Files
deb-python-taskflow/taskflow/decorators.py

103 lines
3.1 KiB
Python

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (C) 2012-2013 Yahoo! 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 functools
from taskflow import task as base
from taskflow import utils
from taskflow.utils import threading_utils
def wraps(fn):
"""This will not be needed in python 3.2 or greater which already has this
built-in to its functools.wraps method.
"""
def wrapper(f):
f = functools.wraps(fn)(f)
f.__wrapped__ = getattr(fn, '__wrapped__', fn)
return f
return wrapper
def locked(*args, **kwargs):
def decorator(f):
attr_name = kwargs.get('lock', '_lock')
@wraps(f)
def wrapper(*args, **kwargs):
lock = getattr(args[0], attr_name)
if isinstance(lock, (tuple, list)):
lock = threading_utils.MultiLock(locks=list(lock))
with lock:
return f(*args, **kwargs)
return wrapper
# This is needed to handle when the decorator has args or the decorator
# doesn't have args, python is rather weird here...
if kwargs or not args:
return decorator
else:
if len(args) == 1:
return decorator(args[0])
else:
return decorator
def _original_function(fun):
"""Get original function from static or class method"""
if isinstance(fun, staticmethod):
return fun.__get__(object())
elif isinstance(fun, classmethod):
return fun.__get__(object()).im_func
return fun
def task(*args, **kwargs):
"""Decorates a given function so that it can be used as a task"""
def decorator(f):
def task_factory(execute, **factory_kwargs):
merged = kwargs.copy()
merged.update(factory_kwargs)
# NOTE(imelnikov): we can't capture f here because for
# bound methods and bound class methods the object it
# is bound to is yet unknown at the moment
#
# See: http://bit.ly/15Cfbjh
return base.FunctorTask(execute, **merged)
w_f = _original_function(f)
setattr(w_f, utils.TASK_FACTORY_ATTRIBUTE, task_factory)
return f
# This is needed to handle when the decorator has args or the decorator
# doesn't have args, python is rather weird here...
if kwargs:
if args:
raise TypeError('task decorator takes 0 positional arguments,'
'%s given' % len(args))
return decorator
else:
if len(args) == 1:
return decorator(args[0])
else:
return decorator