定义一个带参数的装饰器

场景：想定义一个可以接受参数的装饰器。

@decorator(x, y, z)
def func(a, b):
    pass

等价

def func(a, b):
    pass
func = decorator(x, y, z)(func)

假设你想写一个装饰器，给函数添加日志功能，同时允许用户指定日志的级别和其他的选项

from functools import wraps
import logging


def logged(level, name=None):
    """
    Add logging to a function. level is the logging
    level, name is the logger name. If name aren't
    specified, they default to the function's module and name.
    """

    def decorate(func):
        logging.basicConfig(level=logging.DEBUG, format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')
        log_name = name if name else func.__module__
        log = logging.getLogger(log_name)

        @wraps(func)
        def wrapper(*args, **kwargs):
            result = func(*args, **kwargs)
            log.log(level, result)
            return result

        return wrapper

    return decorate

@logged(logging.DEBUG)
def add(x, y):
    return x + y


if __name__ == '__main__':
    delete()
    add(3, 2)

2019-02-19 15:10:27,849 - __main__ - DEBUG - 5