具有異步工作者的多處理池

Question

考慮以下代碼：

class Sandbox:
    def __init__(self):
        self.pool = Pool(4)

    def worker(self, x):
        print(x) # Should be printing "testing123"

    def run(self):
        res = self.pool.apply_async(self.worker, ("testing123",))
        print(res.get()) # NotImplementedError
        self.pool.close()
        self.pool.join()


sandbox = Sandbox()
sandbox.run()

當我運行這個時，我得到

NotImplementedError：池對象不能在進程之間傳遞或腌制

res.get() 揭示了異常——如果我刪除它，什么也不會發生。

Answer 1

async_apply獲取 state 並設置 state，因此您需要修改這些方法，例如：

from multiprocessing import Pool
class Sandbox:
    def __init__(self):
        self.pool = Pool(4)

    def worker(self, x):
        print(x) # Should be printing "testing123"

    def run(self):
        res = self.pool.apply_async(self.worker, ("testing123",))
        print(res.get()) # NotImplementedError
        self.pool.close()
        self.pool.join()

    def __getstate__(self):
        self_dict = self.__dict__.copy()
        del self_dict['pool']
        return self_dict

    def __setstate__(self, state):
        self.__dict__.update(state)


sandbox = Sandbox()
sandbox.run()