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                         $oldService = $other->peekService( $name );
 202
 203                         if ( $oldService instanceof SalvageableService ) {
 204                                 /** @var SalvageableService $newService */
 205                                 $newService = $this->getService( $name );
 206                                 $newService->salvage( $oldService );
 207                         }
 208                 }
 209
 210                 $other->destroy();
 211         }
 212
 213         /**
 214          * Creates a new MediaWikiServices instance and initializes it according to the
 215          * given $bootstrapConfig. In particular, all wiring files defined in the
 216          * ServiceWiringFiles setting are loaded, and the MediaWikiServices hook is called.
 217          *
 218          * @param Config|null $bootstrapConfig The Config object to be registered as the
 219          *        'BootstrapConfig' service.
 220          *
 221          * @param string $loadWiring set this to 'load' to load the wiring files specified
 222          *        in the 'ServiceWiringFiles' setting in $bootstrapConfig.
 223          *
 224          * @return MediaWikiServices
 225          * @throws MWException
 226          * @throws \FatalError
 227          */
 228         private static function newInstance( Config $bootstrapConfig, $loadWiring = '' ) {
 229                 $instance = new self( $bootstrapConfig );
 230
 231                 // Load the default wiring from the specified files.
 232                 if ( $loadWiring === 'load' ) {
 233                         $wiringFiles = $bootstrapConfig->get( 'ServiceWiringFiles' );
 234                         $instance->loadWiringFiles( $wiringFiles );
 235                 }
 236
 237                 // Provide a traditional hook point to allow extensions to configure services.
 238                 Hooks::run( 'MediaWikiServices', [ $instance ] );
 239
 240                 return $instance;
 241         }
 242
 243         /**
 244          * Disables all storage layer services. After calling this, any attempt to access the
 245          * storage layer will result in an error. Use resetGlobalInstance() to restore normal
 246          * operation.
 247          *
 248          * @since 1.28
 249          *
 250          * @warning This is intended for extreme situations only and should never be used
 251          * while serving normal web requests. Legitimate use cases for this method include
 252          * the installation process. Test fixtures may also use this, if the fixture relies
 253          * on globalState.
 254          *
 255          * @see resetGlobalInstance()
 256          * @see resetChildProcessServices()
 257          */
 258         public static function disableStorageBackend() {
 259                 // TODO: also disable some Caches, JobQueues, etc
 260                 $destroy = [ 'DBLoadBalancer', 'DBLoadBalancerFactory' ];
 261                 $services = self::getInstance();
 262
 263                 foreach ( $destroy as $name ) {
 264                         $services->disableService( $name );
 265                 }
 266
 267                 ObjectCache::clear();
 268         }
 269
 270         /**
 271          * Resets any services that may have become stale after a child process
 272          * returns from after pcntl_fork(). It's also safe, but generally unnecessary,
 273          * to call this method from the parent process.
 274          *
 275          * @since 1.28
 276          *
 277          * @note This is intended for use in the context of process forking only!
 278          *
 279          * @see resetGlobalInstance()
 280          * @see disableStorageBackend()
 281          */
 282         public static function resetChildProcessServices() {
 283                 // NOTE: for now, just reset everything. Since we don't know the interdependencies
 284                 // between services, we can't do this more selectively at this time.
 285                 self::resetGlobalInstance();
 286
 287                 // Child, reseed because there is no bug in PHP:
 288                 // http://bugs.php.net/bug.php?id=42465
 289                 mt_srand( getmypid() );
 290         }
 291
 292         /**
 293          * Resets the given service for testing purposes.
 294          *
 295          * @since 1.28
 296          *
 297          * @warning This is generally unsafe! Other services may still retain references
 298          * to the stale service instance, leading to failures and inconsistencies. Subclasses
 299          * may use this method to reset specific services under specific instances, but
 300          * it should not be exposed to application logic.
 301          *
 302          * @note With proper dependency injection used throughout the codebase, this method
 303          * should not be needed. It is provided to allow tests that pollute global service
 304          * instances to clean up.
 305          *
 306          * @param string $name
 307          * @param bool $destroy Whether the service instance should be destroyed if it exists.
 308          *        When set to false, any existing service instance will effectively be detached
 309          *        from the container.
 310          *
 311          * @throws MWException if called outside of PHPUnit tests.
 312          */
 313         public function resetServiceForTesting( $name, $destroy = true ) {
 314                 if ( !defined( 'MW_PHPUNIT_TEST' ) && !defined( 'MW_PARSER_TEST' ) ) {
 315                         throw new MWException( 'resetServiceForTesting() must not be used outside unit tests.' );
 316                 }
 317
 318                 $this->resetService( $name, $destroy );
 319         }
 320
 321         /**
 322          * Convenience method that throws an exception unless it is called during a phase in which
 323          * resetting of global services is allowed. In general, services should not be reset
 324          * individually, since that may introduce inconsistencies.
 325          *
 326          * @since 1.28
 327          *
 328          * This method will throw an exception if:
 329          *
 330          * - self::$resetInProgress is false (to allow all services to be reset together
 331          *   via resetGlobalInstance)
 332          * - and MEDIAWIKI_INSTALL is not defined (to allow services to be reset during installation)
 333          * - and MW_PHPUNIT_TEST is not defined (to allow services to be reset during testing)
 334          *
 335          * This method is intended to be used to safeguard against accidentally resetting
 336          * global service instances that are not yet managed by MediaWikiServices. It is
 337          * defined here in the MediaWikiServices services class to have a central place
 338          * for managing service bootstrapping and resetting.
 339          *
 340          * @param string $method the name of the caller method, as given by __METHOD__.
 341          *
 342          * @throws MWException if called outside bootstrap mode.
 343          *
 344          * @see resetGlobalInstance()
 345          * @see forceGlobalInstance()
 346          * @see disableStorageBackend()
 347          */
 348         public static function failIfResetNotAllowed( $method ) {
 349                 if ( !defined( 'MW_PHPUNIT_TEST' )
 350                         && !defined( 'MW_PARSER_TEST' )
 351                         && !defined( 'MEDIAWIKI_INSTALL' )
 352                         && !defined( 'RUN_MAINTENANCE_IF_MAIN' )
 353                         && defined( 'MW_SERVICE_BOOTSTRAP_COMPLETE' )
 354                 ) {
 355                         throw new MWException( $method . ' may only be called during bootstrapping and unit tests!' );
 356                 }
 357         }
 358
 359         /**
 360          * @param Config $config The Config object to be registered as the 'BootstrapConfig' service.
 361          *        This has to contain at least the information needed to set up the 'ConfigFactory'
 362          *        service.
 363          */
 364         public function __construct( Config $config ) {
 365                 parent::__construct();
 366
 367                 // Register the given Config object as the bootstrap config service.
 368                 $this->defineService( 'BootstrapConfig', function() use ( $config ) {
 369                         return $config;
 370                 } );
 371         }
 372
 373         // CONVENIENCE GETTERS ////////////////////////////////////////////////////
 374
 375         /**
 376          * Returns the Config object containing the bootstrap configuration.
 377          * Bootstrap configuration would typically include database credentials
 378          * and other information that may be needed before the ConfigFactory
 379          * service can be instantiated.
 380          *
 381          * @note This should only be used during bootstrapping, in particular
 382          * when creating the MainConfig service. Application logic should
 383          * use getMainConfig() to get a Config instances.
 384          *
 385          * @since 1.27
 386          * @return Config
 387          */
 388         public function getBootstrapConfig() {
 389                 return $this->getService( 'BootstrapConfig' );
 390         }
 391
 392         /**
 393          * @since 1.27
 394          * @return ConfigFactory
 395          */
 396         public function getConfigFactory() {
 397                 return $this->getService( 'ConfigFactory' );
 398         }
 399
 400         /**
 401          * Returns the Config object that provides configuration for MediaWiki core.
 402          * This may or may not be the same object that is returned by getBootstrapConfig().
 403          *
 404          * @since 1.27
 405          * @return Config
 406          */
 407         public function getMainConfig() {
 408                 return $this->getService( 'MainConfig' );
 409         }
 410
 411         /**
 412          * @since 1.27
 413          * @return SiteLookup
 414          */
 415         public function getSiteLookup() {
 416                 return $this->getService( 'SiteLookup' );
 417         }
 418
 419         /**
 420          * @since 1.27
 421          * @return SiteStore
 422          */
 423         public function getSiteStore() {
 424                 return $this->getService( 'SiteStore' );
 425         }
 426
 427         /**
 428          * @since 1.28
 429          * @return InterwikiLookup
 430          */
 431         public function getInterwikiLookup() {
 432                 return $this->getService( 'InterwikiLookup' );
 433         }
 434
 435         /**
 436          * @since 1.27
 437          * @return StatsdDataFactory
 438          */
 439         public function getStatsdDataFactory() {
 440                 return $this->getService( 'StatsdDataFactory' );
 441         }
 442
 443         /**
 444          * @since 1.27
 445          * @return EventRelayerGroup
 446          */
 447         public function getEventRelayerGroup() {
 448                 return $this->getService( 'EventRelayerGroup' );
 449         }
 450
 451         /**
 452          * @since 1.27
 453          * @return SearchEngine
 454          */
 455         public function newSearchEngine() {
 456                 // New engine object every time, since they keep state
 457                 return $this->getService( 'SearchEngineFactory' )->create();
 458         }
 459
 460         /**
 461          * @since 1.27
 462          * @return SearchEngineFactory
 463          */
 464         public function getSearchEngineFactory() {
 465                 return $this->getService( 'SearchEngineFactory' );
 466         }
 467
 468         /**
 469          * @since 1.27
 470          * @return SearchEngineConfig
 471          */
 472         public function getSearchEngineConfig() {
 473                 return $this->getService( 'SearchEngineConfig' );
 474         }
 475
 476         /**
 477          * @since 1.27
 478          * @return SkinFactory
 479          */
 480         public function getSkinFactory() {
 481                 return $this->getService( 'SkinFactory' );
 482         }
 483
 484         /**
 485          * @since 1.28
 486          * @return LBFactory
 487          */
 488         public function getDBLoadBalancerFactory() {
 489                 return $this->getService( 'DBLoadBalancerFactory' );
 490         }
 491
 492         /**
 493          * @since 1.28
 494          * @return LoadBalancer The main DB load balancer for the local wiki.
 495          */
 496         public function getDBLoadBalancer() {
 497                 return $this->getService( 'DBLoadBalancer' );
 498         }
 499
 500         /**
 501          * @since 1.28
 502          * @return WatchedItemStore
 503          */
 504         public function getWatchedItemStore() {
 505                 return $this->getService( 'WatchedItemStore' );
 506         }
 507
 508         /**
 509          * @since 1.28
 510          * @return WatchedItemQueryService
 511          */
 512         public function getWatchedItemQueryService() {
 513                 return $this->getService( 'WatchedItemQueryService' );
 514         }
 515
 516         /**
 517          * @since 1.28
 518          * @return MediaHandlerFactory
 519          */
 520         public function getMediaHandlerFactory() {
 521                 return $this->getService( 'MediaHandlerFactory' );
 522         }
 523
 524         /**
 525          * @since 1.28
 526          * @return GenderCache
 527          */
 528         public function getGenderCache() {
 529                 return $this->getService( 'GenderCache' );
 530         }
 531
 532         /**
 533          * @since 1.28
 534          * @return LinkCache
 535          */
 536         public function getLinkCache() {
 537                 return $this->getService( 'LinkCache' );
 538         }
 539
 540         /**
 541          * @since 1.28
 542          * @return LinkRendererFactory
 543          */
 544         public function getLinkRendererFactory() {
 545                 return $this->getService( 'LinkRendererFactory' );
 546         }
 547
 548         /**
 549          * LinkRenderer instance that can be used
 550          * if no custom options are needed
 551          *
 552          * @since 1.28
 553          * @return LinkRenderer
 554          */
 555         public function getLinkRenderer() {
 556                 return $this->getService( 'LinkRenderer' );
 557         }
 558
 559         /**
 560          * @since 1.28
 561          * @return TitleFormatter
 562          */
 563         public function getTitleFormatter() {
 564                 return $this->getService( 'TitleFormatter' );
 565         }
 566
 567         /**
 568          * @since 1.28
 569          * @return TitleParser
 570          */
 571         public function getTitleParser() {
 572                 return $this->getService( 'TitleParser' );
 573         }
 574
 575         /**
 576          * @since 1.28
 577          * @return VirtualRESTServiceClient
 578          */
 579         public function getVirtualRESTServiceClient() {
 580                 return $this->getService( 'VirtualRESTServiceClient' );
 581         }
 582
 583         ///////////////////////////////////////////////////////////////////////////
 584         // NOTE: When adding a service getter here, don't forget to add a test
 585         // case for it in MediaWikiServicesTest::provideGetters() and in
 586         // MediaWikiServicesTest::provideGetService()!
 587         ///////////////////////////////////////////////////////////////////////////
 588
 589 }