MDL-35716 report_performance: Performance report for moodle site

This will report config setting which can affect moodle performance.
Few of them are added in this patch:
1. Theme designer mode
2. Cache Javascript
3. Debug message set to developer
4. Backup - Active
5. Stats enabled.

report/performance/db/access.php

@@ -0,0 +1,36 @@
+<?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/>.
+
+/**
+ * Capabilities
+ *
+ * @package   report_performance
+ * @copyright 2013 Rajesh Taneja
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+$capabilities = array(
+    'report/performance:view' => array(
+        'riskbitmask' => RISK_CONFIG,
+        'captype' => 'read',
+        'contextlevel' => CONTEXT_SYSTEM,
+        'archetypes' => array(
+            'manager' => CAP_ALLOW
+        ),
+    )
+);

report/performance/index.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/>.
+
+/**
+ * Performance overview report
+ *
+ * @package   report_performance
+ * @copyright 2013 Rajesh Taneja
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+define('NO_OUTPUT_BUFFERING', true);
+
+require('../../config.php');
+require_once($CFG->dirroot.'/report/performance/locallib.php');
+require_once($CFG->libdir.'/adminlib.php');
+
+require_login();
+
+// Show detailed info about one issue only.
+$issue = optional_param('issue', '', PARAM_ALPHANUMEXT);
+
+$reportperformance = new report_performance();
+$issues = $reportperformance->get_issue_list();
+
+// Test if issue valid string.
+if (array_search($issue, $issues, true) === false) {
+    $issue = '';
+}
+
+// Print the header.
+admin_externalpage_setup('reportperformance', '', null, '', array('pagelayout'=>'report'));
+echo $OUTPUT->header();
+
+echo $OUTPUT->heading(get_string('pluginname', 'report_performance'));
+
+$strissue = get_string('issue', 'report_performance');
+$strvalue = get_string('value', 'report_performance');
+$strcomments = get_string('comments', 'report_performance');
+$stredit = get_string('edit');
+
+$table = new html_table();
+$table->head  = array($strissue, $strvalue, $strcomments, $stredit);
+$table->colclasses = array('mdl-left issue', 'mdl-left value', 'mdl-left comments', 'mdl-left config');
+$table->attributes = array('class' => 'admintable performancereport generaltable');
+$table->id = 'performanceissuereporttable';
+$table->data  = array();
+
+// Print details of one issue only.
+if ($issue and ($issueresult = $reportperformance::$issue())) {
+    $reportperformance->add_issue_to_table($table, $issueresult, true);
+
+    $PAGE->set_docs_path('report/security/' . $issue);
+
+    echo html_writer::table($table);
+
+    echo $OUTPUT->box($issueresult->details, 'generalbox boxwidthnormal boxaligncenter');
+
+    echo $OUTPUT->continue_button(new moodle_url('/report/performance/index.php'));
+} else {
+    // Add Performance report description on main list page.
+    $morehelplink = $OUTPUT->doc_link('report/performance', get_string('morehelp', 'report_performance'));
+    echo $OUTPUT->box(get_string('performancereportdesc', 'report_performance', $morehelplink), 'generalbox mdl-align');
+
+    foreach ($issues as $issue) {
+        $issueresult = $reportperformance::$issue();
+        if (!$issueresult) {
+            // Ignore this test.
+            continue;
+        }
+        $reportperformance->add_issue_to_table($table, $issueresult, false);
+    }
+    echo html_writer::table($table);
+}
+
+echo $OUTPUT->footer();

report/performance/lang/en/report_performance.php

@@ -0,0 +1,50 @@
+<?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/>.
+
+/**
+ * Lang strings
+ *
+ * @package   report_performance
+ * @copyright 2013 Rajesh Taneja
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+$string['check_backup'] = 'Automated backup';
+$string['check_backup_comment_disable'] = 'Performance may be affected during the backup process. If enabled, backups should be scheduled for off-peak times.';
+$string['check_backup_comment_enable'] = 'Performance may be affected during the backup process. Backups should be scheduled for off-peak times.';
+$string['check_backup_details'] = 'Enabling automated backup will automatically create archives of all the courses on the server at the time you specified.<p>During this process, it will consume more server resources and may affect performance.</p>';
+$string['check_cachejs_comment_disable'] = 'If enabled, page loading performance is improved.';
+$string['check_cachejs_comment_enable'] = 'If disabled, page might load slow.';
+$string['check_cachejs_details'] = 'Javascript caching and compression greatly improves page loading performance. It is strongly recommended for production sites.';
+$string['check_debugmsg_comment_nodeveloper'] = 'If set to DEVELOPER, performance may be affected slightly.';
+$string['check_debugmsg_comment_developer'] = 'If set other then DEVELOPER, performance may be improved slightly.';
+$string['check_debugmsg_details'] = 'There is rarely any advantage in going to Developer level, unless you are a developer, in which case it is strongly recommended.<p>Once you have got the error message, and copied and pasted it somewhere. HIGHLY RECOMMENDED to turn Debug back to NONE. Debug messages can give clues to a hacker as to the setup of your site and may affect performance.</p>';
+$string['check_enablestats_comment_disable'] = 'Performance may be affected by statistics processing. If enabled, statistics settings should be set with caution.';
+$string['check_enablestats_comment_enable'] = 'Performance may be affected by statistics processing. Statistics settings should be set with caution.';
+$string['check_enablestats_details'] = 'Enabling this will process the logs in cronjob and gather some statistics. Depending on the amount of traffic on your site, this can take awhile.<p>During this process, it will consume more server resources and may affect performance.</p>';
+$string['check_themedesignermode_comment_enable'] = 'If disabled, images and style sheets are cached, resulting in significant performance improvements.';
+$string['check_themedesignermode_comment_disable'] = 'If enabled, images and style sheets will not be cached, resulting in significant performance degradation.';
+$string['check_themedesignermode_details'] = 'This is often the cause of slow Moodle sites. <p>On average it might take at least twice the amount of CPU to run a Moodle site with theme designer mode enabled.</p>';
+$string['comments'] = 'Comments';
+$string['edit'] = 'Edit';
+$string['enabled'] = 'Enabled';
+$string['disabled'] = 'Disabled';
+$string['issue'] = 'Issue';
+$string['morehelp'] = 'more help';
+$string['performance:view'] = 'View performance report';
+$string['performancereportdesc'] = 'This report lists issues which may affect performance of the site {$a}';
+$string['pluginname'] = 'Performance overview';
+$string['value'] = 'Value';