rdbms: halt on some common broken $wgDBServers configurations

Mention the changes, usually simple, needed to fix the problem.

Bug: T215850
Change-Id: I9911f5f5213682ffb52ac548e3082db548e37b3d

diff --git a/includes/ServiceWiring.php b/includes/ServiceWiring.php
index 12e782d..73e4543 100644 (file)
--- a/includes/ServiceWiring.php
+++ b/includes/ServiceWiring.php
@@ -149,7 +149,10 @@ return [
                $lbConf = MWLBFactory::applyDefaultConfig(
                        $mainConfig->get( 'LBFactoryConf' ),
                        $mainConfig,
-                       $services->getConfiguredReadOnlyMode()
+                       $services->getConfiguredReadOnlyMode(),
+                       $services->getLocalServerObjectCache(),
+                       $services->getMainObjectStash(),
+                       $services->getMainWANObjectCache()
                );
                $class = MWLBFactory::getLBFactoryClass( $lbConf );
 

diff --git a/includes/db/MWLBFactory.php b/includes/db/MWLBFactory.php
index cb1a69d..a930b3b 100644 (file)
--- a/includes/db/MWLBFactory.php
+++ b/includes/db/MWLBFactory.php
@@ -22,7 +22,6 @@
  */
 
 use MediaWiki\Logger\LoggerFactory;
-use MediaWiki\MediaWikiServices;
 use Wikimedia\Rdbms\LBFactory;
 use Wikimedia\Rdbms\DatabaseDomain;
 
@@ -39,10 +38,18 @@ abstract class MWLBFactory {
         * @param array $lbConf Config for LBFactory::__construct()
         * @param Config $mainConfig Main config object from MediaWikiServices
         * @param ConfiguredReadOnlyMode $readOnlyMode
+        * @param BagOStuff $srvCace
+        * @param BagOStuff $mainStash
+        * @param WANObjectCache $wanCache
         * @return array
         */
-       public static function applyDefaultConfig( array $lbConf, Config $mainConfig,
-               ConfiguredReadOnlyMode $readOnlyMode
+       public static function applyDefaultConfig(
+               array $lbConf,
+               Config $mainConfig,
+               ConfiguredReadOnlyMode $readOnlyMode,
+               BagOStuff $srvCace,
+               BagOStuff $mainStash,
+               WANObjectCache $wanCache
        ) {
                global $wgCommandLineMode;
 
@@ -91,6 +98,20 @@ abstract class MWLBFactory {
                                                        'port' => $mainConfig->get( 'DBport' ),
                                                        'useWindowsAuth' => $mainConfig->get( 'DBWindowsAuthentication' )
                                                ];
+                                       } elseif ( $server['type'] === 'mysql' ) {
+                                               // A DB name is not needed to connect to mysql; 'dbname' is useless.
+                                               // This field only defines the DB to use for unspecified DB domains.
+                                               $ldDB = $mainConfig->get( 'DBname' ); // local domain DB
+                                               $srvDB = $server['dbname'] ?? null; // server DB
+                                               if ( $srvDB !== null && $srvDB !== $ldDB ) {
+                                                       self::reportMismatchedDBs( $srvDB, $ldDB );
+                                               }
+                                       }
+
+                                       $ldTP = $mainConfig->get( 'DBprefix' ); // local domain prefix
+                                       $srvTP = $server['tablePrefix'] ?? null; // server table prefix
+                                       if ( $srvTP !== '' && $srvTP !== $ldTP ) {
+                                               self::reportMismatchedPrefixes( $srvTP, $ldTP );
                                        }
 
                                        if ( in_array( $server['type'], $typesWithSchema, true ) ) {
@@ -151,18 +172,28 @@ abstract class MWLBFactory {
                        }
                }
 
-               $services = MediaWikiServices::getInstance();
+               $lbConf = self::applyDefaultCaching( $lbConf, $srvCace, $mainStash, $wanCache );
+
+               return $lbConf;
+       }
 
+       /**
+        * @param array $lbConf
+        * @param BagOStuff $sCache
+        * @param BagOStuff $mStash
+        * @param WANObjectCache $wCache
+        * @return array
+        */
+       private static function applyDefaultCaching(
+               array $lbConf, BagOStuff $sCache, BagOStuff $mStash, WANObjectCache $wCache
+       ) {
                // Use APC/memcached style caching, but avoids loops with CACHE_DB (T141804)
-               $sCache = $services->getLocalServerObjectCache();
                if ( $sCache->getQoS( $sCache::ATTR_EMULATION ) > $sCache::QOS_EMULATION_SQL ) {
                        $lbConf['srvCache'] = $sCache;
                }
-               $mStash = $services->getMainObjectStash();
                if ( $mStash->getQoS( $mStash::ATTR_EMULATION ) > $mStash::QOS_EMULATION_SQL ) {
                        $lbConf['memStash'] = $mStash;
                }
-               $wCache = $services->getMainWANObjectCache();
                if ( $wCache->getQoS( $wCache::ATTR_EMULATION ) > $wCache::QOS_EMULATION_SQL ) {
                        $lbConf['wanCache'] = $wCache;
                }
@@ -170,6 +201,40 @@ abstract class MWLBFactory {
                return $lbConf;
        }
 
+       /**
+        * @param string $srvDB Server config database
+        * @param string $ldDB Local DB domain database
+        */
+       private static function reportMismatchedDBs( $srvDB, $ldDB ) {
+               $e = new UnexpectedValueException(
+                       "\$wgDBservers has dbname='$srvDB' but \$wgDBname='$ldDB'. " .
+                       "Set \$wgDBname to the database used by this wiki project. " .
+                       "There is rarely a need to set 'dbname' in \$wgDBservers. " .
+                       "Functions like wfWikiId(), remote wiki database access, the use " .
+                       "of Database::getDomainId(), and other features are not reliable when " .
+                       "\$wgDBservers does not match the local wiki database/prefix."
+               );
+               MWExceptionRenderer::output( $e, MWExceptionRenderer::AS_PRETTY );
+               exit;
+       }
+
+       /**
+        * @param string $srvTP Server config table prefix
+        * @param string $ldTP Local DB domain database
+        */
+       private static function reportMismatchedPrefixes( $srvTP, $ldTP ) {
+               $e = new UnexpectedValueException(
+                       "\$wgDBservers has tablePrefix='$srvTP' but \$wgDBprefix='$ldTP'. " .
+                       "Set \$wgDBprefix to the table prefix used by this wiki project. " .
+                       "There is rarely a need to set 'tablePrefix' in \$wgDBservers. " .
+                       "Functions like wfWikiId(), remote wiki database access, the use " .
+                       "of Database::getDomainId(), and other features are not reliable when " .
+                       "\$wgDBservers does not match the local wiki database/prefix."
+               );
+               MWExceptionRenderer::output( $e, MWExceptionRenderer::AS_PRETTY );
+               exit;
+       }
+
        /**
         * Returns the LBFactory class to use and the load balancer configuration.
         *