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pythonbluetoothhci

Python: "Unbreakable" infinite loop was exited

I'm recording data with a RuuviTag Bluetooth sensor which sends temperature values to my RaspberryPi.

According to the RuuviTag Python library docu I'm supposed to use the function RuuviTagSensor.get_datas(handle_data) which starts an infinite loop of the function handle_data(). In my case, I designed it like:

def handle_data(found_data):
    temperature_measurement = found_data[1]['temperature']
    publish_via_mqtt(temperature_measurement)

and I wrapped it all up in:

while True:
    try:
        RuuviTagSensor.get_datas(handle_data)
    except Exception:
        logger.exception(f"An error occurred at {datetime.now(timezone.utc)}")
        reconnect_mqtt()

However, overnight, I broke ...

The logs say:

INFO:ruuvitag_sensor.ble_communication:Problem with hciconfig reset. Retry reset.
INFO:ruuvitag_sensor.ble_communication:Problem with hciconfig reset. Retry reset.
INFO:ruuvitag_sensor.ble_communication:Problem with hciconfig reset. Retry reset.
INFO:ruuvitag_sensor.ble_communication:Problem with hciconfig reset. Exit.

So it seems like the RaspberryPi hat a Bluetooth problem and tried to reconnect with the Ruuvis ... and when that did not work 3 times, he just EXITED PYTHON? Am I correct? Is there a way to restart the whole script if it is exited or handle this exit?

Solution

  • In the library code, exit(1) is called if the sensor cannot be started after three attempts.

    Calling exit raises the SystemExit exception. SystemExit does not inherit from Exception, and so is not caught by the try/except block in the code in the question. This behaviour seems to be intentional, according to the project's README:

    In case of errors, application tries to exit immediately, so it can be automatically restarted.

    Trapping SystemExit within the program is possible (except SystemExit:) if you want to force the library to keep retrying.