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Long Term Support Release
- Bug fixes for general core bugs in 4.1.x will end 13 November 2023 (12 months).
- Bug fixes for security issues in 4.1.x will end 10 November 2025 (36 months).
- PHP version: minimum PHP 7.4.0 Note: minimum PHP version has increased since Moodle 4.0. PHP 8.0.x is supported too.
/lib/classes/task/ -> manager.php (source)
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* Scheduled and adhoc task management.
*
* @package core
* @category task
* @copyright 2013 Damyon Wiese
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace core\task;
define('CORE_TASK_TASKS_FILENAME', 'db/tasks.php');
/**
* Collection of task related methods.
*
* Some locking rules for this class:
* All changes to scheduled tasks must be protected with both - the global cron lock and the lock
* for the specific scheduled task (in that order). Locks must be released in the reverse order.
* @copyright 2013 Damyon Wiese
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class manager {
/**
> * @var int Used to tell the adhoc task queue to fairly distribute tasks.
* Given a component name, will load the list of tasks in the db/tasks.php file for that component.
> */
*
> const ADHOC_TASK_QUEUE_MODE_DISTRIBUTING = 0;
* @param string $componentname - The name of the component to fetch the tasks for.
>
* @param bool $expandr - if true (default) an 'R' value in a time is expanded to an appropriate int.
> /**
* If false, they are left as 'R'
> * @var int Used to tell the adhoc task queue to try and fill unused capacity.
* @return \core\task\scheduled_task[] - List of scheduled tasks for this component.
> */
*/
> const ADHOC_TASK_QUEUE_MODE_FILLING = 1;
public static function load_default_scheduled_tasks_for_component($componentname, $expandr = true) {
>
$dir = \core_component::get_component_directory($componentname);
> /**
> * @var array A cached queue of adhoc tasks
if (!$dir) {
> */
return array();
> public static $miniqueue;
}
>
> /**
$file = $dir . '/' . CORE_TASK_TASKS_FILENAME;
> * @var int The last recorded number of unique adhoc tasks.
if (!file_exists($file)) {
> */
return array();
> public static $numtasks;
}
>
> /**
$tasks = null;
> * @var string Used to determine if the adhoc task queue is distributing or filling capacity.
include($file);
> */
> public static $mode;
if (!isset($tasks)) {
>
return array();
> /**
}
$scheduledtasks = array();
foreach ($tasks as $task) {
$record = (object) $task;
$scheduledtask = self::scheduled_task_from_record($record, $expandr, false);
// Safety check in case the task in the DB does not match a real class (maybe something was uninstalled).
if ($scheduledtask) {
$scheduledtask->set_component($componentname);
$scheduledtasks[] = $scheduledtask;
}
}
return $scheduledtasks;
}
/**
* Update the database to contain a list of scheduled task for a component.
* The list of scheduled tasks is taken from @load_scheduled_tasks_for_component.
* Will throw exceptions for any errors.
*
* @param string $componentname - The frankenstyle component name.
*/
public static function reset_scheduled_tasks_for_component($componentname) {
global $DB;
$tasks = self::load_default_scheduled_tasks_for_component($componentname);
$validtasks = array();
foreach ($tasks as $taskid => $task) {
$classname = self::get_canonical_class_name($task);
$validtasks[] = $classname;
if ($currenttask = self::get_scheduled_task($classname)) {
if ($currenttask->is_customised()) {
// If there is an existing task with a custom schedule, do not override it.
continue;
}
// Update the record from the default task data.
self::configure_scheduled_task($task);
} else {
// Ensure that the first run follows the schedule.
$task->set_next_run_time($task->get_next_scheduled_time());
// Insert the new task in the database.
$record = self::record_from_scheduled_task($task);
$DB->insert_record('task_scheduled', $record);
}
}
// Delete any task that is not defined in the component any more.
$sql = "component = :component";
$params = array('component' => $componentname);
if (!empty($validtasks)) {
list($insql, $inparams) = $DB->get_in_or_equal($validtasks, SQL_PARAMS_NAMED, 'param', false);
$sql .= ' AND classname ' . $insql;
$params = array_merge($params, $inparams);
}
$DB->delete_records_select('task_scheduled', $sql, $params);
}
/**
* Checks if the task with the same classname, component and customdata is already scheduled
*
* @param adhoc_task $task
* @return bool
*/
protected static function task_is_scheduled($task) {
return false !== self::get_queued_adhoc_task_record($task);
}
/**
* Checks if the task with the same classname, component and customdata is already scheduled
*
* @param adhoc_task $task
* @return bool
*/
protected static function get_queued_adhoc_task_record($task) {
global $DB;
$record = self::record_from_adhoc_task($task);
$params = [$record->classname, $record->component, $record->customdata];
$sql = 'classname = ? AND component = ? AND ' .
$DB->sql_compare_text('customdata', \core_text::strlen($record->customdata) + 1) . ' = ?';
if ($record->userid) {
$params[] = $record->userid;
$sql .= " AND userid = ? ";
}
return $DB->get_record_select('task_adhoc', $sql, $params);
}
/**
* Schedule a new task, or reschedule an existing adhoc task which has matching data.
*
* Only a task matching the same user, classname, component, and customdata will be rescheduled.
* If these values do not match exactly then a new task is scheduled.
*
* @param \core\task\adhoc_task $task - The new adhoc task information to store.
* @since Moodle 3.7
*/
public static function reschedule_or_queue_adhoc_task(adhoc_task $task) : void {
global $DB;
if ($existingrecord = self::get_queued_adhoc_task_record($task)) {
// Only update the next run time if it is explicitly set on the task.
$nextruntime = $task->get_next_run_time();
if ($nextruntime && ($existingrecord->nextruntime != $nextruntime)) {
$DB->set_field('task_adhoc', 'nextruntime', $nextruntime, ['id' => $existingrecord->id]);
}
} else {
// There is nothing queued yet. Just queue as normal.
self::queue_adhoc_task($task);
}
}
/**
* Queue an adhoc task to run in the background.
*
* @param \core\task\adhoc_task $task - The new adhoc task information to store.
* @param bool $checkforexisting - If set to true and the task with the same user, classname, component and customdata
* is already scheduled then it will not schedule a new task. Can be used only for ASAP tasks.
* @return boolean - True if the config was saved.
*/
public static function queue_adhoc_task(adhoc_task $task, $checkforexisting = false) {
global $DB;
if ($userid = $task->get_userid()) {
// User found. Check that they are suitable.
\core_user::require_active_user(\core_user::get_user($userid, '*', MUST_EXIST), true, true);
}
$record = self::record_from_adhoc_task($task);
// Schedule it immediately if nextruntime not explicitly set.
if (!$task->get_next_run_time()) {
$record->nextruntime = time() - 1;
}
// Check if the same task is already scheduled.
if ($checkforexisting && self::task_is_scheduled($task)) {
return false;
}
// Queue the task.
$result = $DB->insert_record('task_adhoc', $record);
return $result;
}
/**
* Change the default configuration for a scheduled task.
* The list of scheduled tasks is taken from {@link load_scheduled_tasks_for_component}.
*
* @param \core\task\scheduled_task $task - The new scheduled task information to store.
* @return boolean - True if the config was saved.
*/
public static function configure_scheduled_task(scheduled_task $task) {
global $DB;
$classname = self::get_canonical_class_name($task);
$original = $DB->get_record('task_scheduled', array('classname'=>$classname), 'id', MUST_EXIST);
$record = self::record_from_scheduled_task($task);
$record->id = $original->id;
$record->nextruntime = $task->get_next_scheduled_time();
unset($record->lastruntime);
$result = $DB->update_record('task_scheduled', $record);
return $result;
}
/**
* Utility method to create a DB record from a scheduled task.
*
* @param \core\task\scheduled_task $task
* @return \stdClass
*/
public static function record_from_scheduled_task($task) {
$record = new \stdClass();
$record->classname = self::get_canonical_class_name($task);
$record->component = $task->get_component();
$record->blocking = $task->is_blocking();
$record->customised = $task->is_customised();
$record->lastruntime = $task->get_last_run_time();
$record->nextruntime = $task->get_next_run_time();
$record->faildelay = $task->get_fail_delay();
$record->hour = $task->get_hour();
$record->minute = $task->get_minute();
$record->day = $task->get_day();
$record->dayofweek = $task->get_day_of_week();
$record->month = $task->get_month();
$record->disabled = $task->get_disabled();
$record->timestarted = $task->get_timestarted();
$record->hostname = $task->get_hostname();
$record->pid = $task->get_pid();
return $record;
}
/**
* Utility method to create a DB record from an adhoc task.
*
* @param \core\task\adhoc_task $task
* @return \stdClass
*/
public static function record_from_adhoc_task($task) {
$record = new \stdClass();
$record->classname = self::get_canonical_class_name($task);
$record->id = $task->get_id();
$record->component = $task->get_component();
$record->blocking = $task->is_blocking();
$record->nextruntime = $task->get_next_run_time();
$record->faildelay = $task->get_fail_delay();
$record->customdata = $task->get_custom_data_as_string();
$record->userid = $task->get_userid();
$record->timecreated = time();
$record->timestarted = $task->get_timestarted();
$record->hostname = $task->get_hostname();
$record->pid = $task->get_pid();
return $record;
}
/**
* Utility method to create an adhoc task from a DB record.
*
* @param \stdClass $record
* @return \core\task\adhoc_task
*/
public static function adhoc_task_from_record($record) {
$classname = self::get_canonical_class_name($record->classname);
if (!class_exists($classname)) {
debugging("Failed to load task: " . $classname, DEBUG_DEVELOPER);
return false;
}
$task = new $classname;
if (isset($record->nextruntime)) {
$task->set_next_run_time($record->nextruntime);
}
if (isset($record->id)) {
$task->set_id($record->id);
}
if (isset($record->component)) {
$task->set_component($record->component);
}
$task->set_blocking(!empty($record->blocking));
if (isset($record->faildelay)) {
$task->set_fail_delay($record->faildelay);
}
if (isset($record->customdata)) {
$task->set_custom_data_as_string($record->customdata);
}
if (isset($record->userid)) {
$task->set_userid($record->userid);
}
if (isset($record->timestarted)) {
$task->set_timestarted($record->timestarted);
}
if (isset($record->hostname)) {
$task->set_hostname($record->hostname);
}
if (isset($record->pid)) {
$task->set_pid($record->pid);
}
return $task;
}
/**
* Utility method to create a task from a DB record.
*
* @param \stdClass $record
* @param bool $expandr - if true (default) an 'R' value in a time is expanded to an appropriate int.
* If false, they are left as 'R'
* @param bool $override - if true loads overridden settings from config.
* @return \core\task\scheduled_task|false
*/
public static function scheduled_task_from_record($record, $expandr = true, $override = true) {
$classname = self::get_canonical_class_name($record->classname);
if (!class_exists($classname)) {
debugging("Failed to load task: " . $classname, DEBUG_DEVELOPER);
return false;
}
/** @var \core\task\scheduled_task $task */
$task = new $classname;
if ($override) {
// Update values with those defined in the config, if any are set.
$record = self::get_record_with_config_overrides($record);
}
if (isset($record->lastruntime)) {
$task->set_last_run_time($record->lastruntime);
}
if (isset($record->nextruntime)) {
$task->set_next_run_time($record->nextruntime);
}
if (isset($record->customised)) {
$task->set_customised($record->customised);
}
if (isset($record->component)) {
$task->set_component($record->component);
}
$task->set_blocking(!empty($record->blocking));
if (isset($record->minute)) {
$task->set_minute($record->minute, $expandr);
}
if (isset($record->hour)) {
$task->set_hour($record->hour, $expandr);
}
if (isset($record->day)) {
$task->set_day($record->day);
}
if (isset($record->month)) {
$task->set_month($record->month);
}
if (isset($record->dayofweek)) {
$task->set_day_of_week($record->dayofweek, $expandr);
}
if (isset($record->faildelay)) {
$task->set_fail_delay($record->faildelay);
}
if (isset($record->disabled)) {
$task->set_disabled($record->disabled);
}
if (isset($record->timestarted)) {
$task->set_timestarted($record->timestarted);
}
if (isset($record->hostname)) {
$task->set_hostname($record->hostname);
}
if (isset($record->pid)) {
$task->set_pid($record->pid);
}
$task->set_overridden(self::scheduled_task_has_override($classname));
return $task;
}
/**
* Given a component name, will load the list of tasks from the scheduled_tasks table for that component.
* Do not execute tasks loaded from this function - they have not been locked.
* @param string $componentname - The name of the component to load the tasks for.
* @return \core\task\scheduled_task[]
*/
public static function load_scheduled_tasks_for_component($componentname) {
global $DB;
$tasks = array();
// We are just reading - so no locks required.
$records = $DB->get_records('task_scheduled', array('component' => $componentname), 'classname', '*', IGNORE_MISSING);
foreach ($records as $record) {
$task = self::scheduled_task_from_record($record);
// Safety check in case the task in the DB does not match a real class (maybe something was uninstalled).
if ($task) {
$tasks[] = $task;
}
}
return $tasks;
}
/**
* This function load the scheduled task details for a given classname.
*
* @param string $classname
* @return \core\task\scheduled_task or false
*/
public static function get_scheduled_task($classname) {
global $DB;
$classname = self::get_canonical_class_name($classname);
// We are just reading - so no locks required.
$record = $DB->get_record('task_scheduled', array('classname'=>$classname), '*', IGNORE_MISSING);
if (!$record) {
return false;
}
return self::scheduled_task_from_record($record);
}
/**
* This function load the adhoc tasks for a given classname.
*
* @param string $classname
* @return \core\task\adhoc_task[]
*/
public static function get_adhoc_tasks($classname) {
global $DB;
$classname = self::get_canonical_class_name($classname);
// We are just reading - so no locks required.
$records = $DB->get_records('task_adhoc', array('classname' => $classname));
return array_map(function($record) {
return self::adhoc_task_from_record($record);
}, $records);
}
/**
* This function load the default scheduled task details for a given classname.
*
* @param string $classname
* @param bool $expandr - if true (default) an 'R' value in a time is expanded to an appropriate int.
* If false, they are left as 'R'
* @return \core\task\scheduled_task|false
*/
public static function get_default_scheduled_task($classname, $expandr = true) {
$task = self::get_scheduled_task($classname);
$componenttasks = array();
// Safety check in case no task was found for the given classname.
if ($task) {
$componenttasks = self::load_default_scheduled_tasks_for_component(
$task->get_component(), $expandr);
}
foreach ($componenttasks as $componenttask) {
if (get_class($componenttask) == get_class($task)) {
return $componenttask;
}
}
return false;
}
/**
* This function will return a list of all the scheduled tasks that exist in the database.
*
* @return \core\task\scheduled_task[]
*/
public static function get_all_scheduled_tasks() {
global $DB;
$records = $DB->get_records('task_scheduled', null, 'component, classname', '*', IGNORE_MISSING);
$tasks = array();
foreach ($records as $record) {
$task = self::scheduled_task_from_record($record);
// Safety check in case the task in the DB does not match a real class (maybe something was uninstalled).
if ($task) {
$tasks[] = $task;
}
}
return $tasks;
}
/**
* This function will return a list of all adhoc tasks that have a faildelay
*
* @param int $delay filter how long the task has been delayed
* @return \core\task\adhoc_task[]
*/
public static function get_failed_adhoc_tasks(int $delay = 0): array {
global $DB;
$tasks = [];
$records = $DB->get_records_sql('SELECT * from {task_adhoc} WHERE faildelay > ?', [$delay]);
foreach ($records as $record) {
$task = self::adhoc_task_from_record($record);
if ($task) {
$tasks[] = $task;
}
}
return $tasks;
}
/**
* Ensure quality of service for the ad hoc task queue.
*
* This reshuffles the adhoc tasks queue to balance by type to ensure a
* level of quality of service per type, while still maintaining the
* relative order of tasks queued by timestamp.
*
* @param array $records array of task records
* @param array $records array of same task records shuffled
> * @deprecated since Moodle 4.1 MDL-67648 - please do not use this method anymore.
*/
> * @todo MDL-74843 This method will be deleted in Moodle 4.5
public static function ensure_adhoc_task_qos(array $records): array {
> * @see \core\task\manager::get_next_adhoc_task
> debugging('The method \core\task\manager::ensure_adhoc_task_qos is deprecated.
$count = count($records);
> Please use \core\task\manager::get_next_adhoc_task instead.', DEBUG_DEVELOPER);
if ($count == 0) {
return $records;
}
$queues = []; // This holds a queue for each type of adhoc task.
$limits = []; // The relative limits of each type of task.
$limittotal = 0;
// Split the single queue up into queues per type.
foreach ($records as $record) {
$type = $record->classname;
if (!array_key_exists($type, $queues)) {
$queues[$type] = [];
}
if (!array_key_exists($type, $limits)) {
$limits[$type] = 1;
$limittotal += 1;
}
$queues[$type][] = $record;
}
$qos = []; // Our new queue with ensured quality of service.
$seed = $count % $limittotal; // Which task queue to shuffle from first?
$move = 1; // How many tasks to shuffle at a time.
do {
$shuffled = 0;
// Now cycle through task type queues and interleaving the tasks
// back into a single queue.
foreach ($limits as $type => $limit) {
// Just interleaving the queue is not enough, because after
// any task is processed the whole queue is rebuilt again. So
// we need to deterministically start on different types of
// tasks so that *on average* we rotate through each type of task.
//
// We achieve this by using a $seed to start moving tasks off a
// different queue each time. The seed is based on the task count
// modulo the number of types of tasks on the queue. As we count
// down this naturally cycles through each type of record.
if ($seed < 1) {
$shuffled = 1;
$seed += 1;
continue;
}
$tasks = array_splice($queues[$type], 0, $move);
$qos = array_merge($qos, $tasks);
// Stop if we didn't move any tasks onto the main queue.
$shuffled += count($tasks);
}
// Generally the only tasks that matter are those that are near the start so
// after we have shuffled the first few 1 by 1, start shuffling larger groups.
if (count($qos) >= (4 * count($limits))) {
$move *= 2;
}
} while ($shuffled > 0);
return $qos;
}
/**
* This function will dispatch the next adhoc task in the queue. The task will be handed out
* with an open lock - possibly on the entire cron process. Make sure you call either
* {@link adhoc_task_failed} or {@link adhoc_task_complete} to release the lock and reschedule the task.
*
* @param int $timestart
* @param bool $checklimits Should we check limits?
* @return \core\task\adhoc_task or null if not found
* @throws \moodle_exception
*/
public static function get_next_adhoc_task($timestart, $checklimits = true) {
global $DB;
< $where = '(nextruntime IS NULL OR nextruntime < :timestart1)';
< $params = array('timestart1' => $timestart);
< $records = $DB->get_records_select('task_adhoc', $where, $params, 'nextruntime ASC, id ASC', '*', 0, 2000);
< $records = self::ensure_adhoc_task_qos($records);
> $concurrencylimit = get_config('core', 'task_adhoc_concurrency_limit');
> $cachedqueuesize = 1200;
>
> $uniquetasksinqueue = array_map(
> ['\core\task\manager', 'adhoc_task_from_record'],
> $DB->get_records_sql(
> 'SELECT classname FROM {task_adhoc} WHERE nextruntime < :timestart GROUP BY classname',
> ['timestart' => $timestart]
> )
> );
>
> if (!isset(self::$numtasks) || self::$numtasks !== count($uniquetasksinqueue)) {
> self::$numtasks = count($uniquetasksinqueue);
> self::$miniqueue = [];
> }
>
> $concurrencylimits = [];
> if ($checklimits) {
> $concurrencylimits = array_map(
> function ($task) {
> return $task->get_concurrency_limit();
> },
> $uniquetasksinqueue
> );
> }
>
> /*
> * The maximum number of cron runners that an individual task is allowed to use.
> * For example if the concurrency limit is 20 and there are 5 unique types of tasks
> * in the queue, each task should not be allowed to consume more than 3 (i.e., ⌊20/6⌋).
> * The + 1 is needed to prevent the queue from becoming full of only one type of class.
> * i.e., if it wasn't there and there were 20 tasks of the same type in the queue, every
> * runner would become consumed with the same (potentially long-running task) and no more
> * tasks can run. This way, some resources are always available if some new types
> * of tasks enter the queue.
> *
> * We use the short-ternary to force the value to 1 in the case when the number of tasks
> * exceeds the runners (e.g., there are 8 tasks and 4 runners, ⌊4/(8+1)⌋ = 0).
> */
> $slots = floor($concurrencylimit / (count($uniquetasksinqueue) + 1)) ?: 1;
> if (empty(self::$miniqueue)) {
> self::$mode = self::ADHOC_TASK_QUEUE_MODE_DISTRIBUTING;
> self::$miniqueue = self::get_candidate_adhoc_tasks(
> $timestart,
> $cachedqueuesize,
> $slots,
> $concurrencylimits
> );
> }
>
> // The query to cache tasks is expensive on big data sets, so we use this cheap
> // query to get the ordering (which is the interesting part about the main query)
> // We can use this information to filter the cache and also order it.
> $runningtasks = $DB->get_records_sql(
> 'SELECT classname, COALESCE(COUNT(*), 0) running, MIN(timestarted) earliest
> FROM {task_adhoc}
> WHERE timestarted IS NOT NULL
> AND nextruntime < :timestart
> GROUP BY classname
> ORDER BY running ASC, earliest DESC',
> ['timestart' => $timestart]
> );
>
> /*
> * Each runner has a cache, so the same task can be in multiple runners' caches.
> * We need to check that each task we have cached hasn't gone over its fair number
> * of slots. This filtering is only applied during distributing mode as when we are
> * filling capacity we intend for fast tasks to go over their slot limit.
> */
> if (self::$mode === self::ADHOC_TASK_QUEUE_MODE_DISTRIBUTING) {
> self::$miniqueue = array_filter(
> self::$miniqueue,
> function (\stdClass $task) use ($runningtasks, $slots) {
> return !array_key_exists($task->classname, $runningtasks) || $runningtasks[$task->classname]->running < $slots;
> }
> );
> }
>
> /*
> * If this happens that means each task has consumed its fair share of capacity, but there's still
> * runners left over (and we are one of them). Fetch tasks without checking slot limits.
> */
> if (empty(self::$miniqueue) && array_sum(array_column($runningtasks, 'running')) < $concurrencylimit) {
> self::$mode = self::ADHOC_TASK_QUEUE_MODE_FILLING;
> self::$miniqueue = self::get_candidate_adhoc_tasks(
> $timestart,
> $cachedqueuesize,
> false,
> $concurrencylimits
> );
> }
>
> // Used below to order the cache.
> $ordering = array_flip(array_keys($runningtasks));
>
> // Order the queue so it's consistent with the ordering from the DB.
> usort(
> self::$miniqueue,
> function ($a, $b) use ($ordering) {
> return ($ordering[$a->classname] ?? -1) - ($ordering[$b->classname] ?? -1);
> }
> );
$cronlockfactory = \core\lock\lock_config::get_lock_factory('cron');
$skipclasses = array();
< foreach ($records as $record) {
> foreach (self::$miniqueue as $taskid => $record) {
if (in_array($record->classname, $skipclasses)) {
// Skip the task if it can't be started due to per-task concurrency limit.
continue;
}
if ($lock = $cronlockfactory->get_lock('adhoc_' . $record->id, 0)) {
// Safety check, see if the task has been already processed by another cron run.
$record = $DB->get_record('task_adhoc', array('id' => $record->id));
if (!$record) {
$lock->release();
> unset(self::$miniqueue[$taskid]);
continue;
}
$task = self::adhoc_task_from_record($record);
// Safety check in case the task in the DB does not match a real class (maybe something was uninstalled).
if (!$task) {
$lock->release();
> unset(self::$miniqueue[$taskid]);
continue;
}
$tasklimit = $task->get_concurrency_limit();
if ($checklimits && $tasklimit > 0) {
if ($concurrencylock = self::get_concurrent_task_lock($task)) {
$task->set_concurrency_lock($concurrencylock);
} else {
// Unable to obtain a concurrency lock.
mtrace("Skipping $record->classname adhoc task class as the per-task limit of $tasklimit is reached.");
$skipclasses[] = $record->classname;
> unset(self::$miniqueue[$taskid]);
$lock->release();
continue;
}
}
// The global cron lock is under the most contention so request it
// as late as possible and release it as soon as possible.
if (!$cronlock = $cronlockfactory->get_lock('core_cron', 10)) {
$lock->release();
throw new \moodle_exception('locktimeout');
}
$task->set_lock($lock);
if (!$task->is_blocking()) {
$cronlock->release();
} else {
$task->set_cron_lock($cronlock);
}
>
return $task;
> unset(self::$miniqueue[$taskid]);
}
> } else {
}
> unset(self::$miniqueue[$taskid]);
return null;
}
/**
> * Return a list of candidate adhoc tasks to run.
* This function will dispatch the next scheduled task in the queue. The task will be handed out
> *
* with an open lock - possibly on the entire cron process. Make sure you call either
> * @param int $timestart Only return tasks where nextruntime is less than this value
* {@link scheduled_task_failed} or {@link scheduled_task_complete} to release the lock and reschedule the task.
> * @param int $limit Limit the list to this many results
*
> * @param int|null $runmax Only return tasks that have less than this value currently running
* @param int $timestart - The start of the cron process - do not repeat any tasks that have been run more recently than this.
> * @param array $pertasklimits An array of classname => limit specifying how many instance of a task may be returned
* @return \core\task\scheduled_task or null
> * @return array Array of candidate tasks
* @throws \moodle_exception
> */
*/
> public static function get_candidate_adhoc_tasks(
public static function get_next_scheduled_task($timestart) {
> int $timestart,
global $DB;
> int $limit,
$cronlockfactory = \core\lock\lock_config::get_lock_factory('cron');
> ?int $runmax,
> array $pertasklimits = []
$where = "(lastruntime IS NULL OR lastruntime < :timestart1)
> ): array {
AND (nextruntime IS NULL OR nextruntime < :timestart2)
> global $DB;
ORDER BY lastruntime, id ASC";
>
$params = array('timestart1' => $timestart, 'timestart2' => $timestart);
> $pertaskclauses = array_map(
$records = $DB->get_records_select('task_scheduled', $where, $params);
> function (string $class, int $limit, int $index): array {
> $limitcheck = $limit > 0 ? " AND COALESCE(run.running, 0) < :running_$index" : "";
$pluginmanager = \core_plugin_manager::instance();
> $limitparam = $limit > 0 ? ["running_$index" => $limit] : [];
>
foreach ($records as $record) {
> return [
> "sql" => "(q.classname = :classname_$index" . $limitcheck . ")",
$task = self::scheduled_task_from_record($record);
> "params" => ["classname_$index" => $class] + $limitparam
// Safety check in case the task in the DB does not match a real class (maybe something was uninstalled).
> ];
// Also check to see if task is disabled or enabled after applying overrides.
> },
if (!$task || $task->get_disabled()) {
> array_keys($pertasklimits),
continue;
> $pertasklimits,
}
> $pertasklimits ? range(1, count($pertasklimits)) : []
> );
if ($lock = $cronlockfactory->get_lock(($record->classname), 0)) {
>
$classname = '\\' . $record->classname;
> $pertasksql = implode(" OR ", array_column($pertaskclauses, 'sql'));
> $pertaskparams = $pertaskclauses ? array_merge(...array_column($pertaskclauses, 'params')) : [];
$task->set_lock($lock);
>
> $params = ['timestart' => $timestart] +
// See if the component is disabled.
> ($runmax ? ['runmax' => $runmax] : []) +
$plugininfo = $pluginmanager->get_plugin_info($task->get_component());
> $pertaskparams;
>
if ($plugininfo) {
> return $DB->get_records_sql(
if (($plugininfo->is_enabled() === false) && !$task->get_run_if_component_disabled()) {
> "SELECT q.id, q.classname, q.timestarted, COALESCE(run.running, 0) running, run.earliest
$lock->release();
> FROM {task_adhoc} q
continue;
> LEFT JOIN (
}
> SELECT classname, COUNT(*) running, MIN(timestarted) earliest
}
> FROM {task_adhoc} run
> WHERE timestarted IS NOT NULL
if (!self::scheduled_task_has_override($record->classname)) {
> GROUP BY classname
// Make sure the task data is unchanged unless an override is being used.
> ) run ON run.classname = q.classname
if (!$DB->record_exists('task_scheduled', (array)$record)) {
> WHERE nextruntime < :timestart
$lock->release();
> AND q.timestarted IS NULL " .
continue;
> (!empty($pertasksql) ? "AND (" . $pertasksql . ") " : "") .
}
> ($runmax ? "AND (COALESCE(run.running, 0)) < :runmax " : "") .
}
> "ORDER BY COALESCE(run.running, 0) ASC, run.earliest DESC, q.nextruntime ASC, q.id ASC",
> $params,
// The global cron lock is under the most contention so request it
> 0,
// as late as possible and release it as soon as possible.
> $limit
if (!$cronlock = $cronlockfactory->get_lock('core_cron', 10)) {
> );
$lock->release();
> }
throw new \moodle_exception('locktimeout');
>
}
> /**
if (!$task->is_blocking()) {
$cronlock->release();
} else {
$task->set_cron_lock($cronlock);
}
return $task;
}
}
return null;
}
/**
* This function indicates that an adhoc task was not completed successfully and should be retried.
*
* @param \core\task\adhoc_task $task
*/
public static function adhoc_task_failed(adhoc_task $task) {
global $DB;
// Finalise the log output.
logmanager::finalise_log(true);
$delay = $task->get_fail_delay();
// Reschedule task with exponential fall off for failing tasks.
if (empty($delay)) {
$delay = 60;
} else {
$delay *= 2;
}
// Max of 24 hour delay.
if ($delay > 86400) {
$delay = 86400;
}
// Reschedule and then release the locks.
$task->set_timestarted();
$task->set_hostname();
$task->set_pid();
$task->set_next_run_time(time() + $delay);
$task->set_fail_delay($delay);
$record = self::record_from_adhoc_task($task);
$DB->update_record('task_adhoc', $record);
$task->release_concurrency_lock();
if ($task->is_blocking()) {
$task->get_cron_lock()->release();
}
$task->get_lock()->release();
}
/**
* Records that a adhoc task is starting to run.
*
* @param adhoc_task $task Task that is starting
* @param int $time Start time (leave blank for now)
* @throws \dml_exception
* @throws \coding_exception
*/
public static function adhoc_task_starting(adhoc_task $task, int $time = 0) {
global $DB;
$pid = (int)getmypid();
$hostname = (string)gethostname();
if (empty($time)) {
$time = time();
}
$task->set_timestarted($time);
$task->set_hostname($hostname);
$task->set_pid($pid);
$record = self::record_from_adhoc_task($task);
$DB->update_record('task_adhoc', $record);
}
/**
* This function indicates that an adhoc task was completed successfully.
*
* @param \core\task\adhoc_task $task
*/
public static function adhoc_task_complete(adhoc_task $task) {
global $DB;
// Finalise the log output.
logmanager::finalise_log();
$task->set_timestarted();
$task->set_hostname();
$task->set_pid();
// Delete the adhoc task record - it is finished.
$DB->delete_records('task_adhoc', array('id' => $task->get_id()));
// Release the locks.
$task->release_concurrency_lock();
if ($task->is_blocking()) {
$task->get_cron_lock()->release();
}
$task->get_lock()->release();
}
/**
* This function indicates that a scheduled task was not completed successfully and should be retried.
*
* @param \core\task\scheduled_task $task
*/
public static function scheduled_task_failed(scheduled_task $task) {
global $DB;
// Finalise the log output.
logmanager::finalise_log(true);
$delay = $task->get_fail_delay();
// Reschedule task with exponential fall off for failing tasks.
if (empty($delay)) {
$delay = 60;
} else {
$delay *= 2;
}
// Max of 24 hour delay.
if ($delay > 86400) {
$delay = 86400;
}
$task->set_timestarted();
$task->set_hostname();
$task->set_pid();
$classname = self::get_canonical_class_name($task);
$record = $DB->get_record('task_scheduled', array('classname' => $classname));
$record->nextruntime = time() + $delay;
$record->faildelay = $delay;
$record->timestarted = null;
$record->hostname = null;
$record->pid = null;
$DB->update_record('task_scheduled', $record);
if ($task->is_blocking()) {
$task->get_cron_lock()->release();
}
$task->get_lock()->release();
}
/**
* Clears the fail delay for the given task and updates its next run time based on the schedule.
*
* @param scheduled_task $task Task to reset
* @throws \dml_exception If there is a database error
*/
public static function clear_fail_delay(scheduled_task $task) {
global $DB;
$record = new \stdClass();
$record->id = $DB->get_field('task_scheduled', 'id',
['classname' => self::get_canonical_class_name($task)]);
$record->nextruntime = $task->get_next_scheduled_time();
$record->faildelay = 0;
$DB->update_record('task_scheduled', $record);
}
/**
* Records that a scheduled task is starting to run.
*
* @param scheduled_task $task Task that is starting
* @param int $time Start time (0 = current)
* @throws \dml_exception If the task doesn't exist
*/
public static function scheduled_task_starting(scheduled_task $task, int $time = 0) {
global $DB;
$pid = (int)getmypid();
$hostname = (string)gethostname();
if (!$time) {
$time = time();
}
$task->set_timestarted($time);
$task->set_hostname($hostname);
$task->set_pid($pid);
$classname = self::get_canonical_class_name($task);
$record = $DB->get_record('task_scheduled', ['classname' => $classname], '*', MUST_EXIST);
$record->timestarted = $time;
$record->hostname = $hostname;
$record->pid = $pid;
$DB->update_record('task_scheduled', $record);
}
/**
* This function indicates that a scheduled task was completed successfully and should be rescheduled.
*
* @param \core\task\scheduled_task $task
*/
public static function scheduled_task_complete(scheduled_task $task) {
global $DB;
// Finalise the log output.
logmanager::finalise_log();
$task->set_timestarted();
$task->set_hostname();
$task->set_pid();
$classname = self::get_canonical_class_name($task);
$record = $DB->get_record('task_scheduled', array('classname' => $classname));
if ($record) {
$record->lastruntime = time();
$record->faildelay = 0;
$record->nextruntime = $task->get_next_scheduled_time();
$record->timestarted = null;
$record->hostname = null;
$record->pid = null;
$DB->update_record('task_scheduled', $record);
}
// Reschedule and then release the locks.
if ($task->is_blocking()) {
$task->get_cron_lock()->release();
}
$task->get_lock()->release();
}
/**
* Gets a list of currently-running tasks.
*
* @param string $sort Sorting method
* @return array Array of scheduled and adhoc tasks
* @throws \dml_exception
*/
public static function get_running_tasks($sort = ''): array {
global $DB;
if (empty($sort)) {
$sort = 'timestarted ASC, classname ASC';
}
$params = ['now1' => time(), 'now2' => time()];
$sql = "SELECT subquery.*
FROM (SELECT " . $DB->sql_concat("'s'", 'ts.id') . " as uniqueid,
ts.id,
'scheduled' as type,
ts.classname,
(:now1 - ts.timestarted) as time,
ts.timestarted,
ts.hostname,
ts.pid
FROM {task_scheduled} ts
WHERE ts.timestarted IS NOT NULL
UNION ALL
SELECT " . $DB->sql_concat("'a'", 'ta.id') . " as uniqueid,
ta.id,
'adhoc' as type,
ta.classname,
(:now2 - ta.timestarted) as time,
ta.timestarted,
ta.hostname,
ta.pid
FROM {task_adhoc} ta
WHERE ta.timestarted IS NOT NULL) subquery
ORDER BY " . $sort;
return $DB->get_records_sql($sql, $params);
> }
}
>
> /**
/**
> * Cleanup stale task metadata.
* This function is used to indicate that any long running cron processes should exit at the
> */
* next opportunity and restart. This is because something (e.g. DB changes) has changed and
> public static function cleanup_metadata() {
* the static caches may be stale.
> global $DB;
*/
>
public static function clear_static_caches() {
> $cronlockfactory = \core\lock\lock_config::get_lock_factory('cron');
global $DB;
> $runningtasks = self::get_running_tasks();
// Do not use get/set config here because the caches cannot be relied on.
>
$record = $DB->get_record('config', array('name'=>'scheduledtaskreset'));
> foreach ($runningtasks as $runningtask) {
if ($record) {
> if ($runningtask->timestarted > time() - HOURSECS) {
$record->value = time();
> continue;
$DB->update_record('config', $record);
> }
} else {
>
$record = new \stdClass();
> if ($runningtask->type == 'adhoc') {
$record->name = 'scheduledtaskreset';
> $lock = $cronlockfactory->get_lock('adhoc_' . $runningtask->id, 0);
$record->value = time();
> }
$DB->insert_record('config', $record);
>
}
> if ($runningtask->type == 'scheduled') {
}
> $lock = $cronlockfactory->get_lock($runningtask->classname, 0);
> }
/**
>
* Return true if the static caches have been cleared since $starttime.
> // If we got this lock it means one of three things:
* @param int $starttime The time this process started.
> //
* @return boolean True if static caches need resetting.
> // 1. The task was stopped abnormally and the metadata was not cleaned up
*/
> // 2. This is the process running the cleanup task
public static function static_caches_cleared_since($starttime) {
> // 3. We took so long getting to it in this loop that it did finish, and we now have the lock
global $DB;
> //
$record = $DB->get_record('config', array('name'=>'scheduledtaskreset'));
> // In the case of 1. we need to make the task as failed, in the case of 2. and 3. we do nothing.
return $record && (intval($record->value) > $starttime);
> if (!empty($lock)) {
}
> if ($runningtask->classname == "\\" . \core\task\task_lock_cleanup_task::class) {
> $lock->release();
/**
> continue;
* Gets class name for use in database table. Always begins with a \.
> }
*
>
* @param string|task_base $taskorstring Task object or a string
> // We need to get the record again to verify whether or not we are dealing with case 3.
*/
> $taskrecord = $DB->get_record('task_' . $runningtask->type, ['id' => $runningtask->id]);
protected static function get_canonical_class_name($taskorstring) {
>
if (is_string($taskorstring)) {
> if ($runningtask->type == 'scheduled') {
$classname = $taskorstring;
> // Empty timestarted indicates that this task finished (case 3) and was properly cleaned up.
} else {
> if (empty($taskrecord->timestarted)) {
$classname = get_class($taskorstring);
> $lock->release();
}
> continue;
if (strpos($classname, '\\') !== 0) {
> }
$classname = '\\' . $classname;
>
}
> $task = self::scheduled_task_from_record($taskrecord);
return $classname;
> $task->set_lock($lock);
}
> self::scheduled_task_failed($task);
> } else if ($runningtask->type == 'adhoc') {
/**
> // Ad hoc tasks are removed from the DB if they finish successfully.
* Gets the concurrent lock required to run an adhoc task.
> // If we can't re-get this task, that means it finished and was properly
*
> // cleaned up.
* @param adhoc_task $task The task to obtain the lock for
> if (!$taskrecord) {
* @return \core\lock\lock The lock if one was obtained successfully
> $lock->release();
* @throws \coding_exception
> continue;
*/
> }
protected static function get_concurrent_task_lock(adhoc_task $task): ?\core\lock\lock {
>
$adhoclock = null;
> $task = self::adhoc_task_from_record($taskrecord);
$cronlockfactory = \core\lock\lock_config::get_lock_factory(get_class($task));
> $task->set_lock($lock);
> self::adhoc_task_failed($task);
for ($run = 0; $run < $task->get_concurrency_limit(); $run++) {
> }
if ($adhoclock = $cronlockfactory->get_lock("concurrent_run_{$run}", 0)) {
> }
return $adhoclock;
> }
}
}
return null;
}
/**
* Find the path of PHP CLI binary.
*
* @return string|false The PHP CLI executable PATH
*/
protected static function find_php_cli_path() {
global $CFG;
if (!empty($CFG->pathtophp) && is_executable(trim($CFG->pathtophp))) {
return $CFG->pathtophp;
}
return false;
}
/**
* Returns if Moodle have access to PHP CLI binary or not.
*
* @return bool
*/
public static function is_runnable():bool {
return self::find_php_cli_path() !== false;
}
/**
* Executes a cron from web invocation using PHP CLI.
*
* @param \core\task\task_base $task Task that be executed via CLI.
* @return bool
* @throws \moodle_exception
*/
public static function run_from_cli(\core\task\task_base $task):bool {
global $CFG;
if (!self::is_runnable()) {
$redirecturl = new \moodle_url('/admin/settings.php', ['section' => 'systempaths']);
throw new \moodle_exception('cannotfindthepathtothecli', 'tool_task', $redirecturl->out());
} else {
// Shell-escaped path to the PHP binary.
$phpbinary = escapeshellarg(self::find_php_cli_path());
// Shell-escaped path CLI script.
$pathcomponents = [$CFG->dirroot, $CFG->admin, 'cli', 'scheduled_task.php'];
$scriptpath = escapeshellarg(implode(DIRECTORY_SEPARATOR, $pathcomponents));
// Shell-escaped task name.
$classname = get_class($task);
$taskarg = escapeshellarg("--execute={$classname}") . " " . escapeshellarg("--force");
// Build the CLI command.
$command = "{$phpbinary} {$scriptpath} {$taskarg}";
// Execute it.
self::passthru_via_mtrace($command);
}
return true;
}
/**
* This behaves similar to passthru but filters every line via
* the mtrace function so it can be post processed.
*
* @param string $command to run
* @return void
*/
public static function passthru_via_mtrace(string $command) {
$descriptorspec = [
0 => ['pipe', 'r'], // STDIN.
1 => ['pipe', 'w'], // STDOUT.
2 => ['pipe', 'w'], // STDERR.
];
flush();
$process = proc_open($command, $descriptorspec, $pipes, realpath('./'), []);
if (is_resource($process)) {
while ($s = fgets($pipes[1])) {
mtrace($s, '');
flush();
}
}
fclose($pipes[0]);
fclose($pipes[1]);
fclose($pipes[2]);
proc_close($process);
}
/**
* For a given scheduled task record, this method will check to see if any overrides have
* been applied in config and return a copy of the record with any overridden values.
*
* The format of the config value is:
* $CFG->scheduled_tasks = array(
* '$classname' => array(
* 'schedule' => '* * * * *',
* 'disabled' => 1,
* ),
* );
*
* Where $classname is the value of the task's classname, i.e. '\core\task\grade_cron_task'.
*
* @param \stdClass $record scheduled task record
* @return \stdClass scheduled task with any configured overrides
*/
protected static function get_record_with_config_overrides(\stdClass $record): \stdClass {
global $CFG;
$scheduledtaskkey = self::scheduled_task_get_override_key($record->classname);
$overriddenrecord = $record;
if ($scheduledtaskkey) {
$overriddenrecord->customised = true;
$taskconfig = $CFG->scheduled_tasks[$scheduledtaskkey];
if (isset($taskconfig['disabled'])) {
$overriddenrecord->disabled = $taskconfig['disabled'];
}
if (isset($taskconfig['schedule'])) {
list (
$overriddenrecord->minute,
$overriddenrecord->hour,
$overriddenrecord->day,
$overriddenrecord->month,
$overriddenrecord->dayofweek
) = explode(' ', $taskconfig['schedule']);
}
}
return $overriddenrecord;
}
/**
* This checks whether or not there is a value set in config
* for a scheduled task.
*
* @param string $classname Scheduled task's classname
* @return bool true if there is an entry in config
*/
public static function scheduled_task_has_override(string $classname): bool {
return self::scheduled_task_get_override_key($classname) !== null;
}
/**
* Get the key within the scheduled tasks config object that
* for a classname.
*
* @param string $classname the scheduled task classname to find
* @return string the key if found, otherwise null
*/
public static function scheduled_task_get_override_key(string $classname): ?string {
global $CFG;
if (isset($CFG->scheduled_tasks)) {
// Firstly, attempt to get a match against the full classname.
if (isset($CFG->scheduled_tasks[$classname])) {
return $classname;
}
// Check to see if there is a wildcard matching the classname.
foreach (array_keys($CFG->scheduled_tasks) as $key) {
if (strpos($key, '*') === false) {
continue;
}
$pattern = '/' . str_replace('\\', '\\\\', str_replace('*', '.*', $key)) . '/';
if (preg_match($pattern, $classname)) {
return $key;
}
}
}
return null;
}
}
