fbd06b552e
Code that makes name from a callable was moved from functor task to utils and enhanced to better support more use cases. Change-Id: I1280a31553c5051079e60b31cd1796f51485f040
131 lines
4.9 KiB
Python
131 lines
4.9 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
# vim: tabstop=4 shiftwidth=4 softtabstop=4
|
|
|
|
# Copyright (C) 2013 Rackspace Hosting Inc. All Rights Reserved.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License"); you may
|
|
# not use this file except in compliance with the License. You may obtain
|
|
# a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
# License for the specific language governing permissions and limitations
|
|
# under the License.
|
|
|
|
import abc
|
|
import inspect
|
|
|
|
from taskflow import utils
|
|
|
|
# These arguments are ones that we will skip when parsing for requirements
|
|
# for a function to operate (when used as a task).
|
|
AUTO_ARGS = ('self', 'context', 'cls')
|
|
|
|
|
|
class Task(object):
|
|
"""An abstraction that defines a potential piece of work that can be
|
|
applied and can be reverted to undo the work as a single unit.
|
|
"""
|
|
__metaclass__ = abc.ABCMeta
|
|
|
|
def __init__(self, name):
|
|
self._name = name
|
|
# An *immutable* input 'resource' name set this task depends
|
|
# on existing before this task can be applied.
|
|
self.requires = set()
|
|
# An *immutable* input 'resource' name set this task would like to
|
|
# depends on existing before this task can be applied (but does not
|
|
# strongly depend on existing).
|
|
self.optional = set()
|
|
# An *immutable* output 'resource' name set this task
|
|
# produces that other tasks may depend on this task providing.
|
|
self.provides = set()
|
|
# This identifies the version of the task to be ran which
|
|
# can be useful in resuming older versions of tasks. Standard
|
|
# major, minor version semantics apply.
|
|
self.version = (1, 0)
|
|
|
|
@property
|
|
def name(self):
|
|
return self._name
|
|
|
|
def __str__(self):
|
|
return "%s==%s" % (self.name, utils.get_task_version(self))
|
|
|
|
@abc.abstractmethod
|
|
def __call__(self, context, *args, **kwargs):
|
|
"""Activate a given task which will perform some operation and return.
|
|
|
|
This method can be used to apply some given context and given set
|
|
of args and kwargs to accomplish some goal. Note that the result
|
|
that is returned needs to be serializable so that it can be passed
|
|
back into this task if reverting is triggered.
|
|
"""
|
|
|
|
def revert(self, context, result, cause):
|
|
"""Revert this task using the given context, result that the apply
|
|
provided as well as any information which may have caused
|
|
said reversion.
|
|
"""
|
|
|
|
|
|
def _filter_arg(arg):
|
|
if arg in AUTO_ARGS:
|
|
return False
|
|
# In certain decorator cases it seems like we get the function to be
|
|
# decorated as an argument, we don't want to take that as a real argument.
|
|
if not isinstance(arg, basestring):
|
|
return False
|
|
return True
|
|
|
|
|
|
class FunctorTask(Task):
|
|
"""Adaptor to make task from a callable
|
|
|
|
Take any callable and make a task from it.
|
|
"""
|
|
|
|
def __init__(self, execute_with, **kwargs):
|
|
"""Initialize FunctorTask instance with given callable and kwargs
|
|
|
|
:param execute_with: the callable
|
|
:param kwargs: reserved keywords (all optional) are
|
|
name: name of the task, default None (auto generate)
|
|
revert_with: the callable to revert, default None
|
|
version: version of the task, default Task's version 1.0
|
|
optionals: optionals of the task, default ()
|
|
provides: provides of the task, default ()
|
|
requires: requires of the task, default ()
|
|
auto_extract: auto extract execute_with's args and put it into
|
|
requires, default True
|
|
"""
|
|
name = kwargs.pop('name', None)
|
|
if name is None:
|
|
name = utils.get_callable_name(execute_with)
|
|
super(FunctorTask, self).__init__(name)
|
|
self._execute_with = execute_with
|
|
self._revert_with = kwargs.pop('revert_with', None)
|
|
self.version = kwargs.pop('version', self.version)
|
|
self.optional.update(kwargs.pop('optional', ()))
|
|
self.provides.update(kwargs.pop('provides', ()))
|
|
self.requires.update(kwargs.pop('requires', ()))
|
|
if kwargs.pop('auto_extract', True):
|
|
f_args = inspect.getargspec(execute_with).args
|
|
self.requires.update([arg for arg in f_args if _filter_arg(arg)])
|
|
if kwargs:
|
|
raise TypeError('__init__() got an unexpected keyword argument %r'
|
|
% kwargs.keys[0])
|
|
|
|
def __call__(self, *args, **kwargs):
|
|
return self._execute_with(*args, **kwargs)
|
|
|
|
def revert(self, *args, **kwargs):
|
|
if self._revert_with:
|
|
return self._revert_with(*args, **kwargs)
|
|
else:
|
|
return None
|