9d0b16e7fb
Most TaskFlow exception don't have 'Exception' suffix in their names, so we drop it from the few that have it, for sake of consistency and more concise and expressive code. MissingDependencies parent object is changed from InvalidState to InvariantViolation, which is more appropriate. Unused ClosedException is dropped. Breaking change: any client code that used renamed exceptions, ClosedException or relied on catching MissingDependencies as InvariantViolationException is affected. Change-Id: I649b7760d382ccb6df333bdffd667ba6b67a431e
135 lines
4.0 KiB
Python
135 lines
4.0 KiB
Python
# -*- coding: utf-8 -*-
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# 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, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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class TaskFlowException(Exception):
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"""Base class for exceptions emitted from this library."""
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pass
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class Duplicate(TaskFlowException):
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"""Raised when a duplicate entry is found."""
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pass
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class StorageError(TaskFlowException):
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"""Raised when logbook can not be read/saved/deleted."""
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def __init__(self, message, cause=None):
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super(StorageError, self).__init__(message)
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self.cause = cause
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class NotFound(TaskFlowException):
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"""Raised when some entry in some object doesn't exist."""
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pass
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class AlreadyExists(TaskFlowException):
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"""Raised when some entry in some object already exists."""
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pass
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class InvalidState(TaskFlowException):
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"""Raised when a task/job/workflow is in an invalid state when an
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operation is attempting to apply to said task/job/workflow.
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"""
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pass
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class InvariantViolation(TaskFlowException):
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"""Raised when flow invariant violation is attempted."""
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pass
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class UnclaimableJob(TaskFlowException):
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"""Raised when a job can not be claimed."""
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pass
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class JobNotFound(TaskFlowException):
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"""Raised when a job entry can not be found."""
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pass
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class MissingDependencies(InvariantViolation):
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"""Raised when a entity has dependencies that can not be satisfied."""
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message = ("%(who)s requires %(requirements)s but no other entity produces"
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" said requirements")
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def __init__(self, who, requirements):
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message = self.message % {'who': who, 'requirements': requirements}
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super(MissingDependencies, self).__init__(message)
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self.missing_requirements = requirements
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class DependencyFailure(TaskFlowException):
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"""Raised when flow can't resolve dependency."""
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pass
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class EmptyFlow(TaskFlowException):
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"""Raised when flow doesn't contain tasks."""
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pass
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class WrappedFailure(TaskFlowException):
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"""Wraps one or several failures
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When exception cannot be re-raised (for example, because
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the value and traceback is lost in serialization) or
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there are several exceptions, we wrap corresponding Failure
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objects into this exception class.
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"""
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def __init__(self, causes):
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self._causes = []
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for cause in causes:
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if cause.check(type(self)) and cause.exception:
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# NOTE(imelnikov): flatten wrapped failures
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self._causes.extend(cause.exception)
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else:
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self._causes.append(cause)
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def __iter__(self):
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"""Iterate over failures that caused the exception"""
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return iter(self._causes)
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def __len__(self):
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"""Return number of wrapped failures"""
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return len(self._causes)
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def check(self, *exc_classes):
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"""Check if any of exc_classes caused (part of) the failure.
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Arguments of this method can be exception types or type names
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(stings). If any of wrapped failures were caused by exception
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of given type, the corresponding argument is returned. Else,
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None is returned.
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"""
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if not exc_classes:
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return None
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for cause in self:
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result = cause.check(*exc_classes)
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if result is not None:
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return result
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return None
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def __str__(self):
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return 'WrappedFailure: %s' % [str(cause) for cause in self._causes]
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