--- /dev/null
+<?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
+ */
+
+use MediaWiki\MediaWikiServices;
+use MediaWiki\Logger\LoggerFactory;
+use Liuggio\StatsdClient\Factory\StatsdDataFactory;
+use Psr\Log\LoggerAwareInterface;
+use Psr\Log\LoggerInterface;
+use Wikimedia\ScopedCallback;
+use Wikimedia\Rdbms\LBFactory;
+use Wikimedia\Rdbms\DBError;
+use Wikimedia\Rdbms\DBReplicationWaitError;
+
+/**
+ * Job queue runner utility methods
+ *
+ * @ingroup JobQueue
+ * @since 1.24
+ */
+class JobRunner implements LoggerAwareInterface {
+ /** @var Config */
+ protected $config;
+ /** @var callable|null Debug output handler */
+ protected $debug;
+
+ /**
+ * @var LoggerInterface $logger
+ */
+ protected $logger;
+
+ const MAX_ALLOWED_LAG = 3; // abort if more than this much DB lag is present
+ const LAG_CHECK_PERIOD = 1.0; // check replica DB lag this many seconds
+ const ERROR_BACKOFF_TTL = 1; // seconds to back off a queue due to errors
+ const READONLY_BACKOFF_TTL = 30; // seconds to back off a queue due to read-only errors
+
+ /**
+ * @param callable $debug Optional debug output handler
+ */
+ public function setDebugHandler( $debug ) {
+ $this->debug = $debug;
+ }
+
+ /**
+ * @param LoggerInterface $logger
+ * @return void
+ */
+ public function setLogger( LoggerInterface $logger ) {
+ $this->logger = $logger;
+ }
+
+ /**
+ * @param LoggerInterface $logger
+ */
+ public function __construct( LoggerInterface $logger = null ) {
+ if ( $logger === null ) {
+ $logger = LoggerFactory::getInstance( 'runJobs' );
+ }
+ $this->setLogger( $logger );
+ $this->config = MediaWikiServices::getInstance()->getMainConfig();
+ }
+
+ /**
+ * 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,
+ * memory-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 ) {
+ $jobClasses = $this->config->get( 'JobClasses' );
+ $profilerLimits = $this->config->get( 'TrxProfilerLimits' );
+
+ $response = [ 'jobs' => [], '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'];
+
+ // Bail if job type is invalid
+ if ( $type !== false && !isset( $jobClasses[$type] ) ) {
+ $response['reached'] = 'none-possible';
+ return $response;
+ }
+ // Bail out if DB is in read-only mode
+ if ( wfReadOnly() ) {
+ $response['reached'] = 'read-only';
+ return $response;
+ }
+
+ $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
+ // Bail out if there is too much DB lag.
+ // This check should not block as we want to try other wiki queues.
+ list( , $maxLag ) = $lbFactory->getMainLB( wfWikiID() )->getMaxLag();
+ if ( $maxLag >= self::MAX_ALLOWED_LAG ) {
+ $response['reached'] = 'replica-lag-limit';
+ return $response;
+ }
+
+ // Flush any pending DB writes for sanity
+ $lbFactory->commitAll( __METHOD__ );
+
+ // Catch huge single updates that lead to replica DB lag
+ $trxProfiler = Profiler::instance()->getTransactionProfiler();
+ $trxProfiler->setLogger( LoggerFactory::getInstance( 'DBPerformance' ) );
+ $trxProfiler->setExpectations( $profilerLimits['JobRunner'], __METHOD__ );
+
+ // Some jobs types should not run until a certain timestamp
+ $backoffs = []; // map of (type => UNIX expiry)
+ $backoffDeltas = []; // map of (type => seconds)
+ $wait = 'wait'; // block to read backoffs the first time
+
+ $group = JobQueueGroup::singleton();
+ $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
+ $jobsPopped = 0;
+ $timeMsTotal = 0;
+ $startTime = microtime( true ); // time since jobs started running
+ $lastCheckTime = 1; // timestamp of last replica DB check
+ do {
+ // Sync the persistent backoffs with concurrent runners
+ $backoffs = $this->syncBackoffDeltas( $backoffs, $backoffDeltas, $wait );
+ $blacklist = $noThrottle ? [] : array_keys( $backoffs );
+ $wait = 'nowait'; // less important now
+
+ if ( $type === false ) {
+ $job = $group->pop(
+ JobQueueGroup::TYPE_DEFAULT,
+ JobQueueGroup::USE_CACHE,
+ $blacklist
+ );
+ } elseif ( in_array( $type, $blacklist ) ) {
+ $job = false; // requested queue in backoff state
+ } else {
+ $job = $group->pop( $type ); // job from a single queue
+ }
+ $lbFactory->commitMasterChanges( __METHOD__ ); // flush any JobQueueDB writes
+
+ if ( $job ) { // found a job
+ ++$jobsPopped;
+ $popTime = time();
+ $jType = $job->getType();
+
+ WebRequest::overrideRequestId( $job->getRequestId() );
+
+ // 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 );
+ }
+
+ $info = $this->executeJob( $job, $lbFactory, $stats, $popTime );
+ if ( $info['status'] !== false || !$job->allowRetries() ) {
+ $group->ack( $job ); // succeeded or job cannot be retried
+ $lbFactory->commitMasterChanges( __METHOD__ ); // flush any JobQueueDB writes
+ }
+
+ // Back off of certain jobs for a while (for throttling and for errors)
+ if ( $info['status'] === false && mt_rand( 0, 49 ) == 0 ) {
+ $ttw = max( $ttw, $this->getErrorBackoffTTL( $info['error'] ) );
+ $backoffDeltas[$jType] = isset( $backoffDeltas[$jType] )
+ ? $backoffDeltas[$jType] + $ttw
+ : $ttw;
+ }
+
+ $response['jobs'][] = [
+ 'type' => $jType,
+ 'status' => ( $info['status'] === false ) ? 'failed' : 'ok',
+ 'error' => $info['error'],
+ 'time' => $info['timeMs']
+ ];
+ $timeMsTotal += $info['timeMs'];
+
+ // Break out if we hit the job count or wall time limits...
+ if ( $maxJobs && $jobsPopped >= $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 replica DBs get backed up.
+ // This only waits for so long before exiting and letting
+ // other wikis in the farm (on different masters) get a chance.
+ $timePassed = microtime( true ) - $lastCheckTime;
+ if ( $timePassed >= self::LAG_CHECK_PERIOD || $timePassed < 0 ) {
+ try {
+ $lbFactory->waitForReplication( [
+ 'ifWritesSince' => $lastCheckTime,
+ 'timeout' => self::MAX_ALLOWED_LAG
+ ] );
+ } catch ( DBReplicationWaitError $e ) {
+ $response['reached'] = 'replica-lag-limit';
+ break;
+ }
+ $lastCheckTime = microtime( true );
+ }
+ // Don't let any queue replica DBs/backups fall behind
+ if ( $jobsPopped > 0 && ( $jobsPopped % 100 ) == 0 ) {
+ $group->waitForBackups();
+ }
+
+ // Bail if near-OOM instead of in a job
+ if ( !$this->checkMemoryOK() ) {
+ $response['reached'] = 'memory-limit';
+ break;
+ }
+ }
+ } 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 string $error
+ * @return int TTL in seconds
+ */
+ private function getErrorBackoffTTL( $error ) {
+ return strpos( $error, 'DBReadOnlyError' ) !== false
+ ? self::READONLY_BACKOFF_TTL
+ : self::ERROR_BACKOFF_TTL;
+ }
+
+ /**
+ * @param Job $job
+ * @param LBFactory $lbFactory
+ * @param StatsdDataFactory $stats
+ * @param float $popTime
+ * @return array Map of status/error/timeMs
+ */
+ private function executeJob( Job $job, LBFactory $lbFactory, $stats, $popTime ) {
+ $jType = $job->getType();
+ $msg = $job->toString() . " STARTING";
+ $this->logger->debug( $msg, [
+ 'job_type' => $job->getType(),
+ ] );
+ $this->debugCallback( $msg );
+
+ // Run the job...
+ $rssStart = $this->getMaxRssKb();
+ $jobStartTime = microtime( true );
+ try {
+ $fnameTrxOwner = get_class( $job ) . '::run'; // give run() outer scope
+ $lbFactory->beginMasterChanges( $fnameTrxOwner );
+ $status = $job->run();
+ $error = $job->getLastError();
+ $this->commitMasterChanges( $lbFactory, $job, $fnameTrxOwner );
+ // Important: this must be the last deferred update added (T100085, T154425)
+ DeferredUpdates::addCallableUpdate( [ JobQueueGroup::class, 'pushLazyJobs' ] );
+ // Run any deferred update tasks; doUpdates() manages transactions itself
+ DeferredUpdates::doUpdates();
+ } catch ( Exception $e ) {
+ MWExceptionHandler::rollbackMasterChangesAndLog( $e );
+ $status = false;
+ $error = get_class( $e ) . ': ' . $e->getMessage();
+ }
+ // Always attempt to call teardown() even if Job throws exception.
+ try {
+ $job->teardown( $status );
+ } catch ( Exception $e ) {
+ MWExceptionHandler::logException( $e );
+ }
+
+ // Commit all outstanding connections that are in a transaction
+ // to get a fresh repeatable read snapshot on every connection.
+ // Note that jobs are still responsible for handling replica DB lag.
+ $lbFactory->flushReplicaSnapshots( __METHOD__ );
+ // Clear out title cache data from prior snapshots
+ MediaWikiServices::getInstance()->getLinkCache()->clear();
+ $timeMs = intval( ( microtime( true ) - $jobStartTime ) * 1000 );
+ $rssEnd = $this->getMaxRssKb();
+
+ // Record how long jobs wait before getting popped
+ $readyTs = $job->getReadyTimestamp();
+ if ( $readyTs ) {
+ $pickupDelay = max( 0, $popTime - $readyTs );
+ $stats->timing( 'jobqueue.pickup_delay.all', 1000 * $pickupDelay );
+ $stats->timing( "jobqueue.pickup_delay.$jType", 1000 * $pickupDelay );
+ }
+ // Record root job age for jobs being run
+ $rootTimestamp = $job->getRootJobParams()['rootJobTimestamp'];
+ if ( $rootTimestamp ) {
+ $age = max( 0, $popTime - wfTimestamp( TS_UNIX, $rootTimestamp ) );
+ $stats->timing( "jobqueue.pickup_root_age.$jType", 1000 * $age );
+ }
+ // Track the execution time for jobs
+ $stats->timing( "jobqueue.run.$jType", $timeMs );
+ // Track RSS increases for jobs (in case of memory leaks)
+ if ( $rssStart && $rssEnd ) {
+ $stats->updateCount( "jobqueue.rss_delta.$jType", $rssEnd - $rssStart );
+ }
+
+ if ( $status === false ) {
+ $msg = $job->toString() . " t={job_duration} error={job_error}";
+ $this->logger->error( $msg, [
+ 'job_type' => $job->getType(),
+ 'job_duration' => $timeMs,
+ 'job_error' => $error,
+ ] );
+
+ $msg = $job->toString() . " t=$timeMs error={$error}";
+ $this->debugCallback( $msg );
+ } else {
+ $msg = $job->toString() . " t={job_duration} good";
+ $this->logger->info( $msg, [
+ 'job_type' => $job->getType(),
+ 'job_duration' => $timeMs,
+ ] );
+
+ $msg = $job->toString() . " t=$timeMs good";
+ $this->debugCallback( $msg );
+ }
+
+ return [ 'status' => $status, 'error' => $error, 'timeMs' => $timeMs ];
+ }
+
+ /**
+ * @return int|null Max memory RSS in kilobytes
+ */
+ private function getMaxRssKb() {
+ $info = wfGetRusage() ?: [];
+ // see https://linux.die.net/man/2/getrusage
+ return isset( $info['ru_maxrss'] ) ? (int)$info['ru_maxrss'] : null;
+ }
+
+ /**
+ * @param Job $job
+ * @return int Seconds for this runner to avoid doing more jobs of this type
+ * @see $wgJobBackoffThrottling
+ */
+ private function getBackoffTimeToWait( Job $job ) {
+ $throttling = $this->config->get( 'JobBackoffThrottling' );
+
+ if ( !isset( $throttling[$job->getType()] ) || $job instanceof DuplicateJob ) {
+ return 0; // not throttled
+ }
+
+ $itemsPerSecond = $throttling[$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' ) {
+ $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 ) ?: [];
+ foreach ( $cBackoffs as $type => $timestamp ) {
+ if ( $timestamp < $ctime ) {
+ unset( $cBackoffs[$type] );
+ }
+ }
+ } else {
+ $cBackoffs = [];
+ }
+
+ 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, $mode = 'wait' ) {
+ if ( !$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 ) ?: [];
+ 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 = [];
+
+ 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.
+ * @return bool
+ */
+ private function checkMemoryOK() {
+ static $maxBytes = null;
+ if ( $maxBytes === null ) {
+ $m = [];
+ if ( preg_match( '!^(\d+)(k|m|g|)$!i', ini_get( 'memory_limit' ), $m ) ) {
+ list( , $num, $unit ) = $m;
+ $conv = [ '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 ) {
+ $msg = "Detected excessive memory usage ({used_bytes}/{max_bytes}).";
+ $this->logger->error( $msg, [
+ 'used_bytes' => $usedBytes,
+ 'max_bytes' => $maxBytes,
+ ] );
+
+ $msg = "Detected excessive memory usage ($usedBytes/$maxBytes).";
+ $this->debugCallback( $msg );
+
+ return false;
+ }
+
+ return true;
+ }
+
+ /**
+ * Log the job message
+ * @param string $msg The message to log
+ */
+ private function debugCallback( $msg ) {
+ if ( $this->debug ) {
+ call_user_func_array( $this->debug, [ wfTimestamp( TS_DB ) . " $msg\n" ] );
+ }
+ }
+
+ /**
+ * Issue a commit on all masters who are currently in a transaction and have
+ * made changes to the database. It also supports sometimes waiting for the
+ * local wiki's replica DBs to catch up. See the documentation for
+ * $wgJobSerialCommitThreshold for more.
+ *
+ * @param LBFactory $lbFactory
+ * @param Job $job
+ * @param string $fnameTrxOwner
+ * @throws DBError
+ */
+ private function commitMasterChanges( LBFactory $lbFactory, Job $job, $fnameTrxOwner ) {
+ $syncThreshold = $this->config->get( 'JobSerialCommitThreshold' );
+
+ $time = false;
+ $lb = $lbFactory->getMainLB( wfWikiID() );
+ if ( $syncThreshold !== false && $lb->getServerCount() > 1 ) {
+ // Generally, there is one master connection to the local DB
+ $dbwSerial = $lb->getAnyOpenConnection( $lb->getWriterIndex() );
+ // We need natively blocking fast locks
+ if ( $dbwSerial && $dbwSerial->namedLocksEnqueue() ) {
+ $time = $dbwSerial->pendingWriteQueryDuration( $dbwSerial::ESTIMATE_DB_APPLY );
+ if ( $time < $syncThreshold ) {
+ $dbwSerial = false;
+ }
+ } else {
+ $dbwSerial = false;
+ }
+ } else {
+ // There are no replica DBs or writes are all to foreign DB (we don't handle that)
+ $dbwSerial = false;
+ }
+
+ if ( !$dbwSerial ) {
+ $lbFactory->commitMasterChanges(
+ $fnameTrxOwner,
+ // Abort if any transaction was too big
+ [ 'maxWriteDuration' => $this->config->get( 'MaxJobDBWriteDuration' ) ]
+ );
+
+ return;
+ }
+
+ $ms = intval( 1000 * $time );
+
+ $msg = $job->toString() . " COMMIT ENQUEUED [{job_commit_write_ms}ms of writes]";
+ $this->logger->info( $msg, [
+ 'job_type' => $job->getType(),
+ 'job_commit_write_ms' => $ms,
+ ] );
+
+ $msg = $job->toString() . " COMMIT ENQUEUED [{$ms}ms of writes]";
+ $this->debugCallback( $msg );
+
+ // Wait for an exclusive lock to commit
+ if ( !$dbwSerial->lock( 'jobrunner-serial-commit', __METHOD__, 30 ) ) {
+ // This will trigger a rollback in the main loop
+ throw new DBError( $dbwSerial, "Timed out waiting on commit queue." );
+ }
+ $unlocker = new ScopedCallback( function () use ( $dbwSerial ) {
+ $dbwSerial->unlock( 'jobrunner-serial-commit', __METHOD__ );
+ } );
+
+ // Wait for the replica DBs to catch up
+ $pos = $lb->getMasterPos();
+ if ( $pos ) {
+ $lb->waitForAll( $pos );
+ }
+
+ // Actually commit the DB master changes
+ $lbFactory->commitMasterChanges(
+ $fnameTrxOwner,
+ // Abort if any transaction was too big
+ [ 'maxWriteDuration' => $this->config->get( 'MaxJobDBWriteDuration' ) ]
+ );
+ ScopedCallback::consume( $unlocker );
+ }
+}
scripts.mit.edu / autoinstallsdev / mediawiki.git / blobdiff