fix: child events must use unique event IDs

* pulls event ID generation into get_event_id(),
  taking care not to modify how parent event IDs are generated.
* overrides get_event_id() for child events by using the child_id as
  part of the UUID namespace_key.
* updates tests to check that child events and their parent event use
  different event IDs, and the affected problem_check multiple-question
  test data

event_routing_backends/processors/xapi/tests/fixtures/expected/problem_check(server,multiple_questions,correct).json

@@ -47,7 +47,7 @@
   }
 },
 {
-  "id": "b2f56b44-07f9-5044-85d1-c1dbc550d35f",
+  "id": "2cb89608-ab9c-5129-ae6e-4d7d2f9cde68",
   "result": {"response": "blue", "success": true},
   "version": "1.0.3",
   "actor": {
@@ -113,7 +113,7 @@
   }
 },
 {
-  "id": "b2f56b44-07f9-5044-85d1-c1dbc550d35f",
+  "id": "d0b94156-376d-5012-be91-c6235d3a0770",
   "result": {"response": "['a piano', 'a guitar']", "success": true},
   "version": "1.0.3",
   "actor": {
@@ -179,7 +179,7 @@
   }
 },
 {
-  "id": "b2f56b44-07f9-5044-85d1-c1dbc550d35f",
+  "id": "a51f4090-8ebf-5644-a669-a18768523eab",
   "result": {"response": "a chair", "success": true},
   "version": "1.0.3",
   "actor": {

event_routing_backends/processors/xapi/tests/fixtures/expected/problem_check(server,multiple_questions,incorrect).json

@@ -49,7 +49,7 @@
   }
 },
 {
-  "id": "b2f56b44-07f9-5044-85d1-c1dbc550d35f",
+  "id": "2cb89608-ab9c-5129-ae6e-4d7d2f9cde68",
   "result": {"response": "yellow", "success": false},
   "version": "1.0.3",
   "actor": {
@@ -115,7 +115,7 @@
   }
 },
 {
-  "id": "b2f56b44-07f9-5044-85d1-c1dbc550d35f",
+  "id": "d0b94156-376d-5012-be91-c6235d3a0770",
   "result": {"response": "['a window']", "success": false},
   "version": "1.0.3",
   "actor": {
@@ -181,7 +181,7 @@
   }
 },
 {
-  "id": "b2f56b44-07f9-5044-85d1-c1dbc550d35f",
+  "id": "a51f4090-8ebf-5644-a669-a18768523eab",
   "result": {"response": "a bookshelf", "success": false},
   "version": "1.0.3",
   "actor": {

event_routing_backends/processors/xapi/tests/fixtures/expected/problem_check(server,multiple_questions,partial_correct).json

@@ -47,7 +47,7 @@
   }
 },
 {
-  "id": "b2f56b44-07f9-5044-85d1-c1dbc550d35f",
+  "id": "2cb89608-ab9c-5129-ae6e-4d7d2f9cde68",
   "result": {"response": "blue", "success": true},
   "version": "1.0.3",
   "actor": {
@@ -113,7 +113,7 @@
   }
 },
 {
-  "id": "b2f56b44-07f9-5044-85d1-c1dbc550d35f",
+  "id": "d0b94156-376d-5012-be91-c6235d3a0770",
   "result": {"response": "['a piano', 'a guitar']", "success": true},
   "version": "1.0.3",
   "actor": {
@@ -179,7 +179,7 @@
   }
 },
 {
-  "id": "b2f56b44-07f9-5044-85d1-c1dbc550d35f",
+  "id": "a51f4090-8ebf-5644-a669-a18768523eab",
   "result": {"response": "a bookshelf", "success": false},
   "version": "1.0.3",
   "actor": {

event_routing_backends/processors/xapi/tests/test_transformers.py

@@ -42,9 +42,14 @@ def compare_events(self, transformed_event, expected_event):
         if isinstance(expected_event, list):
             assert isinstance(transformed_event, list)
             assert len(transformed_event) == len(expected_event)
+            event_ids = set()
             for idx, e_event in enumerate(expected_event):
+                event_ids.add(transformed_event[idx].id)
                 self._compare_events(transformed_event[idx], e_event)
 
+            # Ensure a unique event ID was applied for the parent + child events
+            assert len(event_ids) == len(transformed_event)
+
         # Compare single events
         else:
             self._compare_events(transformed_event, expected_event)

event_routing_backends/processors/xapi/transformer.py

@@ -52,23 +52,31 @@ def base_transform(self, transformed_event):
         Transform the fields that are common for all events.
         """
         transformed_event = super().base_transform(transformed_event)
-        actor = self.get_actor()
-        event_timestamp = self.get_timestamp()
         transformed_event.update({
-            'actor': actor,
+            'id': self.get_event_id(),
+            'actor': self.get_actor(),
             'context': self.get_context(),
-            'timestamp': event_timestamp,
+            'timestamp': self.get_timestamp(),
         })
-        transformed_event['actor'] = self.get_actor()
-        transformed_event['context'] = self.get_context()
-        transformed_event['timestamp'] = self.get_timestamp()
+        return transformed_event
+
+    def get_event_id(self):
+        """
+        Generates the UUID for this event.
+
+        Uses the actor, event timestamp, and verb to generate a UUID for this event
+        which will be the same even if this event is re-processed.
 
+        Returns:
+            UUID
+        """
         # Warning! changing anything in these 2 lines or changing the "base_uuid" can invalidate
         # billions of rows in the database. Please have a community discussion first before introducing
         # any change in generation of UUID.
+        actor = self.get_actor()
+        event_timestamp = self.get_timestamp()
         uuid_str = f'{actor.to_json()}-{event_timestamp}'
-        transformed_event['id'] = get_uuid5(self.verb.to_json(), uuid_str)  # pylint: disable=no-member
-        return transformed_event
+        return get_uuid5(self.verb.to_json(), uuid_str)  # pylint: disable=no-member
 
     def get_actor(self):
         """
@@ -261,6 +269,26 @@ def __init__(self, parent, child_id, *args, **kwargs):
         self.parent = parent
         self.child_id = child_id
 
+    def get_event_id(self):
+        """
+        Generates the UUID for this event.
+
+        Uses the actor, event timestamp, verb, and child_id to generate a UUID for this child event
+        which ensures a unique event ID for each child event which also differs from the parent event,
+        which will be the same even if this event is re-processed.
+
+        Returns:
+            UUID
+        """
+        # Warning! changing anything in these 2 lines or changing the "base_uuid" can invalidate
+        # billions of rows in the database. Please have a community discussion first before introducing
+        # any change in generation of UUID.
+        actor = self.get_actor()
+        event_timestamp = self.get_timestamp()
+        name = f'{actor.to_json()}-{event_timestamp}'
+        namespace_key = f'{self.verb.to_json()}-{self.child_id}'
+        return get_uuid5(namespace_key, name)
+
     def get_context(self):
         """
         Returns the context for the xAPI transformed child event.