DummyExecutor for Python的`期货'

Question

Python的futures包允许我们享受ThreadPoolExecutor和ProcessPoolExecutor并行执行任务。

但是，对于调试，暂时用一个虚拟代替真正的并行性是有用的，虚拟代理在主线程中以串行方式执行任务，而不会产生任何线程或进程。

是否有任何执行DummyExecutor？

Answer 1

像这样的东西应该这样做：可能是没有必要在这种情况下

from concurrent.futures import Future, Executor 
from threading import Lock 


class DummyExecutor(Executor): 

    def __init__(self): 
     self._shutdown = False 
     self._shutdownLock = Lock() 

    def submit(self, fn, *args, **kwargs): 
     with self._shutdownLock: 
      if self._shutdown: 
       raise RuntimeError('cannot schedule new futures after shutdown') 

      f = Future() 
      try: 
       result = fn(*args, **kwargs) 
      except BaseException as e: 
       f.set_exception(e) 
      else: 
       f.set_result(result) 

      return f 

    def shutdown(self, wait=True): 
     with self._shutdownLock: 
      self._shutdown = True 


if __name__ == '__main__': 

    def fnc(err): 
     if err: 
      raise Exception("test") 
     else: 
      return "ok" 

    ex = DummyExecutor() 
    print(ex.submit(fnc, True)) 
    print(ex.submit(fnc, False)) 
    ex.shutdown() 
    ex.submit(fnc, True) # raises exception 

锁定，但是不能伤到拥有它。