Add mysensors component and switch platform

* Add a general mysensors component. This sets up the serial comm
        with the gateway through pymysensors. The component also
        contains a decorator function for the callback function of
        mysensors platforms. Mysensors platforms should create a
        function that listens for the node update event fired by the
        mysensors component. This function should call another
        function, that uses the decorator, and returns a dict. The dict
        should contain a list of which mysensors V_TYPE values the
        platform handles, the platfrom class and the add_devices
        function (from setup_platform).
    * Change existing mysensors sensor platform to depend on the new
        mysensors component.
    * Add a mysensors switch platform. The switch platform takes
        advantage of new functionality from the the fork of pymysensors
        https://github.com/MartinHjelmare/pymysensors, that enables the
        gateway to send commands to change node child values.
    * Change const and is_metric to global constants, in the mysensors
        component and import const depending on the mysensors version
        used.
    * Change variables devices and gateway to global variables.
    * Add some debug logging at INFO log level.

homeassistant/components/mysensors.py

@@ -0,0 +1,150 @@
+"""
+homeassistant.components.mysensors
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+MySensors component that connects to a MySensors gateway via pymysensors
+API.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/sensor.mysensors.html
+"""
+import logging
+
+from homeassistant.helpers import (validate_config)
+
+from homeassistant.const import (
+    EVENT_HOMEASSISTANT_STOP,
+    TEMP_CELCIUS)
+
+CONF_PORT = 'port'
+CONF_DEBUG = 'debug'
+CONF_PERSISTENCE = 'persistence'
+CONF_PERSISTENCE_FILE = 'persistence_file'
+CONF_VERSION = 'version'
+
+DOMAIN = 'mysensors'
+DEPENDENCIES = []
+REQUIREMENTS = ['file:///home/martin/Dev/pymysensors-fifo_queue.zip'
+                '#pymysensors==0.3']
+_LOGGER = logging.getLogger(__name__)
+ATTR_NODE_ID = 'node_id'
+ATTR_CHILD_ID = 'child_id'
+
+PLATFORM_FORMAT = '{}.{}'
+IS_METRIC = None
+DEVICES = None
+GATEWAY = None
+
+EVENT_MYSENSORS_NODE_UPDATE = 'MYSENSORS_NODE_UPDATE'
+UPDATE_TYPE = 'update_type'
+NODE_ID = 'nid'
+
+CONST = None
+
+
+def setup(hass, config):
+    """ Setup the MySensors component. """
+
+    import mysensors.mysensors as mysensors
+
+    if not validate_config(config,
+                           {DOMAIN: [CONF_PORT]},
+                           _LOGGER):
+        return False
+
+    version = config[DOMAIN].get(CONF_VERSION, '1.4')
+
+    global CONST
+    if version == '1.4':
+        import mysensors.const_14 as const
+        CONST = const
+        _LOGGER.info('CONST = %s, 1.4', const)
+    elif version == '1.5':
+        import mysensors.const_15 as const
+        CONST = const
+        _LOGGER.info('CONST = %s, 1.5', const)
+    else:
+        import mysensors.const_14 as const
+        CONST = const
+        _LOGGER.info('CONST = %s, 1.4 default', const)
+
+    global IS_METRIC
+    # Just assume celcius means that the user wants metric for now.
+    # It may make more sense to make this a global config option in the future.
+    IS_METRIC = (hass.config.temperature_unit == TEMP_CELCIUS)
+    global DEVICES
+    DEVICES = {}    # keep track of devices added to HA
+
+    def node_update(update_type, nid):
+        """ Callback for node updates from the MySensors gateway. """
+        _LOGGER.info('update %s: node %s', update_type, nid)
+
+        hass.bus.fire(EVENT_MYSENSORS_NODE_UPDATE, {
+            UPDATE_TYPE: update_type,
+            NODE_ID: nid
+        })
+
+    port = config[DOMAIN].get(CONF_PORT)
+
+    persistence = config[DOMAIN].get(CONF_PERSISTENCE, True)
+    persistence_file = config[DOMAIN].get(
+        CONF_PERSISTENCE_FILE, hass.config.path('mysensors.pickle'))
+
+    global GATEWAY
+    GATEWAY = mysensors.SerialGateway(port, node_update,
+                                      persistence=persistence,
+                                      persistence_file=persistence_file,
+                                      protocol_version=version)
+    GATEWAY.metric = IS_METRIC
+    GATEWAY.debug = config[DOMAIN].get(CONF_DEBUG, False)
+    GATEWAY.start()
+
+    if persistence:
+        for nid in GATEWAY.sensors:
+            node_update('node_update', nid)
+
+    hass.bus.listen_once(EVENT_HOMEASSISTANT_STOP,
+                         lambda event: GATEWAY.stop())
+
+    return True
+
+
+def mysensors_update(platform_type):
+    """
+    Decorator for callback function for sensor updates from the MySensors
+    component.
+    """
+    def wrapper(gateway, devices, nid):
+        """Wrapper function in the decorator."""
+        sensor = gateway.sensors[nid]
+        if sensor.sketch_name is None:
+            _LOGGER.info('No sketch_name: node %s', nid)
+            return
+        if nid not in devices:
+            devices[nid] = {}
+        node = devices[nid]
+        new_devices = []
+        platform_def = platform_type(gateway, devices, nid)
+        platform_object = platform_def['platform_class']
+        platform_v_types = platform_def['types_to_handle']
+        add_devices = platform_def['add_devices']
+        for child_id, child in sensor.children.items():
+            if child_id not in node:
+                node[child_id] = {}
+            for value_type, value in child.values.items():
+                if value_type not in node[child_id]:
+                    name = '{} {}.{}'.format(
+                        sensor.sketch_name, nid, child.id)
+                    if value_type in platform_v_types:
+                        node[child_id][value_type] = \
+                            platform_object(
+                                gateway, nid, child_id, name, value_type)
+                        new_devices.append(node[child_id][value_type])
+                else:
+                    node[child_id][value_type].update_sensor(
+                        value, sensor.battery_level)
+        _LOGGER.info('sensor_update: %s', new_devices)
+        if new_devices:
+            _LOGGER.info('adding new devices: %s', new_devices)
+            add_devices(new_devices)
+        return
+    return wrapper