fix(): project refactoring and minor fixes

src/backend/apps/events/services.py

@@ -22,6 +22,7 @@ from apps.events.selectors import (
     pending_event_exists,
     pending_events_for_decision,
 )
+from config.errors import ConflictError
 
 PENDING_TTL_DAYS = 7
 
@@ -124,23 +125,22 @@ def _process_exposure_event(
 ) -> None:
     decision_id = event_data["decision_id"]
     subject_id = event_data["subject_id"]
-    timestamp = parse_datetime(event_data["timestamp"]) or timezone.now()
+    timestamp = parse_datetime(event_data["timestamp"])
+    if timestamp is None:
+        raise ValidationError(
+            "Field 'timestamp' must be a valid ISO 8601 datetime."
+        )
 
     decision = decision_get(decision_id)
-    experiment_id = None
-    variant_id = None
     if decision:
-        experiment_id = decision.experiment_id
-        variant_id = decision.variant_id
-
-    with suppress(IntegrityError):
-        Exposure.objects.create(
-            decision_id=decision_id,
-            experiment_id=experiment_id,
-            variant_id=variant_id,
-            subject_id=subject_id,
-            timestamp=timestamp,
-        )
+        with suppress(ConflictError):
+            Exposure.objects.create(
+                decision_id=decision_id,
+                experiment_id=decision.experiment_id,
+                variant_id=decision.variant_id,
+                subject_id=subject_id,
+                timestamp=timestamp,
+            )
 
     Event.objects.create(
         event_id=event_data["event_id"],
@@ -158,7 +158,7 @@ def _process_exposure_event(
 def _promote_pending_events(decision_id: str) -> None:
     pending = pending_events_for_decision(decision_id)
     for pe in pending:
-        with suppress(IntegrityError):
+        with suppress(ConflictError):
             Event.objects.create(
                 event_id=pe.event_id,
                 event_type=pe.event_type,
@@ -178,7 +178,11 @@ def _process_conversion_event(
 ) -> None:
     decision_id = event_data["decision_id"]
     subject_id = event_data["subject_id"]
-    timestamp = parse_datetime(event_data["timestamp"]) or timezone.now()
+    timestamp = parse_datetime(event_data["timestamp"])
+    if timestamp is None:
+        raise ValidationError(
+            "Field 'timestamp' must be a valid ISO 8601 datetime."
+        )
     properties = event_data.get("properties", {})
 
     if not event_type_obj.requires_exposure or exposure_exists(decision_id):