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