JobQueueGroup.php

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<?php
use MediaWiki\MediaWikiServices;

class JobQueueGroup {
    protected static $instances = [];

    protected $cache;

    protected $domain;
    protected $readOnlyReason;
    protected $invalidDomain = false;

    protected $coalescedQueues;

    const TYPE_DEFAULT = 1; // integer; jobs popped by default
    const TYPE_ANY = 2; // integer; any job

    const USE_CACHE = 1; // integer; use process or persistent cache

    const PROC_CACHE_TTL = 15; // integer; seconds

    const CACHE_VERSION = 1; // integer; cache version

    protected function __construct( $domain, $readOnlyReason ) {
        $this->domain = $domain;
        $this->readOnlyReason = $readOnlyReason;
        $this->cache = new MapCacheLRU( 10 );
    }

    public static function singleton( $domain = false ) {
        global $wgLocalDatabases;

        if ( $domain === false ) {
            $domain = WikiMap::getCurrentWikiDbDomain()->getId();
        }

        if ( !isset( self::$instances[$domain] ) ) {
            self::$instances[$domain] = new self( $domain, wfConfiguredReadOnlyReason() );
            // Make sure jobs are not getting pushed to bogus wikis. This can confuse
            // the job runner system into spawning endless RPC requests that fail (T171371).
            $wikiId = WikiMap::getWikiIdFromDbDomain( $domain );
            if (
                !WikiMap::isCurrentWikiDbDomain( $domain ) &&
                !in_array( $wikiId, $wgLocalDatabases )
            ) {
                self::$instances[$domain]->invalidDomain = true;
            }
        }

        return self::$instances[$domain];
    }

    public static function destroySingletons() {
        self::$instances = [];
    }

    public function get( $type ) {
        global $wgJobTypeConf;

        $conf = [ 'domain' => $this->domain, 'type' => $type ];
        if ( isset( $wgJobTypeConf[$type] ) ) {
            $conf = $conf + $wgJobTypeConf[$type];
        } else {
            $conf = $conf + $wgJobTypeConf['default'];
        }
        if ( !isset( $conf['readOnlyReason'] ) ) {
            $conf['readOnlyReason'] = $this->readOnlyReason;
        }

        $services = MediaWikiServices::getInstance();
        $conf['stats'] = $services->getStatsdDataFactory();
        $conf['wanCache'] = $services->getMainWANObjectCache();
        $conf['stash'] = $services->getMainObjectStash();

        return JobQueue::factory( $conf );
    }

    public function push( $jobs ) {
        global $wgJobTypesExcludedFromDefaultQueue;

        if ( $this->invalidDomain ) {
            // Do not enqueue job that cannot be run (T171371)
            $e = new LogicException( "Domain '{$this->domain}' is not recognized." );
            MWExceptionHandler::logException( $e );
            return;
        }

        $jobs = is_array( $jobs ) ? $jobs : [ $jobs ];
        if ( $jobs === [] ) {
            return;
        }

        $this->assertValidJobs( $jobs );

        $jobsByType = []; // (job type => list of jobs)
        foreach ( $jobs as $job ) {
            $jobsByType[$job->getType()][] = $job;
        }

        foreach ( $jobsByType as $type => $jobs ) {
            $this->get( $type )->push( $jobs );
        }

        if ( $this->cache->hasField( 'queues-ready', 'list' ) ) {
            $list = $this->cache->getField( 'queues-ready', 'list' );
            if ( count( array_diff( array_keys( $jobsByType ), $list ) ) ) {
                $this->cache->clear( 'queues-ready' );
            }
        }

        $cache = ObjectCache::getLocalClusterInstance();
        $cache->set(
            $cache->makeGlobalKey( 'jobqueue', $this->domain, 'hasjobs', self::TYPE_ANY ),
            'true',
            15
        );
        if ( array_diff( array_keys( $jobsByType ), $wgJobTypesExcludedFromDefaultQueue ) ) {
            $cache->set(
                $cache->makeGlobalKey( 'jobqueue', $this->domain, 'hasjobs', self::TYPE_DEFAULT ),
                'true',
                15
            );
        }
    }

    public function lazyPush( $jobs ) {
        if ( $this->invalidDomain ) {
            // Do not enqueue job that cannot be run (T171371)
            throw new LogicException( "Domain '{$this->domain}' is not recognized." );
        }

        if ( PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg' ) {
            $this->push( $jobs );
            return;
        }

        $jobs = is_array( $jobs ) ? $jobs : [ $jobs ];

        // Throw errors now instead of on push(), when other jobs may be buffered
        $this->assertValidJobs( $jobs );

        DeferredUpdates::addUpdate( new JobQueueEnqueueUpdate( $this->domain, $jobs ) );
    }

    public function pop( $qtype = self::TYPE_DEFAULT, $flags = 0, array $blacklist = [] ) {
        global $wgJobClasses;

        $job = false;

        if ( !WikiMap::isCurrentWikiDbDomain( $this->domain ) ) {
            throw new JobQueueError(
                "Cannot pop '{$qtype}' job off foreign '{$this->domain}' wiki queue." );
        } elseif ( is_string( $qtype ) && !isset( $wgJobClasses[$qtype] ) ) {
            // Do not pop jobs if there is no class for the queue type
            throw new JobQueueError( "Unrecognized job type '$qtype'." );
        }

        if ( is_string( $qtype ) ) { // specific job type
            if ( !in_array( $qtype, $blacklist ) ) {
                $job = $this->get( $qtype )->pop();
            }
        } else { // any job in the "default" jobs types
            if ( $flags & self::USE_CACHE ) {
                if ( !$this->cache->hasField( 'queues-ready', 'list', self::PROC_CACHE_TTL ) ) {
                    $this->cache->setField( 'queues-ready', 'list', $this->getQueuesWithJobs() );
                }
                $types = $this->cache->getField( 'queues-ready', 'list' );
            } else {
                $types = $this->getQueuesWithJobs();
            }

            if ( $qtype == self::TYPE_DEFAULT ) {
                $types = array_intersect( $types, $this->getDefaultQueueTypes() );
            }

            $types = array_diff( $types, $blacklist ); // avoid selected types
            shuffle( $types ); // avoid starvation

            foreach ( $types as $type ) { // for each queue...
                $job = $this->get( $type )->pop();
                if ( $job ) { // found
                    break;
                } else { // not found
                    $this->cache->clear( 'queues-ready' );
                }
            }
        }

        return $job;
    }

    public function ack( Job $job ) {
        $this->get( $job->getType() )->ack( $job );
    }

    public function deduplicateRootJob( Job $job ) {
        return $this->get( $job->getType() )->deduplicateRootJob( $job );
    }

    public function waitForBackups() {
        global $wgJobTypeConf;

        // Try to avoid doing this more than once per queue storage medium
        foreach ( $wgJobTypeConf as $type => $conf ) {
            $this->get( $type )->waitForBackups();
        }
    }

    public function getQueueTypes() {
        return array_keys( $this->getCachedConfigVar( 'wgJobClasses' ) );
    }

    public function getDefaultQueueTypes() {
        global $wgJobTypesExcludedFromDefaultQueue;

        return array_diff( $this->getQueueTypes(), $wgJobTypesExcludedFromDefaultQueue );
    }

    public function queuesHaveJobs( $type = self::TYPE_ANY ) {
        $cache = ObjectCache::getLocalClusterInstance();
        $key = $cache->makeGlobalKey( 'jobqueue', $this->domain, 'hasjobs', $type );

        $value = $cache->get( $key );
        if ( $value === false ) {
            $queues = $this->getQueuesWithJobs();
            if ( $type == self::TYPE_DEFAULT ) {
                $queues = array_intersect( $queues, $this->getDefaultQueueTypes() );
            }
            $value = count( $queues ) ? 'true' : 'false';
            $cache->add( $key, $value, 15 );
        }

        return ( $value === 'true' );
    }

    public function getQueuesWithJobs() {
        $types = [];
        foreach ( $this->getCoalescedQueues() as $info ) {
            $queue = $info['queue'];
            $nonEmpty = $queue->getSiblingQueuesWithJobs( $this->getQueueTypes() );
            if ( is_array( $nonEmpty ) ) { // batching features supported
                $types = array_merge( $types, $nonEmpty );
            } else { // we have to go through the queues in the bucket one-by-one
                foreach ( $info['types'] as $type ) {
                    if ( !$this->get( $type )->isEmpty() ) {
                        $types[] = $type;
                    }
                }
            }
        }

        return $types;
    }

    public function getQueueSizes() {
        $sizeMap = [];
        foreach ( $this->getCoalescedQueues() as $info ) {
            $queue = $info['queue'];
            $sizes = $queue->getSiblingQueueSizes( $this->getQueueTypes() );
            if ( is_array( $sizes ) ) { // batching features supported
                $sizeMap = $sizeMap + $sizes;
            } else { // we have to go through the queues in the bucket one-by-one
                foreach ( $info['types'] as $type ) {
                    $sizeMap[$type] = $this->get( $type )->getSize();
                }
            }
        }

        return $sizeMap;
    }

    protected function getCoalescedQueues() {
        global $wgJobTypeConf;

        if ( $this->coalescedQueues === null ) {
            $this->coalescedQueues = [];
            foreach ( $wgJobTypeConf as $type => $conf ) {
                $queue = JobQueue::factory(
                    [ 'domain' => $this->domain, 'type' => 'null' ] + $conf );
                $loc = $queue->getCoalesceLocationInternal();
                if ( !isset( $this->coalescedQueues[$loc] ) ) {
                    $this->coalescedQueues[$loc]['queue'] = $queue;
                    $this->coalescedQueues[$loc]['types'] = [];
                }
                if ( $type === 'default' ) {
                    $this->coalescedQueues[$loc]['types'] = array_merge(
                        $this->coalescedQueues[$loc]['types'],
                        array_diff( $this->getQueueTypes(), array_keys( $wgJobTypeConf ) )
                    );
                } else {
                    $this->coalescedQueues[$loc]['types'][] = $type;
                }
            }
        }

        return $this->coalescedQueues;
    }

    private function getCachedConfigVar( $name ) {
        // @TODO: cleanup this whole method with a proper config system
        if ( WikiMap::isCurrentWikiDbDomain( $this->domain ) ) {
            return $GLOBALS[$name]; // common case
        } else {
            $wiki = WikiMap::getWikiIdFromDbDomain( $this->domain );
            $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
            $value = $cache->getWithSetCallback(
                $cache->makeGlobalKey( 'jobqueue', 'configvalue', $this->domain, $name ),
                $cache::TTL_DAY + mt_rand( 0, $cache::TTL_DAY ),
                function () use ( $wiki, $name ) {
                    global $wgConf;
                    // @TODO: use the full domain ID here
                    return [ 'v' => $wgConf->getConfig( $wiki, $name ) ];
                },
                [ 'pcTTL' => WANObjectCache::TTL_PROC_LONG ]
            );

            return $value['v'];
        }
    }

    private function assertValidJobs( array $jobs ) {
        foreach ( $jobs as $job ) { // sanity checks
            if ( !( $job instanceof IJobSpecification ) ) {
                throw new InvalidArgumentException( "Expected IJobSpecification objects" );
            }
        }
    }
}