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Handle MemoryError in aioble_central.py scanner event

Open brianreinhold opened this issue 8 months ago • 1 comments

I am using the scanner as follows in my application code

      # The 'scanner' is of type 'scan' defined in aioble
      async with scan(duration_ms=10000,  # The length of the scan cycle in milliseconds. 
                      interval_us=30000,  # The time between each scan listen start
                      window_us=15000,    # The length of time during the scan interval one is actually listening
                                          # If interval_us = window_us the scan is non stop (so called fully duty cycle)
                                          # Background scanning usually sets the window_us to be less than interval_us.
                      active=True) as scanner:    # active = True means do scan requests to get scan responses
                                                  # For PHD we always want to do active scans.

However, every once and a while in the scan event handler a MemoryError is thrown while trying to load a result into the queue shown below:

    if event == _IRQ_SCAN_RESULT:
        addr_type, addr, adv_type, rssi, adv_data = data    # data here is a tuple[int, bytes, int, int, bytes]
        if not _active_scanner:
            return
        try:
            if queue_scan:
                _active_scanner._queue.append((addr_type, bytes(addr), adv_type, rssi, bytes(adv_data)))
                _active_scanner._event.set()
        except MemoryError:
            queue_scan = False
            logger.error('LNI: AIOBLE: Memory allocation error queuing an advertisement/scan response.') # type: ignore
            import gc
            gc.collect()

I have added a handler for the exception and would like to be able to recover from the error but am not sure what else I need to do. With the code shown above, the scanner restarts after 10 seconds but ScanResult objects are no longer created. Not sure why. Do I need to set the event? Do I need to add a filter that blocks repeat advertisements in a given scan cycle? Maybe it is simply not possible to recover from such an error?

Any help is greatly appreciated, especially from the code author.

brianreinhold avatar May 28 '24 12:05 brianreinhold