d4609ef3d0
Move code that gets callable args from functor task to utils.py and enhance it to support more use cases. We do not rely on naming conventions for 'self' and 'cls' parameters any more; we look at the collable if it is bound method instead. Change-Id: Ie1a9a7cc727b5fbc2780aba28b1d0253e5bc0ea4
116 lines
4.4 KiB
Python
116 lines
4.4 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 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):
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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 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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class FunctorTask(Task):
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"""Adaptor to make task from a callable
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Take any callable and make a task from it.
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"""
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def __init__(self, execute_with, **kwargs):
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"""Initialize FunctorTask instance with given callable and kwargs
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:param execute_with: the callable
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:param kwargs: reserved keywords (all optional) are
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name: name of the task, default None (auto generate)
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revert_with: the callable to revert, default None
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version: version of the task, default Task's version 1.0
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optionals: optionals of the task, default ()
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provides: provides of the task, default ()
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requires: requires of the task, default ()
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auto_extract: auto extract execute_with's args and put it into
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requires, default True
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"""
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name = kwargs.pop('name', None)
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if name is None:
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name = utils.get_callable_name(execute_with)
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super(FunctorTask, self).__init__(name)
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self._execute_with = execute_with
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self._revert_with = kwargs.pop('revert_with', None)
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self.version = kwargs.pop('version', self.version)
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self.optional.update(kwargs.pop('optional', ()))
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self.provides.update(kwargs.pop('provides', ()))
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self.requires.update(kwargs.pop('requires', ()))
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if kwargs.pop('auto_extract', True):
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f_args = utils.get_required_callable_args(execute_with)
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self.requires.update(a for a in f_args if a != 'context')
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if kwargs:
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raise TypeError('__init__() got an unexpected keyword argument %r'
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% kwargs.keys[0])
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def __call__(self, *args, **kwargs):
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return self._execute_with(*args, **kwargs)
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def revert(self, *args, **kwargs):
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if self._revert_with:
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return self._revert_with(*args, **kwargs)
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else:
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return None
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