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