<?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 {
/**
* Given a component name, will load the list of tasks in the db/tasks.php file for that component.
*
* @param string $componentname - The name of the component to fetch the tasks for.
* @return \core\task\scheduled_task[] - List of scheduled tasks for this component.
*/
public static function load_default_scheduled_tasks_for_component($componentname) {
$dir = \core_component::get_component_directory($componentname);
if (!$dir) {
return array();
}
$file = $dir . '/' . CORE_TASK_TASKS_FILENAME;
if (!file_exists($file)) {
return array();
}
$tasks = null;
include($file);
if (!isset($tasks)) {
return array();
}
$scheduledtasks = array();
foreach ($tasks as $task) {
$record = (object) $task;
$scheduledtask = self::scheduled_task_from_record($record);
// Safety check in case the task in the DB does not match a real class (maybe something was uninstalled).
if ($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) {
$classname = get_class($task);
if (strpos($classname, '\\') !== 0) {
$classname = '\\' . $classname;
}
$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);
}
/**
* Queue an adhoc task to run in the background.
*
* @param \core\task\adhoc_task $task - The new adhoc task information to store.
* @return boolean - True if the config was saved.
*/
public static function queue_adhoc_task(adhoc_task $task) {
global $DB;
$record = self::record_from_adhoc_task($task);
// Schedule it immediately if nextruntime not explicitly set.
if (!$task->get_next_run_time()) {
$record->nextruntime = time() - 1;
}
$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;
$classname = get_class($task);
if (strpos($classname, '\\') !== 0) {
$classname = '\\' . $classname;
}
$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();
$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();
$record->classname = get_class($task);
if (strpos($record->classname, '\\') !== 0) {
$record->classname = '\\' . $record->classname;
}
$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();
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();
$record->classname = get_class($task);
if (strpos($record->classname, '\\') !== 0) {
$record->classname = '\\' . $record->classname;
}
$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();
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 = $record->classname;
if (strpos($classname, '\\') !== 0) {
$classname = '\\' . $classname;
}
if (!class_exists($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);
}
return $task;
}
/**
* Utility method to create a task from a DB record.
*
* @param \stdClass $record
* @return \core\task\scheduled_task
*/
public static function scheduled_task_from_record($record) {
$classname = $record->classname;
if (strpos($classname, '\\') !== 0) {
$classname = '\\' . $classname;
}
if (!class_exists($classname)) {
debugging("Failed to load task: " . $classname, DEBUG_DEVELOPER);
return false;
}
/** @var \core\task\scheduled_task $task */
$task = new $classname;
if (isset($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);
}
if (isset($record->hour)) {
$task->set_hour($record->hour);
}
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);
}
if (isset($record->faildelay)) {
$task->set_fail_delay($record->faildelay);
}
if (isset($record->disabled)) {
$task->set_disabled($record->disabled);
}
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 $DB;
if (strpos($classname, '\\') !== 0) {
$classname = '\\' . $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 default scheduled task details for a given classname.
*
* @param string $classname
* @return \core\task\scheduled_task or false
*/
public static function get_default_scheduled_task($classname) {
$task = self::get_scheduled_task($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());
}
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 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 $timestart
* @return \core\task\adhoc_task or null if not found
*/
public static function get_next_adhoc_task($timestart) {
global $DB;
$cronlockfactory = \core\lock\lock_config::get_lock_factory('cron');
if (!$cronlock = $cronlockfactory->get_lock('core_cron', 10)) {
throw new \moodle_exception('locktimeout');
}
$where = '(nextruntime IS NULL OR nextruntime < :timestart1)';
$params = array('timestart1' => $timestart);
$records = $DB->get_records_select('task_adhoc', $where, $params);
foreach ($records as $record) {
if ($lock = $cronlockfactory->get_lock('adhoc_' . $record->id, 10)) {
$classname = '\\' . $record->classname;
$task = self::adhoc_task_from_record($record);
// Safety check in case the task in the DB does not match a real class (maybe something was uninstalled).
if (!$task) {
$lock->release();
continue;
}
$task->set_lock($lock);
if (!$task->is_blocking()) {
$cronlock->release();
} else {
$task->set_cron_lock($cronlock);
}
return $task;
}
}
// No tasks.
$cronlock->release();
return null;
}
/**
* 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
* {@link scheduled_task_failed} or {@link scheduled_task_complete} to release the lock and reschedule the task.
*
* @param int $timestart - The start of the cron process - do not repeat any tasks that have been run more recently than this.
* @return \core\task\scheduled_task or null
*/
public static function get_next_scheduled_task($timestart) {
global $DB;
$cronlockfactory = \core\lock\lock_config::get_lock_factory('cron');
if (!$cronlock = $cronlockfactory->get_lock('core_cron', 10)) {
throw new \moodle_exception('locktimeout');
}
$where = "(lastruntime IS NULL OR lastruntime < :timestart1)
AND (nextruntime IS NULL OR nextruntime < :timestart2)
AND disabled = 0
ORDER BY lastruntime, id ASC";
$params = array('timestart1' => $timestart, 'timestart2' => $timestart);
$records = $DB->get_records_select('task_scheduled', $where, $params);
$pluginmanager = \core_plugin_manager::instance();
foreach ($records as $record) {
if ($lock = $cronlockfactory->get_lock(($record->classname), 10)) {
$classname = '\\' . $record->classname;
$task = self::scheduled_task_from_record($record);
// Safety check in case the task in the DB does not match a real class (maybe something was uninstalled).
if (!$task) {
$lock->release();
continue;
}
$task->set_lock($lock);
// See if the component is disabled.
$plugininfo = $pluginmanager->get_plugin_info($task->get_component());
if ($plugininfo) {
if (($plugininfo->is_enabled() === false) && !$task->get_run_if_component_disabled()) {
$lock->release();
continue;
}
}
// Make sure the task data is unchanged.
if (!$DB->record_exists('task_scheduled', (array) $record)) {
$lock->release();
continue;
}
if (!$task->is_blocking()) {
$cronlock->release();
} else {
$task->set_cron_lock($cronlock);
}
return $task;
}
}
// No tasks.
$cronlock->release();
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;
$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;
}
$classname = get_class($task);
if (strpos($classname, '\\') !== 0) {
$classname = '\\' . $classname;
}
$task->set_next_run_time(time() + $delay);
$task->set_fail_delay($delay);
$record = self::record_from_adhoc_task($task);
$DB->update_record('task_adhoc', $record);
if ($task->is_blocking()) {
$task->get_cron_lock()->release();
}
$task->get_lock()->release();
}
/**
* 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;
// Delete the adhoc task record - it is finished.
$DB->delete_records('task_adhoc', array('id' => $task->get_id()));
// Reschedule and then release the locks.
if ($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;
$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;
}
$classname = get_class($task);
if (strpos($classname, '\\') !== 0) {
$classname = '\\' . $classname;
}
$record = $DB->get_record('task_scheduled', array('classname' => $classname));
$record->nextruntime = time() + $delay;
$record->faildelay = $delay;
$DB->update_record('task_scheduled', $record);
if ($task->is_blocking()) {
$task->get_cron_lock()->release();
}
$task->get_lock()->release();
}
/**
* 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;
$classname = get_class($task);
if (strpos($classname, '\\') !== 0) {
$classname = '\\' . $classname;
}
$record = $DB->get_record('task_scheduled', array('classname' => $classname));
if ($record) {
$record->lastruntime = time();
$record->faildelay = 0;
$record->nextruntime = $task->get_next_scheduled_time();
$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();
}
/**
* 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
* the static caches may be stale.
*/
public static function clear_static_caches() {
global $DB;
// Do not use get/set config here because the caches cannot be relied on.
$record = $DB->get_record('config', array('name'=>'scheduledtaskreset'));
if ($record) {
$record->value = time();
$DB->update_record('config', $record);
} else {
$record = new \stdClass();
$record->name = 'scheduledtaskreset';
$record->value = time();
$DB->insert_record('config', $record);
}
}
/**
* Return true if the static caches have been cleared since $starttime.
* @param int $starttime The time this process started.
* @return boolean True if static caches need resetting.
*/
public static function static_caches_cleared_since($starttime) {
global $DB;
$record = $DB->get_record('config', array('name'=>'scheduledtaskreset'));
return $record && (intval($record->value) > $starttime);
}
}