ControlInterface wrapper to help with timeouts

[migurski]

I use set_rt_frame_socket to send individual frames to my light strings. These are shown for 60 seconds before the string reverts to its last stored movie. Because the xled.control.ControlInterface does not set a short timeout when communicating with the lights, sometimes I see many-minute hangs during which communication is lost. These failed connections are intermittent, so in the absence of an xled timeout argument I’ve found that this wrapper class works well:

class TimeoutControlInterface:
    interface = None

    def __init__(self, *args, **kwargs):
        """Initialize xled.control.ControlInterface with same arguments"""
        self.interface = xled.control.ControlInterface(*args, **kwargs)

    def __getattr__(self, name):
        """Retrieve versions of self.interface methods that use a threaded timeout"""
        original_method, responses = getattr(self.interface, name), []

        def wrapped_method(*args, **kwargs):
            """Call the original method and stash its response"""
            responses.append(original_method(*args, **kwargs))

        def threaded_method(*args, **kwargs):
            """Call the wrapped method inside a thread and return its response"""
            thread = threading.Thread(target=wrapped_method, args=args, kwargs=kwargs)
            thread.start()
            thread.join(timeout=5.0)
            if thread.is_alive():
                raise Exception("Thread still alive")
            return responses[0]

        return threaded_method

It’s used just like xled.control.ControlInterface but raises an exception when a method call requires more than five seconds to complete. Hope it’s useful to someome!