Add Volkszaehler sensor (#16188)

* Add Volkszaehler sensor

* Update icons

* Improve code

.coveragerc

@@ -759,6 +759,7 @@ omit =
     homeassistant/components/sensor/uscis.py
     homeassistant/components/sensor/vasttrafik.py
     homeassistant/components/sensor/viaggiatreno.py
+    homeassistant/components/sensor/volkszaehler.py
     homeassistant/components/sensor/waqi.py
     homeassistant/components/sensor/waze_travel_time.py
     homeassistant/components/sensor/whois.py

homeassistant/components/sensor/volkszaehler.py

@@ -0,0 +1,138 @@
+"""
+Support for consuming values for the Volkszaehler API.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/sensor.volkszaehler/
+"""
+from datetime import timedelta
+import logging
+
+import voluptuous as vol
+
+from homeassistant.components.sensor import PLATFORM_SCHEMA
+from homeassistant.const import (
+    CONF_HOST, CONF_NAME, CONF_PORT, CONF_MONITORED_CONDITIONS)
+from homeassistant.exceptions import PlatformNotReady
+from homeassistant.helpers.aiohttp_client import async_get_clientsession
+import homeassistant.helpers.config_validation as cv
+from homeassistant.helpers.entity import Entity
+from homeassistant.util import Throttle
+
+REQUIREMENTS = ['volkszaehler==0.1.2']
+
+_LOGGER = logging.getLogger(__name__)
+
+CONF_UUID = 'uuid'
+
+DEFAULT_HOST = 'localhost'
+DEFAULT_NAME = 'Volkszaehler'
+DEFAULT_PORT = 80
+
+MIN_TIME_BETWEEN_UPDATES = timedelta(minutes=1)
+
+SENSOR_TYPES = {
+    'average': ['Average', 'W', 'mdi:power-off'],
+    'consumption': ['Consumption', 'Wh', 'mdi:power-plug'],
+    'max': ['Max', 'W', 'mdi:arrow-up'],
+    'min': ['Min', 'W', 'mdi:arrow-down'],
+}
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Required(CONF_UUID): cv.string,
+    vol.Optional(CONF_HOST, default=DEFAULT_HOST): cv.string,
+    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+    vol.Optional(CONF_PORT, default=DEFAULT_PORT): cv.port,
+    vol.Optional(CONF_MONITORED_CONDITIONS, default=['average']):
+        vol.All(cv.ensure_list, [vol.In(SENSOR_TYPES)]),
+})
+
+
+async def async_setup_platform(
+        hass, config, async_add_entities, discovery_info=None):
+    """Set up the Volkszaehler sensors."""
+    from volkszaehler import Volkszaehler
+
+    host = config[CONF_HOST]
+    name = config[CONF_NAME]
+    port = config[CONF_PORT]
+    uuid = config[CONF_UUID]
+    conditions = config[CONF_MONITORED_CONDITIONS]
+
+    session = async_get_clientsession(hass)
+    vz_api = VolkszaehlerData(
+        Volkszaehler(hass.loop, session, uuid, host=host, port=port))
+
+    await vz_api.async_update()
+
+    if vz_api.api.data is None:
+        raise PlatformNotReady
+
+    dev = []
+    for condition in conditions:
+        dev.append(VolkszaehlerSensor(vz_api, name, condition))
+
+    async_add_entities(dev, True)
+
+
+class VolkszaehlerSensor(Entity):
+    """Implementation of a Volkszaehler sensor."""
+
+    def __init__(self, vz_api, name, sensor_type):
+        """Initialize the Volkszaehler sensor."""
+        self.vz_api = vz_api
+        self._name = name
+        self.type = sensor_type
+        self._state = None
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return '{} {}'.format(self._name, SENSOR_TYPES[self.type][0])
+
+    @property
+    def icon(self):
+        """Icon to use in the frontend, if any."""
+        return SENSOR_TYPES[self.type][2]
+
+    @property
+    def unit_of_measurement(self):
+        """Return the unit the value is expressed in."""
+        return SENSOR_TYPES[self.type][1]
+
+    @property
+    def available(self):
+        """Could the device be accessed during the last update call."""
+        return self.vz_api.available
+
+    @property
+    def state(self):
+        """Return the state of the resources."""
+        return self._state
+
+    async def async_update(self):
+        """Get the latest data from REST API."""
+        await self.vz_api.async_update()
+
+        if self.vz_api.api.data is not None:
+            self._state = round(getattr(self.vz_api.api, self.type), 2)
+
+
+class VolkszaehlerData:
+    """The class for handling the data retrieval from the Volkszaehler API."""
+
+    def __init__(self, api):
+        """Initialize the data object."""
+        self.api = api
+        self.available = True
+
+    @Throttle(MIN_TIME_BETWEEN_UPDATES)
+    async def async_update(self):
+        """Get the latest data from the Volkszaehler REST API."""
+        from volkszaehler.exceptions import VolkszaehlerApiConnectionError
+
+        try:
+            await self.api.get_data()
+            self.available = True
+        except VolkszaehlerApiConnectionError:
+            _LOGGER.error("Unable to fetch data from the Volkszaehler API")
+            self.available = False

requirements_all.txt

@@ -1431,6 +1431,9 @@ uvcclient==0.10.1
 # homeassistant.components.climate.venstar
 venstarcolortouch==0.6
 
+# homeassistant.components.sensor.volkszaehler
+volkszaehler==0.1.2
+
 # homeassistant.components.config.config_entries
 voluptuous-serialize==2.0.0