Current File : //data/www_bck/varak.net_bck/havranipapuce.varak.net/includes/jobqueue/JobRunner.php
<?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\Logger\LoggerFactory;
use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerInterface;
/**
* Job queue runner utility methods
*
* @ingroup JobQueue
* @since 1.24
*/
class JobRunner implements LoggerAwareInterface {
/** @var callable|null Debug output handler */
protected $debug;
/**
* @param callable $debug Optional debug output handler
*/
public function setDebugHandler( $debug ) {
$this->debug = $debug;
}
/**
* @var LoggerInterface $logger
*/
protected $logger;
/**
* @param LoggerInterface $logger
*/
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 );
}
/**
* 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 ) {
global $wgJobClasses;
$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'];
if ( $type !== false && !isset( $wgJobClasses[$type] ) ) {
$response['reached'] = 'none-possible';
return $response;
}
$group = JobQueueGroup::singleton();
// Handle any required periodic queue maintenance
$count = $group->executeReadyPeriodicTasks();
if ( $count > 0 ) {
$msg = "Executed $count periodic queue task(s).";
$this->logger->debug( $msg );
$this->debugCallback( $msg );
}
// Bail out if in read-only mode
if ( wfReadOnly() ) {
$response['reached'] = 'read-only';
return $response;
}
// Bail out if there is too much DB lag
list( , $maxLag ) = wfGetLBFactory()->getMainLB( wfWikiID() )->getMaxLag();
if ( $maxLag >= 5 ) {
$response['reached'] = 'slave-lag-limit';
return $response;
}
// 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;
$checkPeriod = 5.0; // seconds
$checkPhase = mt_rand( 0, 1000 * $checkPeriod ) / 1000; // avoid stampedes
$startTime = microtime( true ); // time since jobs started running
$lastTime = microtime( true ) - $checkPhase; // 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 );
}
$msg = $job->toString() . " STARTING";
$this->logger->info( $msg );
$this->debugCallback( $msg );
// Run the job...
$jobStartTime = microtime( true );
try {
++$jobsRun;
$status = $job->run();
$error = $job->getLastError();
wfGetLBFactory()->commitMasterChanges();
} catch ( Exception $e ) {
MWExceptionHandler::rollbackMasterChangesAndLog( $e );
$status = false;
$error = get_class( $e ) . ': ' . $e->getMessage();
MWExceptionHandler::logException( $e );
}
$timeMs = intval( ( microtime( true ) - $jobStartTime ) * 1000 );
$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 ) {
$msg = $job->toString() . " t=$timeMs error={$error}";
$this->logger->error( $msg );
$this->debugCallback( $msg );
} else {
$msg = $job->toString() . " t=$timeMs good";
$this->logger->info( $msg );
$this->debugCallback( $msg );
}
$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.
// This only waits for so long before exiting and letting
// other wikis in the farm (on different masters) get a chance.
$timePassed = microtime( true ) - $lastTime;
if ( $timePassed >= 5 || $timePassed < 0 ) {
if ( !wfWaitForSlaves( $lastTime, false, '*', 5 ) ) {
$response['reached'] = 'slave-lag-limit';
break;
}
$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' ) {
$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, $mode = 'wait' ) {
if ( !$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 debugCallback( $msg ) {
if ( $this->debug ) {
call_user_func_array( $this->debug, array( wfTimestamp( TS_DB ) . " $msg\n" ) );
}
}
}
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