ID that will be used for CACHE_ANYTHING
*
* @internal
* @return string|int
*/
public function getAnythingId() {
$candidates = [
$this->options->get( MainConfigNames::MainCacheType ),
$this->options->get( MainConfigNames::MessageCacheType ),
$this->options->get( MainConfigNames::ParserCacheType )
];
foreach ( $candidates as $candidate ) {
if ( $candidate === CACHE_ACCEL ) {
// CACHE_ACCEL might default to nothing if no APCu
// See includes/ServiceWiring.php
$class = self::getLocalServerCacheClass();
if ( $class !== EmptyBagOStuff::class ) {
return $candidate;
}
} elseif ( $candidate !== CACHE_NONE && $candidate !== CACHE_ANYTHING ) {
return $candidate;
}
}
$services = MediaWikiServices::getInstance();
if ( $services->isServiceDisabled( 'DBLoadBalancer' ) ) {
// The DBLoadBalancer service is disabled, so we can't use the database!
$candidate = CACHE_NONE;
} elseif ( $services->isStorageDisabled() ) {
// Storage services are disabled because MediaWikiServices::disableStorage()
// was called. This is typically the case during installation.
$candidate = CACHE_NONE;
} else {
$candidate = CACHE_DB;
}
return $candidate;
}
/**
* Create a new BagOStuff instance for local-server caching.
*
* Only use this if you explicitly require the creation of
* a fresh instance. Whenever possible, use or inject the object
* from MediaWikiServices::getLocalServerObjectCache() instead.
*
* NOTE: This method is called very early via Setup.php by ExtensionRegistry,
* and thus must remain fairly standalone so as to not cause initialization
* of the MediaWikiServices singleton.
*
* @internal For use by ServiceWiring and ExtensionRegistry. There are use
* cases whereby we want to build up local server cache without service
* wiring available.
* @since 1.43, previously on ObjectCache.php since 1.35
*
* @param string $keyspace
* @return BagOStuff
*/
public static function makeLocalServerCache( string $keyspace ) {
$params = [
'reportDupes' => false,
// Even simple caches must use a keyspace (T247562)
'keyspace' => $keyspace,
];
$class = self::getLocalServerCacheClass();
return new $class( $params );
}
/**
* Determine whether a config ID would access the database
*
* @internal For use by ServiceWiring.php
* @param string|int $id A key in $wgObjectCaches
* @return bool
*/
public function isDatabaseId( $id ) {
// NOTE: Sanity check if $id is set to CACHE_ANYTHING and
// everything is going through service wiring. CACHE_ANYTHING
// would default to CACHE_DB, let's handle that early for cases
// where all cache configs are set to CACHE_ANYTHING (T362686).
if ( $id === CACHE_ANYTHING ) {
$id = $this->getAnythingId();
return $this->isDatabaseId( $id );
}
if ( !isset( $this->options->get( MainConfigNames::ObjectCaches )[$id] ) ) {
return false;
}
$cache = $this->options->get( MainConfigNames::ObjectCaches )[$id];
if ( ( $cache['class'] ?? '' ) === SqlBagOStuff::class ) {
return true;
}
return false;
}
/**
* Get the main cluster-local cache object.
*
* @since 1.43, previously on ObjectCache.php since 1.27
* @return BagOStuff
*/
public function getLocalClusterInstance() {
return $this->getInstance(
$this->options->get( MainConfigNames::MainCacheType )
);
}
}