PLATFORM-9062 | Fix wgCargoDBIndex support

extension.json

@@ -487,6 +487,7 @@
 		"CargoDBprefix": null,
 		"CargoDBRowFormat": null,
 		"CargoDBCluster": null,
+		"CargoDBIndex": null,
 		"CargoDefaultStringBytes": 300,
 		"CargoDefaultQueryLimit": 100,
 		"CargoMaxQueryLimit": 5000,

includes/CargoConnectionProvider.php

@@ -31,6 +31,9 @@ class CargoConnectionProvider {
 		'CargoDBprefix',
 		'CargoDBtype',
 
+		// Fandom change: Optional DB index override to use for Cargo in a single-connection setup (PLATFORM-7466)
+		'CargoDBIndex',
+
 		// Optional external cluster name to use for Cargo.
 		// Supersedes all above configuration if present.
 		'CargoDBCluster'
@@ -114,7 +117,9 @@ public function getDBType(): string {
 	 */
 	private function initConnection(): IDatabase {
 		$lb = $this->lbFactory->getMainLB();
-		$dbr = $lb->getConnection( DB_REPLICA );
+		// Fandom change: Use the DB index specified in the CargoDBIndex option (PLATFORM-7466).
+		$index = $this->serviceOptions->get( 'CargoDBIndex' ) ?? $lb::DB_PRIMARY;
+		$dbr = $lb->getConnection( $index );
 
 		$dbServers = $this->serviceOptions->get( 'DBservers' );
 		$dbUser = $this->serviceOptions->get( 'DBuser' );

tests/phpunit/unit/CargoConnectionProviderUnitTest.php

@@ -49,7 +49,7 @@ public function testShouldCreateAndManageConnectionBasedOnConfigVars(
 
 		$this->dbLoadBalancer->expects( $this->any() )
 			->method( 'getConnection' )
-			->with( DB_REPLICA )
+			->with( $serviceOptions->get( 'CargoDBIndex' ) ?? DB_PRIMARY )
 			->willReturn( $mainConn );
 
 		$mainConn->expects( $this->any() )
@@ -90,6 +90,8 @@ public static function provideConnectionConfigs(): iterable {
 				'CargoDBprefix' => null,
 				'CargoDBtype' => null,
 
+				'CargoDBIndex' => null,
+
 				'CargoDBCluster' => null,
 			],
 			'mysql',
@@ -120,6 +122,8 @@ public static function provideConnectionConfigs(): iterable {
 				'CargoDBprefix' => null,
 				'CargoDBtype' => null,
 
+				'CargoDBIndex' => null,
+
 				'CargoDBCluster' => null,
 			],
 			'mysql',
@@ -132,6 +136,38 @@ public static function provideConnectionConfigs(): iterable {
 			]
 		];
 
+		yield 'inferred from DBservers with CargoDBIndex override' => [
+			[
+				'DBuser' => 'db_user',
+				'DBpassword' => 'db_password',
+				'DBport' => 0,
+				'DBprefix' => '',
+				'DBservers' => [
+					[ 'user' => 'primary_db_user', 'password' => 'primary_db_password' ],
+					[ 'user' => 'replica_db_user', 'password' => 'replica_db_password' ],
+				],
+
+				'CargoDBserver' => null,
+				'CargoDBname' => null,
+				'CargoDBuser' => null,
+				'CargoDBpassword' => null,
+				'CargoDBprefix' => null,
+				'CargoDBtype' => null,
+
+				'CargoDBIndex' => DB_REPLICA,
+
+				'CargoDBCluster' => null,
+			],
+			'mysql',
+			[
+				'host' => 'localhost',
+				'user' => 'replica_db_user',
+				'password' => 'replica_db_password',
+				'dbname' => 'test_wiki_db',
+				'tablePrefix' => 'cargo__',
+			]
+		];
+
 		yield 'inferred from CargoDB overrides' => [
 			[
 				'DBuser' => 'db_user',
@@ -150,6 +186,8 @@ public static function provideConnectionConfigs(): iterable {
 				'CargoDBprefix' => 'cargoprefix',
 				'CargoDBtype' => 'postgres',
 
+				'CargoDBIndex' => null,
+
 				'CargoDBCluster' => null,
 			],
 			'postgres',
@@ -181,6 +219,8 @@ public static function provideConnectionConfigs(): iterable {
 				'CargoDBprefix' => null,
 				'CargoDBtype' => null,
 
+				'CargoDBIndex' => null,
+
 				'CargoDBCluster' => null,
 			],
 			'mysql',
@@ -212,6 +252,8 @@ public function testShouldObtainConnectionFromMediaWikiLoadBalancerIfClusterOpti
 			'CargoDBprefix' => null,
 			'CargoDBtype' => null,
 
+			'CargoDBIndex' => null,
+
 			'CargoDBCluster' => 'testCargoCluster',
 		] );
 
@@ -258,6 +300,8 @@ public function testShouldObtainPrimaryConnectionFromMediaWikiLoadBalancerIfClus
 			'CargoDBprefix' => null,
 			'CargoDBtype' => null,
 
+			'CargoDBIndex' => null,
+
 			'CargoDBCluster' => 'testCargoCluster',
 		] );