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 MediaWiki\Linker\LinkRenderer;
  15 use MediaWiki\Linker\LinkRendererFactory;
  16 use MediaWiki\Services\SalvageableService;
  17 use MediaWiki\Services\ServiceContainer;
  18 use MWException;
  19 use ObjectCache;
  20 use SearchEngine;
  21 use SearchEngineConfig;
  22 use SearchEngineFactory;
  23 use SiteLookup;
  24 use SiteStore;
  25 use WatchedItemStore;
  26 use WatchedItemQueryService;
  27 use SkinFactory;
  28 use TitleFormatter;
  29 use TitleParser;
  30 use MediaWiki\Interwiki\InterwikiLookup;
  31
  32 /**
  33  * Service locator for MediaWiki core services.
  34  *
  35  * This program is free software; you can redistribute it and/or modify
  36  * it under the terms of the GNU General Public License as published by
  37  * the Free Software Foundation; either version 2 of the License, or
  38  * (at your option) any later version.
  39  *
  40  * This program is distributed in the hope that it will be useful,
  41  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  42  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  43  * GNU General Public License for more details.
  44  *
  45  * You should have received a copy of the GNU General Public License along
  46  * with this program; if not, write to the Free Software Foundation, Inc.,
  47  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  48  * http://www.gnu.org/copyleft/gpl.html
  49  *
  50  * @file
  51  *
  52  * @since 1.27
  53  */
  54
  55 /**
  56  * MediaWikiServices is the service locator for the application scope of MediaWiki.
  57  * Its implemented as a simple configurable DI container.
  58  * MediaWikiServices acts as a top level factory/registry for top level services, and builds
  59  * the network of service objects that defines MediaWiki's application logic.
  60  * It acts as an entry point to MediaWiki's dependency injection mechanism.
  61  *
  62  * Services are defined in the "wiring" array passed to the constructor,
  63  * or by calling defineService().
  64  *
  65  * @see docs/injection.txt for an overview of using dependency injection in the
  66  *      MediaWiki code base.
  67  */
  68 class MediaWikiServices extends ServiceContainer {
  69
  70         /**
  71          * @var MediaWikiServices|null
  72          */
  73         private static $instance = null;
  74
  75         /**
  76          * Returns the global default instance of the top level service locator.
  77          *
  78          * @since 1.27
  79          *
  80          * The default instance is initialized using the service instantiator functions
  81          * defined in ServiceWiring.php.
  82          *
  83          * @note This should only be called by static functions! The instance returned here
  84          * should not be passed around! Objects that need access to a service should have
  85          * that service injected into the constructor, never a service locator!
  86          *
  87          * @return MediaWikiServices
  88          */
  89         public static function getInstance() {
  90                 if ( self::$instance === null ) {
  91                         // NOTE: constructing GlobalVarConfig here is not particularly pretty,
  92                         // but some information from the global scope has to be injected here,
  93                         // even if it's just a file name or database credentials to load
  94                         // configuration from.
  95                         $bootstrapConfig = new GlobalVarConfig();
  96                         self::$instance = self::newInstance( $bootstrapConfig, 'load' );
  97                 }
  98
  99                 return self::$instance;
 100         }
 101
 102         /**
 103          * Replaces the global MediaWikiServices instance.
 104          *
 105          * @since 1.28
 106          *
 107          * @note This is for use in PHPUnit tests only!
 108          *
 109          * @throws MWException if called outside of PHPUnit tests.
 110          *
 111          * @param MediaWikiServices $services The new MediaWikiServices object.
 112          *
 113          * @return MediaWikiServices The old MediaWikiServices object, so it can be restored later.
 114          */
 115         public static function forceGlobalInstance( MediaWikiServices $services ) {
 116                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 117                         throw new MWException( __METHOD__ . ' must not be used outside unit tests.' );
 118                 }
 119
 120                 $old = self::getInstance();
 121                 self::$instance = $services;
 122
 123                 return $old;
 124         }
 125
 126         /**
 127          * Creates a new instance of MediaWikiServices and sets it as the global default
 128          * instance. getInstance() will return a different MediaWikiServices object
 129          * after every call to resetGlobalInstance().
 130          *
 131          * @since 1.28
 132          *
 133          * @warning This should not be used during normal operation. It is intended for use
 134          * when the configuration has changed significantly since bootstrap time, e.g.
 135          * during the installation process or during testing.
 136          *
 137          * @warning Calling resetGlobalInstance() may leave the application in an inconsistent
 138          * state. Calling this is only safe under the ASSUMPTION that NO REFERENCE to
 139          * any of the services managed by MediaWikiServices exist. If any service objects
 140          * managed by the old MediaWikiServices instance remain in use, they may INTERFERE
 141          * with the operation of the services managed by the new MediaWikiServices.
 142          * Operating with a mix of services created by the old and the new
 143          * MediaWikiServices instance may lead to INCONSISTENCIES and even DATA LOSS!
 144          * Any class implementing LAZY LOADING is especially prone to this problem,
 145          * since instances would typically retain a reference to a storage layer service.
 146          *
 147          * @see forceGlobalInstance()
 148          * @see resetGlobalInstance()
 149          * @see resetBetweenTest()
 150          *
 151          * @param Config|null $bootstrapConfig The Config object to be registered as the
 152          *        'BootstrapConfig' service. This has to contain at least the information
 153          *        needed to set up the 'ConfigFactory' service. If not given, the bootstrap
 154          *        config of the old instance of MediaWikiServices will be re-used. If there
 155          *        was no previous instance, a new GlobalVarConfig object will be used to
 156          *        bootstrap the services.
 157          *
 158          * @param string $quick Set this to "quick" to allow expensive resources to be re-used.
 159          * See SalvageableService for details.
 160          *
 161          * @throws MWException If called after MW_SERVICE_BOOTSTRAP_COMPLETE has been defined in
 162          *         Setup.php (unless MW_PHPUNIT_TEST or MEDIAWIKI_INSTALL or RUN_MAINTENANCE_IF_MAIN
 163          *          is defined).
 164          */
 165         public static function resetGlobalInstance( Config $bootstrapConfig = null, $quick = '' ) {
 166                 if ( self::$instance === null ) {
 167                         // no global instance yet, nothing to reset
 168                         return;
 169                 }
 170
 171                 self::failIfResetNotAllowed( __METHOD__ );
 172
 173                 if ( $bootstrapConfig === null ) {
 174                         $bootstrapConfig = self::$instance->getBootstrapConfig();
 175                 }
 176
 177                 $oldInstance = self::$instance;
 178
 179                 self::$instance = self::newInstance( $bootstrapConfig );
 180                 self::$instance->importWiring( $oldInstance, [ 'BootstrapConfig' ] );
 181
 182                 if ( $quick === 'quick' ) {
 183                         self::$instance->salvage( $oldInstance );
 184                 } else {
 185                         $oldInstance->destroy();
 186                 }
 187
 188         }
 189
 190         /**
 191          * Salvages the state of any salvageable service instances in $other.
 192          *
 193          * @note $other will have been destroyed when salvage() returns.
 194          *
 195          * @param MediaWikiServices $other
 196          */
 197         private function salvage( self $other ) {
 198                 foreach ( $this->getServiceNames() as $name ) {
 199                         $oldService = $other->peekService( $name );
 200
 201                         if ( $oldService instanceof SalvageableService ) {
 202                                 /** @var SalvageableService $newService */
 203                                 $newService = $this->getService( $name );
 204                                 $newService->salvage( $oldService );
 205                         }
 206                 }
 207
 208                 $other->destroy();
 209         }
 210
 211         /**
 212          * Creates a new MediaWikiServices instance and initializes it according to the
 213          * given $bootstrapConfig. In particular, all wiring files defined in the
 214          * ServiceWiringFiles setting are loaded, and the MediaWikiServices hook is called.
 215          *
 216          * @param Config|null $bootstrapConfig The Config object to be registered as the
 217          *        'BootstrapConfig' service.
 218          *
 219          * @param string $loadWiring set this to 'load' to load the wiring files specified
 220          *        in the 'ServiceWiringFiles' setting in $bootstrapConfig.
 221          *
 222          * @return MediaWikiServices
 223          * @throws MWException
 224          * @throws \FatalError
 225          */
 226         private static function newInstance( Config $bootstrapConfig, $loadWiring = '' ) {
 227                 $instance = new self( $bootstrapConfig );
 228
 229                 // Load the default wiring from the specified files.
 230                 if ( $loadWiring === 'load' ) {
 231                         $wiringFiles = $bootstrapConfig->get( 'ServiceWiringFiles' );
 232                         $instance->loadWiringFiles( $wiringFiles );
 233                 }
 234
 235                 // Provide a traditional hook point to allow extensions to configure services.
 236                 Hooks::run( 'MediaWikiServices', [ $instance ] );
 237
 238                 return $instance;
 239         }
 240
 241         /**
 242          * Disables all storage layer services. After calling this, any attempt to access the
 243          * storage layer will result in an error. Use resetGlobalInstance() to restore normal
 244          * operation.
 245          *
 246          * @since 1.28
 247          *
 248          * @warning This is intended for extreme situations only and should never be used
 249          * while serving normal web requests. Legitimate use cases for this method include
 250          * the installation process. Test fixtures may also use this, if the fixture relies
 251          * on globalState.
 252          *
 253          * @see resetGlobalInstance()
 254          * @see resetChildProcessServices()
 255          */
 256         public static function disableStorageBackend() {
 257                 // TODO: also disable some Caches, JobQueues, etc
 258                 $destroy = [ 'DBLoadBalancer', 'DBLoadBalancerFactory' ];
 259                 $services = self::getInstance();
 260
 261                 foreach ( $destroy as $name ) {
 262                         $services->disableService( $name );
 263                 }
 264
 265                 ObjectCache::clear();
 266         }
 267
 268         /**
 269          * Resets any services that may have become stale after a child process
 270          * returns from after pcntl_fork(). It's also safe, but generally unnecessary,
 271          * to call this method from the parent process.
 272          *
 273          * @since 1.28
 274          *
 275          * @note This is intended for use in the context of process forking only!
 276          *
 277          * @see resetGlobalInstance()
 278          * @see disableStorageBackend()
 279          */
 280         public static function resetChildProcessServices() {
 281                 // NOTE: for now, just reset everything. Since we don't know the interdependencies
 282                 // between services, we can't do this more selectively at this time.
 283                 self::resetGlobalInstance();
 284
 285                 // Child, reseed because there is no bug in PHP:
 286                 // http://bugs.php.net/bug.php?id=42465
 287                 mt_srand( getmypid() );
 288         }
 289
 290         /**
 291          * Resets the given service for testing purposes.
 292          *
 293          * @since 1.28
 294          *
 295          * @warning This is generally unsafe! Other services may still retain references
 296          * to the stale service instance, leading to failures and inconsistencies. Subclasses
 297          * may use this method to reset specific services under specific instances, but
 298          * it should not be exposed to application logic.
 299          *
 300          * @note With proper dependency injection used throughout the codebase, this method
 301          * should not be needed. It is provided to allow tests that pollute global service
 302          * instances to clean up.
 303          *
 304          * @param string $name
 305          * @param bool $destroy Whether the service instance should be destroyed if it exists.
 306          *        When set to false, any existing service instance will effectively be detached
 307          *        from the container.
 308          *
 309          * @throws MWException if called outside of PHPUnit tests.
 310          */
 311         public function resetServiceForTesting( $name, $destroy = true ) {
 312                 if ( !defined( 'MW_PHPUNIT_TEST' ) && !defined( 'MW_PARSER_TEST' ) ) {
 313                         throw new MWException( 'resetServiceForTesting() must not be used outside unit tests.' );
 314                 }
 315
 316                 $this->resetService( $name, $destroy );
 317         }
 318
 319         /**
 320          * Convenience method that throws an exception unless it is called during a phase in which
 321          * resetting of global services is allowed. In general, services should not be reset
 322          * individually, since that may introduce inconsistencies.
 323          *
 324          * @since 1.28
 325          *
 326          * This method will throw an exception if:
 327          *
 328          * - self::$resetInProgress is false (to allow all services to be reset together
 329          *   via resetGlobalInstance)
 330          * - and MEDIAWIKI_INSTALL is not defined (to allow services to be reset during installation)
 331          * - and MW_PHPUNIT_TEST is not defined (to allow services to be reset during testing)
 332          *
 333          * This method is intended to be used to safeguard against accidentally resetting
 334          * global service instances that are not yet managed by MediaWikiServices. It is
 335          * defined here in the MediaWikiServices services class to have a central place
 336          * for managing service bootstrapping and resetting.
 337          *
 338          * @param string $method the name of the caller method, as given by __METHOD__.
 339          *
 340          * @throws MWException if called outside bootstrap mode.
 341          *
 342          * @see resetGlobalInstance()
 343          * @see forceGlobalInstance()
 344          * @see disableStorageBackend()
 345          */
 346         public static function failIfResetNotAllowed( $method ) {
 347                 if ( !defined( 'MW_PHPUNIT_TEST' )
 348                         && !defined( 'MW_PARSER_TEST' )
 349                         && !defined( 'MEDIAWIKI_INSTALL' )
 350                         && !defined( 'RUN_MAINTENANCE_IF_MAIN' )
 351                         && defined( 'MW_SERVICE_BOOTSTRAP_COMPLETE' )
 352                 ) {
 353                         throw new MWException( $method . ' may only be called during bootstrapping and unit tests!' );
 354                 }
 355         }
 356
 357         /**
 358          * @param Config $config The Config object to be registered as the 'BootstrapConfig' service.
 359          *        This has to contain at least the information needed to set up the 'ConfigFactory'
 360          *        service.
 361          */
 362         public function __construct( Config $config ) {
 363                 parent::__construct();
 364
 365                 // Register the given Config object as the bootstrap config service.
 366                 $this->defineService( 'BootstrapConfig', function() use ( $config ) {
 367                         return $config;
 368                 } );
 369         }
 370
 371         // CONVENIENCE GETTERS ////////////////////////////////////////////////////
 372
 373         /**
 374          * Returns the Config object containing the bootstrap configuration.
 375          * Bootstrap configuration would typically include database credentials
 376          * and other information that may be needed before the ConfigFactory
 377          * service can be instantiated.
 378          *
 379          * @note This should only be used during bootstrapping, in particular
 380          * when creating the MainConfig service. Application logic should
 381          * use getMainConfig() to get a Config instances.
 382          *
 383          * @since 1.27
 384          * @return Config
 385          */
 386         public function getBootstrapConfig() {
 387                 return $this->getService( 'BootstrapConfig' );
 388         }
 389
 390         /**
 391          * @since 1.27
 392          * @return ConfigFactory
 393          */
 394         public function getConfigFactory() {
 395                 return $this->getService( 'ConfigFactory' );
 396         }
 397
 398         /**
 399          * Returns the Config object that provides configuration for MediaWiki core.
 400          * This may or may not be the same object that is returned by getBootstrapConfig().
 401          *
 402          * @since 1.27
 403          * @return Config
 404          */
 405         public function getMainConfig() {
 406                 return $this->getService( 'MainConfig' );
 407         }
 408
 409         /**
 410          * @since 1.27
 411          * @return SiteLookup
 412          */
 413         public function getSiteLookup() {
 414                 return $this->getService( 'SiteLookup' );
 415         }
 416
 417         /**
 418          * @since 1.27
 419          * @return SiteStore
 420          */
 421         public function getSiteStore() {
 422                 return $this->getService( 'SiteStore' );
 423         }
 424
 425         /**
 426          * @since 1.28
 427          * @return InterwikiLookup
 428          */
 429         public function getInterwikiLookup() {
 430                 return $this->getService( 'InterwikiLookup' );
 431         }
 432
 433         /**
 434          * @since 1.27
 435          * @return StatsdDataFactory
 436          */
 437         public function getStatsdDataFactory() {
 438                 return $this->getService( 'StatsdDataFactory' );
 439         }
 440
 441         /**
 442          * @since 1.27
 443          * @return EventRelayerGroup
 444          */
 445         public function getEventRelayerGroup() {
 446                 return $this->getService( 'EventRelayerGroup' );
 447         }
 448
 449         /**
 450          * @since 1.27
 451          * @return SearchEngine
 452          */
 453         public function newSearchEngine() {
 454                 // New engine object every time, since they keep state
 455                 return $this->getService( 'SearchEngineFactory' )->create();
 456         }
 457
 458         /**
 459          * @since 1.27
 460          * @return SearchEngineFactory
 461          */
 462         public function getSearchEngineFactory() {
 463                 return $this->getService( 'SearchEngineFactory' );
 464         }
 465
 466         /**
 467          * @since 1.27
 468          * @return SearchEngineConfig
 469          */
 470         public function getSearchEngineConfig() {
 471                 return $this->getService( 'SearchEngineConfig' );
 472         }
 473
 474         /**
 475          * @since 1.27
 476          * @return SkinFactory
 477          */
 478         public function getSkinFactory() {
 479                 return $this->getService( 'SkinFactory' );
 480         }
 481
 482         /**
 483          * @since 1.28
 484          * @return LBFactory
 485          */
 486         public function getDBLoadBalancerFactory() {
 487                 return $this->getService( 'DBLoadBalancerFactory' );
 488         }
 489
 490         /**
 491          * @since 1.28
 492          * @return LoadBalancer The main DB load balancer for the local wiki.
 493          */
 494         public function getDBLoadBalancer() {
 495                 return $this->getService( 'DBLoadBalancer' );
 496         }
 497
 498         /**
 499          * @since 1.28
 500          * @return WatchedItemStore
 501          */
 502         public function getWatchedItemStore() {
 503                 return $this->getService( 'WatchedItemStore' );
 504         }
 505
 506         /**
 507          * @since 1.28
 508          * @return WatchedItemQueryService
 509          */
 510         public function getWatchedItemQueryService() {
 511                 return $this->getService( 'WatchedItemQueryService' );
 512         }
 513
 514         /**
 515          * @since 1.28
 516          * @return GenderCache
 517          */
 518         public function getGenderCache() {
 519                 return $this->getService( 'GenderCache' );
 520         }
 521
 522         /**
 523          * @since 1.28
 524          * @return LinkCache
 525          */
 526         public function getLinkCache() {
 527                 return $this->getService( 'LinkCache' );
 528         }
 529
 530         /**
 531          * @since 1.28
 532          * @return LinkRendererFactory
 533          */
 534         public function getLinkRendererFactory() {
 535                 return $this->getService( 'LinkRendererFactory' );
 536         }
 537
 538         /**
 539          * LinkRenderer instance that can be used
 540          * if no custom options are needed
 541          *
 542          * @since 1.28
 543          * @return LinkRenderer
 544          */
 545         public function getLinkRenderer() {
 546                 return $this->getService( 'LinkRenderer' );
 547         }
 548
 549         /**
 550          * @since 1.28
 551          * @return TitleFormatter
 552          */
 553         public function getTitleFormatter() {
 554                 return $this->getService( 'TitleFormatter' );
 555         }
 556
 557         /**
 558          * @since 1.28
 559          * @return TitleParser
 560          */
 561         public function getTitleParser() {
 562                 return $this->getService( 'TitleParser' );
 563         }
 564
 565         ///////////////////////////////////////////////////////////////////////////
 566         // NOTE: When adding a service getter here, don't forget to add a test
 567         // case for it in MediaWikiServicesTest::provideGetters() and in
 568         // MediaWikiServicesTest::provideGetService()!
 569         ///////////////////////////////////////////////////////////////////////////
 570
 571 }