e2c89f777d
* Introduced new class Workflow that manages life-cycle of running workflows and is responsible for managing workflow persistent state * Moved all workflow level logic to workflow handler and Workflow class * Changed semantics if how workflows start errors are handled. Previously, in case of invalid user input Mistral engine would store information about error in "state_info" field of workflow execution and bubble up an exception to the user. This approach was incorrect for a number of reasons including broken semantics: if an exception was raised due to invalid input it's normal to expect that system state has not changed. After this refactoring, engine only raises an exception in case of bad user input. That way behavior is consistent with the idea of exceptional situations. * Fixed unit tests in according to the previous point * Fixed a number of logical issues in tests. For example, in test_default_engine.py we expected one type of errors (e.g. env not found) but effectively received another one (invalid input). Partially implements: blueprint mistral-engine-error-handling Change-Id: I09070411fd833df8284cb80db69b8401a40eb6fe
186 lines
4.9 KiB
Python
186 lines
4.9 KiB
Python
# Copyright 2013 - Mirantis, Inc.
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# Copyright 2015 - StackStorm, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# TODO(rakhmerov): Can we make one parent for errors and exceptions?
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class MistralError(Exception):
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"""Mistral specific error.
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Reserved for situations that can't be automatically handled. When it occurs
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it signals that there is a major environmental problem like invalid startup
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configuration or implementation problem (e.g. some code doesn't take care
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of certain corner cases). From architectural perspective it's pointless to
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try to handle this type of problems except doing some finalization work
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like transaction rollback, deleting temporary files etc.
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"""
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message = "An unknown error occurred"
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http_code = 500
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def __init__(self, message=None):
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if message is not None:
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self.message = message
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super(MistralError, self).__init__(
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'%d: %s' % (self.http_code, self.message))
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@property
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def code(self):
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"""This is here for webob to read.
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https://github.com/Pylons/webob/blob/master/webob/exc.py
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"""
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return self.http_code
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def __str__(self):
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return self.message
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class MistralException(Exception):
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"""Mistral specific exception.
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Reserved for situations that are not critical for program continuation.
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It is possible to recover from this type of problems automatically and
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continue program execution. Such problems may be related with invalid user
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input (such as invalid syntax) or temporary environmental problems.
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In case if an instance of a certain exception type bubbles up to API layer
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then this type of exception it must be associated with an http code so it's
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clear how to represent it for a client.
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To correctly use this class, inherit from it and define a 'message' and
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'http_code' properties.
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"""
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message = "An unknown exception occurred"
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http_code = 500
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def __init__(self, message=None):
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if message is not None:
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self.message = message
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super(MistralException, self).__init__(
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'%d: %s' % (self.http_code, self.message))
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@property
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def code(self):
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"""This is here for webob to read.
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https://github.com/Pylons/webob/blob/master/webob/exc.py
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"""
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return self.http_code
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def __str__(self):
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return self.message
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# Database errors.
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class DBError(MistralError):
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http_code = 400
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class DBDuplicateEntryError(DBError):
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http_code = 409
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message = "Database object already exists"
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class DBQueryEntryError(DBError):
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http_code = 400
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class DBEntityNotFoundError(DBError):
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http_code = 404
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message = "Object not found"
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# DSL exceptions.
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class DSLParsingException(MistralException):
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http_code = 400
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class YaqlGrammarException(DSLParsingException):
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http_code = 400
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message = "Invalid grammar of YAQL expression"
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class InvalidModelException(DSLParsingException):
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http_code = 400
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message = "Wrong entity definition"
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# Various common exceptions and errors.
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class YaqlEvaluationException(MistralException):
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http_code = 400
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message = "Can not evaluate YAQL expression"
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class DataAccessException(MistralException):
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http_code = 400
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class ActionException(MistralException):
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http_code = 400
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class InvalidActionException(MistralException):
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http_code = 400
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class ActionRegistrationException(MistralException):
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message = "Failed to register action"
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class EngineException(MistralException):
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http_code = 500
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class WorkflowException(MistralException):
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http_code = 400
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class InputException(MistralException):
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http_code = 400
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class ApplicationContextNotFoundException(MistralException):
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http_code = 400
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message = "Application context not found"
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class InvalidResultException(MistralException):
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http_code = 400
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message = "Unable to parse result"
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class SizeLimitExceededException(MistralException):
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http_code = 400
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def __init__(self, field_name, size_kb, size_limit_kb):
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super(SizeLimitExceededException, self).__init__(
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"Size of '%s' is %dKB which exceeds the limit of %dKB"
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% (field_name, size_kb, size_limit_kb))
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class CoordinationException(MistralException):
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http_code = 500
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class NotAllowedException(MistralException):
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http_code = 403
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message = "Operation not allowed"
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