How to safely run unreliable piece of code?

Question

Suppose you are working with some bodgy piece of code which you can\'t trust, is there a way to run it safely without losing control of your script?

An example mig

Answer 1

In your real case application can you switch to multiprocessing? Becasue it seems that what you're asking could be done with multiprocessing + threading.Timer + try/except.

Take a look at this:

class SafeProcess(Process):
    def __init__(self, queue, *args, **kwargs):
        self.queue = queue
        super().__init__(*args, **kwargs)
    def run(self):
        print('Running')
        try:
            result = self._target(*self._args, **self._kwargs)
            self.queue.put_nowait(result)
        except:
            print('Exception')

result = None
while result != 'it worked!!':
    q = Queue()
    p = SafeProcess(q, target=unreliable_code)
    p.start()
    t = Timer(1, p.terminate)   # in case it should hang
    t.start()
    p.join()
    t.cancel()
    try:
        result = q.get_nowait()
    except queues.Empty:
        print('Empty')
    print(result)

That in one (lucky) case gave me:

Running
Empty
None
Running
it worked!!

In your code samples you have 4 out of 5 chances to get an error, so you might also spawn a pool or something to improve your chances of having a correct result.