includes/MediaWikiServices.php

   1 <?php
   2 namespace MediaWiki;
   3
   4 use Config;
   5 use ConfigFactory;
   6 use EventRelayerGroup;
   7 use GenderCache;
   8 use GlobalVarConfig;
   9 use Hooks;
  10 use LBFactory;
  11 use LinkCache;
  12 use Liuggio\StatsdClient\Factory\StatsdDataFactory;
  13 use LoadBalancer;
  14 use MediaHandlerFactory;
  15 use MediaWiki\Linker\LinkRenderer;
  16 use MediaWiki\Linker\LinkRendererFactory;
  17 use MediaWiki\Services\SalvageableService;
  18 use MediaWiki\Services\ServiceContainer;
  19 use MWException;
  20 use ObjectCache;
  21 use SearchEngine;
  22 use SearchEngineConfig;
  23 use SearchEngineFactory;
  24 use SiteLookup;
  25 use SiteStore;
  26 use WatchedItemStore;
  27 use WatchedItemQueryService;
  28 use SkinFactory;
  29 use TitleFormatter;
  30 use TitleParser;
  31 use VirtualRESTServiceClient;
  32 use MediaWiki\Interwiki\InterwikiLookup;
  33
  34 /**
  35  * Service locator for MediaWiki core services.
  36  *
  37  * This program is free software; you can redistribute it and/or modify
  38  * it under the terms of the GNU General Public License as published by
  39  * the Free Software Foundation; either version 2 of the License, or
  40  * (at your option) any later version.
  41  *
  42  * This program is distributed in the hope that it will be useful,
  43  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  44  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  45  * GNU General Public License for more details.
  46  *
  47  * You should have received a copy of the GNU General Public License along
  48  * with this program; if not, write to the Free Software Foundation, Inc.,
  49  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  50  * http://www.gnu.org/copyleft/gpl.html
  51  *
  52  * @file
  53  *
  54  * @since 1.27
  55  */
  56
  57 /**
  58  * MediaWikiServices is the service locator for the application scope of MediaWiki.
  59  * Its implemented as a simple configurable DI container.
  60  * MediaWikiServices acts as a top level factory/registry for top level services, and builds
  61  * the network of service objects that defines MediaWiki's application logic.
  62  * It acts as an entry point to MediaWiki's dependency injection mechanism.
  63  *
  64  * Services are defined in the "wiring" array passed to the constructor,
  65  * or by calling defineService().
  66  *
  67  * @see docs/injection.txt for an overview of using dependency injection in the
  68  *      MediaWiki code base.
  69  */
  70 class MediaWikiServices extends ServiceContainer {
  71
  72         /**
  73          * @var MediaWikiServices|null
  74          */
  75         private static $instance = null;
  76
  77         /**
  78          * Returns the global default instance of the top level service locator.
  79          *
  80          * @since 1.27
  81          *
  82          * The default instance is initialized using the service instantiator functions
  83          * defined in ServiceWiring.php.
  84          *
  85          * @note This should only be called by static functions! The instance returned here
  86          * should not be passed around! Objects that need access to a service should have
  87          * that service injected into the constructor, never a service locator!
  88          *
  89          * @return MediaWikiServices
  90          */
  91         public static function getInstance() {
  92                 if ( self::$instance === null ) {
  93                         // NOTE: constructing GlobalVarConfig here is not particularly pretty,
  94                         // but some information from the global scope has to be injected here,
  95                         // even if it's just a file name or database credentials to load
  96                         // configuration from.
  97                         $bootstrapConfig = new GlobalVarConfig();
  98                         self::$instance = self::newInstance( $bootstrapConfig, 'load' );
  99                 }
 100
 101                 return self::$instance;
 102         }
 103
 104         /**
 105          * Replaces the global MediaWikiServices instance.
 106          *
 107          * @since 1.28
 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                 return $old;
 126         }
 127
 128         /**
 129          * Creates a new instance of MediaWikiServices and sets it as the global default
 130          * instance. getInstance() will return a different MediaWikiServices object
 131          * after every call to resetGlobalInstance().
 132          *
 133          * @since 1.28
 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 resetGlobalInstance() 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          * @param string $quick Set this to "quick" to allow expensive resources to be re-used.
 161          * See SalvageableService for details.
 162          *
 163          * @throws MWException If called after MW_SERVICE_BOOTSTRAP_COMPLETE has been defined in
 164          *         Setup.php (unless MW_PHPUNIT_TEST or MEDIAWIKI_INSTALL or RUN_MAINTENANCE_IF_MAIN
 165          *          is defined).
 166          */
 167         public static function resetGlobalInstance( Config $bootstrapConfig = null, $quick = '' ) {
 168                 if ( self::$instance === null ) {
 169                         // no global instance yet, nothing to reset
 170                         return;
 171                 }
 172
 173                 self::failIfResetNotAllowed( __METHOD__ );
 174
 175                 if ( $bootstrapConfig === null ) {
 176                         $bootstrapConfig = self::$instance->getBootstrapConfig();
 177                 }
 178
 179                 $oldInstance = self::$instance;
 180
 181                 self::$instance = self::newInstance( $bootstrapConfig );
 182                 self::$instance->importWiring( $oldInstance, [ 'BootstrapConfig' ] );
 183
 184                 if ( $quick === 'quick' ) {
 185                         self::$instance->salvage( $oldInstance );
 186                 } else {
 187                         $oldInstance->destroy();
 188                 }
 189
 190         }
 191
 192         /**
 193          * Salvages the state of any salvageable service instances in $other.
 194          *
 195          * @note $other will have been destroyed when salvage() returns.
 196          *
 197          * @param MediaWikiServices $other
 198          */
 199         private function salvage( self $other ) {
 200                 foreach ( $this->getServiceNames() as $name ) {
 201                         // The service could be new in the new instance and not registered in the
 202                         // other instance (e.g. an extension that was loaded after the instantiation of
 203                         // the other instance. Skip this service in this case. See T143974
 204                         try {
 205                                 $oldService = $other->peekService( $name );
 206                         } catch ( NoSuchServiceException $e ) {
 207                                 continue;
 208                         }
 209
 210                         if ( $oldService instanceof SalvageableService ) {
 211                                 /** @var SalvageableService $newService */
 212                                 $newService = $this->getService( $name );
 213                                 $newService->salvage( $oldService );
 214                         }
 215                 }
 216
 217                 $other->destroy();
 218         }
 219
 220         /**
 221          * Creates a new MediaWikiServices instance and initializes it according to the
 222          * given $bootstrapConfig. In particular, all wiring files defined in the
 223          * ServiceWiringFiles setting are loaded, and the MediaWikiServices hook is called.
 224          *
 225          * @param Config|null $bootstrapConfig The Config object to be registered as the
 226          *        'BootstrapConfig' service.
 227          *
 228          * @param string $loadWiring set this to 'load' to load the wiring files specified
 229          *        in the 'ServiceWiringFiles' setting in $bootstrapConfig.
 230          *
 231          * @return MediaWikiServices
 232          * @throws MWException
 233          * @throws \FatalError
 234          */
 235         private static function newInstance( Config $bootstrapConfig, $loadWiring = '' ) {
 236                 $instance = new self( $bootstrapConfig );
 237
 238                 // Load the default wiring from the specified files.
 239                 if ( $loadWiring === 'load' ) {
 240                         $wiringFiles = $bootstrapConfig->get( 'ServiceWiringFiles' );
 241                         $instance->loadWiringFiles( $wiringFiles );
 242                 }
 243
 244                 // Provide a traditional hook point to allow extensions to configure services.
 245                 Hooks::run( 'MediaWikiServices', [ $instance ] );
 246
 247                 return $instance;
 248         }
 249
 250         /**
 251          * Disables all storage layer services. After calling this, any attempt to access the
 252          * storage layer will result in an error. Use resetGlobalInstance() to restore normal
 253          * operation.
 254          *
 255          * @since 1.28
 256          *
 257          * @warning This is intended for extreme situations only and should never be used
 258          * while serving normal web requests. Legitimate use cases for this method include
 259          * the installation process. Test fixtures may also use this, if the fixture relies
 260          * on globalState.
 261          *
 262          * @see resetGlobalInstance()
 263          * @see resetChildProcessServices()
 264          */
 265         public static function disableStorageBackend() {
 266                 // TODO: also disable some Caches, JobQueues, etc
 267                 $destroy = [ 'DBLoadBalancer', 'DBLoadBalancerFactory' ];
 268                 $services = self::getInstance();
 269
 270                 foreach ( $destroy as $name ) {
 271                         $services->disableService( $name );
 272                 }
 273
 274                 ObjectCache::clear();
 275         }
 276
 277         /**
 278          * Resets any services that may have become stale after a child process
 279          * returns from after pcntl_fork(). It's also safe, but generally unnecessary,
 280          * to call this method from the parent process.
 281          *
 282          * @since 1.28
 283          *
 284          * @note This is intended for use in the context of process forking only!
 285          *
 286          * @see resetGlobalInstance()
 287          * @see disableStorageBackend()
 288          */
 289         public static function resetChildProcessServices() {
 290                 // NOTE: for now, just reset everything. Since we don't know the interdependencies
 291                 // between services, we can't do this more selectively at this time.
 292                 self::resetGlobalInstance();
 293
 294                 // Child, reseed because there is no bug in PHP:
 295                 // http://bugs.php.net/bug.php?id=42465
 296                 mt_srand( getmypid() );
 297         }
 298
 299         /**
 300          * Resets the given service for testing purposes.
 301          *
 302          * @since 1.28
 303          *
 304          * @warning This is generally unsafe! Other services may still retain references
 305          * to the stale service instance, leading to failures and inconsistencies. Subclasses
 306          * may use this method to reset specific services under specific instances, but
 307          * it should not be exposed to application logic.
 308          *
 309          * @note With proper dependency injection used throughout the codebase, this method
 310          * should not be needed. It is provided to allow tests that pollute global service
 311          * instances to clean up.
 312          *
 313          * @param string $name
 314          * @param bool $destroy Whether the service instance should be destroyed if it exists.
 315          *        When set to false, any existing service instance will effectively be detached
 316          *        from the container.
 317          *
 318          * @throws MWException if called outside of PHPUnit tests.
 319          */
 320         public function resetServiceForTesting( $name, $destroy = true ) {
 321                 if ( !defined( 'MW_PHPUNIT_TEST' ) && !defined( 'MW_PARSER_TEST' ) ) {
 322                         throw new MWException( 'resetServiceForTesting() must not be used outside unit tests.' );
 323                 }
 324
 325                 $this->resetService( $name, $destroy );
 326         }
 327
 328         /**
 329          * Convenience method that throws an exception unless it is called during a phase in which
 330          * resetting of global services is allowed. In general, services should not be reset
 331          * individually, since that may introduce inconsistencies.
 332          *
 333          * @since 1.28
 334          *
 335          * This method will throw an exception if:
 336          *
 337          * - self::$resetInProgress is false (to allow all services to be reset together
 338          *   via resetGlobalInstance)
 339          * - and MEDIAWIKI_INSTALL is not defined (to allow services to be reset during installation)
 340          * - and MW_PHPUNIT_TEST is not defined (to allow services to be reset during testing)
 341          *
 342          * This method is intended to be used to safeguard against accidentally resetting
 343          * global service instances that are not yet managed by MediaWikiServices. It is
 344          * defined here in the MediaWikiServices services class to have a central place
 345          * for managing service bootstrapping and resetting.
 346          *
 347          * @param string $method the name of the caller method, as given by __METHOD__.
 348          *
 349          * @throws MWException if called outside bootstrap mode.
 350          *
 351          * @see resetGlobalInstance()
 352          * @see forceGlobalInstance()
 353          * @see disableStorageBackend()
 354          */
 355         public static function failIfResetNotAllowed( $method ) {
 356                 if ( !defined( 'MW_PHPUNIT_TEST' )
 357                         && !defined( 'MW_PARSER_TEST' )
 358                         && !defined( 'MEDIAWIKI_INSTALL' )
 359                         && !defined( 'RUN_MAINTENANCE_IF_MAIN' )
 360                         && defined( 'MW_SERVICE_BOOTSTRAP_COMPLETE' )
 361                 ) {
 362                         throw new MWException( $method . ' may only be called during bootstrapping and unit tests!' );
 363                 }
 364         }
 365
 366         /**
 367          * @param Config $config The Config object to be registered as the 'BootstrapConfig' service.
 368          *        This has to contain at least the information needed to set up the 'ConfigFactory'
 369          *        service.
 370          */
 371         public function __construct( Config $config ) {
 372                 parent::__construct();
 373
 374                 // Register the given Config object as the bootstrap config service.
 375                 $this->defineService( 'BootstrapConfig', function() use ( $config ) {
 376                         return $config;
 377                 } );
 378         }
 379
 380         // CONVENIENCE GETTERS ////////////////////////////////////////////////////
 381
 382         /**
 383          * Returns the Config object containing the bootstrap configuration.
 384          * Bootstrap configuration would typically include database credentials
 385          * and other information that may be needed before the ConfigFactory
 386          * service can be instantiated.
 387          *
 388          * @note This should only be used during bootstrapping, in particular
 389          * when creating the MainConfig service. Application logic should
 390          * use getMainConfig() to get a Config instances.
 391          *
 392          * @since 1.27
 393          * @return Config
 394          */
 395         public function getBootstrapConfig() {
 396                 return $this->getService( 'BootstrapConfig' );
 397         }
 398
 399         /**
 400          * @since 1.27
 401          * @return ConfigFactory
 402          */
 403         public function getConfigFactory() {
 404                 return $this->getService( 'ConfigFactory' );
 405         }
 406
 407         /**
 408          * Returns the Config object that provides configuration for MediaWiki core.
 409          * This may or may not be the same object that is returned by getBootstrapConfig().
 410          *
 411          * @since 1.27
 412          * @return Config
 413          */
 414         public function getMainConfig() {
 415                 return $this->getService( 'MainConfig' );
 416         }
 417
 418         /**
 419          * @since 1.27
 420          * @return SiteLookup
 421          */
 422         public function getSiteLookup() {
 423                 return $this->getService( 'SiteLookup' );
 424         }
 425
 426         /**
 427          * @since 1.27
 428          * @return SiteStore
 429          */
 430         public function getSiteStore() {
 431                 return $this->getService( 'SiteStore' );
 432         }
 433
 434         /**
 435          * @since 1.28
 436          * @return InterwikiLookup
 437          */
 438         public function getInterwikiLookup() {
 439                 return $this->getService( 'InterwikiLookup' );
 440         }
 441
 442         /**
 443          * @since 1.27
 444          * @return StatsdDataFactory
 445          */
 446         public function getStatsdDataFactory() {
 447                 return $this->getService( 'StatsdDataFactory' );
 448         }
 449
 450         /**
 451          * @since 1.27
 452          * @return EventRelayerGroup
 453          */
 454         public function getEventRelayerGroup() {
 455                 return $this->getService( 'EventRelayerGroup' );
 456         }
 457
 458         /**
 459          * @since 1.27
 460          * @return SearchEngine
 461          */
 462         public function newSearchEngine() {
 463                 // New engine object every time, since they keep state
 464                 return $this->getService( 'SearchEngineFactory' )->create();
 465         }
 466
 467         /**
 468          * @since 1.27
 469          * @return SearchEngineFactory
 470          */
 471         public function getSearchEngineFactory() {
 472                 return $this->getService( 'SearchEngineFactory' );
 473         }
 474
 475         /**
 476          * @since 1.27
 477          * @return SearchEngineConfig
 478          */
 479         public function getSearchEngineConfig() {
 480                 return $this->getService( 'SearchEngineConfig' );
 481         }
 482
 483         /**
 484          * @since 1.27
 485          * @return SkinFactory
 486          */
 487         public function getSkinFactory() {
 488                 return $this->getService( 'SkinFactory' );
 489         }
 490
 491         /**
 492          * @since 1.28
 493          * @return LBFactory
 494          */
 495         public function getDBLoadBalancerFactory() {
 496                 return $this->getService( 'DBLoadBalancerFactory' );
 497         }
 498
 499         /**
 500          * @since 1.28
 501          * @return LoadBalancer The main DB load balancer for the local wiki.
 502          */
 503         public function getDBLoadBalancer() {
 504                 return $this->getService( 'DBLoadBalancer' );
 505         }
 506
 507         /**
 508          * @since 1.28
 509          * @return WatchedItemStore
 510          */
 511         public function getWatchedItemStore() {
 512                 return $this->getService( 'WatchedItemStore' );
 513         }
 514
 515         /**
 516          * @since 1.28
 517          * @return WatchedItemQueryService
 518          */
 519         public function getWatchedItemQueryService() {
 520                 return $this->getService( 'WatchedItemQueryService' );
 521         }
 522
 523         /**
 524          * @since 1.28
 525          * @return MediaHandlerFactory
 526          */
 527         public function getMediaHandlerFactory() {
 528                 return $this->getService( 'MediaHandlerFactory' );
 529         }
 530
 531         /**
 532          * @since 1.28
 533          * @return GenderCache
 534          */
 535         public function getGenderCache() {
 536                 return $this->getService( 'GenderCache' );
 537         }
 538
 539         /**
 540          * @since 1.28
 541          * @return LinkCache
 542          */
 543         public function getLinkCache() {
 544                 return $this->getService( 'LinkCache' );
 545         }
 546
 547         /**
 548          * @since 1.28
 549          * @return LinkRendererFactory
 550          */
 551         public function getLinkRendererFactory() {
 552                 return $this->getService( 'LinkRendererFactory' );
 553         }
 554
 555         /**
 556          * LinkRenderer instance that can be used
 557          * if no custom options are needed
 558          *
 559          * @since 1.28
 560          * @return LinkRenderer
 561          */
 562         public function getLinkRenderer() {
 563                 return $this->getService( 'LinkRenderer' );
 564         }
 565
 566         /**
 567          * @since 1.28
 568          * @return TitleFormatter
 569          */
 570         public function getTitleFormatter() {
 571                 return $this->getService( 'TitleFormatter' );
 572         }
 573
 574         /**
 575          * @since 1.28
 576          * @return TitleParser
 577          */
 578         public function getTitleParser() {
 579                 return $this->getService( 'TitleParser' );
 580         }
 581
 582         /**
 583          * @since 1.28
 584          * @return VirtualRESTServiceClient
 585          */
 586         public function getVirtualRESTServiceClient() {
 587                 return $this->getService( 'VirtualRESTServiceClient' );
 588         }
 589
 590         ///////////////////////////////////////////////////////////////////////////
 591         // NOTE: When adding a service getter here, don't forget to add a test
 592         // case for it in MediaWikiServicesTest::provideGetters() and in
 593         // MediaWikiServicesTest::provideGetService()!
 594         ///////////////////////////////////////////////////////////////////////////
 595
 596 }