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+<?php
+/**
+ * @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.
+ *
+ * @ingroup Database
+ */
+class LBFactory_Multi extends LBFactory {
+ // Required settings
+ var $sectionsByDB, $sectionLoads, $serverTemplate;
+ // Optional settings
+ var $groupLoadsBySection = array(), $groupLoadsByDB = array(), $hostsByName = array();
+ var $externalLoads = array(), $externalTemplateOverrides, $templateOverridesByServer;
+ var $templateOverridesByCluster, $masterTemplateOverrides;
+ // Other stuff
+ var $conf, $mainLBs = array(), $extLBs = array();
+ var $lastWiki, $lastSection;
+
+ 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' );
+
+ 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];
+ }
+ }
+ }
+
+ function getSectionForWiki( $wiki = false ) {
+ if ( $this->lastWiki === $wiki ) {
+ return $this->lastSection;
+ }
+ list( $dbName, $prefix ) = $this->getDBNameAndPrefix( $wiki );
+ if ( isset( $this->sectionsByDB[$dbName] ) ) {
+ $section = $this->sectionsByDB[$dbName];
+ } else {
+ $section = 'DEFAULT';
+ }
+ $this->lastSection = $section;
+ $this->lastWiki = $wiki;
+ return $section;
+ }
+
+ function newMainLB( $wiki = false ) {
+ list( $dbName, $prefix ) = $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 );
+ }
+
+ function getMainLB( $wiki = false ) {
+ $section = $this->getSectionForWiki( $wiki );
+ if ( !isset( $this->mainLBs[$section] ) ) {
+ $lb = $this->newMainLB( $wiki, $section );
+ $this->chronProt->initLB( $lb );
+ $lb->parentInfo( array( 'id' => "main-$section" ) );
+ $this->mainLBs[$section] = $lb;
+ }
+ return $this->mainLBs[$section];
+ }
+
+ 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() );
+ }
+
+ 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" ) );
+ }
+ return $this->extLBs[$cluster];
+ }
+
+ /**
+ * Make a new load balancer object based on template and load array
+ */
+ function newLoadBalancer( $template, $loads, $groupLoads ) {
+ global $wgMasterWaitTimeout;
+ $servers = $this->makeServerArray( $template, $loads, $groupLoads );
+ $lb = new LoadBalancer( array(
+ 'servers' => $servers,
+ 'masterWaitTimeout' => $wgMasterWaitTimeout
+ ));
+ return $lb;
+ }
+
+ /**
+ * Make a server array as expected by LoadBalancer::__construct, using a template and load 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
+ */
+ 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
+ */
+ 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.
+ */
+ 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 );
+ }
+ $this->chronProt->shutdown();
+ $this->commitMasterChanges();
+ }
+}
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