Move addWiki.php special case to an installer task

Bug: T352113
Depends-On: Ie7c466012d8d5644b1398452e3077416ab0270c5
Change-Id: I752edd8daaebb91a4bd9a7797747ade96d537526

extension.json

@@ -1165,5 +1165,10 @@
 	],
 	"ConfigRegistry": {
 		"Echo": "GlobalVarConfig::newInstance"
-	}
+	},
+	"InstallerTasks": [
+		{
+			"class": "MediaWiki\\Extension\\Notifications\\InstallSchemaTask"
+		}
+	]
 }

includes/InstallSchemaTask.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace MediaWiki\Extension\Notifications;
+
+use MediaWiki\Installer\Task\Task;
+use MediaWiki\Status\Status;
+use Wikimedia\Rdbms\DatabaseDomain;
+
+/**
+ * TODO: replace this with virtual domains
+ *
+ * This is a temporary hack to support WMF production wiki creation, with
+ * database creation in an external cluster. Core knows how to do this for
+ * virtual domains, but this extension is not yet using a virtual domain. (T348573)
+ */
+class InstallSchemaTask extends Task {
+	public function getName() {
+		return 'echo-schema';
+	}
+
+	public function getDescription() {
+		return 'Installing Echo tables';
+	}
+
+	public function getDependencies() {
+		return [ 'services', 'schema' ];
+	}
+
+	public function getAliases() {
+		// Group with extension tables so that things that depend on
+		// extension tables will have this
+		return 'extension-tables';
+	}
+
+	public function execute(): Status {
+		$cluster = $this->getConfigVar( 'EchoCluster' );
+		if ( !$cluster ) {
+			// This case is adequately handled by LoadExtensionSchemaUpdates
+			return Status::newGood();
+		}
+
+		// Get the load balancer
+		$lbFactory = $this->getServices()->getDBLoadBalancerFactory();
+		$databaseCreator = $this->getDatabaseCreator();
+		$domainId = $lbFactory->getLocalDomainID();
+		$database = DatabaseDomain::newFromId( $domainId )->getDatabase();
+		$echoLB = $lbFactory->getExternalLB( $cluster );
+
+		// Create database
+		if ( !$databaseCreator->existsInLoadBalancer( $echoLB, $database ) ) {
+			$databaseCreator->createInLoadBalancer( $echoLB, $database );
+		}
+
+		// Create tables
+		$dbw = $echoLB->getMaintenanceConnectionRef( DB_PRIMARY );
+		$dbw->setSchemaVars( $this->getContext()->getSchemaVars() );
+		return $this->applySourceFile( $dbw, 'tables-generated.sql' );
+	}
+
+}