f414f8f91b
Why: - The JobQueue docs currently do not describe the semantics of handling job execution failures. - Some other features, such as job deduplication, enqueue semantics and the overall execution flow, are also missing from the architecture document. What: - Expand the JobQueue architecture document to describe how jobs that return false from Job::run() or complete exceptionally are treated. - Rework some preexisting sections of the same document for brevity. - Describe JobSpecification and JobQueueGroup in the same document. - Describe the different between push() and lazyPush() semantics. - Describe the execution flow of a Job. - Briefly summarize how job deduplication is expected to function. Change-Id: Ib0c1f165feabefe862710b28977b598faf637ec5
123 lines
4.1 KiB
PHP
123 lines
4.1 KiB
PHP
<?php
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/**
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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*/
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/**
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* Job that has a run() method and metadata accessors for JobQueue::pop() and JobQueue::ack().
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*
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* Instances are not only enqueueable via JobQueue::push(), but they can also be executed by
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* calling their run() method. When constructing a job to be enqueued via JobQueue::push(), it
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* will not be possible to construct a RunnableJob instance if the class for that job is not
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* loaded by the application for the local DB domain. In that case, the general-purpose
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* JobSpecification class can be used instead.
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*
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* See [the architecture doc](@ref jobqueuearch) for more information.
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*
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* @stable to implement
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* @since 1.33
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* @ingroup JobQueue
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*/
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interface RunnableJob extends IJobSpecification {
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/** @var int Job must not be wrapped in the usual explicit LBFactory transaction round */
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public const JOB_NO_EXPLICIT_TRX_ROUND = 1;
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/**
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* Run the job.
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*
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* If this method returns `false` or completes exceptionally, the job runner will retry executing this
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* job unless the number of retries has exceeded its configured retry limit.
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* Retries are allowed by default, unless allowRetries() is overridden to disable retries.
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*
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* See [the architecture doc](@ref jobqueuearch) for more information.
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*
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* @return bool Return `false` to instruct the job runner to retry a failed job.
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* Otherwise return `true` to indicate that a job completed
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* (i.e. succeeded, or failed in a way that's deterministic or redundant).
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*/
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public function run();
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/**
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* @param string|null $field Metadata field or null to get all the metadata
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* @return mixed|null Value; null if missing
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*/
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public function getMetadata( $field = null );
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/**
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* @param string $field Key name to set the value for
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* @param mixed $value The value to set the field for
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* @return mixed|null The prior field value; null if missing
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*/
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public function setMetadata( $field, $value );
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/**
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* @param int $flag JOB_* class constant
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* @return bool
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* @since 1.31
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*/
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public function hasExecutionFlag( $flag );
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/**
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* @return string|null Id of the request that created this job. Follows
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* jobs recursively, allowing to track the id of the request that started a
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* job when jobs insert jobs which insert other jobs.
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* @since 1.27
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*/
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public function getRequestId();
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/**
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* Whether to retry execution of this job if run() returned `false` or threw an exception.
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*
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* @warning In some setups (i.e. when using change-propagation) jobs may
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* still be retried even when this is false if the job fails due to a
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* timeout unless it is also configured in change-prop config (T358939).
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* @return bool Whether this job can be retried on failure by job runners
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* @since 1.21
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*/
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public function allowRetries();
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/**
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* @return int Number of actually "work items" handled in this job
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* @see $wgJobBackoffThrottling
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* @since 1.23
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*/
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public function workItemCount();
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/**
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* @return int|null UNIX timestamp of when the job was runnable, or null
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* @since 1.26
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*/
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public function getReadyTimestamp();
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/**
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* Do any final cleanup after run(), deferred updates, and all DB commits happen
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* @param bool $status Whether the job, its deferred updates, and DB commit all succeeded
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* @since 1.27
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*/
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public function tearDown( $status );
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/**
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* @return string
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*/
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public function getLastError();
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/**
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* @return string Debugging string describing the job
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*/
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public function toString();
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}
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