MDL-57791 analytics: Changes after review

- Split model::predict in parts
- JS promises updated according to eslint-plugin-promise
- New API methods replacing direct DB queries
- Reduce insights nav link display cost
- Increase time limit as well as memory for big processes
- Move prediction action event to core
- Dataset write locking and others
- Refine last time range end time
- Removed dodgy splitting method id to int
- Replace admin_setting_predictor output_html overwrite for write_setting overwrite
- New APIs for access control
- Discard invalid samples also during prediction

lib/classes/event/prediction_action_started.php

@@ -0,0 +1,101 @@
+<?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/>.
+
+/**
+ * Prediction action clicked event.
+ *
+ * @property-read array $other {
+ *      Extra information about event.
+ *
+ *      - string actionname: The action name
+ * }
+ *
+ * @package    core_analytics
+ * @copyright  2017 David Monllao {@link http://www.davidmonllao.com}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core\event;
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Event triggered after a user clicked on one of the prediction suggested actions.
+ *
+ * @package    core_analytics
+ * @copyright  2017 David Monllao {@link http://www.davidmonllao.com}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class prediction_action_started extends \core\event\base {
+
+    /**
+     * Set basic properties for the event.
+     */
+    protected function init() {
+        $this->data['objecttable'] = 'analytics_predictions';
+
+        // Marked as create because even if the action is something like viewing a course
+        // they are starting an action from a prediction, which is kind-of creating an outcome.
+        $this->data['crud'] = 'c';
+        // It will depend on the action, we have no idea really but we need to chose one and
+        // the user is learning from the prediction so LEVEL_PARTICIPATING seems more appropriate
+        // than LEVEL_OTHER.
+        $this->data['edulevel'] = self::LEVEL_PARTICIPATING;
+    }
+
+    /**
+     * Returns localised general event name.
+     *
+     * @return string
+     */
+    public static function get_name() {
+        return get_string('eventpredictionactionstarted', 'analytics');
+    }
+
+    /**
+     * Returns non-localised event description with id's for admin use only.
+     *
+     * @return string
+     */
+    public function get_description() {
+        return "The user with id '$this->userid' has started '{$this->other['actionname']}' action for the prediction with id '".$this->objectid."'.";
+    }
+
+    /**
+     * Returns relevant URL.
+     * @return \moodle_url
+     */
+    public function get_url() {
+        return new \moodle_url('/report/insights/prediction.php', array('id' => $this->objectid));
+    }
+
+    /**
+     * Custom validations.
+     *
+     * @throws \coding_exception
+     * @return void
+     */
+    protected function validate_data() {
+        parent::validate_data();
+
+        if (!isset($this->objectid)) {
+            throw new \coding_exception('The \'objectid\' must be set.');
+        }
+    }
+
+    public static function get_objectid_mapping() {
+        return array('db' => 'analytics_predictions');
+    }
+}

lib/db/caches.php

@@ -312,8 +312,8 @@ $definitions = array(
         ),
     ),
 
-    // Caches analytic models that have already predicted stuff.
-    'modelswithpredictions' => array(
+    // Caches contexts with insights.
+    'contextwithinsights' => array(
         'mode' => cache_store::MODE_APPLICATION,
         'simplekeys' => true,
         'simpledata' => true,

lib/mlbackend/php/classes/processor.php

@@ -176,7 +176,7 @@ class processor implements \core_analytics\predictor {
      *
      * During evaluation we need to shuffle the evaluation dataset samples to detect deviated results,
      * if the dataset is massive we can not load everything into memory. We know that 2GB is the
-     * minimum memory limit we should have (\core_analytics\model::increase_memory), if we substract the memory
+     * minimum memory limit we should have (\core_analytics\model::heavy_duty_mode), if we substract the memory
      * that we already consumed and the memory that Phpml algorithms will need we should still have at
      * least 500MB of memory, which should be enough to evaluate a model. In any case this is a robust
      * solution that will work for all sites but it should minimize memory limit problems. Site admins

lib/mlbackend/python/lang/en/mlbackend_python.php

@@ -1,5 +1,5 @@
 <?php
 
 $string['packageinstalledshouldbe'] = '"moodleinspire" python package should be updated. The required version is "{$a->required}" and the installed version is "{$a->installed}"';
-$string['pluginname'] = 'Python predictor';
+$string['pluginname'] = 'Python machine learning backend';
 $string['pythonpackagenotinstalled'] = 'moodleinspire python package is not installed or there is a problem with it. Please execute "{$a}" from command line interface for more info';