first commit

admin/tool/task/classes/check/adhocqueue.php

@@ -0,0 +1,88 @@
+<?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 tool_task\check;
+
+use action_link;
+use core\check\check;
+use core\check\result;
+use moodle_url;
+
+/**
+ * Ad hoc queue checks
+ *
+ * @package    tool_task
+ * @copyright  2020 Brendan Heywood (brendan@catalyst-au.net)
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class adhocqueue extends check {
+
+    /**
+     * Return result
+     * @return result
+     */
+    public function get_result(): result {
+        global $DB, $CFG;
+
+        $stats = $DB->get_record_sql('
+            SELECT count(*) cnt,
+                   MAX(? - nextruntime) age
+              FROM {task_adhoc}', [time()]);
+
+        $status = result::OK;
+        $summary = get_string('adhocempty', 'tool_task');
+        $details = '';
+
+        if ($stats->cnt > 0) {
+            // A large queue size by itself is not an issue, only when tasks
+            // are not being processed in a timely fashion is it an issue.
+            $status = result::INFO;
+            $summary = get_string('adhocqueuesize', 'tool_task', $stats->cnt);
+        }
+
+        $max = $CFG->adhoctaskagewarn ?? 10 * MINSECS;
+        if ($stats->age > $max) {
+            $status = result::WARNING;
+            $summary = get_string('adhocqueueold', 'tool_task', [
+                'age' => format_time($stats->age),
+                'max' => format_time($max),
+            ]);
+        }
+
+        $max = $CFG->adhoctaskageerror ?? 4 * HOURSECS;
+        if ($stats->age > $max) {
+            $status = result::ERROR;
+            $summary = get_string('adhocqueueold', 'tool_task', [
+                'age' => format_time($stats->age),
+                'max' => format_time($max),
+            ]);
+        }
+
+        return new result($status, $summary, $details);
+    }
+
+    /**
+     * Link to the Ad hoc tasks report
+     *
+     * @return action_link|null
+     */
+    public function get_action_link(): ?action_link {
+        return new action_link(
+            new moodle_url('/admin/tool/task/adhoctasks.php'),
+            get_string('adhoctasks', 'tool_task'),
+        );
+    }
+}

admin/tool/task/classes/check/cronrunning.php

@@ -0,0 +1,125 @@
+<?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/>.
+
+/**
+ * Cron running check
+ *
+ * @package    tool_task
+ * @copyright  2020 Brendan Heywood (brendan@catalyst-au.net)
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace tool_task\check;
+
+defined('MOODLE_INTERNAL') || die();
+
+use core\check\check;
+use core\check\result;
+/**
+ * Cron running check
+ *
+ * @package    tool_task
+ * @copyright  2020 Brendan Heywood (brendan@catalyst-au.net)
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cronrunning extends check {
+
+    /**
+     * A link the running tasks report
+     *
+     * @return action_link|null
+     */
+    public function get_action_link(): ?\action_link {
+        return new \action_link(
+            new \moodle_url('/admin/tool/task/runningtasks.php'),
+            get_string('runningtasks', 'tool_task'));
+    }
+
+    /**
+     * Return result
+     * @return result
+     */
+    public function get_result(): result {
+        global $CFG;
+
+        // Eventually this should replace cron_overdue_warning and
+        // cron_infrequent_warning.
+        $lastcron = get_config('tool_task', 'lastcronstart');
+        $expectedfrequency = $CFG->expectedcronfrequency ?? MINSECS;
+
+        $delta = time() - $lastcron;
+
+        $lastcroninterval = get_config('tool_task', 'lastcroninterval');
+
+        $formatdelta    = format_time($delta);
+        $formatexpected = format_time($expectedfrequency);
+        $formatinterval = format_time($lastcroninterval);
+
+        // Inform user the time since last cron start.
+        $details = get_string('lastcronstart', 'tool_task', $formatdelta);
+
+        if ($delta > $expectedfrequency + MINSECS) {
+            $status = result::WARNING;
+
+            if ($delta > DAYSECS) {
+                $status = result::CRITICAL;
+            }
+
+            if (empty($lastcron)) {
+                if (empty($CFG->cronclionly)) {
+                    $url = new \moodle_url('/admin/cron.php');
+                    $summary = get_string('cronwarningneverweb', 'admin', [
+                        'url' => $url->out(),
+                        'expected' => $formatexpected,
+                    ]);
+                } else {
+                    $summary = get_string('cronwarningnever', 'admin', [
+                        'expected' => $formatexpected,
+                    ]);
+                }
+            } else if (empty($CFG->cronclionly)) {
+                $url = new \moodle_url('/admin/cron.php');
+                $summary = get_string('cronwarning', 'admin', [
+                    'url' => $url->out(),
+                    'actual'   => $formatdelta,
+                    'expected' => $formatexpected,
+                ]);
+            } else {
+                $summary = get_string('cronwarningcli', 'admin', [
+                    'actual'   => $formatdelta,
+                    'expected' => $formatexpected,
+                ]);
+            }
+            return new result($status, $summary, $details);
+        }
+
+        // Add MINSECS to avoid spurious warning if cron is only a few seconds overdue.
+        if ($lastcroninterval > $expectedfrequency + MINSECS) {
+            $status = result::WARNING;
+            $summary = get_string('croninfrequent', 'admin', [
+                'actual'   => $formatinterval,
+                'expected' => $formatexpected,
+            ]);
+            return new result($status, $summary, $details);
+        }
+
+        $status = result::OK;
+        $summary = get_string('cronok', 'tool_task');
+
+        return new result($status, $summary, $details);
+    }
+}
+

admin/tool/task/classes/check/longrunningtasks.php

@@ -0,0 +1,89 @@
+<?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 tool_task\check;
+
+use core\check\check;
+use core\check\result;
+use core\task\manager;
+
+/**
+ * Long running tasks check
+ *
+ * @package    tool_task
+ * @author     Qihui Chan (qihuichan@catalyst-au.net)
+ * @copyright  2022 Catalyst IT Pty Ltd
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class longrunningtasks extends check {
+
+    /**
+     * Links to the running task list
+     *
+     * @return \action_link|null
+     * @throws \coding_exception
+     */
+    public function get_action_link(): ?\action_link {
+        $url = new \moodle_url('/admin/tool/task/runningtasks.php');
+        return new \action_link($url, get_string('runningtasks', 'tool_task'));
+    }
+
+    /**
+     * Return result
+     * @return result
+     */
+    public function get_result(): result {
+        global $CFG;
+        $status = result::OK;
+        $slowtasks = 0;
+        $details = '';
+        $maxruntime = 0;
+        $runtime = 0;
+
+        $tasks = \core\task\manager::get_running_tasks();
+        foreach ($tasks as $record) {
+            $taskmethod = "{$record->type}_task_from_record";
+            $task = manager::$taskmethod($record);
+            $taskname = $task->get_name();
+
+            $result = $task->get_runtime_result();
+            $taskstatus = $result->get_status();
+            $runtime = $task->get_runtime();
+            $runtimedetails = get_string('taskrunningtime', 'tool_task', format_time($runtime));
+            $maxruntime = ($runtime > $maxruntime) ? $runtime : $maxruntime;
+
+            if ($taskstatus == result::OK) {
+                continue;
+            }
+
+            $slowtasks++;
+            $details .= strtoupper($taskstatus) . ": {$taskname}. {$runtimedetails} <br>";
+
+            // The overall check status is the worst tasks status.
+            if ($status !== result::ERROR) {
+                $status = $taskstatus;
+            }
+        }
+
+        $summary = get_string('checklongrunningtaskcount', 'tool_task', $slowtasks);
+        $conclusion = get_string('taskdetails', 'tool_task', ['count' => $slowtasks,
+            'time' => format_time($CFG->taskruntimewarn), 'maxtime' => format_time($maxruntime)]);
+
+        $details = ($slowtasks ? $conclusion : $summary) . "<br>{$details}";
+
+        return new result($status, $summary, $details);
+    }
+}

admin/tool/task/classes/check/maxfaildelay.php

@@ -0,0 +1,107 @@
+<?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/>.
+
+/**
+ * Task fail delay check
+ *
+ * @package    tool_task
+ * @copyright  2020 Brendan Heywood (brendan@catalyst-au.net)
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace tool_task\check;
+
+defined('MOODLE_INTERNAL') || die();
+
+use core\check\check;
+use core\check\result;
+
+/**
+ * Task fail delay check
+ *
+ * @package    tool_task
+ * @copyright  2020 Brendan Heywood (brendan@catalyst-au.net)
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class maxfaildelay extends check {
+
+    /**
+     * Links to the task log report
+     *
+     * @return \action_link|null
+     */
+    public function get_action_link(): ?\action_link {
+        $url = new \moodle_url('/admin/tasklogs.php');
+        return new \action_link($url, get_string('tasklogs', 'tool_task'));
+    }
+
+    /**
+     * Return result
+     * @return result
+     */
+    public function get_result(): result {
+        global $CFG;
+
+        $status = result::OK;
+        $summary = get_string('tasknofailures', 'tool_task');
+        $details = '';
+        $failures = 0;
+        $maxdelay = 0;
+
+        $tasks = \core\task\manager::get_all_scheduled_tasks();
+        foreach ($tasks as $task) {
+            if ($task->get_disabled()) {
+                continue;
+            }
+            $faildelay = $task->get_fail_delay();
+            if ($faildelay > $maxdelay) {
+                $maxdelay = $faildelay;
+            }
+            if ($faildelay > 0) {
+                $failures++;
+                $details .= get_string('faildelay', 'tool_task') . ': ' . format_time($faildelay);
+                $details .= ' - ' . $task->get_name() . ' (' .get_class($task) . ")<br>";
+            }
+        }
+
+        $tasks = \core\task\manager::get_failed_adhoc_tasks();
+        foreach ($tasks as $task) {
+            $faildelay = $task->get_fail_delay();
+            if ($faildelay > $maxdelay) {
+                $maxdelay = $faildelay;
+            }
+            if ($faildelay > 0) {
+                $failures++;
+                $details .= get_string('faildelay', 'tool_task') . ': ' . format_time($faildelay);
+                $details .= ' - ' .get_class($task) . " ID = " . $task->get_id() ."<br>";
+            }
+        }
+
+        if ($failures > 0) {
+            // Intermittent failures are not yet a warning.
+            $status = result::INFO;
+            $summary = get_string('taskfailures', 'tool_task', $failures);
+        }
+        if ($maxdelay > 5 * MINSECS) {
+            $status = result::WARNING;
+        }
+        if ($maxdelay > 4 * HOURSECS) {
+            $status = result::ERROR;
+        }
+
+        return new result($status, $summary, $details);
+    }
+}

admin/tool/task/classes/edit_scheduled_task_form.php

@@ -0,0 +1,153 @@
+<?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/>.
+
+/**
+ * Form for scheduled tasks admin pages.
+ *
+ * @package    tool_task
+ * @copyright  2013 Damyon Wiese <damyon@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->libdir.'/formslib.php');
+
+/**
+ * Edit scheduled task form.
+ *
+ * @copyright  2013 Damyon Wiese <damyon@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class tool_task_edit_scheduled_task_form extends moodleform {
+    public function definition() {
+        global $PAGE;
+
+        $mform = $this->_form;
+        /** @var \core\task\scheduled_task $task */
+        $task = $this->_customdata;
+        $defaulttask = \core\task\manager::get_default_scheduled_task(get_class($task), false);
+        $renderer = $PAGE->get_renderer('tool_task');
+
+        $mform->addElement('static', 'lastrun', get_string('lastruntime', 'tool_task'),
+                $renderer->last_run_time($task));
+
+        $mform->addElement('static', 'nextrun', get_string('nextruntime', 'tool_task'),
+                $renderer->next_run_time($task));
+
+        $mform->addGroup([
+                $mform->createElement('text', 'minute'),
+                $mform->createElement('static', 'minutedefault', '',
+                        get_string('defaultx', 'tool_task', $defaulttask->get_minute())),
+            ], 'minutegroup', get_string('taskscheduleminute', 'tool_task'), null, false);
+        $mform->setType('minute', PARAM_RAW);
+        $mform->addHelpButton('minutegroup', 'taskscheduleminute', 'tool_task');
+
+        $mform->addGroup([
+                $mform->createElement('text', 'hour'),
+                $mform->createElement('static', 'hourdefault', '',
+                        get_string('defaultx', 'tool_task', $defaulttask->get_hour())),
+        ], 'hourgroup', get_string('taskschedulehour', 'tool_task'), null, false);
+        $mform->setType('hour', PARAM_RAW);
+        $mform->addHelpButton('hourgroup', 'taskschedulehour', 'tool_task');
+
+        $mform->addGroup([
+                $mform->createElement('text', 'day'),
+                $mform->createElement('static', 'daydefault', '',
+                        get_string('defaultx', 'tool_task', $defaulttask->get_day())),
+        ], 'daygroup', get_string('taskscheduleday', 'tool_task'), null, false);
+        $mform->setType('day', PARAM_RAW);
+        $mform->addHelpButton('daygroup', 'taskscheduleday', 'tool_task');
+
+        $mform->addGroup([
+                $mform->createElement('text', 'month'),
+                $mform->createElement('static', 'monthdefault', '',
+                        get_string('defaultx', 'tool_task', $defaulttask->get_month())),
+        ], 'monthgroup', get_string('taskschedulemonth', 'tool_task'), null, false);
+        $mform->setType('month', PARAM_RAW);
+        $mform->addHelpButton('monthgroup', 'taskschedulemonth', 'tool_task');
+
+        $mform->addGroup([
+                $mform->createElement('text', 'dayofweek'),
+                $mform->createElement('static', 'dayofweekdefault', '',
+                        get_string('defaultx', 'tool_task', $defaulttask->get_day_of_week())),
+        ], 'dayofweekgroup', get_string('taskscheduledayofweek', 'tool_task'), null, false);
+        $mform->setType('dayofweek', PARAM_RAW);
+        $mform->addHelpButton('dayofweekgroup', 'taskscheduledayofweek', 'tool_task');
+
+        $mform->addElement('advcheckbox', 'disabled', get_string('disabled', 'tool_task'));
+        $mform->addHelpButton('disabled', 'disabled', 'tool_task');
+
+        $mform->addElement('advcheckbox', 'resettodefaults', get_string('resettasktodefaults', 'tool_task'));
+        $mform->addHelpButton('resettodefaults', 'resettasktodefaults', 'tool_task');
+
+        $mform->disabledIf('minute', 'resettodefaults', 'checked');
+        $mform->disabledIf('hour', 'resettodefaults', 'checked');
+        $mform->disabledIf('day', 'resettodefaults', 'checked');
+        $mform->disabledIf('dayofweek', 'resettodefaults', 'checked');
+        $mform->disabledIf('month', 'resettodefaults', 'checked');
+        $mform->disabledIf('disabled', 'resettodefaults', 'checked');
+
+        $mform->addElement('hidden', 'task', get_class($task));
+        $mform->setType('task', PARAM_RAW);
+        $mform->addElement('hidden', 'action', 'edit');
+        $mform->setType('action', PARAM_ALPHANUMEXT);
+        $this->add_action_buttons(true, get_string('savechanges'));
+
+        // Do not use defaults for existing values, the set_data() is the correct way.
+        $this->set_data(\core\task\manager::record_from_scheduled_task($task));
+    }
+
+    /**
+     * Custom validations.
+     *
+     * @param array $data
+     * @param array $files
+     *
+     * @return array
+     */
+    public function validation($data, $files) {
+        $error = parent::validation($data, $files);
+        // Use a checker class.
+        $checker = new \tool_task\scheduled_checker_task();
+        $checker->set_minute($data['minute']);
+        $checker->set_hour($data['hour']);
+        $checker->set_month($data['month']);
+        $checker->set_day_of_week($data['dayofweek']);
+        $checker->set_day($data['day']);
+        $checker->set_disabled(false);
+        $checker->set_customised(false);
+
+        if (!$checker->is_valid($checker::FIELD_MINUTE)) {
+            $error['minutegroup'] = get_string('invaliddata', 'core_error');
+        }
+        if (!$checker->is_valid($checker::FIELD_HOUR)) {
+            $error['hourgroup'] = get_string('invaliddata', 'core_error');
+        }
+        if (!$checker->is_valid($checker::FIELD_DAY)) {
+            $error['daygroup'] = get_string('invaliddata', 'core_error');
+        }
+        if (!$checker->is_valid($checker::FIELD_MONTH)) {
+            $error['monthgroup'] = get_string('invaliddata', 'core_error');
+        }
+        if (!$checker->is_valid($checker::FIELD_DAYOFWEEK)) {
+            $error['dayofweekgroup'] = get_string('invaliddata', 'core_error');
+        }
+
+        return $error;
+    }
+}
+

admin/tool/task/classes/privacy/provider.php

@@ -0,0 +1,46 @@
+<?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/>.
+
+/**
+ * Privacy Subsystem implementation for tool_task.
+ *
+ * @package    tool_task
+ * @copyright  2018 Zig Tan <zig@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace tool_task\privacy;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Privacy Subsystem for tool_task implementing null_provider.
+ *
+ * @copyright  2018 Zig Tan <zig@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class provider implements \core_privacy\local\metadata\null_provider {
+
+    /**
+     * Get the language string identifier with the component's language
+     * file to explain why this plugin stores no data.
+     *
+     * @return  string
+     */
+    public static function get_reason(): string {
+        return 'privacy:metadata';
+    }
+}

admin/tool/task/classes/running_tasks_table.php

@@ -0,0 +1,156 @@
+<?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/>.
+
+/**
+ * Running tasks table.
+ *
+ * @package    tool_task
+ * @copyright  2019 The Open University
+ * @copyright  2020 Mikhail Golenkov <golenkovm@gmail.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace tool_task;
+
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->libdir . '/tablelib.php');
+use core\task\manager;
+
+/**
+ * Table to display list of running task.
+ *
+ * @copyright  2019 The Open University
+ * @copyright  2020 Mikhail Golenkov <golenkovm@gmail.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class running_tasks_table extends \table_sql {
+
+    /**
+     * Constructor for the running tasks table.
+     */
+    public function __construct() {
+        parent::__construct('runningtasks');
+
+        $columnheaders = [
+            'classname'    => get_string('classname', 'tool_task'),
+            'type'         => get_string('tasktype', 'admin'),
+            'time'         => get_string('taskage', 'tool_task'),
+            'timestarted'  => get_string('started', 'tool_task'),
+            'hostname'     => get_string('hostname', 'tool_task'),
+            'pid'          => get_string('pid', 'tool_task'),
+        ];
+        $this->define_columns(array_keys($columnheaders));
+        $this->define_headers(array_values($columnheaders));
+
+        // The name column is a header.
+        $this->define_header_column('classname');
+
+        // This table is not collapsible.
+        $this->collapsible(false);
+
+        // Allow pagination.
+        $this->pageable(true);
+    }
+
+    /**
+     * Query the db. Store results in the table object for use by build_table.
+     *
+     * @param int $pagesize size of page for paginated displayed table.
+     * @param bool $useinitialsbar do you want to use the initials bar. Bar
+     * will only be used if there is a fullname column defined for the table.
+     * @throws \dml_exception
+     */
+    public function query_db($pagesize, $useinitialsbar = true) {
+        $sort = $this->get_sql_sort();
+        $this->rawdata = \core\task\manager::get_running_tasks($sort);
+    }
+
+    /**
+     * Format the classname cell.
+     *
+     * @param   \stdClass $row
+     * @return  string
+     */
+    public function col_classname($row): string {
+        $output = $row->classname;
+        if ($row->type == 'scheduled') {
+            if (class_exists($row->classname)) {
+                $task = new $row->classname;
+                if ($task instanceof \core\task\scheduled_task) {
+                    $output .= \html_writer::tag('div', $task->get_name(), ['class' => 'task-class']);
+                }
+            }
+        } else if ($row->type == 'adhoc') {
+            $output .= \html_writer::tag('div',
+                get_string('adhoctaskid', 'tool_task', $row->id), ['class' => 'task-class']);
+        }
+        return $output;
+    }
+
+    /**
+     * Format the type cell.
+     *
+     * @param   \stdClass $row
+     * @return  string
+     * @throws  \coding_exception
+     */
+    public function col_type($row): string {
+        if ($row->type == 'scheduled') {
+            $output = \html_writer::span(get_string('scheduled', 'tool_task'), 'badge bg-primary text-white');
+        } else if ($row->type == 'adhoc') {
+            $output = \html_writer::span(get_string('adhoc', 'tool_task'), 'badge bg-dark text-white');
+        } else {
+            // This shouldn't ever happen.
+            $output = '';
+        }
+        return $output;
+    }
+
+    /**
+     * Format the time cell.
+     *
+     * @param   \stdClass $row
+     * @return  string
+     */
+    public function col_time($row): string {
+        global $OUTPUT;
+
+        $taskmethod = "{$row->type}_task_from_record";
+        $task = manager::$taskmethod($row);
+
+        $result = $task->get_runtime_result();
+        $extra = '';
+        if ($result->get_status() != $result::OK) {
+            $extra = '<br>';
+            $extra .= $OUTPUT->check_result($result);
+            $extra .= ' ';
+            $extra .= $result->get_details();
+        }
+
+        return format_time($row->time) . $extra;
+    }
+
+    /**
+     * Format the timestarted cell.
+     *
+     * @param   \stdClass $row
+     * @return  string
+     */
+    public function col_timestarted($row): string {
+        return userdate($row->timestarted);
+    }
+}

admin/tool/task/classes/scheduled_checker_task.php

@@ -0,0 +1,40 @@
+<?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 tool_task;
+
+/**
+ * Checker class. Fake scheduled task used only to check that crontab settings are valid.
+ *
+ * @package    tool_task
+ * @copyright  2021 Jordi Pujol-Ahulló <jpahullo@gmail.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class scheduled_checker_task extends \core\task\scheduled_task {
+
+    /**
+     * Gets the checker task name.
+     */
+    public function get_name() {
+        return "Checker task";
+    }
+
+    /**
+     * Does nothing.
+     */
+    public function execute() {
+    }
+}