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+<?php
+/**
+ * Job queue runner utility methods
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup JobQueue
+ */
+
+/**
+ * Job queue runner utility methods
+ *
+ * @ingroup JobQueue
+ * @since 1.24
+ */
+class JobRunner {
+ /** @var callable|null Debug output handler */
+ protected $debug;
+
+ /**
+ * @param callable $debug Optional debug output handler
+ */
+ public function setDebugHandler( $debug ) {
+ $this->debug = $debug;
+ }
+
+ /**
+ * Run jobs of the specified number/type for the specified time
+ *
+ * The response map has a 'job' field that lists status of each job, including:
+ * - type : the job type
+ * - status : ok/failed
+ * - error : any error message string
+ * - time : the job run time in ms
+ * The response map also has:
+ * - backoffs : the (job type => seconds) map of backoff times
+ * - elapsed : the total time spent running tasks in ms
+ * - reached : the reason the script finished, one of (none-ready, job-limit, time-limit)
+ *
+ * This method outputs status information only if a debug handler was set.
+ * Any exceptions are caught and logged, but are not reported as output.
+ *
+ * @param array $options Map of parameters:
+ * - type : the job type (or false for the default types)
+ * - maxJobs : maximum number of jobs to run
+ * - maxTime : maximum time in seconds before stopping
+ * - throttle : whether to respect job backoff configuration
+ * @return array Summary response that can easily be JSON serialized
+ */
+ public function run( array $options ) {
+ $response = array( 'jobs' => array(), 'reached' => 'none-ready' );
+
+ $type = isset( $options['type'] ) ? $options['type'] : false;
+ $maxJobs = isset( $options['maxJobs'] ) ? $options['maxJobs'] : false;
+ $maxTime = isset( $options['maxTime'] ) ? $options['maxTime'] : false;
+ $noThrottle = isset( $options['throttle'] ) && !$options['throttle'];
+
+ $group = JobQueueGroup::singleton();
+ // Handle any required periodic queue maintenance
+ $count = $group->executeReadyPeriodicTasks();
+ if ( $count > 0 ) {
+ $this->runJobsLog( "Executed $count periodic queue task(s)." );
+ }
+
+ // Flush any pending DB writes for sanity
+ wfGetLBFactory()->commitMasterChanges();
+
+ // Some jobs types should not run until a certain timestamp
+ $backoffs = array(); // map of (type => UNIX expiry)
+ $backoffDeltas = array(); // map of (type => seconds)
+ $wait = 'wait'; // block to read backoffs the first time
+
+ $jobsRun = 0;
+ $timeMsTotal = 0;
+ $flags = JobQueueGroup::USE_CACHE;
+ $startTime = microtime( true ); // time since jobs started running
+ $lastTime = microtime( true ); // time since last slave check
+ do {
+ // Sync the persistent backoffs with concurrent runners
+ $backoffs = $this->syncBackoffDeltas( $backoffs, $backoffDeltas, $wait );
+ $blacklist = $noThrottle ? array() : array_keys( $backoffs );
+ $wait = 'nowait'; // less important now
+
+ 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
+ $jType = $job->getType();
+
+ // Back off of certain jobs for a while (for throttling and for errors)
+ $ttw = $this->getBackoffTimeToWait( $job );
+ if ( $ttw > 0 ) {
+ // Always add the delta for other runners in case the time running the
+ // job negated the backoff for each individually but not collectively.
+ $backoffDeltas[$jType] = isset( $backoffDeltas[$jType] )
+ ? $backoffDeltas[$jType] + $ttw
+ : $ttw;
+ $backoffs = $this->syncBackoffDeltas( $backoffs, $backoffDeltas, $wait );
+ }
+
+ $this->runJobsLog( $job->toString() . " STARTING" );
+
+ // Run the job...
+ wfProfileIn( __METHOD__ . '-' . get_class( $job ) );
+ $jobStartTime = microtime( true );
+ try {
+ ++$jobsRun;
+ $status = $job->run();
+ $error = $job->getLastError();
+ wfGetLBFactory()->commitMasterChanges();
+ } catch ( MWException $e ) {
+ MWExceptionHandler::rollbackMasterChangesAndLog( $e );
+ $status = false;
+ $error = get_class( $e ) . ': ' . $e->getMessage();
+ MWExceptionHandler::logException( $e );
+ }
+ $timeMs = intval( ( microtime( true ) - $jobStartTime ) * 1000 );
+ wfProfileOut( __METHOD__ . '-' . get_class( $job ) );
+ $timeMsTotal += $timeMs;
+
+ // Mark the job as done on success or when the job cannot be retried
+ if ( $status !== false || !$job->allowRetries() ) {
+ $group->ack( $job ); // done
+ }
+
+ // Back off of certain jobs for a while (for throttling and for errors)
+ if ( $status === false && mt_rand( 0, 49 ) == 0 ) {
+ $ttw = max( $ttw, 30 ); // too many errors
+ $backoffDeltas[$jType] = isset( $backoffDeltas[$jType] )
+ ? $backoffDeltas[$jType] + $ttw
+ : $ttw;
+ }
+
+ if ( $status === false ) {
+ $this->runJobsLog( $job->toString() . " t=$timeMs error={$error}" );
+ } else {
+ $this->runJobsLog( $job->toString() . " t=$timeMs good" );
+ }
+
+ $response['jobs'][] = array(
+ 'type' => $jType,
+ 'status' => ( $status === false ) ? 'failed' : 'ok',
+ 'error' => $error,
+ 'time' => $timeMs
+ );
+
+ // Break out if we hit the job count or wall time limits...
+ if ( $maxJobs && $jobsRun >= $maxJobs ) {
+ $response['reached'] = 'job-limit';
+ break;
+ } elseif ( $maxTime && ( microtime( true ) - $startTime ) > $maxTime ) {
+ $response['reached'] = 'time-limit';
+ break;
+ }
+
+ // Don't let any of the main DB slaves get backed up
+ $timePassed = microtime( true ) - $lastTime;
+ if ( $timePassed >= 5 || $timePassed < 0 ) {
+ wfWaitForSlaves( $lastTime );
+ $lastTime = microtime( true );
+ }
+ // 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
+ if ( $backoffDeltas ) {
+ $this->syncBackoffDeltas( $backoffs, $backoffDeltas, 'wait' );
+ }
+
+ $response['backoffs'] = $backoffs;
+ $response['elapsed'] = $timeMsTotal;
+
+ return $response;
+ }
+
+ /**
+ * @param Job $job
+ * @return int Seconds for this runner to avoid doing more jobs of this type
+ * @see $wgJobBackoffThrottling
+ */
+ private function getBackoffTimeToWait( Job $job ) {
+ global $wgJobBackoffThrottling;
+
+ if ( !isset( $wgJobBackoffThrottling[$job->getType()] ) ||
+ $job instanceof DuplicateJob // no work was done
+ ) {
+ return 0; // not throttled
+ }
+
+ $itemsPerSecond = $wgJobBackoffThrottling[$job->getType()];
+ if ( $itemsPerSecond <= 0 ) {
+ return 0; // not throttled
+ }
+
+ $seconds = 0;
+ if ( $job->workItemCount() > 0 ) {
+ $exactSeconds = $job->workItemCount() / $itemsPerSecond;
+ // use randomized rounding
+ $seconds = floor( $exactSeconds );
+ $remainder = $exactSeconds - $seconds;
+ $seconds += ( mt_rand() / mt_getrandmax() < $remainder ) ? 1 : 0;
+ }
+
+ return (int)$seconds;
+ }
+
+ /**
+ * Get the previous backoff expiries from persistent storage
+ * On I/O or lock acquisition failure this returns the original $backoffs.
+ *
+ * @param array $backoffs Map of (job type => UNIX timestamp)
+ * @param string $mode Lock wait mode - "wait" or "nowait"
+ * @return array Map of (job type => backoff expiry timestamp)
+ */
+ private function loadBackoffs( array $backoffs, $mode = 'wait' ) {
+ $section = new ProfileSection( __METHOD__ );
+
+ $file = wfTempDir() . '/mw-runJobs-backoffs.json';
+ if ( is_file( $file ) ) {
+ $noblock = ( $mode === 'nowait' ) ? LOCK_NB : 0;
+ $handle = fopen( $file, 'rb' );
+ if ( !flock( $handle, LOCK_SH | $noblock ) ) {
+ fclose( $handle );
+ return $backoffs; // don't wait on lock
+ }
+ $content = stream_get_contents( $handle );
+ flock( $handle, LOCK_UN );
+ fclose( $handle );
+ $ctime = microtime( true );
+ $cBackoffs = json_decode( $content, true ) ?: array();
+ foreach ( $cBackoffs as $type => $timestamp ) {
+ if ( $timestamp < $ctime ) {
+ unset( $cBackoffs[$type] );
+ }
+ }
+ } else {
+ $cBackoffs = array();
+ }
+
+ return $cBackoffs;
+ }
+
+ /**
+ * Merge the current backoff expiries from persistent storage
+ *
+ * The $deltas map is set to an empty array on success.
+ * On I/O or lock acquisition failure this returns the original $backoffs.
+ *
+ * @param array $backoffs Map of (job type => UNIX timestamp)
+ * @param array $deltas Map of (job type => seconds)
+ * @param string $mode Lock wait mode - "wait" or "nowait"
+ * @return array The new backoffs account for $backoffs and the latest file data
+ */
+ private function syncBackoffDeltas( array $backoffs, array &$deltas, $mode = 'wait' ) {
+ $section = new ProfileSection( __METHOD__ );
+
+ if ( !$deltas ) {
+ return $this->loadBackoffs( $backoffs, $mode );
+ }
+
+ $noblock = ( $mode === 'nowait' ) ? LOCK_NB : 0;
+ $file = wfTempDir() . '/mw-runJobs-backoffs.json';
+ $handle = fopen( $file, 'wb+' );
+ if ( !flock( $handle, LOCK_EX | $noblock ) ) {
+ fclose( $handle );
+ return $backoffs; // don't wait on lock
+ }
+ $ctime = microtime( true );
+ $content = stream_get_contents( $handle );
+ $cBackoffs = json_decode( $content, true ) ?: array();
+ foreach ( $deltas as $type => $seconds ) {
+ $cBackoffs[$type] = isset( $cBackoffs[$type] ) && $cBackoffs[$type] >= $ctime
+ ? $cBackoffs[$type] + $seconds
+ : $ctime + $seconds;
+ }
+ foreach ( $cBackoffs as $type => $timestamp ) {
+ if ( $timestamp < $ctime ) {
+ unset( $cBackoffs[$type] );
+ }
+ }
+ ftruncate( $handle, 0 );
+ fwrite( $handle, json_encode( $cBackoffs ) );
+ flock( $handle, LOCK_UN );
+ fclose( $handle );
+
+ $deltas = array();
+
+ return $cBackoffs;
+ }
+
+ /**
+ * Make sure that this script is not too close to the memory usage limit.
+ * It is better to die in between jobs than OOM right in the middle of one.
+ * @throws MWException
+ */
+ 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)." );
+ }
+ }
+
+ /**
+ * Log the job message
+ * @param string $msg The message to log
+ */
+ private function runJobsLog( $msg ) {
+ if ( $this->debug ) {
+ call_user_func_array( $this->debug, array( wfTimestamp( TS_DB ) . " $msg\n" ) );
+ }
+ wfDebugLog( 'runJobs', $msg );
+ }
+}
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