JobQueueGroup.php

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<?php
class JobQueueGroup {
    protected static $instances = array();

    protected $cache;

    protected $wiki; // string; wiki ID

    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 USE_PRIORITY = 2; // integer; respect deprioritization

    const PROC_CACHE_TTL = 15; // integer; seconds

    const CACHE_VERSION = 1; // integer; cache version

    protected function __construct( $wiki ) {
        $this->wiki = $wiki;
        $this->cache = new ProcessCacheLRU( 10 );
    }

    public static function singleton( $wiki = false ) {
        $wiki = ( $wiki === false ) ? wfWikiID() : $wiki;
        if ( !isset( self::$instances[$wiki] ) ) {
            self::$instances[$wiki] = new self( $wiki );
        }
        return self::$instances[$wiki];
    }

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

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

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

        return JobQueue::factory( $conf );
    }

    public function push( $jobs ) {
        $jobs = is_array( $jobs ) ? $jobs : array( $jobs );

        $jobsByType = array(); // (job type => list of jobs)
        foreach ( $jobs as $job ) {
            if ( $job instanceof Job ) {
                $jobsByType[$job->getType()][] = $job;
            } else {
                throw new MWException( "Attempted to push a non-Job object into a queue." );
            }
        }

        $ok = true;
        foreach ( $jobsByType as $type => $jobs ) {
            if ( $this->get( $type )->push( $jobs ) ) {
                JobQueueAggregator::singleton()->notifyQueueNonEmpty( $this->wiki, $type );
            } else {
                $ok = false;
            }
        }

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

        return $ok;
    }

    public function pop( $qtype = self::TYPE_DEFAULT, $flags = 0 ) {
        if ( is_string( $qtype ) ) { // specific job type
            if ( ( $flags & self::USE_PRIORITY ) && $this->isQueueDeprioritized( $qtype ) ) {
                return false; // back off
            }
            $job = $this->get( $qtype )->pop();
            if ( !$job ) {
                JobQueueAggregator::singleton()->notifyQueueEmpty( $this->wiki, $qtype );
            }
            return $job;
        } else { // any job in the "default" jobs types
            if ( $flags & self::USE_CACHE ) {
                if ( !$this->cache->has( 'queues-ready', 'list', self::PROC_CACHE_TTL ) ) {
                    $this->cache->set( 'queues-ready', 'list', $this->getQueuesWithJobs() );
                }
                $types = $this->cache->get( 'queues-ready', 'list' );
            } else {
                $types = $this->getQueuesWithJobs();
            }

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

            foreach ( $types as $type ) { // for each queue...
                if ( ( $flags & self::USE_PRIORITY ) && $this->isQueueDeprioritized( $type ) ) {
                    continue; // back off
                }
                $job = $this->get( $type )->pop();
                if ( $job ) { // found
                    return $job;
                } else { // not found
                    JobQueueAggregator::singleton()->notifyQueueEmpty( $this->wiki, $type );
                    $this->cache->clear( 'queues-ready' );
                }
            }

            return false; // no jobs found
        }
    }

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

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

    public function waitForBackups() {
        global $wgJobTypeConf;

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

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

    public function getDefaultQueueTypes() {
        global $wgJobTypesExcludedFromDefaultQueue;

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

    public function getQueuesWithJobs() {
        $types = array();
        foreach ( $this->getCoalescedQueues() as $info ) {
            $nonEmpty = $info['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 = array();
        foreach ( $this->getCoalescedQueues() as $info ) {
            $sizes = $info['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 = array();
            foreach ( $wgJobTypeConf as $type => $conf ) {
                $queue = JobQueue::factory(
                    array( 'wiki' => $this->wiki, 'type' => 'null' ) + $conf );
                $loc = $queue->getCoalesceLocationInternal();
                if ( !isset( $this->coalescedQueues[$loc] ) ) {
                    $this->coalescedQueues[$loc]['queue'] = $queue;
                    $this->coalescedQueues[$loc]['types'] = array();
                }
                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;
    }

    public function isQueueDeprioritized( $type ) {
        if ( $this->cache->has( 'isDeprioritized', $type, 5 ) ) {
            return $this->cache->get( 'isDeprioritized', $type );
        }
        if ( $type === 'refreshLinks2' ) {
            // Don't keep converting refreshLinks2 => refreshLinks jobs if the
            // later jobs have not been done yet. This helps throttle queue spam.
            $deprioritized = !$this->get( 'refreshLinks' )->isEmpty();
            $this->cache->set( 'isDeprioritized', $type, $deprioritized );
            return $deprioritized;
        }
        return false;
    }

    public function executeReadyPeriodicTasks() {
        global $wgMemc;

        list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
        $key = wfForeignMemcKey( $db, $prefix, 'jobqueuegroup', 'taskruns', 'v1' );
        $lastRuns = $wgMemc->get( $key ); // (queue => task => UNIX timestamp)

        $count = 0;
        $tasksRun = array(); // (queue => task => UNIX timestamp)
        foreach ( $this->getQueueTypes() as $type ) {
            $queue = $this->get( $type );
            foreach ( $queue->getPeriodicTasks() as $task => $definition ) {
                if ( $definition['period'] <= 0 ) {
                    continue; // disabled
                } elseif ( !isset( $lastRuns[$type][$task] )
                    || $lastRuns[$type][$task] < ( time() - $definition['period'] ) )
                {
                    try {
                        if ( call_user_func( $definition['callback'] ) !== null ) {
                            $tasksRun[$type][$task] = time();
                            ++$count;
                        }
                    } catch ( JobQueueError $e ) {
                        MWExceptionHandler::logException( $e );
                    }
                }
            }
        }

        $wgMemc->merge( $key, function( $cache, $key, $lastRuns ) use ( $tasksRun ) {
            if ( is_array( $lastRuns ) ) {
                foreach ( $tasksRun as $type => $tasks ) {
                    foreach ( $tasks as $task => $timestamp ) {
                        if ( !isset( $lastRuns[$type][$task] )
                            || $timestamp > $lastRuns[$type][$task] )
                        {
                            $lastRuns[$type][$task] = $timestamp;
                        }
                    }
                }
            } else {
                $lastRuns = $tasksRun;
            }
            return $lastRuns;
        } );

        return $count;
    }

    private function getCachedConfigVar( $name ) {
        global $wgConf, $wgMemc;

        if ( $this->wiki === wfWikiID() ) {
            return $GLOBALS[$name]; // common case
        } else {
            list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
            $key = wfForeignMemcKey( $db, $prefix, 'configvalue', $name );
            $value = $wgMemc->get( $key ); // ('v' => ...) or false
            if ( is_array( $value ) ) {
                return $value['v'];
            } else {
                $value = $wgConf->getConfig( $this->wiki, $name );
                $wgMemc->set( $key, array( 'v' => $value ), 86400 + mt_rand( 0, 86400 ) );
                return $value;
            }
        }
    }
}