Reenable combined sky maps now using multi-ordering

This MR both enables the following functionality:

• Create multi-order combined sky maps using the GRB localization to re-weight the GW localization
• Change logic in external_triggers.handle_grb_igwn_alert to create combined sky maps as soon as available
• Include combined sky maps in both GCN notices, GCN circulars, and AVRO alert packets.

gwcelery/tasks/alerts.py

@@ -59,7 +59,8 @@ def _create_base_alert_dict(classification, superevent, alert_type,
 
 
 @gracedb.task(shared=False)
-def _add_external_coinc_to_alert(alert_dict, superevent):
+def _add_external_coinc_to_alert(alert_dict, superevent,
+                                 combined_skymap_filename):
     external_event = gracedb.get_event(superevent['em_type'])
 
     alert_dict['external_coinc'] = {
@@ -74,6 +75,10 @@ def _add_external_coinc_to_alert(alert_dict, superevent):
         'time_sky_position_coincidence_far': superevent['space_coinc_far']
     }
 
+    if combined_skymap_filename:
+        alert_dict['external_coinc']['combined_skymap_filename'] = \
+            combined_skymap_filename
+
     return alert_dict
 
 
@@ -131,7 +136,7 @@ def _send(self, alert_dict, skymap, brokerhost):
 
 @app.task(bind=True, ignore_result=True, queue='kafka', shared=False)
 def send(self, skymap_and_classification, superevent, alert_type,
-         raven_coinc=False):
+         raven_coinc=False, combined_skymap_filename=None):
     """Send an public alert to all currently connected kafka brokers.
 
     Parameters
@@ -168,7 +173,8 @@ def send(self, skymap_and_classification, superevent, alert_type,
 
     if raven_coinc and alert_type != 'retraction':
         canvas = (
-            _add_external_coinc_to_alert.s(alert_dict, superevent)
+            _add_external_coinc_to_alert.s(alert_dict, superevent,
+                                           combined_skymap_filename)
             |
             group(
                 (
@@ -199,7 +205,8 @@ def _create_skymap_classification_tuple(skymap, classification):
 
 @app.task(shared=False, ignore_result=True)
 def download_skymap_and_send_alert(classification, superevent, alert_type,
-                                   skymap_filename=None, raven_coinc=False):
+                                   skymap_filename=None, raven_coinc=False,
+                                   combined_skymap_filename=False):
     """Wrapper for send function when caller has not already downloaded the
     skymap.