Use LB server configuration to force DB domains in ExternalStorageDB

[lhc/web/wiklou.git] / includes / externalstore / ExternalStoreDB.php

diff --git a/includes/externalstore/ExternalStoreDB.php b/includes/externalstore/ExternalStoreDB.php
index 7e93299..6ed5047 100644 (file)
--- a/includes/externalstore/ExternalStoreDB.php
+++ b/includes/externalstore/ExternalStoreDB.php
@@ -20,8 +20,15 @@
  * @file
  */
 
+use MediaWiki\MediaWikiServices;
+use Wikimedia\Rdbms\ILoadBalancer;
+use Wikimedia\Rdbms\IDatabase;
+use Wikimedia\Rdbms\DBConnRef;
+use Wikimedia\Rdbms\MaintainableDBConnRef;
+use Wikimedia\Rdbms\DatabaseDomain;
+
 /**
- * DB accessable external objects.
+ * DB accessible external objects.
  *
  * In this system, each store "location" maps to a database "cluster".
  * The clusters must be defined in the normal LBFactory configuration.
@@ -87,9 +94,8 @@ class ExternalStoreDB extends ExternalStoreMedium {
 
        public function store( $location, $data ) {
                $dbw = $this->getMaster( $location );
-               $id = $dbw->nextSequenceValue( 'blob_blob_id_seq' );
                $dbw->insert( $this->getTable( $dbw ),
-                       [ 'blob_id' => $id, 'blob_text' => $data ],
+                       [ 'blob_text' => $data ],
                        __METHOD__ );
                $id = $dbw->insertId();
                if ( !$id ) {
@@ -99,29 +105,32 @@ class ExternalStoreDB extends ExternalStoreMedium {
                return "DB://$location/$id";
        }
 
+       public function isReadOnly( $location ) {
+               return ( $this->getLoadBalancer( $location )->getReadOnlyReason() !== false );
+       }
+
        /**
         * Get a LoadBalancer for the specified cluster
         *
         * @param string $cluster Cluster name
-        * @return LoadBalancer
+        * @return ILoadBalancer
         */
-       function getLoadBalancer( $cluster ) {
-               $wiki = isset( $this->params['wiki'] ) ? $this->params['wiki'] : false;
-
-               return wfGetLBFactory()->getExternalLB( $cluster, $wiki );
+       private function getLoadBalancer( $cluster ) {
+               $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
+               return $lbFactory->getExternalLB( $cluster );
        }
 
        /**
         * Get a replica DB connection for the specified cluster
         *
         * @param string $cluster Cluster name
-        * @return IDatabase
+        * @return DBConnRef
         */
-       function getSlave( $cluster ) {
+       public function getSlave( $cluster ) {
                global $wgDefaultExternalStore;
 
-               $wiki = isset( $this->params['wiki'] ) ? $this->params['wiki'] : false;
                $lb = $this->getLoadBalancer( $cluster );
+               $domainId = $this->getDomainId( $lb->getServerInfo( $lb->getWriterIndex() ) );
 
                if ( !in_array( "DB://" . $cluster, (array)$wgDefaultExternalStore ) ) {
                        wfDebug( "read only external store\n" );
@@ -130,7 +139,7 @@ class ExternalStoreDB extends ExternalStoreMedium {
                        wfDebug( "writable external store\n" );
                }
 
-               $db = $lb->getConnectionRef( DB_REPLICA, [], $wiki );
+               $db = $lb->getConnectionRef( DB_REPLICA, [], $domainId );
                $db->clearFlag( DBO_TRX ); // sanity
 
                return $db;
@@ -140,25 +149,48 @@ class ExternalStoreDB extends ExternalStoreMedium {
         * Get a master database connection for the specified cluster
         *
         * @param string $cluster Cluster name
-        * @return IDatabase
+        * @return MaintainableDBConnRef
         */
-       function getMaster( $cluster ) {
-               $wiki = isset( $this->params['wiki'] ) ? $this->params['wiki'] : false;
+       public function getMaster( $cluster ) {
                $lb = $this->getLoadBalancer( $cluster );
+               $domainId = $this->getDomainId( $lb->getServerInfo( $lb->getWriterIndex() ) );
 
-               $db = $lb->getConnectionRef( DB_MASTER, [], $wiki );
+               $db = $lb->getMaintenanceConnectionRef( DB_MASTER, [], $domainId );
                $db->clearFlag( DBO_TRX ); // sanity
 
                return $db;
        }
 
+       /**
+        * @param array $server Master DB server configuration array for LoadBalancer
+        * @return string|bool Database domain ID or false
+        */
+       private function getDomainId( array $server ) {
+               if ( isset( $server['dbname'] ) ) {
+                       // T200471: for b/c, treat any "dbname" field as forcing which database to use.
+                       // MediaWiki/LoadBalancer previously did not enforce any concept of a local DB
+                       // domain, but rather assumed that the LB server configuration matched $wgDBname.
+                       // This check is useful when the external storage DB for this cluster does not use
+                       // the same name as the corresponding "main" DB(s) for wikis.
+                       $domain = new DatabaseDomain(
+                               $server['dbname'],
+                               $server['schema'] ?? null,
+                               $server['tablePrefix'] ?? ''
+                       );
+
+                       return $domain->getId();
+               }
+
+               return $this->params['wiki'] ?? false; // local domain unless explictly given
+       }
+
        /**
         * Get the 'blobs' table name for this database
         *
         * @param IDatabase $db
         * @return string Table name ('blobs' by default)
         */
-       function getTable( $db ) {
+       public function getTable( $db ) {
                $table = $db->getLBInfo( 'blobs table' );
                if ( is_null( $table ) ) {
                        $table = 'blobs';
@@ -175,9 +207,8 @@ class ExternalStoreDB extends ExternalStoreMedium {
         * @param string $id
         * @param string $itemID
         * @return HistoryBlob|bool Returns false if missing
-        * @private
         */
-       function fetchBlob( $cluster, $id, $itemID ) {
+       private function fetchBlob( $cluster, $id, $itemID ) {
                /**
                 * One-step cache variable to hold base blobs; operations that
                 * pull multiple revisions may often pull multiple times from
@@ -230,7 +261,7 @@ class ExternalStoreDB extends ExternalStoreMedium {
         * @return array A map from the blob_id's requested to their content.
         *   Unlocated ids are not represented
         */
-       function batchFetchBlobs( $cluster, array $ids ) {
+       private function batchFetchBlobs( $cluster, array $ids ) {
                $dbr = $this->getSlave( $cluster );
                $res = $dbr->select( $this->getTable( $dbr ),
                        [ 'blob_id', 'blob_text' ], [ 'blob_id' => array_keys( $ids ) ], __METHOD__ );