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Diffstat (limited to 'includes/db/LBFactoryMulti.php')
| -rw-r--r-- | includes/db/LBFactoryMulti.php | 399 |
1 files changed, 399 insertions, 0 deletions
diff --git a/includes/db/LBFactoryMulti.php b/includes/db/LBFactoryMulti.php new file mode 100644 index 00000000..bac96523 --- /dev/null +++ b/includes/db/LBFactoryMulti.php @@ -0,0 +1,399 @@ +<?php +/** + * Advanced generator of database load balancing objects for wiki farms. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * http://www.gnu.org/copyleft/gpl.html + * + * @file + * @ingroup Database + */ + +/** + * A multi-wiki, multi-master factory for Wikimedia and similar installations. + * Ignores the old configuration globals + * + * Configuration: + * sectionsByDB A map of database names to section names. + * + * sectionLoads A 2-d map. For each section, gives a map of server names to + * load ratios. For example: + * array( + * 'section1' => array( + * 'db1' => 100, + * 'db2' => 100 + * ) + * ) + * + * serverTemplate A server info associative array as documented for $wgDBservers. + * The host, hostName and load entries will be overridden. + * + * groupLoadsBySection A 3-d map giving server load ratios for each section and group. + * For example: + * array( + * 'section1' => array( + * 'group1' => array( + * 'db1' => 100, + * 'db2' => 100 + * ) + * ) + * ) + * + * groupLoadsByDB A 3-d map giving server load ratios by DB name. + * + * hostsByName A map of hostname to IP address. + * + * externalLoads A map of external storage cluster name to server load map. + * + * externalTemplateOverrides A set of server info keys overriding serverTemplate for external + * storage. + * + * templateOverridesByServer A 2-d map overriding serverTemplate and + * externalTemplateOverrides on a server-by-server basis. Applies + * to both core and external storage. + * + * templateOverridesByCluster A 2-d map overriding the server info by external storage cluster. + * + * masterTemplateOverrides An override array for all master servers. + * + * readOnlyBySection A map of section name to read-only message. + * Missing or false for read/write. + * + * @ingroup Database + */ +class LBFactoryMulti extends LBFactory { + // Required settings + + /** @var array A map of database names to section names */ + protected $sectionsByDB; + + /** + * @var array A 2-d map. For each section, gives a map of server names to + * load ratios + */ + protected $sectionLoads; + + /** + * @var array A server info associative array as documented for + * $wgDBservers. The host, hostName and load entries will be + * overridden + */ + protected $serverTemplate; + + // Optional settings + + /** @var array A 3-d map giving server load ratios for each section and group */ + protected $groupLoadsBySection = array(); + + /** @var array A 3-d map giving server load ratios by DB name */ + protected $groupLoadsByDB = array(); + + /** @var array A map of hostname to IP address */ + protected $hostsByName = array(); + + /** @var array A map of external storage cluster name to server load map */ + protected $externalLoads = array(); + + /** + * @var array A set of server info keys overriding serverTemplate for + * external storage + */ + protected $externalTemplateOverrides; + + /** + * @var array A 2-d map overriding serverTemplate and + * externalTemplateOverrides on a server-by-server basis. Applies to both + * core and external storage + */ + protected $templateOverridesByServer; + + /** @var array A 2-d map overriding the server info by external storage cluster */ + protected $templateOverridesByCluster; + + /** @var array An override array for all master servers */ + protected $masterTemplateOverrides; + + /** + * @var array|bool A map of section name to read-only message. Missing or + * false for read/write + */ + protected $readOnlyBySection = array(); + + // Other stuff + + /** @var array Load balancer factory configuration */ + protected $conf; + + /** @var LoadBalancer[] */ + protected $mainLBs = array(); + + /** @var LoadBalancer[] */ + protected $extLBs = array(); + + /** @var string */ + protected $lastWiki; + + /** @var string */ + protected $lastSection; + + /** + * @param array $conf + * @throws MWException + */ + function __construct( $conf ) { + $this->chronProt = new ChronologyProtector; + $this->conf = $conf; + $required = array( 'sectionsByDB', 'sectionLoads', 'serverTemplate' ); + $optional = array( 'groupLoadsBySection', 'groupLoadsByDB', 'hostsByName', + 'externalLoads', 'externalTemplateOverrides', 'templateOverridesByServer', + 'templateOverridesByCluster', 'masterTemplateOverrides', + 'readOnlyBySection' ); + + foreach ( $required as $key ) { + if ( !isset( $conf[$key] ) ) { + throw new MWException( __CLASS__ . ": $key is required in configuration" ); + } + $this->$key = $conf[$key]; + } + + foreach ( $optional as $key ) { + if ( isset( $conf[$key] ) ) { + $this->$key = $conf[$key]; + } + } + + // Check for read-only mode + $section = $this->getSectionForWiki(); + if ( !empty( $this->readOnlyBySection[$section] ) ) { + global $wgReadOnly; + $wgReadOnly = $this->readOnlyBySection[$section]; + } + } + + /** + * @param bool|string $wiki + * @return string + */ + function getSectionForWiki( $wiki = false ) { + if ( $this->lastWiki === $wiki ) { + return $this->lastSection; + } + list( $dbName, ) = $this->getDBNameAndPrefix( $wiki ); + if ( isset( $this->sectionsByDB[$dbName] ) ) { + $section = $this->sectionsByDB[$dbName]; + } else { + $section = 'DEFAULT'; + } + $this->lastSection = $section; + $this->lastWiki = $wiki; + + return $section; + } + + /** + * @param bool|string $wiki + * @return LoadBalancer + */ + function newMainLB( $wiki = false ) { + list( $dbName, ) = $this->getDBNameAndPrefix( $wiki ); + $section = $this->getSectionForWiki( $wiki ); + $groupLoads = array(); + if ( isset( $this->groupLoadsByDB[$dbName] ) ) { + $groupLoads = $this->groupLoadsByDB[$dbName]; + } + + if ( isset( $this->groupLoadsBySection[$section] ) ) { + $groupLoads = array_merge_recursive( $groupLoads, $this->groupLoadsBySection[$section] ); + } + + return $this->newLoadBalancer( + $this->serverTemplate, + $this->sectionLoads[$section], + $groupLoads + ); + } + + /** + * @param bool|string $wiki + * @return LoadBalancer + */ + function getMainLB( $wiki = false ) { + $section = $this->getSectionForWiki( $wiki ); + if ( !isset( $this->mainLBs[$section] ) ) { + $lb = $this->newMainLB( $wiki, $section ); + $lb->parentInfo( array( 'id' => "main-$section" ) ); + $this->chronProt->initLB( $lb ); + $this->mainLBs[$section] = $lb; + } + + return $this->mainLBs[$section]; + } + + /** + * @param string $cluster + * @param bool|string $wiki + * @throws MWException + * @return LoadBalancer + */ + function newExternalLB( $cluster, $wiki = false ) { + if ( !isset( $this->externalLoads[$cluster] ) ) { + throw new MWException( __METHOD__ . ": Unknown cluster \"$cluster\"" ); + } + $template = $this->serverTemplate; + if ( isset( $this->externalTemplateOverrides ) ) { + $template = $this->externalTemplateOverrides + $template; + } + if ( isset( $this->templateOverridesByCluster[$cluster] ) ) { + $template = $this->templateOverridesByCluster[$cluster] + $template; + } + + return $this->newLoadBalancer( $template, $this->externalLoads[$cluster], array() ); + } + + /** + * @param string $cluster External storage cluster, or false for core + * @param bool|string $wiki Wiki ID, or false for the current wiki + * @return LoadBalancer + */ + function &getExternalLB( $cluster, $wiki = false ) { + if ( !isset( $this->extLBs[$cluster] ) ) { + $this->extLBs[$cluster] = $this->newExternalLB( $cluster, $wiki ); + $this->extLBs[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) ); + $this->chronProt->initLB( $this->extLBs[$cluster] ); + } + + return $this->extLBs[$cluster]; + } + + /** + * Make a new load balancer object based on template and load array + * + * @param array $template + * @param array $loads + * @param array $groupLoads + * @return LoadBalancer + */ + function newLoadBalancer( $template, $loads, $groupLoads ) { + $servers = $this->makeServerArray( $template, $loads, $groupLoads ); + $lb = new LoadBalancer( array( + 'servers' => $servers, + ) ); + + return $lb; + } + + /** + * Make a server array as expected by LoadBalancer::__construct, using a template and load array + * + * @param array $template + * @param array $loads + * @param array $groupLoads + * @return array + */ + function makeServerArray( $template, $loads, $groupLoads ) { + $servers = array(); + $master = true; + $groupLoadsByServer = $this->reindexGroupLoads( $groupLoads ); + foreach ( $groupLoadsByServer as $server => $stuff ) { + if ( !isset( $loads[$server] ) ) { + $loads[$server] = 0; + } + } + foreach ( $loads as $serverName => $load ) { + $serverInfo = $template; + if ( $master ) { + $serverInfo['master'] = true; + if ( isset( $this->masterTemplateOverrides ) ) { + $serverInfo = $this->masterTemplateOverrides + $serverInfo; + } + $master = false; + } + if ( isset( $this->templateOverridesByServer[$serverName] ) ) { + $serverInfo = $this->templateOverridesByServer[$serverName] + $serverInfo; + } + if ( isset( $groupLoadsByServer[$serverName] ) ) { + $serverInfo['groupLoads'] = $groupLoadsByServer[$serverName]; + } + if ( isset( $this->hostsByName[$serverName] ) ) { + $serverInfo['host'] = $this->hostsByName[$serverName]; + } else { + $serverInfo['host'] = $serverName; + } + $serverInfo['hostName'] = $serverName; + $serverInfo['load'] = $load; + $servers[] = $serverInfo; + } + + return $servers; + } + + /** + * Take a group load array indexed by group then server, and reindex it by server then group + * @param array $groupLoads + * @return array + */ + function reindexGroupLoads( $groupLoads ) { + $reindexed = array(); + foreach ( $groupLoads as $group => $loads ) { + foreach ( $loads as $server => $load ) { + $reindexed[$server][$group] = $load; + } + } + + return $reindexed; + } + + /** + * Get the database name and prefix based on the wiki ID + * @param bool|string $wiki + * @return array + */ + function getDBNameAndPrefix( $wiki = false ) { + if ( $wiki === false ) { + global $wgDBname, $wgDBprefix; + + return array( $wgDBname, $wgDBprefix ); + } else { + return wfSplitWikiID( $wiki ); + } + } + + /** + * Execute a function for each tracked load balancer + * The callback is called with the load balancer as the first parameter, + * and $params passed as the subsequent parameters. + * @param callable $callback + * @param array $params + */ + function forEachLB( $callback, $params = array() ) { + foreach ( $this->mainLBs as $lb ) { + call_user_func_array( $callback, array_merge( array( $lb ), $params ) ); + } + foreach ( $this->extLBs as $lb ) { + call_user_func_array( $callback, array_merge( array( $lb ), $params ) ); + } + } + + function shutdown() { + foreach ( $this->mainLBs as $lb ) { + $this->chronProt->shutdownLB( $lb ); + } + foreach ( $this->extLBs as $extLB ) { + $this->chronProt->shutdownLB( $extLB ); + } + $this->chronProt->shutdown(); + $this->commitMasterChanges(); + } +} |