38a9908be4
Make decorator code lean and mean by employing FunctorTask to implement them. This results in: - making everything we call 'task' to provide same interface; - encouraging distinction between task classes and task instances; - code becoming simpler. Implements: blueprint refactor-decorators Change-Id: I43f4ae2db2b7a20f294e2f2d91d53e151a60b139
78 lines
2.8 KiB
Python
78 lines
2.8 KiB
Python
# -*- coding: utf-8 -*-
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (C) 2013 Rackspace Hosting 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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import abc
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from taskflow.openstack.common import uuidutils
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from taskflow import utils
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class Task(object):
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"""An abstraction that defines a potential piece of work that can be
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applied and can be reverted to undo the work as a single unit.
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"""
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__metaclass__ = abc.ABCMeta
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def __init__(self, name, task_id=None):
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if task_id:
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self._uuid = task_id
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else:
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self._uuid = uuidutils.generate_uuid()
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self._name = name
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# An *immutable* input 'resource' name set this task depends
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# on existing before this task can be applied.
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self.requires = set()
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# An *immutable* input 'resource' name set this task would like to
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# depends on existing before this task can be applied (but does not
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# strongly depend on existing).
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self.optional = set()
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# An *immutable* output 'resource' name set this task
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# produces that other tasks may depend on this task providing.
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self.provides = set()
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# This identifies the version of the task to be ran which
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# can be useful in resuming older versions of tasks. Standard
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# major, minor version semantics apply.
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self.version = (1, 0)
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@property
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def uuid(self):
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return self._uuid
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@property
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def name(self):
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return self._name
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def __str__(self):
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return "%s==%s" % (self.name, utils.get_task_version(self))
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@abc.abstractmethod
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def __call__(self, context, *args, **kwargs):
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"""Activate a given task which will perform some operation and return.
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This method can be used to apply some given context and given set
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of args and kwargs to accomplish some goal. Note that the result
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that is returned needs to be serializable so that it can be passed
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back into this task if reverting is triggered.
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"""
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def revert(self, context, result, cause):
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"""Revert this task using the given context, result that the apply
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provided as well as any information which may have caused
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said reversion.
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"""
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