Create command_sensor.py

This adds a binary command_sensor

homeassistant/components/binary_sensor/command_sensor.py

@@ -0,0 +1,101 @@
+"""
+homeassistant.components.sensor.command_sensor
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+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_sensor/
+"""
+import logging
+import subprocess
+from datetime import timedelta
+
+from homeassistant.const import CONF_VALUE_TEMPLATE
+from homeassistant.components.binary_sensor import BinarySensorDevice
+from homeassistant.util import template, Throttle
+
+_LOGGER = logging.getLogger(__name__)
+
+DEFAULT_NAME = "Command Sensor"
+DEFAULT_PAYLOAD_ON = 'ON'
+DEFAULT_PAYLOAD_OFF = 'OFF'
+
+# 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, discovery_info=None):
+    """ Add the Command Sensor. """
+
+    if config.get('command') is None:
+        _LOGGER.error('Missing required variable: "command"')
+        return False
+
+    data = CommandSensorData(config.get('command'))
+
+    add_devices([CommandBinarySensor(
+        hass,
+        data,
+        config.get('name', DEFAULT_NAME),
+        config.get('payload_on', DEFAULT_PAYLOAD_ON),
+        config.get('payload_off', DEFAULT_PAYLOAD_OFF),
+        config.get(CONF_VALUE_TEMPLATE)
+    )])
+
+
+# pylint: disable=too-many-arguments
+class CommandBinarySensor(BinarySensorDevice):
+    """ Represents a binary sensor that is returning a value of a shell commands. """
+    def __init__(self, hass, data, name, payload_on, payload_off, value_template):
+        self._hass = hass
+        self.data = data
+        self._name = name
+        self._state = False
+        self._payload_on = payload_on
+        self._payload_off = payload_off
+        self._value_template = value_template
+        self.update()
+
+    @property
+    def name(self):
+        """ The name of the sensor. """
+        return self._name
+
+    @property
+    def is_on(self):
+        """ True if the binary sensor is on. """
+        return self._state
+
+    def update(self):
+        """ Gets the latest data and updates the state. """
+        self.data.update()
+        value = self.data.value
+
+        if self._value_template is not None:
+            value = template.render_with_possible_json_value(
+                self._hass, self.value_template, value, False)
+        if value == self._payload_on:
+            self._state = True
+        elif value == self._payload_off:
+            self._state = False
+
+
+# pylint: disable=too-few-public-methods
+class CommandSensorData(object):
+    """ Class for handling the data retrieval. """
+
+    def __init__(self, command):
+        self.command = command
+        self.value = None
+
+    @Throttle(MIN_TIME_BETWEEN_UPDATES)
+    def update(self):
+        """ Gets the latest data with a shell command. """
+        _LOGGER.info('Running command: %s', self.command)
+
+        try:
+            return_value = subprocess.check_output(self.command, shell=True)
+            self.value = return_value.strip().decode('utf-8')
+        except subprocess.CalledProcessError:
+            _LOGGER.error('Command failed: %s', self.command)