Also update preferred event when manually launching RAVEN alert; fixes #550

This MR fixes #550 (closed) by ensuring the events we indicate we want to send out is the one included in the alert by changing the preferred external event to the given external event.

gwcelery/views.py

@@ -327,14 +327,36 @@ def download_upload_external_skymap():
     return redirect(url_for('index'))
 
 
+@celery_app.task(queue='exttrig',
+                 shared=False)
+def _update_preferred_external_event(ext_event, superevent_id):
+    """Update preferred external event to given external event."""
+    if ext_event['search'] in {'GRB', 'SubGRB', 'SubGRBTargeted'}:
+        coinc_far_dict = gracedb.download(
+            'coincidence_far.json', ext_event['graceid'])
+        time_coinc_far = coinc_far_dict['temporal_coinc_far']
+        space_coinc_far = coinc_far_dict['spatiotemporal_coinc_far']
+    else:
+        time_coinc_far = None
+        space_coinc_far = None
+    gracedb.update_superevent(superevent_id, em_type=ext_event['graceid'],
+                              time_coinc_far=time_coinc_far,
+                              space_coinc_far=space_coinc_far)
+
+
 @app.route('/apply_raven_labels', methods=['POST'])
 def apply_raven_labels():
-    """Applying RAVEN alert label for the missed coincident alerts."""
+    """Applying RAVEN alert label and update the preferred external event
+    to the given coincidence."""
     keys = ('superevent_id', 'ext_id', 'event_id')
     superevent_id, ext_id, event_id, *_ = tuple(request.form.get(key)
                                                 for key in keys)
     if superevent_id and ext_id and event_id:
         (
+                gracedb.get_event.si(ext_id)
+                |
+                _update_preferred_external_event.s(superevent_id)
+                |
                 gracedb.create_label.si('RAVEN_ALERT', superevent_id)
                 |
                 gracedb.create_label.si('RAVEN_ALERT', ext_id)