如何将多个参数传递给由 concurrent.futures.ProcessPoolExecutor 中的 executor.map() 迭代的函数

Question

The issue was posted several times here in stackoverflow, but none of them could help me as my case is very specific.

I have a function Myfunction(p1,p2,p3,p4) which need 4 parameters to run.

I need to run Myfunction on multiprocessing way.

I use concurrent.futures.ProcessPoolExecutor to do this job.

I know how to pass a list as an argument in the executor.map(Myfunction, argument)

But this time, I have a list of tuples which is the list of my 4 arguments for my multiprocessing.

Here is my code:

def Myfunction(p_udid,p_systemPort,p_deviceName, p_version, p_os):
    desired_caps = {}
    desired_caps['platformName'] = p_os
    desired_caps['platformVersion'] = p_version
    desired_caps['deviceName'] = p_deviceName
    desired_caps['udid'] = p_udid
    desired_caps['noReset'] = 'true'



if __name__ == '__main__':
    list=[('41492968379078','4730','S6S5IN3G','6','Android'),('53519716736397','4731','S6S5IN3G','6','Android'),('0123456789ABCDEF','4732','20','7','Android')]
    with concurrent.futures.ProcessPoolExecutor() as executor:
        multiprocesses = executor.map(Myfunction, list)

Of course I get an error :

concurrent.futures.process._RemoteTraceback: """ Traceback (most recent call last): File "C:\\Users\\Nino\\AppData\\Local\\Programs\\Python\\Python37\\lib\\concurrent\\futures\\process.py", line 239, in _process_worker r = call_item.fn(*call_item.args, **call_item.kwargs) File "C:\\Users\\Nino\\AppData\\Local\\Programs\\Python\\Python37\\lib\\concurrent\\futures\\process.py", line 198, in _process_chunk return [fn(*args) for args in chunk] File "C:\\Users\\Nino\\AppData\\Local\\Programs\\Python\\Python37\\lib\\concurrent\\futures\\process.py", line 198, in return [fn(*args) for args in chunk] TypeError: Myfunction() missing 4 required positional arguments: 'p_systemPort', 'p_deviceName', 'p_version', and 'p_os' """

The above exception was the direct cause of the following exception:

Traceback (most recent call last): File "E:/DropboxBACKUP14112018/Cff/Python/project_GITHUB/test2.py", line 24, in for multiprocess in multiprocesses: File "C:\\Users\\Nino\\AppData\\Local\\Programs\\Python\\Python37\\lib\\concurrent\\futures\\process.py", line 483, in _chain_from_iterable_of_lists for element in iterable: File "C:\\Users\\Nino\\AppData\\Local\\Programs\\Python\\Python37\\lib\\concurrent\\futures_base.py", line 598, in result_iterator yield fs.pop().result() File "C:\\Users\\Nino\\AppData\\Local\\Programs\\Python\\Python37\\lib\\concurrent\\futures_base.py", line 435, in result return self.__get_result() File "C:\\Users\\Nino\\AppData\\Local\\Programs\\Python\\Python37\\lib\\concurrent\\futures_base.py", line 384, in __get_result raise self._exception TypeError: Myfunction() missing 4 required positional arguments: 'p_systemPort', 'p_deviceName', 'p_version', and 'p_os

I tried different stuff from all the answers similar to my issue, but I didn't succeed.

Can someone help me please?

Answer 1

Here's a way you can make it work:

def Myfunction(*args):

    p_udid,p_systemPort,p_deviceName, p_version, p_os = args[0]

    desired_caps = {}
    desired_caps['platformName'] = p_os
    desired_caps['platformVersion'] = p_version
    desired_caps['deviceName'] = p_deviceName
    desired_caps['udid'] = p_udid
    desired_caps['noReset'] = 'true'
    return desired_caps

def cpu_tasks(func, *args):

    # set chunksize to be even 
    with ProcessPoolExecutor() as tp:
        result = tp.map(func, chunksize=10, *args)
    return list(result)

if __name__ == '__main__':
    lst=[('41492968379078','4730','S6S5IN3G','6','Android'),('53519716736397','4731','S6S5IN3G','6','Android'),('0123456789ABCDEF','4732','20','7','Android')]
    ans = cpu_tasks(Myfunction, *[lst])

    print(ans)

[{'platformName': 'Android',
  'platformVersion': '6',
  'deviceName': 'S6S5IN3G',
  'udid': '41492968379078',
  'noReset': 'true'},
 {'platformName': 'Android',
  'platformVersion': '6',
  'deviceName': 'S6S5IN3G',
  'udid': '53519716736397',
  'noReset': 'true'},
 {'platformName': 'Android',
  'platformVersion': '7',
  'deviceName': '20',
  'udid': '0123456789ABCDEF',
  'noReset': 'true'}]