[#151] Add new sitecheck page

classes/check/tasklatencycheck.php

@@ -77,9 +77,9 @@ public function get_result(): result {
             $valid = $task !== false;
 
             // Cast to int, will force non-int strings to 0, so we only need to care about negative time as invalid.
-            $valid &= ((int) $runtime >= 0);
-            $valid &= ((int) $startdelay >= 0);
-            $valid &= ((int) $completiondelay >= 0);
+            $valid &= ((int) $runtime >= 0); // 30
+            $valid &= ((int) $startdelay >= 0); // 6
+            $valid &= ((int) $completiondelay >= 0); // 45
 
             if (!$valid) {
                 return new result(result::ERROR, get_string('taskconfigbad', 'tool_heartbeat', $taskclass));

classes/checker.php

@@ -0,0 +1,194 @@
+<?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_heartbeat;
+
+use core\check\check;
+use core\check\result;
+use Throwable;
+
+/**
+ * Check API checker class
+ *
+ * Processes check API results and returns them in a nice format for nagios output.
+ *
+ * @package   tool_heartbeat
+ * @author    Matthew Hilton <[email protected]>
+ * @copyright 2023, Catalyst IT
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class checker {
+    /** @var array Nagios level prefixes **/
+    public const NAGIOS_PREFIXES = [
+        0 => "OK",
+        1 => "WARNING",
+        2 => "CRITICAL",
+        3 => "UNKNOWN",
+    ];
+
+    /**
+     * Returns an array of check API messages.
+     * If exceptions are thrown, they are caught and returned as result messages as well.
+     *
+     * @return array array of resultmessage objects
+     */
+    public static function get_check_messages(): array {
+        // First try to get the checks, if this fails return a critical message (code is very broken).
+        $checks = [];
+
+        try {
+            $checks = \core\check\manager::get_checks('status');
+        } catch (Throwable $e) {
+            return [self::exception_to_message("Error getting checks: ", $e)];
+        }
+
+        // Execute each check and store their messages.
+        $messages = [];
+
+        foreach ($checks as $check) {
+            try {
+                $messages[] = self::process_check_and_get_result($check);
+            } catch (Throwable $e) {
+                $messages[] = self::exception_to_message("Error processing check " . $check->get_ref() . ": ", $e);
+            }
+        }
+
+        return $messages;
+    }
+
+    /**
+     * Turns the given exception into a warning resultmessage.
+     * @param string $prefix
+     * @param Throwable $e
+     * @return resultmessage
+     */
+    private static function exception_to_message(string $prefix, Throwable $e): resultmessage {
+        $res = new resultmessage();
+        $res->level = resultmessage::LEVEL_WARN;
+        $res->title = $prefix . $e->getMessage();
+        $res->message = (string) $e;
+        return $res;
+    }
+
+    /**
+     * Processes the check and maps its result and status to a resultmessage.
+     * @param check $check
+     * @return resultmessage
+     */
+    private static function process_check_and_get_result(check $check): resultmessage {
+        $res = new resultmessage();
+
+        $checkresult = $check->get_result();
+
+        // Map check result to nagios level.
+        $map = [
+            result::WARNING => resultmessage::LEVEL_WARN,
+            result::CRITICAL => resultmessage::LEVEL_CRITICAL,
+            result::OK => resultmessage::LEVEL_OK,
+            result::NA => resultmessage::LEVEL_OK,
+            result::WARNING => resultmessage::LEVEL_WARN,
+            result::UNKNOWN => resultmessage::LEVEL_UNKNOWN,
+            result::ERROR => resultmessage::LEVEL_CRITICAL,
+        ];
+
+        // Get the level, or default to unknown.
+        $status = $checkresult->get_status();
+        $res->level = isset($map[$status]) ? $map[$status] : resultmessage::LEVEL_UNKNOWN;
+
+        $res->title = $check->get_name();
+
+        // Add the first line of summary to the title.
+        $summarylines = explode("\n", $checkresult->get_summary());
+        $res->title .= ": " . $summarylines[0] ?: '';
+
+        $res->message = $checkresult->get_summary();
+
+        return $res;
+    }
+
+    /**
+     * From an array of resultmessage, determines the highest nagios level.
+     * Note, it considers UNKNOWN to be less than CRITICAL or WARNING.
+     *
+     * @param array $messages array of resultmessage objects
+     * @return int the calculated nagios level
+     */
+    public static function determine_nagios_level(array $messages): int {
+        // Find the highest level.
+        $levels = array_column($messages, "level");
+
+        // Add a default "OK" in case no messages were returned.
+        $levels[] = resultmessage::LEVEL_OK;
+
+        $hasunknown = !empty(array_filter($levels, function($l) {
+            return $l == resultmessage::LEVEL_UNKNOWN;
+        }));
+
+        // Remove unknowns.
+        $levels = array_filter($levels, function($l) {
+            return $l != resultmessage::LEVEL_UNKNOWN;
+        });
+
+        $highest = max($levels);
+
+        // If highest was OK but it had an unknown, return unknown.
+        // This stops UNKNOWN from masking WARNING or CRITICAL.
+        if ($highest == resultmessage::LEVEL_OK && $hasunknown) {
+            return resultmessage::LEVEL_UNKNOWN;
+        }
+
+        // Else return OK.
+        return $highest;
+    }
+
+    /**
+     * Creates a summary from the given messages.
+     * If there are no messages or only OK, OK is returned.
+     * If there is a single message, its details are returned.
+     * If there are multiple messages, the levels are aggregated and turned into a summary.
+     *
+     * @param array $messages array of resultmessage objects
+     * @return string
+     */
+    public static function create_summary(array $messages): string {
+        // Filter out any OK messages.
+        $messages = array_filter($messages, function($m) {
+            return $m->level != resultmessage::LEVEL_OK;
+        });
+
+        // If no messages, return OK.
+        if (count($messages) == 0) {
+            return "OK";
+        }
+
+        // If only one message, use it as the top level.
+        if (count($messages) == 1) {
+            return $messages[0]->title;
+        }
+
+        // Otherwise count how many of each level.
+        $counts = array_count_values(array_column($messages, 'level'));
+
+        $countswithprefixes = [];
+        foreach ($counts as $level => $occurrences) {
+                $prefix = self::NAGIOS_PREFIXES[$level];
+             $countswithprefixes[] = "{$occurrences} {$prefix}";
+        }
+
+        return "Multiple problems detected: " . implode(", ", $countswithprefixes);
+    }
+}
+

classes/resultmessage.php

@@ -0,0 +1,49 @@
+<?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_heartbeat;
+
+/**
+ * A data-only class for holding a message about a result from a check API class.
+ *
+ * @package   tool_heartbeat
+ * @author    Matthew Hilton <[email protected]>
+ * @copyright 2023, Catalyst IT
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class resultmessage {
+    /** @var int OK level **/
+    public const LEVEL_OK = 0;
+
+    /** @var int WARN level **/
+    public const LEVEL_WARN = 1;
+
+    /** @var int CRITICAL level **/
+    public const LEVEL_CRITICAL = 2;
+
+    /** @var int UNKNOWN level **/
+    public const LEVEL_UNKNOWN = 3;
+
+    /** @var int $level The level of this message **/
+    public $level = self::LEVEL_UNKNOWN;
+
+    /** @var string $title Title of the message **/
+    public $title = '';
+
+    /** @var string $message Details of this message **/
+    public $message = '';
+}
+

sitecheck.php

@@ -0,0 +1,86 @@
+<?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/>.
+
+/**
+ * Check API Health Check
+ *
+ * @package    tool_heartbeat
+ * @copyright  2023 Matthew Hilton <[email protected]>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ *
+ * This can be run either as a web api, or on the CLI. When run on the
+ * CLI it conforms to the Nagios plugin standard.
+ *
+ * See also:
+ *  - http://nagios.sourceforge.net/docs/3_0/pluginapi.html
+ *  - https://nagios-plugins.org/doc/guidelines.html#PLUGOUTPUT
+ *
+ */
+
+use tool_heartbeat\checker;
+use tool_heartbeat\resultmessage;
+
+// @codingStandardsIgnoreStart
+define('NO_UPGRADE_CHECK', true);
+
+// Start output buffering. This stops for e.g. debugging messages from breaking the output.
+// When a nagios.php send_* function is called, they will collect the buffer
+// and warn if it is not empty (but do it nicely).
+ob_start();
+
+$dirroot = __DIR__ . '/../../../';
+require($dirroot.'config.php');
+require_once(__DIR__.'/nagios.php');
+
+global $PAGE;
+
+if (isset($CFG->mnet_dispatcher_mode) and $CFG->mnet_dispatcher_mode !== 'off') {
+    // This is a core bug workaround, see MDL-77247 for more details.
+    require_once($CFG->dirroot.'/mnet/lib.php');
+}
+
+$messages = checker::get_check_messages();
+
+// Filter out any OK ones, we only care about the others.
+$messages = array_filter($messages, function($m) {
+    return $m->level != resultmessage::LEVEL_OK;
+});
+
+// Construct the output message.
+$PAGE->set_context(\context_system::instance());
+
+// Indent the messages.
+$msg = array_map(function($message) {
+    global $OUTPUT;
+
+    // Indent messages.
+    $spacer = "&nbsp;&nbsp;";
+    $indentedmessage = $spacer . str_replace("\n", "\n" . $spacer, $message->message);
+
+    return $OUTPUT->render_from_template('tool_heartbeat/resultmessage', [
+        'prefix' => checker::NAGIOS_PREFIXES[$message->level],
+        'title' => $message->title,
+        'message' => nl2br($indentedmessage),
+    ]);
+}, $messages);
+
+$summary = checker::create_summary($messages);
+$msg = $summary . "<br />" . implode("", $msg);
+
+$level = checker::determine_nagios_level($messages);
+
+send($level, $msg);
+

templates/resultmessage.mustache

@@ -0,0 +1,40 @@
+
+{{!
+    This file is part of Moodle - https://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 />.
+    }}
+    {{!
+        @template tool_heartbeat/resultmessage
+        
+        Template by JS to render output of result report getting (loading, url, error)
+        
+        Classes required for JS:
+        * none
+        
+        Context variables required for this template:
+        * none
+        
+        Example context (json):
+        {  
+            "prefix": "CRTIICAL",
+            "title": "Something broke",
+            "message": "Some more details"
+        }
+    }}
+
+* {{prefix}} {{title}}<br/>
+  {{{message}}}<br/>
+<br />