fix: catch json errors on empty responses from ralph (#461)

* fix: catch json errors on empty responses from ralph

* fix: move JSONDecodeError catch statement to xapi lrs

* fix: move JSONDecodeError catch statement to xapi lrs

* chore: remove unnecessary condition

* refactor: define response outside try-except

* test: add tests for jsondecode error

* chore: update duplicated message

* chore: quality changes

* chore: quality changes

event_routing_backends/backends/tests/test_events_router.py

@@ -4,6 +4,7 @@
 import datetime
 import json
 from copy import copy
+from json import JSONDecodeError
 from unittest.mock import MagicMock, call, patch, sentinel
 
 import ddt
@@ -273,6 +274,22 @@ def test_duplicate_xapi_event_id(self, mocked_logger):
             mocked_logger.info.mock_calls
         )
 
+    @patch('event_routing_backends.utils.xapi_lrs_client.logger')
+    def test_duplicate_xapi_event_id_json(self, mocked_logger):
+        """
+        Test that when we receive a 204 response (and the LRSClient fails to parse to JSON
+        the response) when bulk inserting XAPI statements it may indicates all events are already stored.
+        """
+        client = LrsClient({})
+        client.lrs_client = MagicMock()
+        client.lrs_client.save_statements.side_effect = JSONDecodeError(msg="msg", doc="...", pos=0)
+
+        client.bulk_send(statement_data=[])
+        self.assertIn(
+            call('JSON Decode Error, this may indicate that all sent events are already stored: []'),
+            mocked_logger.warning.mock_calls
+        )
+
     @override_settings(
         EVENT_ROUTING_BACKEND_BATCHING_ENABLED=True,
         EVENT_ROUTING_BACKEND_BATCH_SIZE=2

event_routing_backends/utils/xapi_lrs_client.py

@@ -1,6 +1,7 @@
 """
 An LRS client for xAPI stores.
 """
+from json.decoder import JSONDecodeError
 from logging import getLogger
 
 from tincan.remote_lrs import RemoteLRS
@@ -71,8 +72,17 @@ def bulk_send(self, statement_data):
             requests.Response object
         """
         logger.debug('Sending {} xAPI statements to {}'.format(len(statement_data), self.URL))
+        response = None
 
-        response = self.lrs_client.save_statements(statement_data)
+        try:
+            response = self.lrs_client.save_statements(statement_data)
+        except JSONDecodeError:
+            logger.warning(
+                f"JSON Decode Error, this may indicate that all sent events are already stored: {statement_data}"
+            )
+
+        if not response:
+            return
 
         if not response.success:
             if response.response.code == 409: