core/homeassistant/components/sensor/command_line.py

105 lines
3.2 KiB
Python

"""
Allows to configure custom shell commands to turn a value for a sensor.
For more details about this platform, please refer to the documentation at
https://home-assistant.io/components/sensor.command_line/
"""
import logging
import subprocess
from datetime import timedelta
from homeassistant.const import CONF_VALUE_TEMPLATE
from homeassistant.helpers.entity import Entity
from homeassistant.helpers import template
from homeassistant.util import Throttle
_LOGGER = logging.getLogger(__name__)
DEFAULT_NAME = "Command Sensor"
# Return cached results if last scan was less then this time ago
MIN_TIME_BETWEEN_UPDATES = timedelta(seconds=60)
# pylint: disable=unused-argument
def setup_platform(hass, config, add_devices_callback, discovery_info=None):
"""Setup the Command Sensor."""
if config.get('command') is None:
_LOGGER.error('Missing required variable: "command"')
return False
data = CommandSensorData(config.get('command'))
add_devices_callback([CommandSensor(
hass,
data,
config.get('name', DEFAULT_NAME),
config.get('unit_of_measurement'),
config.get(CONF_VALUE_TEMPLATE)
)])
# pylint: disable=too-many-arguments
class CommandSensor(Entity):
"""Representation of a sensor that is using shell commands."""
def __init__(self, hass, data, name, unit_of_measurement, value_template):
"""Initialize the sensor."""
self._hass = hass
self.data = data
self._name = name
self._state = False
self._unit_of_measurement = unit_of_measurement
self._value_template = value_template
self.update()
@property
def name(self):
"""Return the name of the sensor."""
return self._name
@property
def unit_of_measurement(self):
"""Return the unit the value is expressed in."""
return self._unit_of_measurement
@property
def state(self):
"""Return the state of the device."""
return self._state
def update(self):
"""Get the latest data and updates the state."""
self.data.update()
value = self.data.value
if self._value_template is not None:
self._state = template.render_with_possible_json_value(
self._hass, self._value_template, value, 'N/A')
else:
self._state = value
# pylint: disable=too-few-public-methods
class CommandSensorData(object):
"""The class for handling the data retrieval."""
def __init__(self, command):
"""Initialize the data object."""
self.command = command
self.value = None
@Throttle(MIN_TIME_BETWEEN_UPDATES)
def update(self):
"""Get the latest data with a shell command."""
_LOGGER.info('Running command: %s', self.command)
try:
return_value = subprocess.check_output(self.command, shell=True,
timeout=15)
self.value = return_value.strip().decode('utf-8')
except subprocess.CalledProcessError:
_LOGGER.error('Command failed: %s', self.command)
except subprocess.TimeoutExpired:
_LOGGER.error('Timeout for command: %s', self.command)