objectcache: Remove $wgMainWANCache and $wgWANObjectCaches

We always wrap the local cluster cache, and there are no subclasses of WANObjectCache. It was never documented or recommended how these would be used. It is a left-over from the original 2015 Multi-DC plan in which WANObjectCache would work differently. See task for details. Note that this requires no configuration changes, even in the theoretical case of these variables being used, as the only option is to use the main cache, and that's also the default. * Update WAN overrides to override the underlying main cache instead. * Fix EditPageTest which was previously implicitly using a 'hash' as main cache but also relying on wan cache to be 'none'. The part that it actually needs is the 'none'. When WAN cache is enabled, testUpdateNoMinor fails due to an edit conflict because one of the edits it makes is made with a current timestamp whereas it expects to simulate wpEdittime in the year 2012 which, when caching is enabled, is ignored and becomes the current time instead. I don't understand exactly why, but I'm going to conserve that behaviour for now. * Fix TemplateCategoriesTest, which was failing due to an unexpected cache hit: > [objectcache] fetchOrRegenerate(…:page:10:…): volatile hit This could be solved in a more realistic way by splitting the test, or by explicitly resetting services half-way the test to clear WikiPageFactory, PageStore and WANCache process state. For now, keep the prior behaviour of no cache in this test. Bug: T305093 Bug: T329680 Depends-On: If890622eed0d0f8b4bd73d36ba1815a3d760ea05 Depends-On: Ie1def75208822bdf19bb2cfd7e6edf32c2000e6b Depends-On: I35cce61dc3ee90dcee3dd6f0b36f84133be029ed Change-Id: I53781a8c06ebb2583f6ca83dd91bbfe8a5c88b13
wikimedia · Mar 7, 2023 · 39ead04 · 39ead04
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diff --git a/.phan/config.php b/.phan/config.php
@@ -173,7 +173,6 @@ class_exists( WeakMap::class ) ? [] : [ '.phan/stubs/WeakMap.php' ],
 	'wgLogActionsHandlers' => 'array<string,class-string>',
 	'wgPasswordPolicy' => 'array<string,array<string,string|array>>',
 	'wgVirtualRestConfig' => 'array<string,array>',
-	'wgWANObjectCaches' => 'array[]',
 	'wgLocalInterwikis' => 'string[]',
 	'wgDebugLogGroups' => 'string|false|array{destination:string,sample?:int,level:int}',
 	'wgCookiePrefix' => 'string|false',

diff --git a/RELEASE-NOTES-1.40 b/RELEASE-NOTES-1.40
@@ -49,6 +49,12 @@ For notes on 1.39.x and older releases, see HISTORY.
 ==== Removed configuration ====
 * $wgShellboxUrl that was deprecated in 1.37 has now been removed,
   set $wgShellboxUrls instead.
+* $wgMainWANCache and $wgWANObjectCaches have been removed. To inject
+  WANObjectCache parameters, use $wgWANObjectCache instead. These variables
+  were introduced for multi-DC wiki farms to add a separate memcached
+  proxy for cross-DC relaying of purges. The configuration was never used
+  because WANObjectCache works based on route prefixes, that can be
+  transparently handled by the main memcached proxy.
 * $wgParserTestFiles which was deprecated in 1.30 has now been removed;
   extensions can place their parser test files in `tests/parser` instead.
 * (T231412) $wgAutoloadAttemptLowercase, which was deprecated in 1.35,

diff --git a/docs/config-schema.yaml b/docs/config-schema.yaml
@@ -2304,6 +2304,11 @@ config-schema:
             - CACHE_ACCEL:      APC, APCU or WinCache
             - (other):          A string may be used which identifies a cache
                                 configuration in $wgObjectCaches.
+            For a multi-datacenter setup, the underlying service should be configured
+            to broadcast operations by WANObjectCache using Mcrouter or Dynomite.
+            See @ref wanobjectcache-deployment "Deploying WANObjectCache".
+            To configure the `broadcastRoutingPrefix` WANObjectCache parameter,
+            use $wgWANObjectCache.
             @see $wgMessageCacheType, $wgParserCacheType
     MessageCacheType:
         default: -1
@@ -2416,51 +2421,13 @@ config-schema:
             For MemcachedPhpBagOStuff parameters see {@link MemcachedPhpBagOStuff::__construct}
             For MemcachedPeclBagOStuff parameters see {@link MemcachedPeclBagOStuff::__construct}
             For RedisBagOStuff parameters see {@link RedisBagOStuff::__construct}
-    MainWANCache:
-        default: false
-        type:
-            - integer
-            - string
-            - boolean
+    WANObjectCache:
+        default: {  }
+        type: object
         description: |-
-            Main Wide-Area-Network cache type.
-            By default, this will wrap $wgMainCacheType (which is disabled, since the basic
-            stock default of CACHE_DB is not fast enough to make it worthwhile).
-            For single server or single datacenter setup, setting $wgMainCacheType
-            is enough.
-            For a multiple datacenter setup, WANObjectCache should be configured to
-            broadcast some if its operations using Mcrouter or Dynomite.
+            Extra parameters to the WANObjectCache constructor.
             See @ref wanobjectcache-deployment "Deploying WANObjectCache".
-            The options are:
-              - false:            Configure the cache using $wgMainCacheType, without using
-                                  a relayer (only matters if there are multiple datacenters)
-              - CACHE_NONE:       Do not cache
-              - (other):          A string may be used which identifies a cache
-                                  configuration in $wgWANObjectCaches
-            @since 1.26
-    WANObjectCaches:
-        default:
-            - { class: WANObjectCache, cacheId: 0 }
-        type: object
-        description: |-
-            Advanced WAN object cache configuration.
-            The format is an associative array where the key is an identifier
-            that may be referenced by $wgMainWANCache, and the value is an array of options:
-             - class:   (Required) The class to use (must be WANObjectCache or a subclass).
-             - cacheId: (Required) A cache identifier from $wgObjectCaches.
-             - secret:  (Optional) Stable secret for hashing long strings in key components.
-                        Default: $wgSecretKey.
-            Any other options are treated as constructor parameters to WANObjectCache,
-            except for 'cache', 'logger', 'stats' and 'asyncHandler' which are
-            unconditionally set by MediaWiki core's ServiceWiring.
-            **Example:**
-            ```
-            $wgWANObjectCaches['memcached-php'] => [
-              'class' => WANObjectCache::class,
-              'cacheId' => 'memcached-php',
-            ];
-            ```
-            @since 1.26
+            @since 1.40
     MainStash:
         default: db-replicated
         description: |-

diff --git a/docs/config-vars.php b/docs/config-vars.php
@@ -1470,16 +1470,10 @@
 $wgObjectCaches = null;
 
 /**
- * Config variable stub for the MainWANCache setting, for use by phpdoc and IDEs.
- * @see MediaWiki\MainConfigSchema::MainWANCache
+ * Config variable stub for the WANObjectCache setting, for use by phpdoc and IDEs.
+ * @see MediaWiki\MainConfigSchema::WANObjectCache
  */
-$wgMainWANCache = null;
-
-/**
- * Config variable stub for the WANObjectCaches setting, for use by phpdoc and IDEs.
- * @see MediaWiki\MainConfigSchema::WANObjectCaches
- */
-$wgWANObjectCaches = null;
+$wgWANObjectCache = null;
 
 /**
  * Config variable stub for the MainStash setting, for use by phpdoc and IDEs.

diff --git a/includes/MainConfigNames.php b/includes/MainConfigNames.php
@@ -1485,16 +1485,10 @@ class MainConfigNames {
 	public const ObjectCaches = 'ObjectCaches';
 
 	/**
-	 * Name constant for the MainWANCache setting, for use with Config::get()
-	 * @see MainConfigSchema::MainWANCache
+	 * Name constant for the WANObjectCache setting, for use with Config::get()
+	 * @see MainConfigSchema::WANObjectCache
 	 */
-	public const MainWANCache = 'MainWANCache';
-
-	/**
-	 * Name constant for the WANObjectCaches setting, for use with Config::get()
-	 * @see MainConfigSchema::WANObjectCaches
-	 */
-	public const WANObjectCaches = 'WANObjectCaches';
+	public const WANObjectCache = 'WANObjectCache';
 
 	/**
 	 * Name constant for the MainStash setting, for use with Config::get()

diff --git a/includes/MainConfigSchema.php b/includes/MainConfigSchema.php
@@ -79,7 +79,6 @@
 use UserEditCountInitJob;
 use UserGroupExpiryJob;
 use UserOptionsUpdateJob;
-use WANObjectCache;
 use WatchlistExpiryJob;
 use WebRequest;
 use WikitextContentHandler;
@@ -3746,6 +3745,12 @@ public static function getDefaultDBerrorLogTZ( $localtimezone ) {
 	 * - (other):          A string may be used which identifies a cache
 	 *                     configuration in $wgObjectCaches.
 	 *
+	 * For a multi-datacenter setup, the underlying service should be configured
+	 * to broadcast operations by WANObjectCache using Mcrouter or Dynomite.
+	 * See @ref wanobjectcache-deployment "Deploying WANObjectCache".
+	 * To configure the `broadcastRoutingPrefix` WANObjectCache parameter,
+	 * use $wgWANObjectCache.
+	 *
 	 * @see $wgMessageCacheType, $wgParserCacheType
 	 */
 	public const MainCacheType = [
@@ -3929,65 +3934,14 @@ public static function getDefaultDBerrorLogTZ( $localtimezone ) {
 	];
 
 	/**
-	 * Main Wide-Area-Network cache type.
-	 *
-	 * By default, this will wrap $wgMainCacheType (which is disabled, since the basic
-	 * stock default of CACHE_DB is not fast enough to make it worthwhile).
-	 *
-	 * For single server or single datacenter setup, setting $wgMainCacheType
-	 * is enough.
+	 * Extra parameters to the WANObjectCache constructor.
 	 *
-	 * For a multiple datacenter setup, WANObjectCache should be configured to
-	 * broadcast some if its operations using Mcrouter or Dynomite.
 	 * See @ref wanobjectcache-deployment "Deploying WANObjectCache".
 	 *
-	 * The options are:
-	 *   - false:            Configure the cache using $wgMainCacheType, without using
-	 *                       a relayer (only matters if there are multiple datacenters)
-	 *   - CACHE_NONE:       Do not cache
-	 *   - (other):          A string may be used which identifies a cache
-	 *                       configuration in $wgWANObjectCaches
-	 *
-	 * @since 1.26
-	 */
-	public const MainWANCache = [
-		'default' => false,
-		'type' => 'integer|string|false',
-	];
-
-	/**
-	 * Advanced WAN object cache configuration.
-	 *
-	 * The format is an associative array where the key is an identifier
-	 * that may be referenced by $wgMainWANCache, and the value is an array of options:
-	 *
-	 *  - class:   (Required) The class to use (must be WANObjectCache or a subclass).
-	 *  - cacheId: (Required) A cache identifier from $wgObjectCaches.
-	 *  - secret:  (Optional) Stable secret for hashing long strings in key components.
-	 *             Default: $wgSecretKey.
-	 *
-	 * Any other options are treated as constructor parameters to WANObjectCache,
-	 * except for 'cache', 'logger', 'stats' and 'asyncHandler' which are
-	 * unconditionally set by MediaWiki core's ServiceWiring.
-	 *
-	 * **Example:**
-	 *
-	 * ```
-	 * $wgWANObjectCaches['memcached-php'] => [
-	 *   'class' => WANObjectCache::class,
-	 *   'cacheId' => 'memcached-php',
-	 * ];
-	 * ```
-	 *
-	 * @since 1.26
+	 * @since 1.40
 	 */
-	public const WANObjectCaches = [
-		'default' => [
-			CACHE_NONE => [
-				'class' => WANObjectCache::class,
-				'cacheId' => CACHE_NONE,
-			]
-		],
+	public const WANObjectCache = [
+		'default' => [],
 		'type' => 'map',
 	];
 

diff --git a/includes/ServiceWiring.php b/includes/ServiceWiring.php
@@ -1018,45 +1018,24 @@ static function () use ( $services ) {
 	'MainWANObjectCache' => static function ( MediaWikiServices $services ): WANObjectCache {
 		$mainConfig = $services->getMainConfig();
 
-		$wanId = $mainConfig->get( MainConfigNames::MainWANCache );
-		$wanParams = $mainConfig->get( MainConfigNames::WANObjectCaches )[$wanId] ?? null;
-		if ( !$wanParams ) {
-			throw new UnexpectedValueException(
-				"wgWANObjectCaches must have \"$wanId\" set (via wgMainWANCache)"
-			);
-		}
-
-		$cacheId = $wanParams['cacheId'];
-		$wanClass = $wanParams['class'];
-		unset( $wanParams['cacheId'] );
-		unset( $wanParams['class'] );
-
-		$storeParams = $mainConfig->get( MainConfigNames::ObjectCaches )[$cacheId] ?? null;
-		if ( !$storeParams ) {
-			throw new UnexpectedValueException(
-				"wgObjectCaches must have \"$cacheId\" set (via wgWANObjectCaches)"
-			);
-		}
-		$store = ObjectCache::newFromParams( $storeParams, $services );
+		$store = $services->get( '_LocalClusterCache' );
 		$logger = $store->getLogger();
 		$logger->debug( 'MainWANObjectCache using store {class}', [
 			'class' => get_class( $store )
 		] );
 
-		$wanParams['cache'] = $store;
-		$wanParams['logger'] = $logger;
-		$wanParams['secret'] ??= $mainConfig->get( MainConfigNames::SecretKey );
+		$wanParams = $mainConfig->get( MainConfigNames::WANObjectCache ) + [
+			'cache' => $store,
+			'logger' => $logger,
+			'secret' => $mainConfig->get( MainConfigNames::SecretKey ),
+		];
 		if ( !$GLOBALS[ 'wgCommandLineMode' ] ) {
 			// Send the statsd data post-send on HTTP requests; avoid in CLI mode (T181385)
 			$wanParams['stats'] = $services->getStatsdDataFactory();
 			// Let pre-emptive refreshes happen post-send on HTTP requests
 			$wanParams['asyncHandler'] = [ DeferredUpdates::class, 'addCallableUpdate' ];
 		}
-
-		$instance = new $wanClass( $wanParams );
-
-		'@phan-var WANObjectCache $instance';
-		return $instance;
+		return new WANObjectCache( $wanParams );
 	},
 
 	'MediaHandlerFactory' => static function ( MediaWikiServices $services ): MediaHandlerFactory {

diff --git a/includes/SetupDynamicConfig.php b/includes/SetupDynamicConfig.php
@@ -14,15 +14,6 @@
 	$wgLogo = $wgLogos['1x'];
 }
 
-if ( $wgMainWANCache === false ) {
-	// Create a WAN cache from $wgMainCacheType
-	$wgMainWANCache = 'mediawiki-main-default';
-	$wgWANObjectCaches[$wgMainWANCache] = [
-		'class'    => WANObjectCache::class,
-		'cacheId'  => $wgMainCacheType,
-	];
-}
-
 // Back-compat
 if ( isset( $wgFileBlacklist ) ) {
 	$wgProhibitedFileExtensions = array_merge( $wgProhibitedFileExtensions, $wgFileBlacklist );

diff --git a/includes/config-schema.php b/includes/config-schema.php
@@ -516,12 +516,7 @@
 					'reportDupes' => false,
 				],
 			],
-			'MainWANCache' => false,
-			'WANObjectCaches' => [
-				0 => [
-					'class' => 'WANObjectCache',
-					'cacheId' => 0,
-				],
+			'WANObjectCache' => [
 			],
 			'MainStash' => 'db-replicated',
 			'ParsoidCacheConfig' => [
@@ -2619,12 +2614,7 @@
 			],
 			'MultiShardSiteStats' => 'boolean',
 			'ObjectCaches' => 'object',
-			'MainWANCache' => [
-				0 => 'integer',
-				1 => 'string',
-				2 => 'boolean',
-			],
-			'WANObjectCaches' => 'object',
+			'WANObjectCache' => 'object',
 			'ParsoidCacheConfig' => 'object',
 			'ChronologyProtectorStash' => [
 				0 => 'string',

diff --git a/tests/common/TestSetup.php b/tests/common/TestSetup.php
@@ -28,7 +28,7 @@ public static function snapshotGlobals() {
 	 * of a Maintenance subclass which then gets called via MW_SETUP_CALLBACK in Setup.php.
 	 */
 	public static function applyInitialConfig() {
-		global $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType, $wgMainWANCache, $wgSessionCacheType;
+		global $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType, $wgSessionCacheType;
 		global $wgMainStash, $wgChronologyProtectorStash;
 		global $wgObjectCaches;
 		global $wgLanguageConverterCacheType, $wgUseDatabaseMessages;
@@ -53,7 +53,6 @@ public static function applyInitialConfig() {
 		// See also MediaWikiIntegrationTestCase::run() which mocks CACHE_DB and APC.
 
 		// Disabled per default in MainConfigSchema, override local settings
-		$wgMainWANCache =
 		$wgMainCacheType = CACHE_NONE;
 		// Uses CACHE_ANYTHING per default in MainConfigSchema, use hash instead of db
 		$wgMessageCacheType =

diff --git a/tests/phpunit/includes/EditPageTest.php b/tests/phpunit/includes/EditPageTest.php
@@ -12,12 +12,8 @@
 
 /**
  * @group Editing
- *
  * @group Database
- *        ^--- tell jenkins this test needs the database
- *
  * @group medium
- *        ^--- tell phpunit that these test cases may take longer than 2 seconds.
  */
 class EditPageTest extends MediaWikiLangTestCase {
 
@@ -34,6 +30,9 @@ protected function setUp(): void {
 				[ 'testing' => 'DummyContentHandlerForTesting' ] +
 				MainConfigSchema::getDefaultValue( MainConfigNames::ContentHandlers ),
 		] );
+
+		// Disable WAN cache to avoid edit conflicts in testUpdateNoMinor
+		$this->setMainCache( CACHE_NONE );
 	}
 
 	/**

diff --git a/tests/phpunit/includes/ResourceLoader/MessageBlobStoreTest.php b/tests/phpunit/includes/ResourceLoader/MessageBlobStoreTest.php
@@ -29,8 +29,6 @@ class MessageBlobStoreTest extends \PHPUnit\Framework\TestCase {
 
 	protected function setUp(): void {
 		parent::setUp();
-		// MediaWiki's test wrapper sets $wgMainWANCache to CACHE_NONE.
-		// Use HashBagOStuff here so that we can observe caching.
 		$this->wanCache = new WANObjectCache( [
 			'cache' => new HashBagOStuff()
 		] );

diff --git a/tests/phpunit/includes/TemplateCategoriesTest.php b/tests/phpunit/includes/TemplateCategoriesTest.php
@@ -7,6 +7,13 @@
  */
 class TemplateCategoriesTest extends MediaWikiIntegrationTestCase {
 
+	protected function setUp(): void {
+		parent::setUp();
+
+		// Don't let PageStore hit WANObjectCache process cache for revision metadata
+		$this->setMainCache( CACHE_NONE );
+	}
+
 	/**
 	 * @covers Title::getParentCategories
 	 */