Refactoring exception hierarchy

* Clear separation for problems that can be handled so that the program
  can continue and problems that can't handled automatically due to major
  issues in configuration, environment or code itself
* Split YAQL exceptions into two types: grammar exception and evaluation
  exception
* General NotFoundException is replaced with more specific DBEntryNotFoundException
  for better consistency with other DB exceptions and more clear semantics
* Fixed corresponding tests

Change-Id: I07f495ab316b0f164caece78b1f101219199e68c
Implements: blueprint mistral-engine-error-handling

mistral/db/v2/sqlalchemy/api.py

@@ -183,8 +183,9 @@ def get_workbook(name):
     wb = _get_workbook(name)
 
     if not wb:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
-            "Workbook not found [workbook_name=%s]" % name)
+            "Workbook not found [workbook_name=%s]" % name
+        )
 
     return wb
 
@@ -218,8 +219,9 @@ def update_workbook(name, values, session=None):
     wb = _get_workbook(name)
 
     if not wb:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
-            "Workbook not found [workbook_name=%s]" % name)
+            "Workbook not found [workbook_name=%s]" % name
+        )
 
     wb.update(values.copy())
 
@@ -239,8 +241,9 @@ def delete_workbook(name, session=None):
     wb = _get_workbook(name)
 
     if not wb:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
-            "Workbook not found [workbook_name=%s]" % name)
+            "Workbook not found [workbook_name=%s]" % name
+        )
 
     session.delete(wb)
 
@@ -281,7 +284,7 @@ def get_workflow_definition(identifier):
               else _get_workflow_definition(identifier))
 
     if not wf_def:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Workflow not found [workflow_identifier=%s]" % identifier
         )
 
@@ -292,7 +295,7 @@ def get_workflow_definition_by_id(id):
     wf_def = _get_workflow_definition_by_id(id)
 
     if not wf_def:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Workflow not found [workflow_id=%s]" % id
         )
 
@@ -363,7 +366,7 @@ def update_workflow_definition(identifier, values, session=None):
 
         try:
             [get_cron_trigger(name) for name in cron_triggers]
-        except exc.NotFoundException:
+        except exc.DBEntityNotFoundException:
             raise exc.NotAllowedException(
                 "Can not update scope of workflow that has triggers "
                 "associated in other tenants."
@@ -446,7 +449,7 @@ def get_action_definition_by_id(id):
     action_def = _get_db_object_by_id(models.ActionDefinition, id)
 
     if not action_def:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Action not found [action_id=%s]" % id
         )
 
@@ -457,7 +460,7 @@ def get_action_definition(name):
     a_def = _get_action_definition(name)
 
     if not a_def:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Action definition not found [action_name=%s]" % name
         )
 
@@ -509,8 +512,9 @@ def update_action_definition(name, values, session=None):
     a_def = _get_action_definition(name)
 
     if not a_def:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
-            "Action definition not found [action_name=%s]" % name)
+            "Action definition not found [action_name=%s]" % name
+        )
 
     a_def.update(values.copy())
 
@@ -530,7 +534,7 @@ def delete_action_definition(name, session=None):
     a_def = _get_action_definition(name)
 
     if not a_def:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Action definition not found [action_name=%s]" % name
         )
 
@@ -552,7 +556,7 @@ def get_execution(id):
     ex = _get_execution(id)
 
     if not ex:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Execution not found [execution_id=%s]" % id
         )
 
@@ -592,7 +596,7 @@ def update_execution(id, values, session=None):
     ex = _get_execution(id)
 
     if not ex:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Execution not found [execution_id=%s]" % id
         )
 
@@ -614,8 +618,9 @@ def delete_execution(id, session=None):
     ex = _get_execution(id)
 
     if not ex:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
-            "Execution not found [execution_id=%s]" % id)
+            "Execution not found [execution_id=%s]" % id
+        )
 
     session.delete(ex)
 
@@ -639,8 +644,9 @@ def get_action_execution(id):
     a_ex = _get_action_execution(id)
 
     if not a_ex:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
-            "ActionExecution not found [id=%s]" % id)
+            "ActionExecution not found [id=%s]" % id
+        )
 
     return a_ex
 
@@ -678,7 +684,7 @@ def update_action_execution(id, values, session=None):
     a_ex = _get_action_execution(id)
 
     if not a_ex:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "ActionExecution not found [id=%s]" % id
         )
 
@@ -700,7 +706,7 @@ def delete_action_execution(id, session=None):
     a_ex = _get_action_execution(id)
 
     if not a_ex:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "ActionExecution not found [id=%s]" % id
         )
 
@@ -726,7 +732,9 @@ def get_workflow_execution(id):
     wf_ex = _get_workflow_execution(id)
 
     if not wf_ex:
-        raise exc.NotFoundException("WorkflowExecution not found [id=%s]" % id)
+        raise exc.DBEntityNotFoundException(
+            "WorkflowExecution not found [id=%s]" % id
+        )
 
     return wf_ex
 
@@ -780,7 +788,9 @@ def update_workflow_execution(id, values, session=None):
     wf_ex = _get_workflow_execution(id)
 
     if not wf_ex:
-        raise exc.NotFoundException("WorkflowExecution not found [id=%s]" % id)
+        raise exc.DBEntityNotFoundException(
+            "WorkflowExecution not found [id=%s]" % id
+        )
 
     wf_ex.update(values.copy())
 
@@ -800,7 +810,9 @@ def delete_workflow_execution(id, session=None):
     wf_ex = _get_workflow_execution(id)
 
     if not wf_ex:
-        raise exc.NotFoundException("WorkflowExecution not found [id=%s]" % id)
+        raise exc.DBEntityNotFoundException(
+            "WorkflowExecution not found [id=%s]" % id
+        )
 
     session.delete(wf_ex)
 
@@ -820,7 +832,9 @@ def get_task_execution(id):
     task_ex = _get_task_execution(id)
 
     if not task_ex:
-        raise exc.NotFoundException("Task execution not found [id=%s]" % id)
+        raise exc.DBEntityNotFoundException(
+            "Task execution not found [id=%s]" % id
+        )
 
     return task_ex
 
@@ -854,7 +868,9 @@ def update_task_execution(id, values, session=None):
     task_ex = _get_task_execution(id)
 
     if not task_ex:
-        raise exc.NotFoundException("TaskExecution not found [id=%s]" % id)
+        raise exc.DBEntityNotFoundException(
+            "TaskExecution not found [id=%s]" % id
+        )
 
     task_ex.update(values.copy())
 
@@ -874,7 +890,9 @@ def delete_task_execution(id, session=None):
     task_ex = _get_task_execution(id)
 
     if not task_ex:
-        raise exc.NotFoundException("TaskExecution not found [id=%s]" % id)
+        raise exc.DBEntityNotFoundException(
+            "TaskExecution not found [id=%s]" % id
+        )
 
     session.delete(task_ex)
 
@@ -914,7 +932,7 @@ def delete_delayed_call(id, session=None):
     delayed_call = _get_delayed_call(id)
 
     if not delayed_call:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "DelayedCall not found [id=%s]" % id
         )
 
@@ -964,7 +982,9 @@ def get_delayed_call(id, session=None):
     delayed_call = _get_delayed_call(id=id, session=session)
 
     if not delayed_call:
-        raise exc.NotFoundException("Delayed Call not found [id=%s]" % id)
+        raise exc.DBEntityNotFoundException(
+            "Delayed Call not found [id=%s]" % id
+        )
 
     return delayed_call
 
@@ -1000,8 +1020,9 @@ def get_cron_trigger(name):
     cron_trigger = _get_cron_trigger(name)
 
     if not cron_trigger:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
-            "Cron trigger not found [name=%s]" % name)
+            "Cron trigger not found [name=%s]" % name
+        )
 
     return cron_trigger
 
@@ -1052,7 +1073,9 @@ def update_cron_trigger(name, values, session=None, query_filter=None):
     cron_trigger = _get_cron_trigger(name)
 
     if not cron_trigger:
-        raise exc.NotFoundException("Cron trigger not found [name=%s]" % name)
+        raise exc.DBEntityNotFoundException(
+            "Cron trigger not found [name=%s]" % name
+        )
 
     if query_filter:
         try:
@@ -1099,7 +1122,9 @@ def delete_cron_trigger(name, session=None):
     cron_trigger = _get_cron_trigger(name)
 
     if not cron_trigger:
-        raise exc.NotFoundException("Cron trigger not found [name=%s]" % name)
+        raise exc.DBEntityNotFoundException(
+            "Cron trigger not found [name=%s]" % name
+        )
 
     # Delete the cron trigger by ID and get the affected row count.
     table = models.CronTrigger.__table__
@@ -1131,7 +1156,9 @@ def get_environment(name):
     env = _get_environment(name)
 
     if not env:
-        raise exc.NotFoundException("Environment not found [name=%s]" % name)
+        raise exc.DBEntityNotFoundException(
+            "Environment not found [name=%s]" % name
+        )
 
     return env
 
@@ -1165,7 +1192,9 @@ def update_environment(name, values, session=None):
     env = _get_environment(name)
 
     if not env:
-        raise exc.NotFoundException("Environment not found [name=%s]" % name)
+        raise exc.DBEntityNotFoundException(
+            "Environment not found [name=%s]" % name
+        )
 
     env.update(values)
 
@@ -1187,7 +1216,9 @@ def delete_environment(name, session=None):
     env = _get_environment(name)
 
     if not env:
-        raise exc.NotFoundException("Environment not found [name=%s]" % name)
+        raise exc.DBEntityNotFoundException(
+            "Environment not found [name=%s]" % name
+        )
 
     session.delete(env)
 
@@ -1268,7 +1299,7 @@ def get_resource_member(resource_id, res_type, member_id):
     ).first()
 
     if not res_member:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Resource member not found [resource_id=%s, member_id=%s]" %
             (resource_id, member_id)
         )
@@ -1298,7 +1329,7 @@ def update_resource_member(resource_id, res_type, member_id, values,
     # Only member who is not the owner of the resource can update the
     # membership status.
     if member_id != security.get_project_id():
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Resource member not found [resource_id=%s, member_id=%s]" %
             (resource_id, member_id)
         )
@@ -1312,7 +1343,7 @@ def update_resource_member(resource_id, res_type, member_id, values,
     ).first()
 
     if not res_member:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Resource member not found [resource_id=%s, member_id=%s]" %
             (resource_id, member_id)
         )
@@ -1331,7 +1362,7 @@ def delete_resource_member(resource_id, res_type, member_id, session=None):
     res_member = query.filter(_get_criterion(resource_id, member_id)).first()
 
     if not res_member:
-        raise exc.NotFoundException(
+        raise exc.DBEntityNotFoundException(
             "Resource member not found [resource_id=%s, member_id=%s]" %
             (resource_id, member_id)
         )

mistral/exceptions.py

@@ -14,16 +14,34 @@
 #    limitations under the License.
 
 
-class Error(Exception):
+class MistralError(Exception):
+    """Mistral specific error.
+
+    Reserved for situations that can't automatically handled. When it occurs
+    it signals that there is a major environmental problem like invalid startup
+    configuration or implementation problem (e.g. some code doesn't take care
+    of certain corner cases). From architectural perspective it's pointless to
+    try to handle this type of problems except doing some finalization work
+    like transaction rollback, deleting temporary files etc.
+    """
     def __init__(self, message=None):
-        super(Error, self).__init__(message)
+        super(MistralError, self).__init__(message)
 
 
-class MistralException(Error):
+class MistralException(Exception):
-    """Base Exception for the project
+    """Mistral specific exception.
 
-    To correctly use this class, inherit from it and define
+    Reserved for situations that are not critical for program continuation.
-    a 'message' and 'http_code' properties.
+    It is possible to recover from this type of problems automatically and
+    continue program execution. Such problems may be related with invalid user
+    input (such as invalid syntax) or temporary environmental problems.
+
+    In case if an instance of a certain exception type bubbles up to API layer
+    then this type of exception it must be associated with an http code so it's
+    clear how to represent it for a client.
+
+    To correctly use this class, inherit from it and define a 'message' and
+    'http_code' properties.
     """
     message = "An unknown exception occurred"
     http_code = 500
@@ -42,29 +60,55 @@ class MistralException(Error):
     def __init__(self, message=None):
         if message is not None:
             self.message = message
+
         super(MistralException, self).__init__(
             '%d: %s' % (self.http_code, self.message))
 
 
+# Database exceptions.
+
 class DBException(MistralException):
     http_code = 400
 
 
-class DataAccessException(MistralException):
+class DBDuplicateEntryException(DBException):
-    http_code = 400
-
-
-class NotFoundException(MistralException):
-    http_code = 404
-    message = "Object not found"
-
-
-class DBDuplicateEntryException(MistralException):
     http_code = 409
     message = "Database object already exists"
 
 
-class DBQueryEntryException(MistralException):
+class DBQueryEntryException(DBException):
+    http_code = 400
+
+
+class DBEntityNotFoundException(DBException):
+    http_code = 404
+    message = "Object not found"
+
+
+# DSL exceptions.
+
+class DSLParsingException(MistralException):
+    http_code = 400
+
+
+class YaqlGrammarException(DSLParsingException):
+    http_code = 400
+    message = "Invalid grammar of YAQL expression"
+
+
+class InvalidModelException(DSLParsingException):
+    http_code = 400
+    message = "Wrong entity definition"
+
+
+# Various common exceptions.
+
+class YaqlEvaluationException(MistralException):
+    http_code = 400
+    message = "Can not evaluate YAQL expression"
+
+
+class DataAccessException(MistralException):
     http_code = 400
 
 
@@ -97,20 +141,6 @@ class ApplicationContextNotFoundException(MistralException):
     message = "Application context not found"
 
 
-class DSLParsingException(MistralException):
-    http_code = 400
-
-
-class YaqlEvaluationException(DSLParsingException):
-    http_code = 400
-    message = "Can not evaluate YAQL expression"
-
-
-class InvalidModelException(DSLParsingException):
-    http_code = 400
-    message = "Wrong entity definition"
-
-
 class InvalidResultException(MistralException):
     http_code = 400
     message = "Unable to parse result"

mistral/expressions.py

@@ -78,7 +78,7 @@ class YAQLEvaluator(Evaluator):
         try:
             YAQL_ENGINE(expression)
         except (yaql_exc.YaqlException, KeyError, ValueError, TypeError) as e:
-            raise exc.YaqlEvaluationException(getattr(e, 'message', e))
+            raise exc.YaqlGrammarException(getattr(e, 'message', e))
 
     @classmethod
     def evaluate(cls, expression, data_context):

mistral/services/periodic.py

@@ -108,7 +108,7 @@ def advance_cron_trigger(t):
                     'next_execution_time': t.next_execution_time
                 }
             )
-    except exc.NotFoundException as e:
+    except exc.DBEntityNotFoundException as e:
         # Cron trigger was probably already deleted by a different process.
         LOG.debug(
             "Cron trigger named '%s' does not exist anymore: %s",

mistral/tests/unit/api/v2/test_action_executions.py

@@ -116,7 +116,7 @@ MOCK_ACTION_NOT_COMPLETE = mock.MagicMock(
 MOCK_AD_HOC_ACTION = mock.MagicMock(return_value=AD_HOC_ACTION_EX_DB)
 MOCK_ACTIONS = mock.MagicMock(return_value=[ACTION_EX_DB])
 MOCK_EMPTY = mock.MagicMock(return_value=[])
-MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.NotFoundException())
+MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundException())
 MOCK_DELETE = mock.MagicMock(return_value=None)
 
 

mistral/tests/unit/api/v2/test_actions.py

@@ -90,7 +90,7 @@ MOCK_ACTIONS = mock.MagicMock(return_value=[ACTION_DB])
 MOCK_UPDATED_ACTION = mock.MagicMock(return_value=UPDATED_ACTION_DB)
 MOCK_DELETE = mock.MagicMock(return_value=None)
 MOCK_EMPTY = mock.MagicMock(return_value=[])
-MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.NotFoundException())
+MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundException())
 MOCK_DUPLICATE = mock.MagicMock(side_effect=exc.DBDuplicateEntryException())
 
 

mistral/tests/unit/api/v2/test_cron_triggers.py

@@ -63,7 +63,7 @@ MOCK_TRIGGER = mock.MagicMock(return_value=TRIGGER_DB)
 MOCK_TRIGGERS = mock.MagicMock(return_value=[TRIGGER_DB])
 MOCK_DELETE = mock.MagicMock(return_value=None)
 MOCK_EMPTY = mock.MagicMock(return_value=[])
-MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.NotFoundException())
+MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundException())
 MOCK_DUPLICATE = mock.MagicMock(side_effect=exc.DBDuplicateEntryException())
 
 

mistral/tests/unit/api/v2/test_environment.py

@@ -107,7 +107,7 @@ MOCK_ENVIRONMENT = mock.MagicMock(return_value=ENVIRONMENT_DB)
 MOCK_ENVIRONMENTS = mock.MagicMock(return_value=[ENVIRONMENT_DB])
 MOCK_UPDATED_ENVIRONMENT = mock.MagicMock(return_value=UPDATED_ENVIRONMENT_DB)
 MOCK_EMPTY = mock.MagicMock(return_value=[])
-MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.NotFoundException())
+MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundException())
 MOCK_DUPLICATE = mock.MagicMock(side_effect=exc.DBDuplicateEntryException())
 MOCK_DELETE = mock.MagicMock(return_value=None)
 

mistral/tests/unit/api/v2/test_executions.py

@@ -111,7 +111,7 @@ MOCK_WF_EXECUTIONS = mock.MagicMock(return_value=[WF_EX])
 MOCK_UPDATED_WF_EX = mock.MagicMock(return_value=UPDATED_WF_EX)
 MOCK_DELETE = mock.MagicMock(return_value=None)
 MOCK_EMPTY = mock.MagicMock(return_value=[])
-MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.NotFoundException())
+MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundException())
 MOCK_ACTION_EXC = mock.MagicMock(side_effect=exc.ActionException())
 
 

mistral/tests/unit/api/v2/test_tasks.py

@@ -127,7 +127,7 @@ MOCK_WF_EX = mock.MagicMock(return_value=WF_EX)
 MOCK_TASK = mock.MagicMock(return_value=TASK_EX)
 MOCK_TASKS = mock.MagicMock(return_value=[TASK_EX])
 MOCK_EMPTY = mock.MagicMock(return_value=[])
-MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.NotFoundException())
+MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundException())
 MOCK_ERROR_TASK = mock.MagicMock(return_value=ERROR_TASK_EX)
 MOCK_ERROR_ITEMS_TASK = mock.MagicMock(return_value=ERROR_ITEMS_TASK_EX)
 

mistral/tests/unit/api/v2/test_workbooks.py

@@ -97,7 +97,7 @@ MOCK_WORKBOOKS = mock.MagicMock(return_value=[WORKBOOK_DB])
 MOCK_UPDATED_WORKBOOK = mock.MagicMock(return_value=UPDATED_WORKBOOK_DB)
 MOCK_DELETE = mock.MagicMock(return_value=None)
 MOCK_EMPTY = mock.MagicMock(return_value=[])
-MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.NotFoundException())
+MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundException())
 MOCK_DUPLICATE = mock.MagicMock(side_effect=exc.DBDuplicateEntryException())
 
 

mistral/tests/unit/api/v2/test_workflows.py

@@ -160,7 +160,7 @@ MOCK_WFS = mock.MagicMock(return_value=[WF_DB])
 MOCK_UPDATED_WF = mock.MagicMock(return_value=UPDATED_WF_DB)
 MOCK_DELETE = mock.MagicMock(return_value=None)
 MOCK_EMPTY = mock.MagicMock(return_value=[])
-MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.NotFoundException())
+MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundException())
 MOCK_DUPLICATE = mock.MagicMock(side_effect=exc.DBDuplicateEntryException())
 
 

mistral/tests/unit/db/v2/test_sqlalchemy_db_api.py

@@ -153,7 +153,7 @@ class WorkbookTest(SQLAlchemyTest):
         db_api.delete_workbook(created.name)
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_workbook,
             created.name
         )
@@ -424,7 +424,7 @@ class WorkflowDefinitionTest(SQLAlchemyTest):
             db_api.delete_workflow_definition(identifier)
 
             self.assertRaises(
-                exc.NotFoundException,
+                exc.DBEntityNotFoundException,
                 db_api.get_workflow_definition,
                 identifier
             )
@@ -606,7 +606,7 @@ class ActionDefinitionTest(SQLAlchemyTest):
         db_api.delete_action_definition(created.name)
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_action_definition,
             created.name
         )
@@ -726,7 +726,7 @@ class ActionExecutionTest(SQLAlchemyTest):
         db_api.delete_action_execution(created.id)
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_action_execution,
             created.id
         )
@@ -738,7 +738,7 @@ class ActionExecutionTest(SQLAlchemyTest):
         auth_context.set_ctx(test_base.get_context(default=False))
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.delete_action_execution,
             created.id
         )
@@ -880,7 +880,7 @@ class WorkflowExecutionTest(SQLAlchemyTest):
         db_api.delete_workflow_execution(created.id)
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_workflow_execution,
             created.id
         )
@@ -1130,7 +1130,7 @@ class TaskExecutionTest(SQLAlchemyTest):
         db_api.delete_task_execution(created.id)
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_task_execution,
             created.id
         )
@@ -1302,7 +1302,7 @@ class CronTriggerTest(SQLAlchemyTest):
 
         self.assertEqual(1, rowcount)
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_cron_trigger,
             created.name
         )
@@ -1432,7 +1432,7 @@ class EnvironmentTest(SQLAlchemyTest):
         db_api.delete_environment(created.name)
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_environment,
             created.name
         )
@@ -1462,7 +1462,7 @@ class TXTest(SQLAlchemyTest):
 
         self.assertFalse(self.is_db_session_open())
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_workbook,
             created['id']
         )
@@ -1525,12 +1525,12 @@ class TXTest(SQLAlchemyTest):
 
         self.assertFalse(self.is_db_session_open())
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_workflow_execution,
             created.id
         )
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_workbook,
             created_wb.name
         )
@@ -1553,7 +1553,7 @@ class TXTest(SQLAlchemyTest):
 
         self.assertFalse(self.is_db_session_open())
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_workbook,
             created.name
         )
@@ -1633,7 +1633,7 @@ class ResourceMemberTest(SQLAlchemyTest):
 
         # Tenant A can not see membership of resource shared to Tenant B.
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_resource_member,
             '123e4567-e89b-12d3-a456-426655440000',
             'workflow',
@@ -1695,7 +1695,7 @@ class ResourceMemberTest(SQLAlchemyTest):
         created = db_api.create_resource_member(RESOURCE_MEMBERS[0])
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.update_resource_member,
             created.resource_id,
             'workflow',
@@ -1726,7 +1726,7 @@ class ResourceMemberTest(SQLAlchemyTest):
         auth_context.set_ctx(user_context)
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.delete_resource_member,
             created.resource_id,
             'workflow',
@@ -1743,7 +1743,7 @@ class ResourceMemberTest(SQLAlchemyTest):
         )
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.delete_resource_member,
             created.resource_id,
             'workflow',
@@ -1752,7 +1752,7 @@ class ResourceMemberTest(SQLAlchemyTest):
 
     def test_delete_nonexistent_resource_member(self):
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.delete_resource_member,
             'nonexitent_resource',
             'workflow',
@@ -1768,7 +1768,7 @@ class WorkflowSharingTest(SQLAlchemyTest):
         auth_context.set_ctx(user_context)
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_workflow_definition,
             wf.id
         )
@@ -1836,7 +1836,7 @@ class WorkflowSharingTest(SQLAlchemyTest):
         auth_context.set_ctx(user_context)
 
         self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             db_api.get_workflow_definition,
             wf.id
         )

mistral/tests/unit/engine/test_default_engine.py

@@ -89,7 +89,7 @@ ENVIRONMENT_DB = models.Environment(
 )
 
 MOCK_ENVIRONMENT = mock.MagicMock(return_value=ENVIRONMENT_DB)
-MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.NotFoundException())
+MOCK_NOT_FOUND = mock.MagicMock(side_effect=exc.DBEntityNotFoundException())
 
 
 class DefaultEngineTest(base.DbTestCase):
@@ -233,7 +233,7 @@ class DefaultEngineTest(base.DbTestCase):
 
     @mock.patch.object(db_api, "get_environment", MOCK_NOT_FOUND)
     def test_start_workflow_env_not_found(self):
-        self.assertRaises(exc.NotFoundException,
+        self.assertRaises(exc.DBEntityNotFoundException,
                           self.engine.start_workflow,
                           'wb.wf',
                           {'param1': '<% env().key1 %>'},

mistral/tests/unit/services/test_scheduler.py

@@ -289,7 +289,7 @@ class SchedulerServiceTest(base.DbTestCase):
 
         eventlet.sleep(WAIT)
 
-        self.assertRaises(exc.NotFoundException,
+        self.assertRaises(exc.DBEntityNotFoundException,
                           db_api.get_delayed_call,
                           calls[0].id
                           )
@@ -336,7 +336,7 @@ class SchedulerServiceTest(base.DbTestCase):
         eventlet.sleep(WAIT)
 
         # If the scheduler does handel calls that failed on update
-        # NotFoundException will raise.
+        # DBEntityNotFoundException will raise.
         db_api.get_delayed_call(calls[0].id)
 
         db_api.delete_delayed_call(calls[0].id)

mistral/tests/unit/services/test_workflow_service.py

@@ -165,7 +165,7 @@ class WorkflowServiceTest(base.DbTestCase):
 
     def test_update_non_existing_workflow_failed(self):
         exception = self.assertRaises(
-            exc.NotFoundException,
+            exc.DBEntityNotFoundException,
             wf_service.update_workflows,
             WORKFLOW
         )

mistral/tests/unit/test_exception_base.py

@@ -24,13 +24,13 @@ class ExceptionTestCase(base.BaseTest):
     """Test cases for exception code."""
 
     def test_nf_with_message(self):
-        exc = exceptions.NotFoundException('check_for_this')
+        exc = exceptions.DBEntityNotFoundException('check_for_this')
         self.assertIn('check_for_this',
                       six.text_type(exc))
         self.assertEqual(404, exc.http_code)
 
     def test_nf_with_no_message(self):
-        exc = exceptions.NotFoundException()
+        exc = exceptions.DBEntityNotFoundException()
         self.assertIn("Object not found",
                       six.text_type(exc))
         self.assertEqual(404, exc.http_code,)

mistral/tests/unit/test_expressions.py

@@ -99,15 +99,15 @@ class YaqlEvaluatorTest(base.BaseTest):
         self._evaluator.validate('$.a1 * $.a2')
 
     def test_validate_failed(self):
-        self.assertRaises(exc.YaqlEvaluationException,
+        self.assertRaises(exc.YaqlGrammarException,
                           self._evaluator.validate,
                           '*')
 
-        self.assertRaises(exc.YaqlEvaluationException,
+        self.assertRaises(exc.YaqlGrammarException,
                           self._evaluator.validate,
                           [1, 2, 3])
 
-        self.assertRaises(exc.YaqlEvaluationException,
+        self.assertRaises(exc.YaqlGrammarException,
                           self._evaluator.validate,
                           {'a': 1})
 
@@ -184,7 +184,7 @@ class InlineYAQLEvaluatorTest(base.BaseTest):
         self._evaluator.validate('The value is <% $.a1 %>.')
 
     def test_validate_failed(self):
-        self.assertRaises(exc.YaqlEvaluationException,
+        self.assertRaises(exc.YaqlGrammarException,
                           self._evaluator.validate,
                           'The value is <% * %>.')
 

mistral/workflow/base.py

@@ -53,7 +53,7 @@ def get_controller(wf_ex, wf_spec=None):
             break
 
     if not ctrl_cls:
-        raise exc.NotFoundException(
+        raise exc.MistralError(
             'Failed to find a workflow controller [type=%s]' % wf_type
         )