runJobs.php

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<?php
require_once __DIR__ . '/Maintenance.php';

class RunJobs extends Maintenance {
    public function __construct() {
        parent::__construct();
        $this->mDescription = "Run pending jobs";
        $this->addOption( 'maxjobs', 'Maximum number of jobs to run', false, true );
        $this->addOption( 'maxtime', 'Maximum amount of wall-clock time', false, true );
        $this->addOption( 'type', 'Type of job to run', false, true );
        $this->addOption( 'procs', 'Number of processes to use', false, true );
        $this->addOption( 'nothrottle', 'Ignore job throttling configuration', false, false );
    }

    public function memoryLimit() {
        if ( $this->hasOption( 'memory-limit' ) ) {
            return parent::memoryLimit();
        }
        // Don't eat all memory on the machine if we get a bad job.
        return "150M";
    }

    public function execute() {
        if ( wfReadOnly() ) {
            $this->error( "Unable to run jobs; the wiki is in read-only mode.", 1 ); // die
        }

        if ( $this->hasOption( 'procs' ) ) {
            $procs = intval( $this->getOption( 'procs' ) );
            if ( $procs < 1 || $procs > 1000 ) {
                $this->error( "Invalid argument to --procs", true );
            } elseif ( $procs != 1 ) {
                $fc = new ForkController( $procs );
                if ( $fc->start() != 'child' ) {
                    exit( 0 );
                }
            }
        }

        $type = $this->getOption( 'type', false );
        $maxJobs = $this->getOption( 'maxjobs', false );
        $maxTime = $this->getOption( 'maxtime', false );
        $noThrottle = $this->hasOption( 'nothrottle' );
        $startTime = time();

        $group = JobQueueGroup::singleton();
        // Handle any required periodic queue maintenance
        $count = $group->executeReadyPeriodicTasks();
        if ( $count > 0 ) {
            $this->runJobsLog( "Executed $count periodic queue task(s)." );
        }

        $backoffs = $this->loadBackoffs(); // map of (type => UNIX expiry)
        $startingBackoffs = $backoffs; // avoid unnecessary writes
        $backoffExpireFunc = function( $t ) { return $t > time(); };

        $jobsRun = 0; // counter
        $flags = JobQueueGroup::USE_CACHE;
        $lastTime = time(); // time since last slave check
        do {
            $backoffs = array_filter( $backoffs, $backoffExpireFunc );
            $blacklist = $noThrottle ? array() : array_keys( $backoffs );
            if ( $type === false ) {
                $job = $group->pop( JobQueueGroup::TYPE_DEFAULT, $flags, $blacklist );
            } elseif ( in_array( $type, $blacklist ) ) {
                $job = false; // requested queue in backoff state
            } else {
                $job = $group->pop( $type ); // job from a single queue
            }
            if ( $job ) { // found a job
                ++$jobsRun;
                $this->runJobsLog( $job->toString() . " STARTING" );

                // Set timer to stop the job if too much CPU time is used
                set_time_limit( $maxTime ?: 0 );
                // Run the job...
                wfProfileIn( __METHOD__ . '-' . get_class( $job ) );
                $t = microtime( true );
                try {
                    $status = $job->run();
                    $error = $job->getLastError();
                } catch ( MWException $e ) {
                    MWExceptionHandler::rollbackMasterChangesAndLog( $e );
                    $status = false;
                    $error = get_class( $e ) . ': ' . $e->getMessage();
                    $e->report(); // write error to STDERR and the log
                }
                $timeMs = intval( ( microtime( true ) - $t ) * 1000 );
                wfProfileOut( __METHOD__ . '-' . get_class( $job ) );
                // Disable the timer
                set_time_limit( 0 );

                // Mark the job as done on success or when the job cannot be retried
                if ( $status !== false || !$job->allowRetries() ) {
                    $group->ack( $job ); // done
                }

                if ( $status === false ) {
                    $this->runJobsLog( $job->toString() . " t=$timeMs error={$error}" );
                } else {
                    $this->runJobsLog( $job->toString() . " t=$timeMs good" );
                }

                // Back off of certain jobs for a while
                $ttw = $this->getBackoffTimeToWait( $job );
                if ( $ttw > 0 ) {
                    $jType = $job->getType();
                    $backoffs[$jType] = isset( $backoffs[$jType] ) ? $backoffs[$jType] : 0;
                    $backoffs[$jType] = max( $backoffs[$jType], time() + $ttw );
                }

                // Break out if we hit the job count or wall time limits...
                if ( $maxJobs && $jobsRun >= $maxJobs ) {
                    break;
                } elseif ( $maxTime && ( time() - $startTime ) > $maxTime ) {
                    break;
                }

                // Don't let any of the main DB slaves get backed up
                $timePassed = time() - $lastTime;
                if ( $timePassed >= 5 || $timePassed < 0 ) {
                    wfWaitForSlaves();
                    $lastTime = time();
                }
                // Don't let any queue slaves/backups fall behind
                if ( $jobsRun > 0 && ( $jobsRun % 100 ) == 0 ) {
                    $group->waitForBackups();
                }

                // Bail if near-OOM instead of in a job
                $this->assertMemoryOK();
            }
        } while ( $job ); // stop when there are no jobs
        // Sync the persistent backoffs for the next runJobs.php pass
        $backoffs = array_filter( $backoffs, $backoffExpireFunc );
        if ( $backoffs !== $startingBackoffs ) {
            $this->syncBackoffs( $backoffs );
        }
    }

    private function getBackoffTimeToWait( Job $job ) {
        global $wgJobBackoffThrottling;

        if ( !isset( $wgJobBackoffThrottling[$job->getType()] ) ) {
            return 0; // not throttled
        }
        $itemsPerSecond = $wgJobBackoffThrottling[$job->getType()];
        if ( $itemsPerSecond <= 0 ) {
            return 0; // not throttled
        }

        $seconds = 0;
        if ( $job->workItemCount() > 0 ) {
            $seconds = floor( $job->workItemCount() / $itemsPerSecond );
            $remainder = $job->workItemCount() % $itemsPerSecond;
            $seconds += ( mt_rand( 1, $itemsPerSecond ) <= $remainder ) ? 1 : 0;
        }

        return (int)$seconds;
    }

    private function loadBackoffs() {
        $section = new ProfileSection( __METHOD__ );

        $backoffs = array();
        $file = wfTempDir() . '/mw-runJobs-backoffs.json';
        if ( is_file( $file ) ) {
            $handle = fopen( $file, 'rb' );
            flock( $handle, LOCK_SH );
            $content = stream_get_contents( $handle );
            flock( $handle, LOCK_UN );
            fclose( $handle );
            $backoffs = json_decode( $content, true ) ?: array();
        }

        return $backoffs;
    }

    private function syncBackoffs( array $backoffs ) {
        $section = new ProfileSection( __METHOD__ );

        $file = wfTempDir() . '/mw-runJobs-backoffs.json';
        $handle = fopen( $file, 'wb+' );
        flock( $handle, LOCK_EX );
        $content = stream_get_contents( $handle );
        $cBackoffs = json_decode( $content, true ) ?: array();
        foreach ( $backoffs as $type => $timestamp ) {
            $cBackoffs[$type] = isset( $cBackoffs[$type] ) ? $cBackoffs[$type] : 0;
            $cBackoffs[$type] = max( $cBackoffs[$type], $backoffs[$type] );
        }
        ftruncate( $handle, 0 );
        fwrite( $handle, json_encode( $backoffs ) );
        flock( $handle, LOCK_UN );
        fclose( $handle );
    }

    private function assertMemoryOK() {
        static $maxBytes = null;
        if ( $maxBytes === null ) {
            $m = array();
            if ( preg_match( '!^(\d+)(k|m|g|)$!i', ini_get( 'memory_limit' ), $m ) ) {
                list( , $num, $unit ) = $m;
                $conv = array( 'g' => 1073741824, 'm' => 1048576, 'k' => 1024, '' => 1 );
                $maxBytes = $num * $conv[strtolower( $unit )];
            } else {
                $maxBytes = 0;
            }
        }
        $usedBytes = memory_get_usage();
        if ( $maxBytes && $usedBytes >= 0.95 * $maxBytes ) {
            throw new MWException( "Detected excessive memory usage ($usedBytes/$maxBytes)." );
        }
    }

    private function runJobsLog( $msg ) {
        $this->output( wfTimestamp( TS_DB ) . " $msg\n" );
        wfDebugLog( 'runJobs', $msg );
    }
}

$maintClass = "RunJobs";
require_once RUN_MAINTENANCE_IF_MAIN;