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 MediaWiki\Interwiki\InterwikiLookup;
  32
  33 /**
  34  * Service locator for MediaWiki core services.
  35  *
  36  * This program is free software; you can redistribute it and/or modify
  37  * it under the terms of the GNU General Public License as published by
  38  * the Free Software Foundation; either version 2 of the License, or
  39  * (at your option) any later version.
  40  *
  41  * This program is distributed in the hope that it will be useful,
  42  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  43  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  44  * GNU General Public License for more details.
  45  *
  46  * You should have received a copy of the GNU General Public License along
  47  * with this program; if not, write to the Free Software Foundation, Inc.,
  48  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  49  * http://www.gnu.org/copyleft/gpl.html
  50  *
  51  * @file
  52  *
  53  * @since 1.27
  54  */
  55
  56 /**
  57  * MediaWikiServices is the service locator for the application scope of MediaWiki.
  58  * Its implemented as a simple configurable DI container.
  59  * MediaWikiServices acts as a top level factory/registry for top level services, and builds
  60  * the network of service objects that defines MediaWiki's application logic.
  61  * It acts as an entry point to MediaWiki's dependency injection mechanism.
  62  *
  63  * Services are defined in the "wiring" array passed to the constructor,
  64  * or by calling defineService().
  65  *
  66  * @see docs/injection.txt for an overview of using dependency injection in the
  67  *      MediaWiki code base.
  68  */
  69 class MediaWikiServices extends ServiceContainer {
  70
  71         /**
  72          * @var MediaWikiServices|null
  73          */
  74         private static $instance = null;
  75
  76         /**
  77          * Returns the global default instance of the top level service locator.
  78          *
  79          * @since 1.27
  80          *
  81          * The default instance is initialized using the service instantiator functions
  82          * defined in ServiceWiring.php.
  83          *
  84          * @note This should only be called by static functions! The instance returned here
  85          * should not be passed around! Objects that need access to a service should have
  86          * that service injected into the constructor, never a service locator!
  87          *
  88          * @return MediaWikiServices
  89          */
  90         public static function getInstance() {
  91                 if ( self::$instance === null ) {
  92                         // NOTE: constructing GlobalVarConfig here is not particularly pretty,
  93                         // but some information from the global scope has to be injected here,
  94                         // even if it's just a file name or database credentials to load
  95                         // configuration from.
  96                         $bootstrapConfig = new GlobalVarConfig();
  97                         self::$instance = self::newInstance( $bootstrapConfig, 'load' );
  98                 }
  99
 100                 return self::$instance;
 101         }
 102
 103         /**
 104          * Replaces the global MediaWikiServices instance.
 105          *
 106          * @since 1.28
 107          *
 108          * @note This is for use in PHPUnit tests only!
 109          *
 110          * @throws MWException if called outside of PHPUnit tests.
 111          *
 112          * @param MediaWikiServices $services The new MediaWikiServices object.
 113          *
 114          * @return MediaWikiServices The old MediaWikiServices object, so it can be restored later.
 115          */
 116         public static function forceGlobalInstance( MediaWikiServices $services ) {
 117                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 118                         throw new MWException( __METHOD__ . ' must not be used outside unit tests.' );
 119                 }
 120
 121                 $old = self::getInstance();
 122                 self::$instance = $services;
 123
 124                 return $old;
 125         }
 126
 127         /**
 128          * Creates a new instance of MediaWikiServices and sets it as the global default
 129          * instance. getInstance() will return a different MediaWikiServices object
 130          * after every call to resetGlobalInstance().
 131          *
 132          * @since 1.28
 133          *
 134          * @warning This should not be used during normal operation. It is intended for use
 135          * when the configuration has changed significantly since bootstrap time, e.g.
 136          * during the installation process or during testing.
 137          *
 138          * @warning Calling resetGlobalInstance() may leave the application in an inconsistent
 139          * state. Calling this is only safe under the ASSUMPTION that NO REFERENCE to
 140          * any of the services managed by MediaWikiServices exist. If any service objects
 141          * managed by the old MediaWikiServices instance remain in use, they may INTERFERE
 142          * with the operation of the services managed by the new MediaWikiServices.
 143          * Operating with a mix of services created by the old and the new
 144          * MediaWikiServices instance may lead to INCONSISTENCIES and even DATA LOSS!
 145          * Any class implementing LAZY LOADING is especially prone to this problem,
 146          * since instances would typically retain a reference to a storage layer service.
 147          *
 148          * @see forceGlobalInstance()
 149          * @see resetGlobalInstance()
 150          * @see resetBetweenTest()
 151          *
 152          * @param Config|null $bootstrapConfig The Config object to be registered as the
 153          *        'BootstrapConfig' service. This has to contain at least the information
 154          *        needed to set up the 'ConfigFactory' service. If not given, the bootstrap
 155          *        config of the old instance of MediaWikiServices will be re-used. If there
 156          *        was no previous instance, a new GlobalVarConfig object will be used to
 157          *        bootstrap the services.
 158          *
 159          * @param string $quick Set this to "quick" to allow expensive resources to be re-used.
 160          * See SalvageableService for details.
 161          *
 162          * @throws MWException If called after MW_SERVICE_BOOTSTRAP_COMPLETE has been defined in
 163          *         Setup.php (unless MW_PHPUNIT_TEST or MEDIAWIKI_INSTALL or RUN_MAINTENANCE_IF_MAIN
 164          *          is defined).
 165          */
 166         public static function resetGlobalInstance( Config $bootstrapConfig = null, $quick = '' ) {
 167                 if ( self::$instance === null ) {
 168                         // no global instance yet, nothing to reset
 169                         return;
 170                 }
 171
 172                 self::failIfResetNotAllowed( __METHOD__ );
 173
 174                 if ( $bootstrapConfig === null ) {
 175                         $bootstrapConfig = self::$instance->getBootstrapConfig();
 176                 }
 177
 178                 $oldInstance = self::$instance;
 179
 180                 self::$instance = self::newInstance( $bootstrapConfig );
 181                 self::$instance->importWiring( $oldInstance, [ 'BootstrapConfig' ] );
 182
 183                 if ( $quick === 'quick' ) {
 184                         self::$instance->salvage( $oldInstance );
 185                 } else {
 186                         $oldInstance->destroy();
 187                 }
 188
 189         }
 190
 191         /**
 192          * Salvages the state of any salvageable service instances in $other.
 193          *
 194          * @note $other will have been destroyed when salvage() returns.
 195          *
 196          * @param MediaWikiServices $other
 197          */
 198         private function salvage( self $other ) {
 199                 foreach ( $this->getServiceNames() as $name ) {
 200                         $oldService = $other->peekService( $name );
 201
 202                         if ( $oldService instanceof SalvageableService ) {
 203                                 /** @var SalvageableService $newService */
 204                                 $newService = $this->getService( $name );
 205                                 $newService->salvage( $oldService );
 206                         }
 207                 }
 208
 209                 $other->destroy();
 210         }
 211
 212         /**
 213          * Creates a new MediaWikiServices instance and initializes it according to the
 214          * given $bootstrapConfig. In particular, all wiring files defined in the
 215          * ServiceWiringFiles setting are loaded, and the MediaWikiServices hook is called.
 216          *
 217          * @param Config|null $bootstrapConfig The Config object to be registered as the
 218          *        'BootstrapConfig' service.
 219          *
 220          * @param string $loadWiring set this to 'load' to load the wiring files specified
 221          *        in the 'ServiceWiringFiles' setting in $bootstrapConfig.
 222          *
 223          * @return MediaWikiServices
 224          * @throws MWException
 225          * @throws \FatalError
 226          */
 227         private static function newInstance( Config $bootstrapConfig, $loadWiring = '' ) {
 228                 $instance = new self( $bootstrapConfig );
 229
 230                 // Load the default wiring from the specified files.
 231                 if ( $loadWiring === 'load' ) {
 232                         $wiringFiles = $bootstrapConfig->get( 'ServiceWiringFiles' );
 233                         $instance->loadWiringFiles( $wiringFiles );
 234                 }
 235
 236                 // Provide a traditional hook point to allow extensions to configure services.
 237                 Hooks::run( 'MediaWikiServices', [ $instance ] );
 238
 239                 return $instance;
 240         }
 241
 242         /**
 243          * Disables all storage layer services. After calling this, any attempt to access the
 244          * storage layer will result in an error. Use resetGlobalInstance() to restore normal
 245          * operation.
 246          *
 247          * @since 1.28
 248          *
 249          * @warning This is intended for extreme situations only and should never be used
 250          * while serving normal web requests. Legitimate use cases for this method include
 251          * the installation process. Test fixtures may also use this, if the fixture relies
 252          * on globalState.
 253          *
 254          * @see resetGlobalInstance()
 255          * @see resetChildProcessServices()
 256          */
 257         public static function disableStorageBackend() {
 258                 // TODO: also disable some Caches, JobQueues, etc
 259                 $destroy = [ 'DBLoadBalancer', 'DBLoadBalancerFactory' ];
 260                 $services = self::getInstance();
 261
 262                 foreach ( $destroy as $name ) {
 263                         $services->disableService( $name );
 264                 }
 265
 266                 ObjectCache::clear();
 267         }
 268
 269         /**
 270          * Resets any services that may have become stale after a child process
 271          * returns from after pcntl_fork(). It's also safe, but generally unnecessary,
 272          * to call this method from the parent process.
 273          *
 274          * @since 1.28
 275          *
 276          * @note This is intended for use in the context of process forking only!
 277          *
 278          * @see resetGlobalInstance()
 279          * @see disableStorageBackend()
 280          */
 281         public static function resetChildProcessServices() {
 282                 // NOTE: for now, just reset everything. Since we don't know the interdependencies
 283                 // between services, we can't do this more selectively at this time.
 284                 self::resetGlobalInstance();
 285
 286                 // Child, reseed because there is no bug in PHP:
 287                 // http://bugs.php.net/bug.php?id=42465
 288                 mt_srand( getmypid() );
 289         }
 290
 291         /**
 292          * Resets the given service for testing purposes.
 293          *
 294          * @since 1.28
 295          *
 296          * @warning This is generally unsafe! Other services may still retain references
 297          * to the stale service instance, leading to failures and inconsistencies. Subclasses
 298          * may use this method to reset specific services under specific instances, but
 299          * it should not be exposed to application logic.
 300          *
 301          * @note With proper dependency injection used throughout the codebase, this method
 302          * should not be needed. It is provided to allow tests that pollute global service
 303          * instances to clean up.
 304          *
 305          * @param string $name
 306          * @param bool $destroy Whether the service instance should be destroyed if it exists.
 307          *        When set to false, any existing service instance will effectively be detached
 308          *        from the container.
 309          *
 310          * @throws MWException if called outside of PHPUnit tests.
 311          */
 312         public function resetServiceForTesting( $name, $destroy = true ) {
 313                 if ( !defined( 'MW_PHPUNIT_TEST' ) && !defined( 'MW_PARSER_TEST' ) ) {
 314                         throw new MWException( 'resetServiceForTesting() must not be used outside unit tests.' );
 315                 }
 316
 317                 $this->resetService( $name, $destroy );
 318         }
 319
 320         /**
 321          * Convenience method that throws an exception unless it is called during a phase in which
 322          * resetting of global services is allowed. In general, services should not be reset
 323          * individually, since that may introduce inconsistencies.
 324          *
 325          * @since 1.28
 326          *
 327          * This method will throw an exception if:
 328          *
 329          * - self::$resetInProgress is false (to allow all services to be reset together
 330          *   via resetGlobalInstance)
 331          * - and MEDIAWIKI_INSTALL is not defined (to allow services to be reset during installation)
 332          * - and MW_PHPUNIT_TEST is not defined (to allow services to be reset during testing)
 333          *
 334          * This method is intended to be used to safeguard against accidentally resetting
 335          * global service instances that are not yet managed by MediaWikiServices. It is
 336          * defined here in the MediaWikiServices services class to have a central place
 337          * for managing service bootstrapping and resetting.
 338          *
 339          * @param string $method the name of the caller method, as given by __METHOD__.
 340          *
 341          * @throws MWException if called outside bootstrap mode.
 342          *
 343          * @see resetGlobalInstance()
 344          * @see forceGlobalInstance()
 345          * @see disableStorageBackend()
 346          */
 347         public static function failIfResetNotAllowed( $method ) {
 348                 if ( !defined( 'MW_PHPUNIT_TEST' )
 349                         && !defined( 'MW_PARSER_TEST' )
 350                         && !defined( 'MEDIAWIKI_INSTALL' )
 351                         && !defined( 'RUN_MAINTENANCE_IF_MAIN' )
 352                         && defined( 'MW_SERVICE_BOOTSTRAP_COMPLETE' )
 353                 ) {
 354                         throw new MWException( $method . ' may only be called during bootstrapping and unit tests!' );
 355                 }
 356         }
 357
 358         /**
 359          * @param Config $config The Config object to be registered as the 'BootstrapConfig' service.
 360          *        This has to contain at least the information needed to set up the 'ConfigFactory'
 361          *        service.
 362          */
 363         public function __construct( Config $config ) {
 364                 parent::__construct();
 365
 366                 // Register the given Config object as the bootstrap config service.
 367                 $this->defineService( 'BootstrapConfig', function() use ( $config ) {
 368                         return $config;
 369                 } );
 370         }
 371
 372         // CONVENIENCE GETTERS ////////////////////////////////////////////////////
 373
 374         /**
 375          * Returns the Config object containing the bootstrap configuration.
 376          * Bootstrap configuration would typically include database credentials
 377          * and other information that may be needed before the ConfigFactory
 378          * service can be instantiated.
 379          *
 380          * @note This should only be used during bootstrapping, in particular
 381          * when creating the MainConfig service. Application logic should
 382          * use getMainConfig() to get a Config instances.
 383          *
 384          * @since 1.27
 385          * @return Config
 386          */
 387         public function getBootstrapConfig() {
 388                 return $this->getService( 'BootstrapConfig' );
 389         }
 390
 391         /**
 392          * @since 1.27
 393          * @return ConfigFactory
 394          */
 395         public function getConfigFactory() {
 396                 return $this->getService( 'ConfigFactory' );
 397         }
 398
 399         /**
 400          * Returns the Config object that provides configuration for MediaWiki core.
 401          * This may or may not be the same object that is returned by getBootstrapConfig().
 402          *
 403          * @since 1.27
 404          * @return Config
 405          */
 406         public function getMainConfig() {
 407                 return $this->getService( 'MainConfig' );
 408         }
 409
 410         /**
 411          * @since 1.27
 412          * @return SiteLookup
 413          */
 414         public function getSiteLookup() {
 415                 return $this->getService( 'SiteLookup' );
 416         }
 417
 418         /**
 419          * @since 1.27
 420          * @return SiteStore
 421          */
 422         public function getSiteStore() {
 423                 return $this->getService( 'SiteStore' );
 424         }
 425
 426         /**
 427          * @since 1.28
 428          * @return InterwikiLookup
 429          */
 430         public function getInterwikiLookup() {
 431                 return $this->getService( 'InterwikiLookup' );
 432         }
 433
 434         /**
 435          * @since 1.27
 436          * @return StatsdDataFactory
 437          */
 438         public function getStatsdDataFactory() {
 439                 return $this->getService( 'StatsdDataFactory' );
 440         }
 441
 442         /**
 443          * @since 1.27
 444          * @return EventRelayerGroup
 445          */
 446         public function getEventRelayerGroup() {
 447                 return $this->getService( 'EventRelayerGroup' );
 448         }
 449
 450         /**
 451          * @since 1.27
 452          * @return SearchEngine
 453          */
 454         public function newSearchEngine() {
 455                 // New engine object every time, since they keep state
 456                 return $this->getService( 'SearchEngineFactory' )->create();
 457         }
 458
 459         /**
 460          * @since 1.27
 461          * @return SearchEngineFactory
 462          */
 463         public function getSearchEngineFactory() {
 464                 return $this->getService( 'SearchEngineFactory' );
 465         }
 466
 467         /**
 468          * @since 1.27
 469          * @return SearchEngineConfig
 470          */
 471         public function getSearchEngineConfig() {
 472                 return $this->getService( 'SearchEngineConfig' );
 473         }
 474
 475         /**
 476          * @since 1.27
 477          * @return SkinFactory
 478          */
 479         public function getSkinFactory() {
 480                 return $this->getService( 'SkinFactory' );
 481         }
 482
 483         /**
 484          * @since 1.28
 485          * @return LBFactory
 486          */
 487         public function getDBLoadBalancerFactory() {
 488                 return $this->getService( 'DBLoadBalancerFactory' );
 489         }
 490
 491         /**
 492          * @since 1.28
 493          * @return LoadBalancer The main DB load balancer for the local wiki.
 494          */
 495         public function getDBLoadBalancer() {
 496                 return $this->getService( 'DBLoadBalancer' );
 497         }
 498
 499         /**
 500          * @since 1.28
 501          * @return WatchedItemStore
 502          */
 503         public function getWatchedItemStore() {
 504                 return $this->getService( 'WatchedItemStore' );
 505         }
 506
 507         /**
 508          * @since 1.28
 509          * @return WatchedItemQueryService
 510          */
 511         public function getWatchedItemQueryService() {
 512                 return $this->getService( 'WatchedItemQueryService' );
 513         }
 514
 515         /**
 516          * @since 1.28
 517          * @return MediaHandlerFactory
 518          */
 519         public function getMediaHandlerFactory() {
 520                 return $this->getService( 'MediaHandlerFactory' );
 521         }
 522
 523         /**
 524          * @since 1.28
 525          * @return GenderCache
 526          */
 527         public function getGenderCache() {
 528                 return $this->getService( 'GenderCache' );
 529         }
 530
 531         /**
 532          * @since 1.28
 533          * @return LinkCache
 534          */
 535         public function getLinkCache() {
 536                 return $this->getService( 'LinkCache' );
 537         }
 538
 539         /**
 540          * @since 1.28
 541          * @return LinkRendererFactory
 542          */
 543         public function getLinkRendererFactory() {
 544                 return $this->getService( 'LinkRendererFactory' );
 545         }
 546
 547         /**
 548          * LinkRenderer instance that can be used
 549          * if no custom options are needed
 550          *
 551          * @since 1.28
 552          * @return LinkRenderer
 553          */
 554         public function getLinkRenderer() {
 555                 return $this->getService( 'LinkRenderer' );
 556         }
 557
 558         /**
 559          * @since 1.28
 560          * @return TitleFormatter
 561          */
 562         public function getTitleFormatter() {
 563                 return $this->getService( 'TitleFormatter' );
 564         }
 565
 566         /**
 567          * @since 1.28
 568          * @return TitleParser
 569          */
 570         public function getTitleParser() {
 571                 return $this->getService( 'TitleParser' );
 572         }
 573
 574         ///////////////////////////////////////////////////////////////////////////
 575         // NOTE: When adding a service getter here, don't forget to add a test
 576         // case for it in MediaWikiServicesTest::provideGetters() and in
 577         // MediaWikiServicesTest::provideGetService()!
 578         ///////////////////////////////////////////////////////////////////////////
 579
 580 }