62 lines
1.5 KiB
Python
62 lines
1.5 KiB
Python
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'''
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Implementation of exception-aware threads, including a listener to be put in
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the top-level thread
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'''
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import queue
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from threading import Thread, Event
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# Killswitch for exception queue listener. Pass this to top-level thread so it
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# can be called as part of clean up code
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excStopper = Event()
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# queue to shuttle exceptions from children to top-level thread
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_excQueue = queue.Queue()
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def excChildListener():
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'''
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Queue listener to intercept exceptions thrown in child threads that are
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exception-aware
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'''
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while not excStopper.isSet():
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try:
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raise _excQueue.get(True)
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_excQueue.task_done()
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except queue.Empty:
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pass
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while 1:
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try:
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raise _excQueue.get(False)
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_excQueue.task_done()
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except queue.Empty:
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break
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class ExceptionThread(Thread):
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'''
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Thread that passes exceptions to a queue, which is handled by
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excChildListener in top-level thread
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'''
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def __init__(self, group=None, target=None, name=None, args=(), kwargs=None, *, daemon=None):
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super().__init__(group, target, name, args, kwargs, daemon=daemon)
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self._queue = _excQueue
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def run(self):
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try:
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Thread.run(self)
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except BaseException as e:
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self._queue.put(e)
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class async:
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'''
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Wraps any function in an exception-aware thread and starts the thread.
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Intended to be used as a decorator
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'''
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def __init__(self, daemon=False):
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self._daemon = daemon
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def __call__(self, f):
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def wrapper(*args, **kwargs):
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t = ExceptionThread(target=f, daemon=self._daemon, args=args, kwargs=kwargs)
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t.start()
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return wrapper
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