added error handling to external queries

CHANGELOG.md

@@ -48,6 +48,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 #### Fixed
 
+- Added an error handler for the external source queries (e.g. SIMBAD) [#616](https://github.com/askap-vast/vast-pipeline/pull/616).
 - Stopped JS9 from changing the page titles [#597](https://github.com/askap-vast/vast-pipeline/pull/597).
 - Fixed regression issues with pandas 1.4 [#586](https://github.com/askap-vast/vast-pipeline/pull/586).
 - Fixed config being copied before run was confirmed to actually go ahead for existing runs [#595](https://github.com/askap-vast/vast-pipeline/pull/595).
@@ -69,6 +70,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 #### List of PRs
 
+- [#616](https://github.com/askap-vast/vast-pipeline/pull/616): fix: added error handling to external queries.
 - [#614](https://github.com/askap-vast/vast-pipeline/pull/614): feat: Refactored add to favourites button to avoid refresh.
 - [#597](https://github.com/askap-vast/vast-pipeline/pull/597): fix: Update detail page titles.
 - [#586](https://github.com/askap-vast/vast-pipeline/pull/586): feat, dep, doc: Add an eta-v analysis page for the source query.

vast_pipeline/utils/external_query.py

@@ -34,7 +34,12 @@ def simbad(coord: SkyCoord, radius: Angle) -> List[Dict[str, Any]]:
         "otype(V)",
         "otypes",
     )
-    simbad_result_table = CustomSimbad.query_region(coord, radius=radius)
+    try:
+        simbad_result_table = CustomSimbad.query_region(coord, radius=radius)
+    except requests.HTTPError:
+        # try the Harvard mirror
+        CustomSimbad.SIMBAD_URL = "https://simbad.harvard.edu/simbad/sim-script"
+        simbad_result_table = CustomSimbad.query_region(coord, radius=radius)
     if simbad_result_table is None:
         simbad_results_dict_list = []
     else:

vast_pipeline/views.py

@@ -35,6 +35,7 @@
 
 from django_q.tasks import async_task
 
+import requests
 from rest_framework import status
 import rest_framework.decorators
 from rest_framework.request import Request
@@ -2466,6 +2467,21 @@ class UtilitiesSet(ViewSet):
     authentication_classes = [SessionAuthentication, BasicAuthentication]
     permission_classes = [IsAuthenticated]
 
+    @staticmethod
+    def _external_search_error_handler(
+        external_query_func,
+        coord: SkyCoord,
+        radius: Angle,
+        service_name: str,
+        request: Request,
+    ) -> List[Dict[str, Any]]:
+        try:
+            results = external_query_func(coord, radius)
+        except requests.HTTPError:
+            messages.error(request, f"Unable to get {service_name} query results.")
+            results = []
+        return results
+
     @rest_framework.decorators.action(methods=['get'], detail=False)
     def sesame_search(self, request: Request) -> Response:
         """Query the Sesame name resolver service and return a coordinate.
@@ -2560,9 +2576,15 @@ def external_search(self, request: Request) -> Response:
         except ValueError as e:
             raise serializers.ValidationError({"radius": str(e.args[0])})
 
-        simbad_results = external_query.simbad(coord, radius)
-        ned_results = external_query.ned(coord, radius)
-        tns_results = external_query.tns(coord, radius)
+        simbad_results = self._external_search_error_handler(
+            external_query.simbad, coord, radius, "SIMBAD", request
+        )
+        ned_results = self._external_search_error_handler(
+            external_query.ned, coord, radius, "NED", request
+        )
+        tns_results = self._external_search_error_handler(
+            external_query.tns, coord, radius, "TNS", request
+        )
 
         results = simbad_results + ned_results + tns_results
         serializer = ExternalSearchSerializer(data=results, many=True)