下面是我的@logged()裝飾器制造商。它的工作原理大致如下：它接受一個logger實例和一個disabled標志。如果disabled是False，則在裝飾函數之前/之后輸出一些日志。如果disabled是True，則它不輸出任何內容并抑制logger裝飾函數的 。無論是logger和disabled參數有自己的缺省值。但是，當我想使用默認值時，我仍然需要寫空括號，如下所示：@logged()def foo(): pass當我只想要默認參數時，有沒有辦法擺脫這些空括號？這是我想要的一個例子：@loggeddef foo(): pass@logged(disabled=True)def bar(): pass@logged()裝飾器制造商的代碼：import loggingimport logging.configfrom functools import wrapsdef logged(logger=logging.getLogger('default'), disabled=False): ''' Create a configured decorator that controls logging output of a function :param logger: the logger to send output to :param disabled: True if the logger should be disabled, False otherwise ''' def logged_decorator(foo): ''' Decorate a function and surround its call with enter/leave logs Produce logging output of the form: > enter foo ... > leave foo (returned value) ''' @wraps(foo) def wrapper(*args, **kwargs): was_disabled = logger.disabled # If the logger was not already disabled by something else, see if # it should be disabled by us. Important effect: if foo uses the # same logger, then any inner logging will be disabled as well. if not was_disabled: logger.disabled = disabled logger.debug(f'enter {foo.__qualname__}') result = foo(*args, **kwargs) logger.debug(f'leave {foo.__qualname__} ({result})') # Restore previous logger state: logger.disabled = was_disabled return result return wrapper return logged_decoratorlogging.config.dictConfig({ 'version': 1, 'formatters': { 'verbose': { 'format': '%(asctime)22s %(levelname)7s %(module)10s %(process)6d %(thread)15d %(message)s' } , 'simple': { 'format': '%(levelname)s %(message)s' } }
3 回答
夢里花落0921
TA貢獻1772條經驗 獲得超6個贊
它支持兩種開發風格：嵌套（如在 python 裝飾器工廠中）和平面（少一層嵌套）。這是您的示例在平面模式下的實現方式：
from decopatch import function_decorator, DECORATED
from makefun import wraps
@function_decorator
def logged(disabled=False, logger=logging.getLogger('default'), func=DECORATED):
# (1) create a signature-preserving wrapper
@wraps(func)
def _func_wrapper(*f_args, **f_kwargs):
# stuff
result = func(*f_args, **f_kwargs)
# stuff
return result
# (2) return it
return _func_wrapper
請注意，我使用makefun.wraps而不是functools.wraps此處，以便完全保留簽名（如果參數無效，則根本不會調用包裝器）。
decopatch支持另一種開發風格，我稱之為double-flat，專門用于創建這樣的簽名保留函數包裝器。您的示例將像這樣實現：
from decopatch import function_decorator, WRAPPED, F_ARGS, F_KWARGS
@function_decorator
def logged(disabled=False, logger=logging.getLogger('default'),
func=WRAPPED, f_args=F_ARGS, f_kwargs=F_KWARGS):
# this is directly the signature-preserving wrapper
# stuff
result = func(*f_args, **f_kwargs)
# stuff
return result
您可以檢查兩種樣式是否按預期工作：
@logged(disabled=True)
def foo():
pass
@logged
def bar():
pass
foo()
bar()
請查看文檔以獲取詳細信息。
POPMUISE
TA貢獻1765條經驗 獲得超5個贊
或者使用部分（在 Python 食譜中找到的解決方案：9.6）
from functools import wraps, partial
def foo(func=None, *, a=None, b=None):
if func is None:
return partial(foo, a=a, b=b)
@wraps(func)
def wrapper(*args, **kwargs):
return func(*args, **kwargs)
return wrapper
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