django自定义命令中的多处理引发PermissionError：[WinError 5]访问被拒绝

Question

我想通过Django运行命令时对函数进行多进程处理。 我有以下代码：

class Command(BaseCommand):
    #...
    def process_q(self):
        self.stdout.write(self.style.SUCCESS("starting"))

    def handle(self, *args, **options):
        p = multiprocessing.Process(target=self.process_q)
        p.start()

当我运行命令时，出现以下错误：

Traceback (most recent call last):
  File ".\manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\management\__init__.py", line 364, in execute_from_command_line
    utility.execute()
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\management\__init__.py", line 356, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\management\base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\management\base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "C:\Users\user\projects\leadne_django\leadne\chatbot_manager\management\commands\handle_mevent.py", line 43, in handle
    p.start()
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\multiprocessing\process.py", line 105, in start
    self._popen = self._Popen(self)
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\multiprocessing\context.py", line 223, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\multiprocessing\context.py", line 322, in _Popen
    return Popen(process_obj)
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\multiprocessing\popen_spawn_win32.py", line 65, in __init__
    reduction.dump(process_obj, to_child)
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\multiprocessing\reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)
TypeError: cannot serialize '_io.TextIOWrapper' object
PS C:\Users\user\projects\leadne_django\leadne> Traceback (most recent call last):
PS C:\Users\user\projects\leadne_django\leadne>
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\multiprocessing\spawn.py", line 99, in spawn_main
    new_handle = reduction.steal_handle(parent_pid, pipe_handle)
  File "C:\Users\user\AppData\Local\Programs\Python\Python36-32\lib\multiprocessing\reduction.py", line 87, in steal_handle
    _winapi.DUPLICATE_SAME_ACCESS | _winapi.DUPLICATE_CLOSE_SOURCE)
PermissionError: [WinError 5] Access is denied