feat: Adds resendfailedbatches setting to allow failed statements t…

…o be retried. (#367 - Thanks @garemoko)

classes/log/store.php

@@ -115,6 +115,7 @@ public function process_events(array $events) {
                 'lrs_username' => $this->get_config('username', ''),
                 'lrs_password' => $this->get_config('password', ''),
                 'lrs_max_batch_size' => $this->get_max_batch_size(),
+                'lrs_resend_failed_batches' => $this->get_config('resendfailedbatches', false),
             ],
         ];
         $loadedevents = \src\handler($handlerconfig, $events);

classes/task/emit_task.php

@@ -41,6 +41,16 @@ private function get_failed_events($events) {
         return $failedevents;
     }
 
+    private function get_successful_events($events) {
+        $loadedevents = array_filter($events, function ($loadedevent) {
+            return $loadedevent['loaded'] === true;
+        });
+        $successfulevents = array_map(function ($loadedevent) {
+            return $loadedevent['event'];
+        }, $loadedevents);
+        return $successfulevents;
+    }
+
     private function get_event_ids($loadedevents) {
         return array_map(function ($loadedevent) {
             return $loadedevent['event']->id;
@@ -61,13 +71,17 @@ private function delete_processed_events($events) {
         global $DB;
         $eventids = $this->get_event_ids($events);
         $DB->delete_records_list('logstore_xapi_log', 'id', $eventids);
-        mtrace("Events (".implode(', ', $eventids).") have been successfully sent to LRS.");
     }
 
     private function store_failed_events($events) {
         global $DB;
         $failedevents = $this->get_failed_events($events);
         $DB->insert_records('logstore_xapi_failed_log', $failedevents);
+        mtrace(count($failedevents) . " event(s) have failed to send to the LRS.");
+    }
+
+    private function record_successful_events($events) {
+        mtrace(count($this->get_successful_events($events)) . " event(s) have been successfully sent to the LRS.");
     }
 
     /**
@@ -81,6 +95,7 @@ public function execute() {
         $extractedevents = $this->extract_events($store->get_max_batch_size());
         $loadedevents = $store->process_events($extractedevents);
         $this->store_failed_events($loadedevents);
+        $this->record_successful_events($loadedevents);
         $this->delete_processed_events($loadedevents);
     }
 }

lang/en/logstore_xapi.php

@@ -49,3 +49,5 @@
 $string['sendidnumber_desc'] = 'Statements will include the ID number (admin defined) for courses and activities in the object extensions';
 $string['send_response_choices'] = 'Send response choices';
 $string['send_response_choices_desc'] = 'Statements for multiple choice question answers will be sent to the LRS with the correct response and potential choices';
+$string['resendfailedbatches'] = 'Resend failed batches';
+$string['resendfailedbatches_desc'] = 'When processing events in batches, try re-sending events in smaller batches if a batch fails. If not selected, the whole batch will not be sent in the event of a failed event.';

settings.php

@@ -39,6 +39,10 @@
         get_string('maxbatchsize', 'logstore_xapi'),
         get_string('maxbatchsize_desc', 'logstore_xapi'), 30, PARAM_INT));
 
+    $settings->add(new admin_setting_configcheckbox('logstore_xapi/resendfailedbatches',
+        get_string('resendfailedbatches', 'logstore_xapi'),
+        get_string('resendfailedbatches_desc', 'logstore_xapi'), 0));
+
     $settings->add(new admin_setting_configcheckbox('logstore_xapi/mbox',
         get_string('mbox', 'logstore_xapi'),
         get_string('mbox_desc', 'logstore_xapi'), 0));

src/loader/lrs.php

@@ -49,7 +49,7 @@ function load(array $config, array $events) {
         curl_close($request);
 
         if ($responsecode !== 200) {
-            throw new \Exception($responsetext);
+            throw new \Exception($responsetext, $responsecode);
         }
     };
     return utils\load_in_batches($config, $events, $sendhttpstatements);

src/loader/moodle_curl_lrs.php

@@ -50,7 +50,7 @@ function load(array $config, array $events) {
         $responsecode = $request->info['http_code'];
 
         if ($responsecode !== 200) {
-            throw new \Exception($responsetext);
+            throw new \Exception($responsetext, $responsecode);
         }
     };
     return utils\load_in_batches($config, $events, $sendhttpstatements);

src/loader/utils/load_batch.php

@@ -28,10 +28,24 @@ function load_batch(array $config, array $transformedevents, callable $loader) {
         $loadedevents = construct_loaded_events($transformedevents, true);
         return $loadedevents;
     } catch (\Exception $e) {
+        $batchsize = count($transformedevents);
         $logerror = $config['log_error'];
-        $logerror("Failed load for event id #" . $eventobj->id . ": " .  $e->getMessage());
+        $logerror("Failed load batch (" . $batchsize . " events)" .  $e->getMessage());
         $logerror($e->getTraceAsString());
-        $loadedevents = construct_loaded_events($transformedevents, false);
+
+        // In the event of a 400 error, recursively retry sending statements in increasingly
+        // smaller batches so that only the actual bad data fails.
+        if ($batchsize === 1 || $e->getCode() !== 400 || $config['lrs_resend_failed_batches'] !== '1') {
+            $loadedevents = construct_loaded_events($transformedevents, false);
+        } else {
+            $newconfig = $config;
+            $newconfig['lrs_max_batch_size'] = round($batchsize / 2);
+            $batches = get_event_batches($newconfig, $transformedevents);
+            $loadedevents = array_reduce($batches, function ($result, $batch) use ($newconfig, $loader) {
+                $loadedbatchevents = load_batch($newconfig, $batch, $loader);
+                return array_merge($result, $loadedbatchevents);
+            }, []);
+        }
         return $loadedevents;
     }
 }