core/homeassistant/components/sensor/template.py

132 lines
3.9 KiB
Python

"""
homeassistant.components.sensor.template
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allows the creation of a sensor that breaks out state_attributes
from other entities.
For more details about this platform, please refer to the documentation at
https://home-assistant.io/components/sensor.template/
"""
import logging
from homeassistant.helpers.entity import Entity, generate_entity_id
from homeassistant.core import EVENT_STATE_CHANGED
from homeassistant.const import (
ATTR_FRIENDLY_NAME,
CONF_VALUE_TEMPLATE,
ATTR_UNIT_OF_MEASUREMENT)
from homeassistant.util import template, slugify
from homeassistant.exceptions import TemplateError
from homeassistant.components.sensor import DOMAIN
ENTITY_ID_FORMAT = DOMAIN + '.{}'
_LOGGER = logging.getLogger(__name__)
CONF_SENSORS = 'sensors'
STATE_ERROR = 'error'
# pylint: disable=unused-argument
def setup_platform(hass, config, add_devices, discovery_info=None):
""" Sets up the sensors. """
sensors = []
if config.get(CONF_SENSORS) is None:
_LOGGER.error("Missing configuration data for sensor platform")
return False
for device, device_config in config[CONF_SENSORS].items():
if device != slugify(device):
_LOGGER.error("Found invalid key for sensor.template: %s. "
"Use %s instead", device, slugify(device))
continue
if not isinstance(device_config, dict):
_LOGGER.error("Missing configuration data for sensor %s", device)
continue
friendly_name = device_config.get(ATTR_FRIENDLY_NAME, device)
unit_of_measurement = device_config.get(ATTR_UNIT_OF_MEASUREMENT)
state_template = device_config.get(CONF_VALUE_TEMPLATE)
if state_template is None:
_LOGGER.error(
"Missing %s for sensor %s", CONF_VALUE_TEMPLATE, device)
continue
sensors.append(
SensorTemplate(
hass,
device,
friendly_name,
unit_of_measurement,
state_template)
)
if not sensors:
_LOGGER.error("No sensors added")
return False
add_devices(sensors)
return True
class SensorTemplate(Entity):
""" Represents a Template Sensor. """
# pylint: disable=too-many-arguments
def __init__(self,
hass,
device_id,
friendly_name,
unit_of_measurement,
state_template):
self.entity_id = generate_entity_id(
ENTITY_ID_FORMAT, device_id,
hass=hass)
self.hass = hass
self._name = friendly_name
self._unit_of_measurement = unit_of_measurement
self._template = state_template
self.update()
def _update_callback(_event):
""" Called when the target device changes state. """
self.update_ha_state(True)
self.hass.bus.listen(EVENT_STATE_CHANGED, _update_callback)
@property
def name(self):
""" Returns the name of the device. """
return self._name
@property
def state(self):
""" Returns the state of the device. """
return self._state
@property
def unit_of_measurement(self):
""" Returns the unit_of_measurement of the device. """
return self._unit_of_measurement
@property
def should_poll(self):
""" Tells Home Assistant not to poll this entity. """
return False
def update(self):
try:
self._state = template.render(self.hass, self._template)
except TemplateError as ex:
self._state = STATE_ERROR
if ex.args and ex.args[0].startswith(
"UndefinedError: 'None' has no attribute"):
# Common during HA startup - so just a warning
_LOGGER.warning(ex)
return
_LOGGER.error(ex)