Allow setting the retain flag for mqtt switch.

Some devices can read the initial value on startup.
If the retain flag is set they always receive the value as last set by
home assistant.

homeassistant/components/mqtt/__init__.py

@@ -28,6 +28,7 @@ MQTT_CLIENT = None
 DEFAULT_PORT = 1883
 DEFAULT_KEEPALIVE = 60
 DEFAULT_QOS = 0
+DEFAULT_RETAIN = False
 
 SERVICE_PUBLISH = 'publish'
 EVENT_MQTT_MESSAGE_RECEIVED = 'MQTT_MESSAGE_RECEIVED'
@@ -46,11 +47,12 @@ CONF_CERTIFICATE = 'certificate'
 ATTR_TOPIC = 'topic'
 ATTR_PAYLOAD = 'payload'
 ATTR_QOS = 'qos'
+ATTR_RETAIN = 'retain'
 
 MAX_RECONNECT_WAIT = 300  # seconds
 
 
-def publish(hass, topic, payload, qos=None):
+def publish(hass, topic, payload, qos=None, retain=None):
     """ Send an MQTT message. """
     data = {
         ATTR_TOPIC: topic,
@@ -58,6 +60,10 @@ def publish(hass, topic, payload, qos=None):
     }
     if qos is not None:
         data[ATTR_QOS] = qos
+
+    if retain is not None:
+        data[ATTR_RETAIN] = retain
+
     hass.services.call(DOMAIN, SERVICE_PUBLISH, data)
 
 
@@ -119,9 +125,10 @@ def setup(hass, config):
         msg_topic = call.data.get(ATTR_TOPIC)
         payload = call.data.get(ATTR_PAYLOAD)
         qos = call.data.get(ATTR_QOS, DEFAULT_QOS)
+        retain = call.data.get(ATTR_RETAIN, DEFAULT_RETAIN)
         if msg_topic is None or payload is None:
             return
-        MQTT_CLIENT.publish(msg_topic, payload, qos)
+        MQTT_CLIENT.publish(msg_topic, payload, qos, retain)
 
     hass.bus.listen_once(EVENT_HOMEASSISTANT_START, start_mqtt)
 
@@ -190,9 +197,9 @@ class MQTT(object):
 
         self._mqttc.connect(broker, port, keepalive)
 
-    def publish(self, topic, payload, qos):
+    def publish(self, topic, payload, qos, retain):
         """ Publish a MQTT message. """
-        self._mqttc.publish(topic, payload, qos)
+        self._mqttc.publish(topic, payload, qos, retain)
 
     def start(self):
         """ Run the MQTT client. """

homeassistant/components/switch/mqtt.py

@@ -17,6 +17,7 @@ DEFAULT_QOS = 0
 DEFAULT_PAYLOAD_ON = "ON"
 DEFAULT_PAYLOAD_OFF = "OFF"
 DEFAULT_OPTIMISTIC = False
+DEFAULT_RETAIN = False
 
 DEPENDENCIES = ['mqtt']
 
@@ -35,6 +36,7 @@ def setup_platform(hass, config, add_devices_callback, discovery_info=None):
         config.get('state_topic'),
         config.get('command_topic'),
         config.get('qos', DEFAULT_QOS),
+        config.get('retain', DEFAULT_RETAIN),
         config.get('payload_on', DEFAULT_PAYLOAD_ON),
         config.get('payload_off', DEFAULT_PAYLOAD_OFF),
         config.get('optimistic', DEFAULT_OPTIMISTIC),
@@ -44,7 +46,7 @@ def setup_platform(hass, config, add_devices_callback, discovery_info=None):
 # pylint: disable=too-many-arguments, too-many-instance-attributes
 class MqttSwitch(SwitchDevice):
     """ Represents a switch that can be toggled using MQTT. """
-    def __init__(self, hass, name, state_topic, command_topic, qos,
+    def __init__(self, hass, name, state_topic, command_topic, qos, retain,
                  payload_on, payload_off, optimistic, state_format):
         self._state = False
         self._hass = hass
@@ -52,6 +54,7 @@ class MqttSwitch(SwitchDevice):
         self._state_topic = state_topic
         self._command_topic = command_topic
         self._qos = qos
+        self._retain = retain
         self._payload_on = payload_on
         self._payload_off = payload_off
         self._optimistic = optimistic
@@ -93,7 +96,7 @@ class MqttSwitch(SwitchDevice):
     def turn_on(self, **kwargs):
         """ Turn the device on. """
         mqtt.publish(self.hass, self._command_topic, self._payload_on,
-                     self._qos)
+                     self._qos, self._retain)
         if self._optimistic:
             # optimistically assume that switch has changed state
             self._state = True
@@ -102,7 +105,7 @@ class MqttSwitch(SwitchDevice):
     def turn_off(self, **kwargs):
         """ Turn the device off. """
         mqtt.publish(self.hass, self._command_topic, self._payload_off,
-                     self._qos)
+                     self._qos, self._retain)
         if self._optimistic:
             # optimistically assume that switch has changed state
             self._state = False