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 MediaWiki\Services\NoSuchServiceException;
  20 use MWException;
  21 use ObjectCache;
  22 use ProxyLookup;
  23 use SearchEngine;
  24 use SearchEngineConfig;
  25 use SearchEngineFactory;
  26 use SiteLookup;
  27 use SiteStore;
  28 use WatchedItemStore;
  29 use WatchedItemQueryService;
  30 use SkinFactory;
  31 use TitleFormatter;
  32 use TitleParser;
  33 use VirtualRESTServiceClient;
  34 use MediaWiki\Interwiki\InterwikiLookup;
  35
  36 /**
  37  * Service locator for MediaWiki core services.
  38  *
  39  * This program is free software; you can redistribute it and/or modify
  40  * it under the terms of the GNU General Public License as published by
  41  * the Free Software Foundation; either version 2 of the License, or
  42  * (at your option) any later version.
  43  *
  44  * This program is distributed in the hope that it will be useful,
  45  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  46  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  47  * GNU General Public License for more details.
  48  *
  49  * You should have received a copy of the GNU General Public License along
  50  * with this program; if not, write to the Free Software Foundation, Inc.,
  51  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  52  * http://www.gnu.org/copyleft/gpl.html
  53  *
  54  * @file
  55  *
  56  * @since 1.27
  57  */
  58
  59 /**
  60  * MediaWikiServices is the service locator for the application scope of MediaWiki.
  61  * Its implemented as a simple configurable DI container.
  62  * MediaWikiServices acts as a top level factory/registry for top level services, and builds
  63  * the network of service objects that defines MediaWiki's application logic.
  64  * It acts as an entry point to MediaWiki's dependency injection mechanism.
  65  *
  66  * Services are defined in the "wiring" array passed to the constructor,
  67  * or by calling defineService().
  68  *
  69  * @see docs/injection.txt for an overview of using dependency injection in the
  70  *      MediaWiki code base.
  71  */
  72 class MediaWikiServices extends ServiceContainer {
  73
  74         /**
  75          * @var MediaWikiServices|null
  76          */
  77         private static $instance = null;
  78
  79         /**
  80          * Returns the global default instance of the top level service locator.
  81          *
  82          * @since 1.27
  83          *
  84          * The default instance is initialized using the service instantiator functions
  85          * defined in ServiceWiring.php.
  86          *
  87          * @note This should only be called by static functions! The instance returned here
  88          * should not be passed around! Objects that need access to a service should have
  89          * that service injected into the constructor, never a service locator!
  90          *
  91          * @return MediaWikiServices
  92          */
  93         public static function getInstance() {
  94                 if ( self::$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( $bootstrapConfig, 'load' );
 101                 }
 102
 103                 return self::$instance;
 104         }
 105
 106         /**
 107          * Replaces the global MediaWikiServices instance.
 108          *
 109          * @since 1.28
 110          *
 111          * @note This is for use in PHPUnit tests only!
 112          *
 113          * @throws MWException if called outside of PHPUnit tests.
 114          *
 115          * @param MediaWikiServices $services The new MediaWikiServices object.
 116          *
 117          * @return MediaWikiServices The old MediaWikiServices object, so it can be restored later.
 118          */
 119         public static function forceGlobalInstance( MediaWikiServices $services ) {
 120                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 121                         throw new MWException( __METHOD__ . ' must not be used outside unit tests.' );
 122                 }
 123
 124                 $old = self::getInstance();
 125                 self::$instance = $services;
 126
 127                 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 resetGlobalInstance().
 134          *
 135          * @since 1.28
 136          *
 137          * @warning This should not be used during normal operation. It is intended for use
 138          * when the configuration has changed significantly since bootstrap time, e.g.
 139          * during the installation process or during testing.
 140          *
 141          * @warning Calling resetGlobalInstance() may leave the application in an inconsistent
 142          * state. Calling this is only safe under the ASSUMPTION that NO REFERENCE to
 143          * any of the services managed by MediaWikiServices exist. If any service objects
 144          * managed by the old MediaWikiServices instance remain in use, they may INTERFERE
 145          * with the operation of the services managed by the new MediaWikiServices.
 146          * Operating with a mix of services created by the old and the new
 147          * MediaWikiServices instance may lead to INCONSISTENCIES and even DATA LOSS!
 148          * Any class implementing LAZY LOADING is especially prone to this problem,
 149          * since instances would typically retain a reference to a storage layer service.
 150          *
 151          * @see forceGlobalInstance()
 152          * @see resetGlobalInstance()
 153          * @see resetBetweenTest()
 154          *
 155          * @param Config|null $bootstrapConfig The Config object to be registered as the
 156          *        'BootstrapConfig' service. This has to contain at least the information
 157          *        needed to set up the 'ConfigFactory' service. If not given, the bootstrap
 158          *        config of the old instance of MediaWikiServices will be re-used. If there
 159          *        was no previous instance, a new GlobalVarConfig object will be used to
 160          *        bootstrap the services.
 161          *
 162          * @param string $quick Set this to "quick" to allow expensive resources to be re-used.
 163          * See SalvageableService for details.
 164          *
 165          * @throws MWException If called after MW_SERVICE_BOOTSTRAP_COMPLETE has been defined in
 166          *         Setup.php (unless MW_PHPUNIT_TEST or MEDIAWIKI_INSTALL or RUN_MAINTENANCE_IF_MAIN
 167          *          is defined).
 168          */
 169         public static function resetGlobalInstance( Config $bootstrapConfig = null, $quick = '' ) {
 170                 if ( self::$instance === null ) {
 171                         // no global instance yet, nothing to reset
 172                         return;
 173                 }
 174
 175                 self::failIfResetNotAllowed( __METHOD__ );
 176
 177                 if ( $bootstrapConfig === null ) {
 178                         $bootstrapConfig = self::$instance->getBootstrapConfig();
 179                 }
 180
 181                 $oldInstance = self::$instance;
 182
 183                 self::$instance = self::newInstance( $bootstrapConfig );
 184                 self::$instance->importWiring( $oldInstance, [ 'BootstrapConfig' ] );
 185
 186                 if ( $quick === 'quick' ) {
 187                         self::$instance->salvage( $oldInstance );
 188                 } else {
 189                         $oldInstance->destroy();
 190                 }
 191
 192         }
 193
 194         /**
 195          * Salvages the state of any salvageable service instances in $other.
 196          *
 197          * @note $other will have been destroyed when salvage() returns.
 198          *
 199          * @param MediaWikiServices $other
 200          */
 201         private function salvage( self $other ) {
 202                 foreach ( $this->getServiceNames() as $name ) {
 203                         // The service could be new in the new instance and not registered in the
 204                         // other instance (e.g. an extension that was loaded after the instantiation of
 205                         // the other instance. Skip this service in this case. See T143974
 206                         try {
 207                                 $oldService = $other->peekService( $name );
 208                         } catch ( NoSuchServiceException $e ) {
 209                                 continue;
 210                         }
 211
 212                         if ( $oldService instanceof SalvageableService ) {
 213                                 /** @var SalvageableService $newService */
 214                                 $newService = $this->getService( $name );
 215                                 $newService->salvage( $oldService );
 216                         }
 217                 }
 218
 219                 $other->destroy();
 220         }
 221
 222         /**
 223          * Creates a new MediaWikiServices instance and initializes it according to the
 224          * given $bootstrapConfig. In particular, all wiring files defined in the
 225          * ServiceWiringFiles setting are loaded, and the MediaWikiServices hook is called.
 226          *
 227          * @param Config|null $bootstrapConfig The Config object to be registered as the
 228          *        'BootstrapConfig' service.
 229          *
 230          * @param string $loadWiring set this to 'load' to load the wiring files specified
 231          *        in the 'ServiceWiringFiles' setting in $bootstrapConfig.
 232          *
 233          * @return MediaWikiServices
 234          * @throws MWException
 235          * @throws \FatalError
 236          */
 237         private static function newInstance( Config $bootstrapConfig, $loadWiring = '' ) {
 238                 $instance = new self( $bootstrapConfig );
 239
 240                 // Load the default wiring from the specified files.
 241                 if ( $loadWiring === 'load' ) {
 242                         $wiringFiles = $bootstrapConfig->get( 'ServiceWiringFiles' );
 243                         $instance->loadWiringFiles( $wiringFiles );
 244                 }
 245
 246                 // Provide a traditional hook point to allow extensions to configure services.
 247                 Hooks::run( 'MediaWikiServices', [ $instance ] );
 248
 249                 return $instance;
 250         }
 251
 252         /**
 253          * Disables all storage layer services. After calling this, any attempt to access the
 254          * storage layer will result in an error. Use resetGlobalInstance() to restore normal
 255          * operation.
 256          *
 257          * @since 1.28
 258          *
 259          * @warning This is intended for extreme situations only and should never be used
 260          * while serving normal web requests. Legitimate use cases for this method include
 261          * the installation process. Test fixtures may also use this, if the fixture relies
 262          * on globalState.
 263          *
 264          * @see resetGlobalInstance()
 265          * @see resetChildProcessServices()
 266          */
 267         public static function disableStorageBackend() {
 268                 // TODO: also disable some Caches, JobQueues, etc
 269                 $destroy = [ 'DBLoadBalancer', 'DBLoadBalancerFactory' ];
 270                 $services = self::getInstance();
 271
 272                 foreach ( $destroy as $name ) {
 273                         $services->disableService( $name );
 274                 }
 275
 276                 ObjectCache::clear();
 277         }
 278
 279         /**
 280          * Resets any services that may have become stale after a child process
 281          * returns from after pcntl_fork(). It's also safe, but generally unnecessary,
 282          * to call this method from the parent process.
 283          *
 284          * @since 1.28
 285          *
 286          * @note This is intended for use in the context of process forking only!
 287          *
 288          * @see resetGlobalInstance()
 289          * @see disableStorageBackend()
 290          */
 291         public static function resetChildProcessServices() {
 292                 // NOTE: for now, just reset everything. Since we don't know the interdependencies
 293                 // between services, we can't do this more selectively at this time.
 294                 self::resetGlobalInstance();
 295
 296                 // Child, reseed because there is no bug in PHP:
 297                 // http://bugs.php.net/bug.php?id=42465
 298                 mt_srand( getmypid() );
 299         }
 300
 301         /**
 302          * Resets the given service for testing purposes.
 303          *
 304          * @since 1.28
 305          *
 306          * @warning This is generally unsafe! Other services may still retain references
 307          * to the stale service instance, leading to failures and inconsistencies. Subclasses
 308          * may use this method to reset specific services under specific instances, but
 309          * it should not be exposed to application logic.
 310          *
 311          * @note With proper dependency injection used throughout the codebase, this method
 312          * should not be needed. It is provided to allow tests that pollute global service
 313          * instances to clean up.
 314          *
 315          * @param string $name
 316          * @param bool $destroy Whether the service instance should be destroyed if it exists.
 317          *        When set to false, any existing service instance will effectively be detached
 318          *        from the container.
 319          *
 320          * @throws MWException if called outside of PHPUnit tests.
 321          */
 322         public function resetServiceForTesting( $name, $destroy = true ) {
 323                 if ( !defined( 'MW_PHPUNIT_TEST' ) && !defined( 'MW_PARSER_TEST' ) ) {
 324                         throw new MWException( 'resetServiceForTesting() must not be used outside unit tests.' );
 325                 }
 326
 327                 $this->resetService( $name, $destroy );
 328         }
 329
 330         /**
 331          * Convenience method that throws an exception unless it is called during a phase in which
 332          * resetting of global services is allowed. In general, services should not be reset
 333          * individually, since that may introduce inconsistencies.
 334          *
 335          * @since 1.28
 336          *
 337          * This method will throw an exception if:
 338          *
 339          * - self::$resetInProgress is false (to allow all services to be reset together
 340          *   via resetGlobalInstance)
 341          * - and MEDIAWIKI_INSTALL is not defined (to allow services to be reset during installation)
 342          * - and MW_PHPUNIT_TEST is not defined (to allow services to be reset during testing)
 343          *
 344          * This method is intended to be used to safeguard against accidentally resetting
 345          * global service instances that are not yet managed by MediaWikiServices. It is
 346          * defined here in the MediaWikiServices services class to have a central place
 347          * for managing service bootstrapping and resetting.
 348          *
 349          * @param string $method the name of the caller method, as given by __METHOD__.
 350          *
 351          * @throws MWException if called outside bootstrap mode.
 352          *
 353          * @see resetGlobalInstance()
 354          * @see forceGlobalInstance()
 355          * @see disableStorageBackend()
 356          */
 357         public static function failIfResetNotAllowed( $method ) {
 358                 if ( !defined( 'MW_PHPUNIT_TEST' )
 359                         && !defined( 'MW_PARSER_TEST' )
 360                         && !defined( 'MEDIAWIKI_INSTALL' )
 361                         && !defined( 'RUN_MAINTENANCE_IF_MAIN' )
 362                         && defined( 'MW_SERVICE_BOOTSTRAP_COMPLETE' )
 363                 ) {
 364                         throw new MWException( $method . ' may only be called during bootstrapping and unit tests!' );
 365                 }
 366         }
 367
 368         /**
 369          * @param Config $config The Config object to be registered as the 'BootstrapConfig' service.
 370          *        This has to contain at least the information needed to set up the 'ConfigFactory'
 371          *        service.
 372          */
 373         public function __construct( Config $config ) {
 374                 parent::__construct();
 375
 376                 // Register the given Config object as the bootstrap config service.
 377                 $this->defineService( 'BootstrapConfig', function() use ( $config ) {
 378                         return $config;
 379                 } );
 380         }
 381
 382         // CONVENIENCE GETTERS ////////////////////////////////////////////////////
 383
 384         /**
 385          * Returns the Config object containing the bootstrap configuration.
 386          * Bootstrap configuration would typically include database credentials
 387          * and other information that may be needed before the ConfigFactory
 388          * service can be instantiated.
 389          *
 390          * @note This should only be used during bootstrapping, in particular
 391          * when creating the MainConfig service. Application logic should
 392          * use getMainConfig() to get a Config instances.
 393          *
 394          * @since 1.27
 395          * @return Config
 396          */
 397         public function getBootstrapConfig() {
 398                 return $this->getService( 'BootstrapConfig' );
 399         }
 400
 401         /**
 402          * @since 1.27
 403          * @return ConfigFactory
 404          */
 405         public function getConfigFactory() {
 406                 return $this->getService( 'ConfigFactory' );
 407         }
 408
 409         /**
 410          * Returns the Config object that provides configuration for MediaWiki core.
 411          * This may or may not be the same object that is returned by getBootstrapConfig().
 412          *
 413          * @since 1.27
 414          * @return Config
 415          */
 416         public function getMainConfig() {
 417                 return $this->getService( 'MainConfig' );
 418         }
 419
 420         /**
 421          * @since 1.27
 422          * @return SiteLookup
 423          */
 424         public function getSiteLookup() {
 425                 return $this->getService( 'SiteLookup' );
 426         }
 427
 428         /**
 429          * @since 1.27
 430          * @return SiteStore
 431          */
 432         public function getSiteStore() {
 433                 return $this->getService( 'SiteStore' );
 434         }
 435
 436         /**
 437          * @since 1.28
 438          * @return InterwikiLookup
 439          */
 440         public function getInterwikiLookup() {
 441                 return $this->getService( 'InterwikiLookup' );
 442         }
 443
 444         /**
 445          * @since 1.27
 446          * @return StatsdDataFactory
 447          */
 448         public function getStatsdDataFactory() {
 449                 return $this->getService( 'StatsdDataFactory' );
 450         }
 451
 452         /**
 453          * @since 1.27
 454          * @return EventRelayerGroup
 455          */
 456         public function getEventRelayerGroup() {
 457                 return $this->getService( 'EventRelayerGroup' );
 458         }
 459
 460         /**
 461          * @since 1.27
 462          * @return SearchEngine
 463          */
 464         public function newSearchEngine() {
 465                 // New engine object every time, since they keep state
 466                 return $this->getService( 'SearchEngineFactory' )->create();
 467         }
 468
 469         /**
 470          * @since 1.27
 471          * @return SearchEngineFactory
 472          */
 473         public function getSearchEngineFactory() {
 474                 return $this->getService( 'SearchEngineFactory' );
 475         }
 476
 477         /**
 478          * @since 1.27
 479          * @return SearchEngineConfig
 480          */
 481         public function getSearchEngineConfig() {
 482                 return $this->getService( 'SearchEngineConfig' );
 483         }
 484
 485         /**
 486          * @since 1.27
 487          * @return SkinFactory
 488          */
 489         public function getSkinFactory() {
 490                 return $this->getService( 'SkinFactory' );
 491         }
 492
 493         /**
 494          * @since 1.28
 495          * @return LBFactory
 496          */
 497         public function getDBLoadBalancerFactory() {
 498                 return $this->getService( 'DBLoadBalancerFactory' );
 499         }
 500
 501         /**
 502          * @since 1.28
 503          * @return LoadBalancer The main DB load balancer for the local wiki.
 504          */
 505         public function getDBLoadBalancer() {
 506                 return $this->getService( 'DBLoadBalancer' );
 507         }
 508
 509         /**
 510          * @since 1.28
 511          * @return WatchedItemStore
 512          */
 513         public function getWatchedItemStore() {
 514                 return $this->getService( 'WatchedItemStore' );
 515         }
 516
 517         /**
 518          * @since 1.28
 519          * @return WatchedItemQueryService
 520          */
 521         public function getWatchedItemQueryService() {
 522                 return $this->getService( 'WatchedItemQueryService' );
 523         }
 524
 525         /**
 526          * @since 1.28
 527          * @return MediaHandlerFactory
 528          */
 529         public function getMediaHandlerFactory() {
 530                 return $this->getService( 'MediaHandlerFactory' );
 531         }
 532
 533         /**
 534          * @since 1.28
 535          * @return ProxyLookup
 536          */
 537         public function getProxyLookup() {
 538                 return $this->getService( 'ProxyLookup' );
 539         }
 540
 541         /**
 542          * @since 1.28
 543          * @return GenderCache
 544          */
 545         public function getGenderCache() {
 546                 return $this->getService( 'GenderCache' );
 547         }
 548
 549         /**
 550          * @since 1.28
 551          * @return LinkCache
 552          */
 553         public function getLinkCache() {
 554                 return $this->getService( 'LinkCache' );
 555         }
 556
 557         /**
 558          * @since 1.28
 559          * @return LinkRendererFactory
 560          */
 561         public function getLinkRendererFactory() {
 562                 return $this->getService( 'LinkRendererFactory' );
 563         }
 564
 565         /**
 566          * LinkRenderer instance that can be used
 567          * if no custom options are needed
 568          *
 569          * @since 1.28
 570          * @return LinkRenderer
 571          */
 572         public function getLinkRenderer() {
 573                 return $this->getService( 'LinkRenderer' );
 574         }
 575
 576         /**
 577          * @since 1.28
 578          * @return TitleFormatter
 579          */
 580         public function getTitleFormatter() {
 581                 return $this->getService( 'TitleFormatter' );
 582         }
 583
 584         /**
 585          * @since 1.28
 586          * @return TitleParser
 587          */
 588         public function getTitleParser() {
 589                 return $this->getService( 'TitleParser' );
 590         }
 591
 592         /**
 593          * @since 1.28
 594          * @return VirtualRESTServiceClient
 595          */
 596         public function getVirtualRESTServiceClient() {
 597                 return $this->getService( 'VirtualRESTServiceClient' );
 598         }
 599
 600         ///////////////////////////////////////////////////////////////////////////
 601         // NOTE: When adding a service getter here, don't forget to add a test
 602         // case for it in MediaWikiServicesTest::provideGetters() and in
 603         // MediaWikiServicesTest::provideGetService()!
 604         ///////////////////////////////////////////////////////////////////////////
 605
 606 }