3 * Job queue runner utility methods
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13 * GNU General Public License for more details.
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24 use MediaWiki\Logger\LoggerFactory
;
25 use Psr\Log\LoggerAwareInterface
;
26 use Psr\Log\LoggerInterface
;
29 * Job queue runner utility methods
34 class JobRunner
implements LoggerAwareInterface
{
35 /** @var callable|null Debug output handler */
39 * @param callable $debug Optional debug output handler
41 public function setDebugHandler( $debug ) {
42 $this->debug
= $debug;
46 * @var LoggerInterface $logger
51 * @param LoggerInterface $logger
53 public function setLogger( LoggerInterface
$logger ) {
54 $this->logger
= $logger;
58 * @param LoggerInterface $logger
60 public function __construct( LoggerInterface
$logger = null ) {
61 if ( $logger === null ) {
62 $logger = LoggerFactory
::getInstance( 'runJobs' );
64 $this->setLogger( $logger );
68 * Run jobs of the specified number/type for the specified time
70 * The response map has a 'job' field that lists status of each job, including:
71 * - type : the job type
72 * - status : ok/failed
73 * - error : any error message string
74 * - time : the job run time in ms
75 * The response map also has:
76 * - backoffs : the (job type => seconds) map of backoff times
77 * - elapsed : the total time spent running tasks in ms
78 * - reached : the reason the script finished, one of (none-ready, job-limit, time-limit)
80 * This method outputs status information only if a debug handler was set.
81 * Any exceptions are caught and logged, but are not reported as output.
83 * @param array $options Map of parameters:
84 * - type : the job type (or false for the default types)
85 * - maxJobs : maximum number of jobs to run
86 * - maxTime : maximum time in seconds before stopping
87 * - throttle : whether to respect job backoff configuration
88 * @return array Summary response that can easily be JSON serialized
90 public function run( array $options ) {
93 $response = array( 'jobs' => array(), 'reached' => 'none-ready' );
95 $type = isset( $options['type'] ) ?
$options['type'] : false;
96 $maxJobs = isset( $options['maxJobs'] ) ?
$options['maxJobs'] : false;
97 $maxTime = isset( $options['maxTime'] ) ?
$options['maxTime'] : false;
98 $noThrottle = isset( $options['throttle'] ) && !$options['throttle'];
100 if ( $type !== false && !isset( $wgJobClasses[$type] ) ) {
101 $response['reached'] = 'none-possible';
105 $group = JobQueueGroup
::singleton();
106 // Handle any required periodic queue maintenance
107 $count = $group->executeReadyPeriodicTasks();
109 $msg = "Executed $count periodic queue task(s).";
110 $this->logger
->debug( $msg );
111 $this->debugCallback( $msg );
114 // Bail out if in read-only mode
115 if ( wfReadOnly() ) {
116 $response['reached'] = 'read-only';
120 // Catch huge single updates that lead to slave lag
121 $trxProfiler = Profiler
::instance()->getTransactionProfiler();
122 $trxProfiler->setLogger( LoggerFactory
::getInstance( 'DBPerformance' ) );
123 $trxProfiler->setExpectation( 'maxAffected', 500, __METHOD__
);
125 // Bail out if there is too much DB lag
126 list( , $maxLag ) = wfGetLBFactory()->getMainLB( wfWikiID() )->getMaxLag();
127 if ( $maxLag >= 5 ) {
128 $response['reached'] = 'slave-lag-limit';
132 // Flush any pending DB writes for sanity
133 wfGetLBFactory()->commitMasterChanges();
135 // Some jobs types should not run until a certain timestamp
136 $backoffs = array(); // map of (type => UNIX expiry)
137 $backoffDeltas = array(); // map of (type => seconds)
138 $wait = 'wait'; // block to read backoffs the first time
142 $flags = JobQueueGroup
::USE_CACHE
;
143 $checkPeriod = 5.0; // seconds
144 $checkPhase = mt_rand( 0, 1000 * $checkPeriod ) / 1000; // avoid stampedes
145 $startTime = microtime( true ); // time since jobs started running
146 $lastTime = microtime( true ) - $checkPhase; // time since last slave check
148 // Sync the persistent backoffs with concurrent runners
149 $backoffs = $this->syncBackoffDeltas( $backoffs, $backoffDeltas, $wait );
150 $blacklist = $noThrottle ?
array() : array_keys( $backoffs );
151 $wait = 'nowait'; // less important now
153 if ( $type === false ) {
154 $job = $group->pop( JobQueueGroup
::TYPE_DEFAULT
, $flags, $blacklist );
155 } elseif ( in_array( $type, $blacklist ) ) {
156 $job = false; // requested queue in backoff state
158 $job = $group->pop( $type ); // job from a single queue
161 if ( $job ) { // found a job
162 $jType = $job->getType();
164 // Back off of certain jobs for a while (for throttling and for errors)
165 $ttw = $this->getBackoffTimeToWait( $job );
167 // Always add the delta for other runners in case the time running the
168 // job negated the backoff for each individually but not collectively.
169 $backoffDeltas[$jType] = isset( $backoffDeltas[$jType] )
170 ?
$backoffDeltas[$jType] +
$ttw
172 $backoffs = $this->syncBackoffDeltas( $backoffs, $backoffDeltas, $wait );
175 $msg = $job->toString() . " STARTING";
176 $this->logger
->info( $msg );
177 $this->debugCallback( $msg );
180 $jobStartTime = microtime( true );
183 $status = $job->run();
184 $error = $job->getLastError();
185 wfGetLBFactory()->commitMasterChanges();
186 } catch ( Exception
$e ) {
187 MWExceptionHandler
::rollbackMasterChangesAndLog( $e );
189 $error = get_class( $e ) . ': ' . $e->getMessage();
190 MWExceptionHandler
::logException( $e );
192 $timeMs = intval( ( microtime( true ) - $jobStartTime ) * 1000 );
193 $timeMsTotal +
= $timeMs;
195 // Mark the job as done on success or when the job cannot be retried
196 if ( $status !== false ||
!$job->allowRetries() ) {
197 $group->ack( $job ); // done
200 // Back off of certain jobs for a while (for throttling and for errors)
201 if ( $status === false && mt_rand( 0, 49 ) == 0 ) {
202 $ttw = max( $ttw, 30 ); // too many errors
203 $backoffDeltas[$jType] = isset( $backoffDeltas[$jType] )
204 ?
$backoffDeltas[$jType] +
$ttw
208 if ( $status === false ) {
209 $msg = $job->toString() . " t=$timeMs error={$error}";
210 $this->logger
->error( $msg );
211 $this->debugCallback( $msg );
213 $msg = $job->toString() . " t=$timeMs good";
214 $this->logger
->info( $msg );
215 $this->debugCallback( $msg );
218 $response['jobs'][] = array(
220 'status' => ( $status === false ) ?
'failed' : 'ok',
225 // Break out if we hit the job count or wall time limits...
226 if ( $maxJobs && $jobsRun >= $maxJobs ) {
227 $response['reached'] = 'job-limit';
229 } elseif ( $maxTime && ( microtime( true ) - $startTime ) > $maxTime ) {
230 $response['reached'] = 'time-limit';
234 // Don't let any of the main DB slaves get backed up.
235 // This only waits for so long before exiting and letting
236 // other wikis in the farm (on different masters) get a chance.
237 $timePassed = microtime( true ) - $lastTime;
238 if ( $timePassed >= 5 ||
$timePassed < 0 ) {
239 if ( !wfWaitForSlaves( $lastTime, false, '*', 5 ) ) {
240 $response['reached'] = 'slave-lag-limit';
243 $lastTime = microtime( true );
245 // Don't let any queue slaves/backups fall behind
246 if ( $jobsRun > 0 && ( $jobsRun %
100 ) == 0 ) {
247 $group->waitForBackups();
250 // Bail if near-OOM instead of in a job
251 $this->assertMemoryOK();
253 } while ( $job ); // stop when there are no jobs
255 // Sync the persistent backoffs for the next runJobs.php pass
256 if ( $backoffDeltas ) {
257 $this->syncBackoffDeltas( $backoffs, $backoffDeltas, 'wait' );
260 $response['backoffs'] = $backoffs;
261 $response['elapsed'] = $timeMsTotal;
268 * @return int Seconds for this runner to avoid doing more jobs of this type
269 * @see $wgJobBackoffThrottling
271 private function getBackoffTimeToWait( Job
$job ) {
272 global $wgJobBackoffThrottling;
274 if ( !isset( $wgJobBackoffThrottling[$job->getType()] ) ||
275 $job instanceof DuplicateJob
// no work was done
277 return 0; // not throttled
280 $itemsPerSecond = $wgJobBackoffThrottling[$job->getType()];
281 if ( $itemsPerSecond <= 0 ) {
282 return 0; // not throttled
286 if ( $job->workItemCount() > 0 ) {
287 $exactSeconds = $job->workItemCount() / $itemsPerSecond;
288 // use randomized rounding
289 $seconds = floor( $exactSeconds );
290 $remainder = $exactSeconds - $seconds;
291 $seconds +
= ( mt_rand() / mt_getrandmax() < $remainder ) ?
1 : 0;
294 return (int)$seconds;
298 * Get the previous backoff expiries from persistent storage
299 * On I/O or lock acquisition failure this returns the original $backoffs.
301 * @param array $backoffs Map of (job type => UNIX timestamp)
302 * @param string $mode Lock wait mode - "wait" or "nowait"
303 * @return array Map of (job type => backoff expiry timestamp)
305 private function loadBackoffs( array $backoffs, $mode = 'wait' ) {
307 $file = wfTempDir() . '/mw-runJobs-backoffs.json';
308 if ( is_file( $file ) ) {
309 $noblock = ( $mode === 'nowait' ) ? LOCK_NB
: 0;
310 $handle = fopen( $file, 'rb' );
311 if ( !flock( $handle, LOCK_SH |
$noblock ) ) {
313 return $backoffs; // don't wait on lock
315 $content = stream_get_contents( $handle );
316 flock( $handle, LOCK_UN
);
318 $ctime = microtime( true );
319 $cBackoffs = json_decode( $content, true ) ?
: array();
320 foreach ( $cBackoffs as $type => $timestamp ) {
321 if ( $timestamp < $ctime ) {
322 unset( $cBackoffs[$type] );
326 $cBackoffs = array();
333 * Merge the current backoff expiries from persistent storage
335 * The $deltas map is set to an empty array on success.
336 * On I/O or lock acquisition failure this returns the original $backoffs.
338 * @param array $backoffs Map of (job type => UNIX timestamp)
339 * @param array $deltas Map of (job type => seconds)
340 * @param string $mode Lock wait mode - "wait" or "nowait"
341 * @return array The new backoffs account for $backoffs and the latest file data
343 private function syncBackoffDeltas( array $backoffs, array &$deltas, $mode = 'wait' ) {
346 return $this->loadBackoffs( $backoffs, $mode );
349 $noblock = ( $mode === 'nowait' ) ? LOCK_NB
: 0;
350 $file = wfTempDir() . '/mw-runJobs-backoffs.json';
351 $handle = fopen( $file, 'wb+' );
352 if ( !flock( $handle, LOCK_EX |
$noblock ) ) {
354 return $backoffs; // don't wait on lock
356 $ctime = microtime( true );
357 $content = stream_get_contents( $handle );
358 $cBackoffs = json_decode( $content, true ) ?
: array();
359 foreach ( $deltas as $type => $seconds ) {
360 $cBackoffs[$type] = isset( $cBackoffs[$type] ) && $cBackoffs[$type] >= $ctime
361 ?
$cBackoffs[$type] +
$seconds
364 foreach ( $cBackoffs as $type => $timestamp ) {
365 if ( $timestamp < $ctime ) {
366 unset( $cBackoffs[$type] );
369 ftruncate( $handle, 0 );
370 fwrite( $handle, json_encode( $cBackoffs ) );
371 flock( $handle, LOCK_UN
);
380 * Make sure that this script is not too close to the memory usage limit.
381 * It is better to die in between jobs than OOM right in the middle of one.
382 * @throws MWException
384 private function assertMemoryOK() {
385 static $maxBytes = null;
386 if ( $maxBytes === null ) {
388 if ( preg_match( '!^(\d+)(k|m|g|)$!i', ini_get( 'memory_limit' ), $m ) ) {
389 list( , $num, $unit ) = $m;
390 $conv = array( 'g' => 1073741824, 'm' => 1048576, 'k' => 1024, '' => 1 );
391 $maxBytes = $num * $conv[strtolower( $unit )];
396 $usedBytes = memory_get_usage();
397 if ( $maxBytes && $usedBytes >= 0.95 * $maxBytes ) {
398 throw new MWException( "Detected excessive memory usage ($usedBytes/$maxBytes)." );
403 * Log the job message
404 * @param string $msg The message to log
406 private function debugCallback( $msg ) {
407 if ( $this->debug
) {
408 call_user_func_array( $this->debug
, array( wfTimestamp( TS_DB
) . " $msg\n" ) );