core: rework base for SkipObject exception to better support control flow exceptions (#10186)

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

authentik/core/expression/exceptions.py

@@ -1,5 +1,6 @@
 """authentik core exceptions"""
 
+from authentik.lib.expression.exceptions import ControlFlowException
 from authentik.lib.sentry import SentryIgnoredException
 
 
@@ -12,11 +13,7 @@ class PropertyMappingExpressionException(SentryIgnoredException):
         self.mapping = mapping
 
 
-class SkipObjectException(PropertyMappingExpressionException):
+class SkipObjectException(ControlFlowException):
     """Exception which can be raised in a property mapping to skip syncing an object.
     Only applies to Property mappings which sync objects, and not on mappings which transitively
     apply to a single user"""
-
-    def __init__(self) -> None:
-        # For this class only, both of these are set by the function evaluating the property mapping
-        super().__init__(exc=None, mapping=None)

authentik/core/models.py

@@ -26,6 +26,7 @@ from authentik.blueprints.models import ManagedModel
 from authentik.core.expression.exceptions import PropertyMappingExpressionException
 from authentik.core.types import UILoginButton, UserSettingSerializer
 from authentik.lib.avatars import get_avatar
+from authentik.lib.expression.exceptions import ControlFlowException
 from authentik.lib.generators import generate_id
 from authentik.lib.models import (
     CreatedUpdatedModel,
@@ -783,6 +784,8 @@ class PropertyMapping(SerializerModel, ManagedModel):
         evaluator = PropertyMappingEvaluator(self, user, request, **kwargs)
         try:
             return evaluator.evaluate(self.expression)
+        except ControlFlowException as exc:
+            raise exc
         except Exception as exc:
             raise PropertyMappingExpressionException(self, exc) from exc
 

authentik/core/tests/test_property_mapping.py

@@ -3,7 +3,10 @@
 from django.test import RequestFactory, TestCase
 from guardian.shortcuts import get_anonymous_user
 
-from authentik.core.expression.exceptions import PropertyMappingExpressionException
+from authentik.core.expression.exceptions import (
+    PropertyMappingExpressionException,
+    SkipObjectException,
+)
 from authentik.core.models import PropertyMapping
 from authentik.core.tests.utils import create_test_admin_user
 from authentik.events.models import Event, EventAction
@@ -42,6 +45,17 @@ class TestPropertyMappings(TestCase):
         self.assertTrue(events.exists())
         self.assertEqual(len(events), 1)
 
+    def test_expression_skip(self):
+        """Test expression error"""
+        expr = "raise SkipObject"
+        mapping = PropertyMapping.objects.create(name=generate_id(), expression=expr)
+        with self.assertRaises(SkipObjectException):
+            mapping.evaluate(None, None)
+        events = Event.objects.filter(
+            action=EventAction.PROPERTY_MAPPING_EXCEPTION, context__expression=expr
+        )
+        self.assertFalse(events.exists())
+
     def test_expression_error_extended(self):
         """Test expression error (with user and http request"""
         expr = "return aaa"

authentik/lib/expression/evaluator.py

@@ -19,6 +19,7 @@ from structlog.stdlib import get_logger
 
 from authentik.core.models import User
 from authentik.events.models import Event
+from authentik.lib.expression.exceptions import ControlFlowException
 from authentik.lib.utils.http import get_http_session
 from authentik.policies.models import Policy, PolicyBinding
 from authentik.policies.process import PolicyProcess
@@ -216,7 +217,8 @@ class BaseEvaluator:
                 # so the user only sees information relevant to them
                 # and none of our surrounding error handling
                 exc.__traceback__ = exc.__traceback__.tb_next
-                self.handle_error(exc, expression_source)
+                if not isinstance(exc, ControlFlowException):
+                    self.handle_error(exc, expression_source)
                 raise exc
             return result
 

authentik/lib/expression/exceptions.py

@@ -0,0 +1,6 @@
+from authentik.lib.sentry import SentryIgnoredException
+
+
+class ControlFlowException(SentryIgnoredException):
+    """Exceptions used to control the flow from exceptions, not reported as a warning/
+    error in logs"""

authentik/lib/sync/mapper.py

@@ -6,9 +6,9 @@ from django.http import HttpRequest
 from authentik.core.expression.evaluator import PropertyMappingEvaluator
 from authentik.core.expression.exceptions import (
     PropertyMappingExpressionException,
-    SkipObjectException,
 )
 from authentik.core.models import PropertyMapping, User
+from authentik.lib.expression.exceptions import ControlFlowException
 
 
 class PropertyMappingManager:
@@ -60,11 +60,7 @@ class PropertyMappingManager:
             mapping.set_context(user, request, **kwargs)
             try:
                 value = mapping.evaluate(mapping.model.expression)
-            except SkipObjectException as exc:
+            except (PropertyMappingExpressionException, ControlFlowException) as exc:
-                exc.exc = exc
-                exc.mapping = mapping
-                raise exc from exc
-            except PropertyMappingExpressionException as exc:
                 raise exc from exc
             except Exception as exc:
                 raise PropertyMappingExpressionException(exc, mapping.model) from exc

authentik/lib/sync/outgoing/base.py

@@ -9,9 +9,9 @@ from structlog.stdlib import get_logger
 
 from authentik.core.expression.exceptions import (
     PropertyMappingExpressionException,
-    SkipObjectException,
 )
 from authentik.events.models import Event, EventAction
+from authentik.lib.expression.exceptions import ControlFlowException
 from authentik.lib.sync.mapper import PropertyMappingManager
 from authentik.lib.sync.outgoing.exceptions import NotFoundSyncException, StopSync
 from authentik.lib.utils.errors import exception_to_string
@@ -92,7 +92,7 @@ class BaseOutgoingSyncClient[
             eval_kwargs.setdefault("user", None)
             for value in self.mapper.iter_eval(**eval_kwargs):
                 always_merger.merge(raw_final_object, value)
-        except SkipObjectException as exc:
+        except ControlFlowException as exc:
             raise exc from exc
         except PropertyMappingExpressionException as exc:
             # Value error can be raised when assigning invalid data to an attribute