LBFactory_Multi.php

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<?php
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, $readOnlyBySection = array();
    // 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',
            '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];
        }
    }

    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;
    }

    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 );
    }

    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];
    }

    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" ) );
            $this->chronProt->initLB( $this->extLBs[$cluster] );
        }
        return $this->extLBs[$cluster];
    }

    function newLoadBalancer( $template, $loads, $groupLoads ) {
        global $wgMasterWaitTimeout;
        $servers = $this->makeServerArray( $template, $loads, $groupLoads );
        $lb = new LoadBalancer( array(
            'servers' => $servers,
            'masterWaitTimeout' => $wgMasterWaitTimeout
        ));
        return $lb;
    }

    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;
    }

    function reindexGroupLoads( $groupLoads ) {
        $reindexed = array();
        foreach ( $groupLoads as $group => $loads ) {
            foreach ( $loads as $server => $load ) {
                $reindexed[$server][$group] = $load;
            }
        }
        return $reindexed;
    }

    function getDBNameAndPrefix( $wiki = false ) {
        if ( $wiki === false ) {
            global $wgDBname, $wgDBprefix;
            return array( $wgDBname, $wgDBprefix );
        } else {
            return wfSplitWikiID( $wiki );
        }
    }

    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();
    }
}