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