Source code for

from import Value

[docs]class Switch: """A simple Switch that changes its value whenever a given threshold is reached.""" def __init__(self, threshold: float, invert: bool = False): """Creates a new Switch. The switch evaluates to True (False, if invert is True), if its value is smaller than the given threshold. Args: threshold: Threshold for switch. invert: If True, invert result of evaluation. """ self._threshold = threshold self._invert = invert
[docs] def __call__(self, sensor): """Evaluates this evaluator. Args: sensor: Sensor to evaluate. Returns: Result of evaluation. """ # get last value value = Value.objects.filter(sensor=sensor).order_by('-time').first() # non-existing values are always bad if value is None or value.value is None: return False # are we good? is_good = value.value < self._threshold # invert? if self._invert: is_good = not is_good # return it return is_good
[docs] def areas(self) -> list: """Returns list of areas for plot.""" return [{ 'type': 'danger', 'min' if self._invert else 'max': self._threshold }]