具有装饰功能的多处理池给了我 "object has no attribute"

Question

下面是一个可重现的代码：

from multiprocessing import Pool

def method_exception_catcher(method):

    def method_exception_caught(*args, **kwargs):

        try:
            return method(*args, **kwargs)

        except Exception as e:
            raise type(e)(str(e) + ' from [{}] method'.format(method.__name__)) 

    return method_exception_caught

class MyClass():

    @method_exception_catcher
    def do_something(self, elem):
        return 1/0

    @method_exception_catcher
    def parallel_do_something(self):

        with contextlib.closing(Pool(processes=1)) as p:

            procs = [p.apply_async(self.do_something, args=(3, )) for k in range(1)]
            results = [proc.get() for proc in procs]
            p.close()
            p.join()

        return results

MyClass().parallel_do_something()

该代码给我 "AttributeError: 'MyClass' object has no attribute 'method_exception_caught'" 错误。

我该如何解决这个问题并让它成功地提高除以 0 的错误？谢谢！！

更新：

这是完整的错误输出：

Process ForkPoolWorker-4:
Traceback (most recent call last):
  File "/usr/lib64/python3.6/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/usr/lib64/python3.6/multiprocessing/process.py", line 93, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/lib64/python3.6/multiprocessing/pool.py", line 108, in worker
    task = get()
  File "/usr/lib64/python3.6/multiprocessing/queues.py", line 337, in get
    return _ForkingPickler.loads(res)
AttributeError: 'MyClass' object has no attribute 'method_exception_caught'

Answer 1

Pickling 一个函数只是写下它的（模块和）名称； unpickling（导入模块并）查找名称。因为你的 class 的方法（即，从装饰器返回的函数）有一个 __name__ 的 method_exception_caught，这就是酸洗使用的。

答案（出于其他原因，这也是一个好主意）是使用 functools.wraps 让您的包装函数模拟包装函数：

def decorator(f):
  @functools.wraps(f)
  def wrap(*a,**kw): return f(*a,**kw)
  return wrap

具有装饰功能的多处理池给了我 "object has no attribute"

multiprocessing Pool with decorated function gives me "object has no attribute"

python

python-multiprocessing