includes/MediaWikiServices.php

   1 <?php
   2 namespace MediaWiki;
   3
   4 use ApiQueryInfo;
   5 use CentralIdLookup;
   6 use Config;
   7 use ConfigFactory;
   8 use DeferredUpdates;
   9 use FileBackendGroup;
  10 use GlobalVarConfig;
  11 use Hooks;
  12 use IP;
  13 use JobQueueAggregator;
  14 use Language;
  15 use LBFactory;
  16 use LinkCache;
  17 use LoadBalancer;
  18 use LockManagerGroup;
  19 use MagicWord;
  20 use MediaHandler;
  21 use MediaWiki\Services\ServiceContainer;
  22 use MediaWiki\Session\SessionManager;
  23 use MessageCache;
  24 use MWException;
  25 use MWNamespace;
  26 use MWTidy;
  27 use ObjectCache;
  28 use RedisConnectionPool;
  29 use RepoGroup;
  30 use RequestContext;
  31 use ResourceLoader;
  32 use SiteLookup;
  33 use SiteStore;
  34 use SpecialPageFactory;
  35 use Title;
  36 use User;
  37 use WatchedItemStore;
  38 use Wikimedia\Assert\Assert;
  39
  40 /**
  41  * Service locator for MediaWiki core services.
  42  *
  43  * This program is free software; you can redistribute it and/or modify
  44  * it under the terms of the GNU General Public License as published by
  45  * the Free Software Foundation; either version 2 of the License, or
  46  * (at your option) any later version.
  47  *
  48  * This program is distributed in the hope that it will be useful,
  49  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  50  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  51  * GNU General Public License for more details.
  52  *
  53  * You should have received a copy of the GNU General Public License along
  54  * with this program; if not, write to the Free Software Foundation, Inc.,
  55  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  56  * http://www.gnu.org/copyleft/gpl.html
  57  *
  58  * @file
  59  *
  60  * @since 1.27
  61  */
  62
  63 /**
  64  * MediaWikiServices is the service locator for the application scope of MediaWiki.
  65  * Its implemented as a simple configurable DI container.
  66  * MediaWikiServices acts as a top level factory/registry for top level services, and builds
  67  * the network of service objects that defines MediaWiki's application logic.
  68  * It acts as an entry point to MediaWiki's dependency injection mechanism.
  69  *
  70  * Services are defined in the "wiring" array passed to the constructor,
  71  * or by calling defineService().
  72  *
  73  * @see docs/injection.txt for an overview of using dependency injection in the
  74  *      MediaWiki code base.
  75  */
  76 class MediaWikiServices extends ServiceContainer {
  77
  78         /**
  79          * @var MediaWikiServices|null
  80          */
  81         private static $instance = null;
  82
  83         /**
  84          * Returns the global default instance of the top level service locator.
  85          *
  86          * The default instance is initialized using the service instantiator functions
  87          * defined in ServiceWiring.php.
  88          *
  89          * @note This should only be called by static functions! The instance returned here
  90          * should not be passed around! Objects that need access to a service should have
  91          * that service injected into the constructor, never a service locator!
  92          *
  93          * @return MediaWikiServices
  94          */
  95         public static function getInstance() {
  96                 if ( self::$instance === null ) {
  97                         // NOTE: constructing GlobalVarConfig here is not particularly pretty,
  98                         // but some information from the global scope has to be injected here,
  99                         // even if it's just a file name or database credentials to load
 100                         // configuration from.
 101                         $bootstrapConfig = new GlobalVarConfig();
 102                         self::$instance = self::newInstance( $bootstrapConfig );
 103                 }
 104
 105                 return self::$instance;
 106         }
 107
 108         /**
 109          * Replaces the global MediaWikiServices instance.
 110          *
 111          * @note This is for use in PHPUnit tests only!
 112          *
 113          * @throws MWException if called outside of PHPUnit tests.
 114          *
 115          * @param MediaWikiServices $services The new MediaWikiServices object.
 116          *
 117          * @return MediaWikiServices The old MediaWikiServices object, so it can be restored later.
 118          */
 119         public static function forceGlobalInstance( MediaWikiServices $services ) {
 120                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 121                         throw new MWException( __METHOD__ . ' must not be used outside unit tests.' );
 122                 }
 123
 124                 $old = self::getInstance();
 125                 self::$instance = $services;
 126
 127                 self::resetLegacyServices();
 128
 129                 return $old;
 130         }
 131
 132         /**
 133          * Creates a new instance of MediaWikiServices and sets it as the global default
 134          * instance. getInstance() will return a different MediaWikiServices object
 135          * after every call to resetGlobalServiceLocator().
 136          *
 137          * @warning This should not be used during normal operation. It is intended for use
 138          * when the configuration has changed significantly since bootstrap time, e.g.
 139          * during the installation process or during testing.
 140          *
 141          * @warning Calling resetGlobalServiceLocator() may leave the application in an inconsistent
 142          * state. Calling this is only safe under the ASSUMPTION that NO REFERENCE to
 143          * any of the services managed by MediaWikiServices exist. If any service objects
 144          * managed by the old MediaWikiServices instance remain in use, they may INTERFERE
 145          * with the operation of the services managed by the new MediaWikiServices.
 146          * Operating with a mix of services created by the old and the new
 147          * MediaWikiServices instance may lead to INCONSISTENCIES and even DATA LOSS!
 148          * Any class implementing LAZY LOADING is especially prone to this problem,
 149          * since instances would typically retain a reference to a storage layer service.
 150          *
 151          * @see forceGlobalInstance()
 152          * @see resetGlobalInstance()
 153          * @see resetBetweenTest()
 154          *
 155          * @param Config|null $bootstrapConfig The Config object to be registered as the
 156          *        'BootstrapConfig' service. This has to contain at least the information
 157          *        needed to set up the 'ConfigFactory' service. If not given, the bootstrap
 158          *        config of the old instance of MediaWikiServices will be re-used. If there
 159          *        was no previous instance, a new GlobalVarConfig object will be used to
 160          *        bootstrap the services.
 161          *
 162          * @throws MWException
 163          */
 164         public static function resetGlobalInstance( Config $bootstrapConfig = null ) {
 165                 if ( self::$instance === null ) {
 166                         // no global instance yet, nothing to reset
 167                         return;
 168                 }
 169
 170                 if ( $bootstrapConfig === null ) {
 171                         $bootstrapConfig = self::$instance->getBootstrapConfig();
 172                 }
 173
 174                 self::$instance->destroy();
 175
 176                 self::$instance = self::newInstance( $bootstrapConfig );
 177
 178                 self::resetLegacyServices();
 179         }
 180
 181         /**
 182          * Creates a new MediaWikiServices instance and initializes it according to the
 183          * given $bootstrapConfig. In particular, all wiring files defined in the
 184          * ServiceWiringFiles setting are loaded, and the MediaWikiServices hook is called.
 185          *
 186          * @param Config|null $bootstrapConfig The Config object to be registered as the
 187          *        'BootstrapConfig' service. This has to contain at least the information
 188          *        needed to set up the 'ConfigFactory' service. If not provided, any call
 189          *        to getBootstrapConfig(), getConfigFactory, or getMainConfig will fail.
 190          *        A MediaWikiServices instance without access to configuration is called
 191          *        "primordial".
 192          *
 193          * @return MediaWikiServices
 194          * @throws MWException
 195          */
 196         private static function newInstance( Config $bootstrapConfig ) {
 197                 $instance = new self( $bootstrapConfig );
 198
 199                 // Load the default wiring from the specified files.
 200                 $wiringFiles = $bootstrapConfig->get( 'ServiceWiringFiles' );
 201                 $instance->loadWiringFiles( $wiringFiles );
 202
 203                 // Provide a traditional hook point to allow extensions to configure services.
 204                 Hooks::run( 'MediaWikiServices', [ $instance ] );
 205
 206                 return $instance;
 207         }
 208
 209         /**
 210          * Resets global instances of services that have not yet been ported to using
 211          * MediaWikiServices to manage their default instance.
 212          *
 213          * @note eventually, all global service instances are to be managed by MediaWikiServices.
 214          * To emulate the effect of resetting the global service locator, we reset the individual
 215          * static singletons for now.
 216          *
 217          * @note As long as we don't know the interdependencies between the services, the only way
 218          * to reset services consistently is to reset all services at once. This should be ok since
 219          * there should rarely be a need to reset all processes.
 220          */
 221         private static function resetLegacyServices() {
 222                 global $wgContLang, $wgUser, $wgMemc, $wgRequest;
 223
 224                 $services = self::getInstance();
 225                 $config = $services->getMainConfig();
 226
 227                 // NOTE: all the services instance that get reset below should be migrated
 228                 // to be managed by MediaWikiServices. Eventually, this method can then be
 229                 // removed.
 230
 231                 User::resetIdByNameCache();
 232                 LinkCache::singleton()->clear();
 233                 Title::clearCaches();
 234
 235                 MWTidy::destroySingleton();
 236                 MagicWord::clearCache();
 237                 SpecialPageFactory::resetList();
 238                 JobQueueAggregator::destroySingleton();
 239                 DeferredUpdates::clearPendingUpdates();
 240                 CentralIdLookup::resetCache();
 241                 MediaHandler::resetCache();
 242                 IP::clearCaches();
 243                 ResourceLoader::clearCache();
 244
 245                 ApiQueryInfo::resetTokenCache();
 246
 247                 RepoGroup::destroySingleton();
 248
 249                 MessageCache::destroyInstance();
 250
 251                 MWNamespace::getCanonicalNamespaces( true ); # reset namespace cache
 252                 Language::$mLangObjCache = [];
 253                 Language::getLocalisationCache()->unloadAll();
 254
 255                 ObjectCache::clear();
 256                 RedisConnectionPool::destroySingletons();
 257                 FileBackendGroup::destroySingleton();
 258                 LockManagerGroup::destroySingletons();
 259
 260                 RequestContext::resetMain();
 261                 $wgRequest = RequestContext::getMain()->getRequest(); // BackCompat
 262
 263                 $wgContLang = Language::factory( $config->get( 'LanguageCode' ) );
 264                 $wgContLang->resetNamespaces(); # reset namespace cache
 265
 266                 $wgMemc = ObjectCache::getLocalClusterInstance();
 267                 $wgUser = RequestContext::getMain()->getUser();
 268
 269                 SessionManager::resetCache();
 270
 271                 // Provide a hook point for extensions that need to reset global service instances.
 272                 Hooks::run( 'MediaWikiServices::resetLegacyServices', [ $services ] );
 273         }
 274
 275         /**
 276          * Disables all storage layer services. After calling this, any attempt to access the
 277          * storage layer will result in an error. Use resetGlobalInstance() to restore normal
 278          * operation.
 279          *
 280          * @warning This is intended for extreme situations only and should never be used
 281          * while serving normal web requests. Legitimate use cases for this method include
 282          * the installation process. Test fixtures may also use this, if the fixture relies
 283          * on globalState.
 284          *
 285          * @see resetGlobalInstance()
 286          * @see resetChildProcessServices()
 287          */
 288         public static function disableStorageBackend() {
 289                 // TODO: also disable some Caches, JobQueues, etc
 290                 $destroy = [ 'DBLoadBalancer', 'DBLoadBalancerFactory' ];
 291                 $services = self::getInstance();
 292
 293                 foreach ( $destroy as $name ) {
 294                         $services->disableService( $name );
 295                 }
 296         }
 297
 298         /**
 299          * Resets any services that may have become stale after a child process
 300          * returns from after pcntl_fork(). It's also safe, but generally unnecessary,
 301          * to call this method from the parent process.
 302          *
 303          * @note This is intended for use in the context of process forking only!
 304          *
 305          * @see resetGlobalInstance()
 306          * @see disableStorageBackend()
 307          */
 308         public static function resetChildProcessServices() {
 309                 // NOTE: for now, just reset everything. Since we don't know the interdependencies
 310                 // between services, we can't do this more selectively at this time.
 311                 self::resetGlobalInstance();
 312
 313                 // Child, reseed because there is no bug in PHP:
 314                 // http://bugs.php.net/bug.php?id=42465
 315                 mt_srand( getmypid() );
 316         }
 317
 318         /**
 319          * Resets the given service for testing purposes.
 320          *
 321          * @warning This is generally unsafe! Other services may still retain references
 322          * to the stale service instance, leading to failures and inconsistencies. Subclasses
 323          * may use this method to reset specific services under specific instances, but
 324          * it should not be exposed to application logic.
 325          *
 326          * @note With proper dependency injection used throughout the codebase, this method
 327          * should not be needed. It is provided to allow tests that pollute global service
 328          * instances to clean up.
 329          *
 330          * @param string $name
 331          * @param string $destroy Whether the service instance should be destroyed if it exists.
 332          *        When set to false, any existing service instance will effectively be detached
 333          *        from the container.
 334          *
 335          * @throws MWException if called outside of PHPUnit tests.
 336          */
 337         public function resetServiceForTesting( $name, $destroy = true ) {
 338                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 339                         throw new MWException( 'resetServiceForTesting() must not be used outside unit tests.' );
 340                 }
 341
 342                 $this->resetService( $name, $destroy );
 343         }
 344
 345         /**
 346          * Convenience method that throws an exception if called outside the service bootstrapping
 347          * phase as indicated by the MW_SERVICE_BOOTSTRAP_COMPLETE constant - that is, after
 348          * Setup.php has called resetGlobalInstance(). Additionally, no exception is thrown if
 349          * this method is called during unit testing (as indicated by MW_PHPUNIT_TEST) or
 350          * during installation (as indicated by MEDIAWIKI_INSTALL).
 351          *
 352          * This method is intended to be used to safeguard against accidentally resetting
 353          * global service instances that are not yet managed by MediaWikiServices. It is
 354          * defined here in the MediaWikiServices services class to keep the knowledge about
 355          * how the bootstrapping phase is managed central.
 356          *
 357          * @param string $method the name of the caller method, as given by __METHOD__.
 358          *
 359          * @throws MWException if called outside bootstrap mode.
 360          *
 361          * @see resetGlobalInstance()
 362          * @see forceGlobalInstance()
 363          * @see disableStorageBackend()
 364          */
 365         public static function failUnlessBootstrapping( $method ) {
 366                 if ( !defined( 'MW_PHPUNIT_TEST' )
 367                         && !defined( 'MEDIAWIKI_INSTALL' )
 368                         && defined( 'MW_SERVICE_BOOTSTRAP_COMPLETE' )
 369                 ) {
 370                         throw new MWException( $method . ' may only be called during bootstrapping unit tests!' );
 371                 }
 372
 373                 ObjectCache::clear();
 374         }
 375
 376         /**
 377          * @param Config $config The Config object to be registered as the 'BootstrapConfig' service.
 378          *        This has to contain at least the information needed to set up the 'ConfigFactory'
 379          *        service.
 380          */
 381         public function __construct( Config $config ) {
 382                 parent::__construct();
 383
 384                 // Register the given Config object as the bootstrap config service.
 385                 $this->defineService( 'BootstrapConfig', function() use ( $config ) {
 386                         return $config;
 387                 } );
 388         }
 389
 390         // CONVENIENCE GETTERS ////////////////////////////////////////////////////
 391
 392         /**
 393          * Returns the Config object containing the bootstrap configuration.
 394          * Bootstrap configuration would typically include database credentials
 395          * and other information that may be needed before the ConfigFactory
 396          * service can be instantiated.
 397          *
 398          * @note This should only be used during bootstrapping, in particular
 399          * when creating the MainConfig service. Application logic should
 400          * use getMainConfig() to get a Config instances.
 401          *
 402          * @return Config
 403          */
 404         public function getBootstrapConfig() {
 405                 return $this->getService( 'BootstrapConfig' );
 406         }
 407
 408         /**
 409          * @return ConfigFactory
 410          */
 411         public function getConfigFactory() {
 412                 return $this->getService( 'ConfigFactory' );
 413         }
 414
 415         /**
 416          * Returns the Config object that provides configuration for MediaWiki core.
 417          * This may or may not be the same object that is returned by getBootstrapConfig().
 418          *
 419          * @return Config
 420          */
 421         public function getMainConfig() {
 422                 return $this->getService( 'MainConfig' );
 423         }
 424
 425         /**
 426          * @return SiteLookup
 427          */
 428         public function getSiteLookup() {
 429                 return $this->getService( 'SiteLookup' );
 430         }
 431
 432         /**
 433          * @return SiteStore
 434          */
 435         public function getSiteStore() {
 436                 return $this->getService( 'SiteStore' );
 437         }
 438
 439         /**
 440          * @return LBFactory
 441          */
 442         public function getDBLoadBalancerFactory() {
 443                 return $this->getService( 'DBLoadBalancerFactory' );
 444         }
 445
 446         /**
 447          * @return LoadBalancer The main DB load balancer for the local wiki.
 448          */
 449         public function getDBLoadBalancer() {
 450                 return $this->getService( 'DBLoadBalancer' );
 451         }
 452
 453         /**
 454          * @return WatchedItemStore
 455          */
 456         public function getWatchedItemStore() {
 457                 return $this->getService( 'WatchedItemStore' );
 458         }
 459
 460         ///////////////////////////////////////////////////////////////////////////
 461         // NOTE: When adding a service getter here, don't forget to add a test
 462         // case for it in MediaWikiServicesTest::provideGetters() and in
 463         // MediaWikiServicesTest::provideGetService()!
 464         ///////////////////////////////////////////////////////////////////////////
 465
 466 }