import time from platypush.backend import Backend from platypush.context import get_plugin from platypush.message.event.sensor import SensorDataChangeEvent, \ SensorDataAboveThresholdEvent, SensorDataBelowThresholdEvent class SensorBackend(Backend): """ Abstract backend for polling sensors. Triggers: * :class:`platypush.message.event.sensor.SensorDataChangeEvent` if the measurements of a sensor have changed * :class:`platypush.message.event.sensor.SensorDataAboveThresholdEvent` if the measurements of a sensor have gone above a configured threshold * :class:`platypush.message.event.sensor.SensorDataBelowThresholdEvent` if the measurements of a sensor have gone below a configured threshold """ default_tolerance = 1e-7 def __init__(self, plugin=None, plugin_args=None, thresholds=None, tolerance=default_tolerance, poll_seconds=None, enabled_sensors=None, **kwargs): """ :param plugin: If set, then this plugin instance, referenced by plugin id, will be polled through ``get_plugin()``. Example: ``'gpio.sensor.bme280'`` or ``'gpio.sensor.envirophat'``. :type plugin: str :param plugin_args: If plugin is set and its ``get_measurement()`` method accepts optional arguments, then you can pass those arguments through ``plugin_args``. :type plugin_args: dict :param thresholds: Thresholds can be either a scalar value or a dictionary (e.g. ``{"temperature": 20.0}``). Sensor threshold events will be fired when measurements get above or below these values. Set it as a scalar if your get_measurement() code returns a scalar, as a dictionary if it returns a dictionary of values. For instance, if your sensor code returns both humidity and temperature in a format like ``{'humidity':60.0, 'temperature': 25.0}``, you'll want to set up a threshold on temperature with a syntax like ``{'temperature':20.0}`` to trigger events when the temperature goes above/below 20 degrees. :param tolerance: If set, then the sensor change events will be triggered only if the difference between the new value and the previous value is higher than the specified tolerance. Example:: { "temperature": 0.01, # Tolerance on the 2nd decimal digit "humidity": 0.1 # Tolerance on the 1st decimal digit } :type tolerance: dict or float :param poll_seconds: If set, the thread will wait for the specified number of seconds between a read and the next one. :type poll_seconds: float :param enabled_sensors: If ``get_measurement()`` returns data in dict form, then ``enabled_sensors`` selects which keys should be taken into account when monitoring for new events (e.g. "temperature" or "humidity"). :type enabled_sensors: dict (in the form ``name -> [True/False]``), set or list """ super().__init__(**kwargs) self.data = None self.plugin = plugin self.plugin_args = plugin_args or {} self.thresholds = thresholds self.tolerance = tolerance self.poll_seconds = poll_seconds if isinstance(enabled_sensors, list): enabled_sensors = set(enabled_sensors) if isinstance(enabled_sensors, set): enabled_sensors = {k: True for k in enabled_sensors} self.enabled_sensors = enabled_sensors or {} def get_measurement(self): """ Wrapper around ``plugin.get_measurement()`` that can filter events on specified enabled sensors data or on specified tolerance values. It can be overridden by derived classes. """ if not self.plugin: raise NotImplementedError('No plugin specified') plugin = get_plugin(self.plugin) data = plugin.get_data(**self.plugin_args).output if self.enabled_sensors: data = { sensor: data[sensor] for sensor, enabled in self.enabled_sensors.items() if enabled and sensor in data } return data def get_new_data(self, new_data): if self.data is None or new_data is None: return new_data # noinspection PyBroadException try: # Scalar data case new_data = float(new_data) return new_data if abs(new_data - self.data) >= self.tolerance else None except: # If it's not a scalar then it should be a dict assert isinstance(new_data, dict) ret = {} for k, v in new_data.items(): if (v is None and self.data.get(k) is not None) \ or k not in self.data \ or self.tolerance is None: ret[k] = v continue if v is None: continue tolerance = None is_nan = False old_v = None try: v = float(v) old_v = float(self.data.get(k)) except (TypeError, ValueError): is_nan = True if not is_nan: if isinstance(self.tolerance, dict): tolerance = float(self.tolerance.get(k, self.default_tolerance)) else: try: tolerance = float(self.tolerance) except (TypeError, ValueError): pass if tolerance is None or is_nan or abs(v - old_v) >= tolerance: ret[k] = v return ret def on_stop(self): if not self.plugin: return plugin = get_plugin(self.plugin) if plugin and hasattr(plugin, 'close'): plugin.close() def run(self): super().run() self.logger.info('Initialized {} sensor backend'.format(self.__class__.__name__)) while not self.should_stop(): data = self.get_measurement() new_data = self.get_new_data(data) if new_data: self.bus.post(SensorDataChangeEvent(data=new_data)) data_below_threshold = {} data_above_threshold = {} if self.thresholds: if isinstance(self.thresholds, dict) and isinstance(data, dict): for (measure, thresholds) in self.thresholds.items(): if measure not in data: continue if not isinstance(thresholds, list): thresholds = [thresholds] for threshold in thresholds: if data[measure] > threshold and (self.data is None or ( measure in self.data and self.data[measure] <= threshold)): data_above_threshold[measure] = data[measure] elif data[measure] < threshold and (self.data is None or ( measure in self.data and self.data[measure] >= threshold)): data_below_threshold[measure] = data[measure] if data_below_threshold: self.bus.post(SensorDataBelowThresholdEvent(data=data_below_threshold)) if data_above_threshold: self.bus.post(SensorDataAboveThresholdEvent(data=data_above_threshold)) self.data = data if new_data: if isinstance(new_data, dict): for k, v in new_data.items(): self.data[k] = v else: self.data = new_data if self.poll_seconds: time.sleep(self.poll_seconds) # vim:sw=4:ts=4:et: