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<?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/>.namespace core;use coding_exception;use core_php_time_limit;use moodle_exception;use stdClass;// Disable the moodle.PHP.ForbiddenFunctions.FoundWithAlternative sniff for this file.// It detects uses of error_log() which are valid in this file.// phpcs:disable moodle.PHP.ForbiddenFunctions.FoundWithAlternative/*** Cron and adhoc task functionality.** @package core* @copyright 2023 Andrew Lyons <andrew@nicols.co.uk>* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later*/class cron {/** @var ?stdClass A copy of the standard cron 'user' */protected static ?stdClass $cronuser = null;/** @var ?stdClass The cron user's session data */protected static ?stdClass $cronsession = null;/*** Use a default value of 3 minutes.* The recommended cron frequency is every minute, and the default adhoc concurrency is 3.* A default value of 3 minutes allows all adhoc tasks to be run concurrently at their default value.** @var int The default keepalive value for the main cron runner*/public const DEFAULT_MAIN_PROCESS_KEEPALIVE = 3 * MINSECS;/*** @var int The max keepalive value for the main cron runner*/public const MAX_MAIN_PROCESS_KEEPALIVE = 15 * MINSECS;/*** Execute cron tasks** @param int|null $keepalive The keepalive time for this cron run.*/public static function run_main_process(?int $keepalive = null): void {global $CFG, $DB;if (CLI_MAINTENANCE) {echo "CLI maintenance mode active, cron execution suspended.\n";exit(1);}if (moodle_needs_upgrading()) {echo "Moodle upgrade pending, cron execution suspended.\n";exit(1);}require_once($CFG->libdir . '/adminlib.php');if (!empty($CFG->showcronsql)) {$DB->set_debug(true);}if (!empty($CFG->showcrondebugging)) {set_debugging(DEBUG_DEVELOPER, true);}core_php_time_limit::raise();// Increase memory limit.raise_memory_limit(MEMORY_EXTRA);// Emulate normal session. - we use admin account by default.self::setup_user();// Start output log.$timenow = time();mtrace("Server Time: " . date('r', $timenow) . "\n\n");// Record start time and interval between the last cron runs.$laststart = get_config('tool_task', 'lastcronstart');set_config('lastcronstart', $timenow, 'tool_task');if ($laststart) {// Record the interval between last two runs (always store at least 1 second).set_config('lastcroninterval', max(1, $timenow - $laststart), 'tool_task');}// Determine the time when the cron should finish.if ($keepalive === null) {$keepalive = get_config('core', 'cron_keepalive');if ($keepalive === false) {$keepalive = self::DEFAULT_MAIN_PROCESS_KEEPALIVE;}}if ($keepalive > self::MAX_MAIN_PROCESS_KEEPALIVE) {// Attempt to prevent abnormally long keepalives.mtrace("Cron keepalive time is too long, reducing to 15 minutes.");$keepalive = self::MAX_MAIN_PROCESS_KEEPALIVE;}// Calculate the finish time based on the start time and keepalive.$finishtime = $timenow + $keepalive;do {$startruntime = microtime();// Run all scheduled tasks.self::run_scheduled_tasks(time(), $timenow);// Run adhoc tasks.self::run_adhoc_tasks(time(), 0, true, $timenow);mtrace("Cron run completed correctly");gc_collect_cycles();$completiontime = date('H:i:s');$difftime = microtime_diff($startruntime, microtime());$memoryused = display_size(memory_get_usage());$message = "Cron completed at {$completiontime} in {$difftime} seconds. Memory used: {$memoryused}.";// Check if we should continue to run.// Only continue to run if:// - The finish time has not been reached; and// - The graceful exit flag has not been set; and// - The static caches have not been cleared since the start of the cron run.$remaining = $finishtime - time();$runagain = $remaining > 0;$runagain = $runagain && !\core\local\cli\shutdown::should_gracefully_exit();$runagain = $runagain && !\core\task\manager::static_caches_cleared_since($timenow);if ($runagain) {$message .= " Continuing to check for tasks for {$remaining} more seconds.";mtrace($message);sleep(1);// Re-check the graceful exit and cache clear flags after sleeping as these may have changed.$runagain = $runagain && !\core\local\cli\shutdown::should_gracefully_exit();$runagain = $runagain && !\core\task\manager::static_caches_cleared_since($timenow);} else {mtrace($message);}} while ($runagain);}/*** Execute all queued scheduled tasks, applying necessary concurrency limits and time limits.** @param int $startruntime The time this run started.* @param null|int $startprocesstime The time the process that owns this runner started.* @throws \moodle_exception*/public static function run_scheduled_tasks(int $startruntime,?int $startprocesstime = null,): void {// Allow a restriction on the number of scheduled task runners at once.$cronlockfactory = \core\lock\lock_config::get_lock_factory('cron');$maxruns = get_config('core', 'task_scheduled_concurrency_limit');$maxruntime = get_config('core', 'task_scheduled_max_runtime');if ($startprocesstime === null) {$startprocesstime = $startruntime;}$scheduledlock = null;for ($run = 0; $run < $maxruns; $run++) {// If we can't get a lock instantly it means runner N is already running// so fail as fast as possible and try N+1 so we don't limit the speed at// which we bring new runners into the pool.if ($scheduledlock = $cronlockfactory->get_lock("scheduled_task_runner_{$run}", 0)) {break;}}if (!$scheduledlock) {mtrace("Skipping processing of scheduled tasks. Concurrency limit reached.");return;}$starttime = time();// Run all scheduled tasks.try {while (!\core\local\cli\shutdown::should_gracefully_exit() &&!\core\task\manager::static_caches_cleared_since($startprocesstime) &&$task = \core\task\manager::get_next_scheduled_task($startruntime)) {self::run_inner_scheduled_task($task);unset($task);if ((time() - $starttime) > $maxruntime) {mtrace("Stopping processing of scheduled tasks as time limit has been reached.");break;}}} finally {// Release the scheduled task runner lock.$scheduledlock->release();}}/*** Execute all queued adhoc tasks, applying necessary concurrency limits and time limits.** @param int $startruntime The time this run started.* @param int $keepalive Keep this public static function alive for N seconds and poll for new adhoc tasks.* @param bool $checklimits Should we check limits?* @param null|int $startprocesstime The time this process started.* @param int|null $maxtasks Limit number of tasks to run`* @param null|string $classname Run only tasks of this class* @throws \moodle_exception*/public static function run_adhoc_tasks(int $startruntime,$keepalive = 0,$checklimits = true,?int $startprocesstime = null,?int $maxtasks = null,?string $classname = null,): void {// Allow a restriction on the number of adhoc task runners at once.$cronlockfactory = \core\lock\lock_config::get_lock_factory('cron');$maxruns = get_config('core', 'task_adhoc_concurrency_limit');$maxruntime = get_config('core', 'task_adhoc_max_runtime');if ($startprocesstime === null) {$startprocesstime = $startruntime;}$adhoclock = null;if ($checklimits) {for ($run = 0; $run < $maxruns; $run++) {// If we can't get a lock instantly it means runner N is already running// so fail as fast as possible and try N+1 so we don't limit the speed at// which we bring new runners into the pool.if ($adhoclock = $cronlockfactory->get_lock("adhoc_task_runner_{$run}", 0)) {break;}}if (!$adhoclock) {mtrace("Skipping processing of adhoc tasks. Concurrency limit reached.");return;}}$humantimenow = date('r', $startruntime);$finishtime = $startruntime + $keepalive;$waiting = false;$taskcount = 0;// Run all adhoc tasks.while (!\core\local\cli\shutdown::should_gracefully_exit() &&!\core\task\manager::static_caches_cleared_since($startprocesstime)) {if ($checklimits && (time() - $startruntime) >= $maxruntime) {if ($waiting) {$waiting = false;mtrace('');}mtrace("Stopping processing of adhoc tasks as time limit has been reached.");break;}try {$task = \core\task\manager::get_next_adhoc_task(time(), $checklimits, $classname);} catch (\Throwable $e) {if ($adhoclock) {// Release the adhoc task runner lock.$adhoclock->release();}throw $e;}if ($task) {if ($waiting) {mtrace('');}$waiting = false;self::run_inner_adhoc_task($task);self::set_process_title("Waiting for next adhoc task");$taskcount++;if ($maxtasks && $taskcount >= $maxtasks) {break;}unset($task);} else {$timeleft = $finishtime - time();if ($timeleft <= 0) {break;}if (!$waiting) {mtrace('Waiting for more adhoc tasks to be queued ', '');} else {mtrace('.', '');}$waiting = true;self::set_process_title("Waiting {$timeleft}s for next adhoc task");sleep(1);}}if ($waiting) {mtrace('');}mtrace("Ran {$taskcount} adhoc tasks found at {$humantimenow}");if ($adhoclock) {// Release the adhoc task runner lock.$adhoclock->release();}}/*** Execute an adhoc task.** @param int $taskid*/public static function run_adhoc_task(int $taskid): void {$task = \core\task\manager::get_adhoc_task($taskid);if (!$task->get_fail_delay() && $task->get_next_run_time() > time()) {throw new \moodle_exception('wontrunfuturescheduledtask');}self::run_inner_adhoc_task($task);self::set_process_title("Running adhoc task $taskid");}/*** Execute all failed adhoc tasks.** @param string|null $classname Run only tasks of this class*/public static function run_failed_adhoc_tasks(?string $classname = null): void {global $DB;$where = 'faildelay > 0';$params = [];if ($classname) {$where .= ' AND classname = :classname';$params['classname'] = \core\task\manager::get_canonical_class_name($classname);}// Only rerun the failed tasks that allow to be re-tried or have the remaining attempts available.$where .= ' AND (attemptsavailable > 0 OR attemptsavailable IS NULL)';$tasks = $DB->get_records_sql("SELECT * from {task_adhoc} WHERE $where", $params);foreach ($tasks as $t) {self::run_adhoc_task($t->id);}}/*** Shared code that handles running of a single scheduled task within the cron.** Not intended for calling directly outside of this library!** @param \core\task\task_base $task*/public static function run_inner_scheduled_task(\core\task\task_base $task) {global $CFG, $DB;$debuglevel = $CFG->debug;$debugdisplay = $CFG->debugdisplay;$CFG->debugdisplay = 1;\core\task\manager::scheduled_task_starting($task);\core\task\logmanager::start_logging($task);$fullname = $task->get_name() . ' (' . get_class($task) . ')';mtrace('Execute scheduled task: ' . $fullname);self::set_process_title('Scheduled task: ' . get_class($task));self::trace_time_and_memory();$predbqueries = null;$predbqueries = $DB->perf_get_queries();$pretime = microtime(1);// Ensure that we have a clean session with the correct cron user.self::setup_user();try {get_mailer('buffer');self::prepare_core_renderer();// Temporarily increase debug level if task has failed and debugging isn't already at maximum.if ($debuglevel !== DEBUG_DEVELOPER && $faildelay = $task->get_fail_delay()) {mtrace('Debugging increased temporarily due to faildelay of ' . $faildelay);set_debugging(DEBUG_DEVELOPER, 1);}$task->execute();if ($DB->is_transaction_started()) {throw new coding_exception("Task left transaction open");}if (isset($predbqueries)) {mtrace("... used " . ($DB->perf_get_queries() - $predbqueries) . " dbqueries");mtrace("... used " . (microtime(1) - $pretime) . " seconds");}mtrace('Scheduled task complete: ' . $fullname);\core\task\manager::scheduled_task_complete($task);} catch (\Throwable $e) {if ($DB && $DB->is_transaction_started()) {error_log('Database transaction aborted automatically in ' . get_class($task));$DB->force_transaction_rollback();}if (isset($predbqueries)) {mtrace("... used " . ($DB->perf_get_queries() - $predbqueries) . " dbqueries");mtrace("... used " . (microtime(1) - $pretime) . " seconds");}mtrace('Scheduled task failed: ' . $fullname . ',' . $e->getMessage());if ($CFG->debugdeveloper) {if (!empty($e->debuginfo)) {mtrace("Debug info:");mtrace($e->debuginfo);}mtrace("Backtrace:");mtrace(format_backtrace($e->getTrace(), true));}\core\task\manager::scheduled_task_failed($task);} finally {// Reset debugging if it changed.if ($CFG->debug !== $debuglevel) {set_debugging($debuglevel);}// Reset debugdisplay back.$CFG->debugdisplay = $debugdisplay;// Reset back to the standard admin user.self::setup_user();self::set_process_title('Waiting for next scheduled task');self::prepare_core_renderer(true);}get_mailer('close');}/*** Shared code that handles running of a single adhoc task within the cron.** @param \core\task\adhoc_task $task*/public static function run_inner_adhoc_task(\core\task\adhoc_task $task) {global $CFG, $DB;$debuglevel = $CFG->debug;$debugdisplay = $CFG->debugdisplay;$CFG->debugdisplay = 1;\core\task\manager::adhoc_task_starting($task);\core\task\logmanager::start_logging($task);mtrace("Execute adhoc task: " . get_class($task));mtrace("Adhoc task id: " . $task->get_id());mtrace("Adhoc task custom data: " . $task->get_custom_data_as_string());self::set_process_title('Adhoc task: ' . $task->get_id() . ' ' . get_class($task));self::trace_time_and_memory();$predbqueries = null;$predbqueries = $DB->perf_get_queries();$pretime = microtime(1);if ($userid = $task->get_userid()) {// This task has a userid specified.if ($user = \core_user::get_user($userid)) {// User found. Check that they are suitable.try {\core_user::require_active_user($user, true, true);} catch (moodle_exception $e) {mtrace("User {$userid} cannot be used to run an adhoc task: " . get_class($task) . ". Cancelling task.");$user = null;}} else {// Unable to find the user for this task.// A user missing in the database will never reappear.mtrace("User {$userid} could not be found for adhoc task: " . get_class($task) . ". Cancelling task.");}if (empty($user)) {// A user missing in the database will never reappear so the task needs to be failed to ensure that locks are// removed, and then removed to prevent future runs.// A task running as a user should only be run as that user.\core\task\manager::adhoc_task_failed($task);$DB->delete_records('task_adhoc', ['id' => $task->get_id()]);return;}self::setup_user($user);} else {// No user specified, ensure that we have a clean session with the correct cron user.self::setup_user();}try {get_mailer('buffer');self::prepare_core_renderer();// Temporarily increase debug level if task has failed and debugging isn't already at maximum.if ($debuglevel !== DEBUG_DEVELOPER && $faildelay = $task->get_fail_delay()) {mtrace('Debugging increased temporarily due to faildelay of ' . $faildelay);set_debugging(DEBUG_DEVELOPER, 1);}$task->execute();if ($DB->is_transaction_started()) {throw new coding_exception("Task left transaction open");}if (isset($predbqueries)) {mtrace("... used " . ($DB->perf_get_queries() - $predbqueries) . " dbqueries");mtrace("... used " . (microtime(1) - $pretime) . " seconds");}mtrace("Adhoc task complete: " . get_class($task));\core\task\manager::adhoc_task_complete($task);} catch (\Throwable $e) {if ($DB && $DB->is_transaction_started()) {error_log('Database transaction aborted automatically in ' . get_class($task));$DB->force_transaction_rollback();}if (isset($predbqueries)) {mtrace("... used " . ($DB->perf_get_queries() - $predbqueries) . " dbqueries");mtrace("... used " . (microtime(1) - $pretime) . " seconds");}mtrace("Adhoc task failed: " . get_class($task) . "," . $e->getMessage());if ($CFG->debugdeveloper) {if (!empty($e->debuginfo)) {mtrace("Debug info:");mtrace($e->debuginfo);}mtrace("Backtrace:");mtrace(format_backtrace($e->getTrace(), true));}\core\task\manager::adhoc_task_failed($task);} finally {// Reset debug level if it changed.if ($CFG->debug !== $debuglevel) {set_debugging($debuglevel);}// Reset debugdisplay back.$CFG->debugdisplay = $debugdisplay;// Reset back to the standard admin user.self::setup_user();self::prepare_core_renderer(true);}get_mailer('close');}/*** Sets the process title** This makes it very easy for a sysadmin to immediately see what task* a cron process is running at any given moment.** @param string $title process status title*/public static function set_process_title(string $title) {global $CFG;if (CLI_SCRIPT) {require_once($CFG->libdir . '/clilib.php');$datetime = userdate(time(), '%b %d, %H:%M:%S');cli_set_process_title_suffix("$datetime $title");}}/*** Output some standard information during cron runs. Specifically current time* and memory usage. This method also does gc_collect_cycles() (before displaying* memory usage) to try to help PHP manage memory better.*/public static function trace_time_and_memory() {gc_collect_cycles();mtrace('... started ' . date('H:i:s') . '. Current memory use ' . display_size(memory_get_usage()) . '.');}/*** Prepare the output renderer for the cron run.** This involves creating a new $PAGE, and $OUTPUT fresh for each task and prevents any one task from influencing* any other.** @param bool $restore Whether to restore the original PAGE and OUTPUT*/public static function prepare_core_renderer($restore = false) {global $OUTPUT, $PAGE;// Store the original PAGE and OUTPUT values so that they can be reset at a later point to the original.// This should not normally be required, but may be used in places such as the scheduled task tool's "Run now"// functionality.static $page = null;static $output = null;if (null === $page) {$page = $PAGE;}if (null === $output) {$output = $OUTPUT;}if (!empty($restore)) {$PAGE = $page;$page = null;$OUTPUT = $output;$output = null;} else {// Setup a new General renderer.// Cron tasks may produce output to be used in web, so we must use the appropriate renderer target.// This allows correct use of templates, etc.$PAGE = new \moodle_page();$OUTPUT = new \core_renderer($PAGE, RENDERER_TARGET_GENERAL);}}/*** Sets up a user and course environment in cron.** Note: This function is intended only for use in:* - the cron runner scripts* - individual tasks which extend the adhoc_task and scheduled_task classes* - unit tests related to tasks* - other parts of the cron/task system** Please note that this function stores cache data statically.* @see reset_user_cache() to reset this cache.** @param null|stdClass $user full user object, null means default cron user (admin)* @param null|stdClass $course full course record, null means $SITE* @param null|bool $leavepagealone If specified, stops it messing with global page object*/public static function setup_user(?stdClass $user = null, ?stdClass $course = null, bool $leavepagealone = false): void {// This function uses the $GLOBALS super global. Disable the VariableNameLowerCase sniff for this function.// phpcs:disable moodle.NamingConventions.ValidVariableName.VariableNameLowerCaseglobal $CFG, $SITE, $PAGE;if (!CLI_SCRIPT && !$leavepagealone) {throw new coding_exception('It is not possible to use \core\cron\setup_user() in normal requests!');}if (empty(self::$cronuser)) {// The cron user is essentially the admin user, but with some value removed.// We ginore the timezone language, and locale preferences - use the site default instead.self::$cronuser = get_admin();self::$cronuser->timezone = $CFG->timezone;self::$cronuser->lang = '';self::$cronuser->theme = '';unset(self::$cronuser->description);self::$cronsession = new stdClass();}if (!$user) {// Cached default cron user (==modified admin for now).\core\session\manager::init_empty_session();\core\session\manager::set_user(self::$cronuser);$GLOBALS['SESSION'] = self::$cronsession;} else {// Emulate real user session - needed for caps in cron.if ($GLOBALS['USER']->id != $user->id) {\core\session\manager::init_empty_session();\core\session\manager::set_user($user);}}// TODO MDL-19774 relying on global $PAGE in cron is a bad idea.// Temporary hack so that cron does not give fatal errors.if (!$leavepagealone) {$PAGE = new \moodle_page();$PAGE->set_course($course ?? $SITE);}// TODO: it should be possible to improve perf by caching some limited number of users here.// phpcs:enable}/*** Resets the cache for the cron user used by `setup_user()`.*/public static function reset_user_cache(): void {self::$cronuser = null;self::$cronsession = null;\core\session\manager::init_empty_session();}}