Closes #19633

conditions.py - Change condition with self.negate to result XOR self.negate for compactness.
context_managers.py added context manager suppress_event_exp to prevent missing exceptions in cycles related to sequential event handling
events.py - using cm suppress_event_exp.
test_event_rules.py - added test to emulate the exception in process_event_function and verify that exception was logged properly.

netbox/extras/conditions.py

@@ -80,16 +80,15 @@ class Condition:
         except TypeError:
             # Invalid key path
             value = None
+
         if value is None:
             # Handle comparison case when value is None.
             if self.op in (self.GT, self.GTE, self.LT, self.LTE, self.IN, self.CONTAINS, self.REGEX):
-                result = False
-        else:
+                return False ^ self.negate
+
         result = self.eval_func(value)
 
-        if self.negate:
-            return not result
-        return result
+        return result ^ self.negate
 
     # Equivalency
 

netbox/extras/events.py

@@ -11,6 +11,7 @@ from django_rq import get_queue
 from core.events import *
 from netbox.config import get_config
 from netbox.constants import RQ_QUEUE_DEFAULT
+from netbox.context_managers import suppress_event_exp
 from netbox.registry import registry
 from users.models import User
 from utilities.api import get_serializer_for_model
@@ -86,6 +87,8 @@ def process_event_rules(event_rules, object_type, event_type, data, username=Non
 
     for event_rule in event_rules:
 
+        with suppress_event_exp(logger):
+
             # Evaluate event rule conditions (if any)
             if not event_rule.eval_conditions(data):
                 continue
@@ -160,6 +163,7 @@ def process_event_queue(events):
     events_cache = defaultdict(dict)
 
     for event in events:
+        with suppress_event_exp(logger):
             event_type = event['event_type']
             object_type = event['object_type']
 

netbox/extras/tests/test_event_rules.py

@@ -390,6 +390,70 @@ class EventRuleTest(APITestCase):
         with patch.object(Session, 'send', dummy_send):
             send_webhook(**job.kwargs)
 
+    def test_suppression_flush_events(self):
+
+        # Use context manager to verify that exception was logged as we expected
+        with self.assertLogs('netbox.events_processor', level='ERROR') as cm:
+
+            # Get the known event
+            event = EventRule.objects.get(name='Event Rule 2')
+
+            site = Site.objects.create(name='Site 1', slug='site-1', status=SiteStatusChoices.STATUS_PLANNED)
+
+            # Update an object via the REST API
+            data = {
+                'name': 'Site X',
+                'status': SiteStatusChoices.STATUS_ACTIVE,
+            }
+            url = reverse('dcim-api:site-detail', kwargs={'pk': site.pk})
+            self.add_permissions('dcim.change_site')
+            response = self.client.patch(url, data, format='json', **self.header)
+            self.assertHttpStatus(response, status.HTTP_200_OK)
+
+            # Verify that a background task was queued for the updated object
+            self.assertEqual(self.queue.count, 1)
+            job = self.queue.jobs[0]
+            self.assertEqual(job.kwargs['event_rule'], event)
+            self.assertEqual(job.kwargs['event_type'], OBJECT_UPDATED)
+            self.assertEqual(job.kwargs['model_name'], 'site')
+            self.assertEqual(job.kwargs['data']['id'], site.pk)
+            self.assertEqual(job.kwargs['data']['status']['value'], SiteStatusChoices.STATUS_ACTIVE)
+            self.assertEqual(job.kwargs['snapshots']['prechange']['name'], 'Site 1')
+            self.assertEqual(job.kwargs['snapshots']['prechange']['status'], SiteStatusChoices.STATUS_PLANNED)
+            self.assertEqual(job.kwargs['snapshots']['postchange']['name'], 'Site X')
+            self.assertEqual(job.kwargs['snapshots']['postchange']['status'], SiteStatusChoices.STATUS_ACTIVE)
+
+            # Update the event with non-existent
+            event.action_type = 'non-existent-action-type'
+            event.save()
+
+            # Cleanup queue
+            self.queue.empty()
+
+            # Verify that a queue is empty
+            self.assertEqual(self.queue.count, 0)
+
+            # Update an object via the REST API
+            data = {
+                'name': 'Site X',
+                'status': SiteStatusChoices.STATUS_PLANNED,
+            }
+            url = reverse('dcim-api:site-detail', kwargs={'pk': site.pk})
+            self.add_permissions('dcim.change_site')
+            response = self.client.patch(url, data, format='json', **self.header)
+            self.assertHttpStatus(response, status.HTTP_200_OK)
+
+            # Verify that a queue is still empty
+            self.assertEqual(self.queue.count, 0)
+
+        # Verify that we have only one ERROR message in our log
+        self.assertEqual(len(cm.output), 1)
+
+        # Verify message format
+        pattern = (r"Error ValueError in ValueError at .*? - Unknown action type for"
+                   r" an event rule: non-existent-action-type")
+        self.assertRegex(cm.output[0], pattern)
+
     def test_duplicate_triggers(self):
         """
         Test for erroneous duplicate event triggers resulting from saving an object multiple times

netbox/netbox/context_managers.py

@@ -1,8 +1,8 @@
+import traceback
 from contextlib import contextmanager
 
 from netbox.context import current_request, events_queue
 from netbox.utils import register_request_processor
-from extras.events import flush_events
 
 
 @register_request_processor
@@ -14,6 +14,8 @@ def event_tracking(request):
 
     :param request: WSGIRequest object with a unique `id` set
     """
+    from extras.events import flush_events
+
     current_request.set(request)
     events_queue.set({})
 
@@ -26,3 +28,19 @@ def event_tracking(request):
     # Clear context vars
     current_request.set(None)
     events_queue.set({})
+
+
+@contextmanager
+def suppress_event_exp(logger=None):
+    """
+    Suppress exceptions that may occur during event handling.
+    """
+    try:
+        yield
+    except Exception as e:
+        if logger:
+            tb = e.__traceback__
+            last_frame = tb.tb_frame if tb else None
+            filename = last_frame.f_code.co_filename if last_frame else 'unknown'
+            lineno = tb.tb_lineno if tb else 0
+            logger.error(f"Error {e.__class__.__name__} in {e.__class__.__name__} at {filename}:{lineno} - {str(e)}")