Use a cache object to reduce the frequency of calls to APCUPSd

homeassistant/components/apcupsd.py

@@ -5,6 +5,9 @@ Sets up and provides access to the status output of APCUPSd via its Network
 Information Server (NIS).
 """
 import logging
+from datetime import timedelta
+
+from homeassistant.util import Throttle
 
 
 DOMAIN = "apcupsd"
@@ -21,31 +24,59 @@ KEY_STATUS = "STATUS"
 
 VALUE_ONLINE = "ONLINE"
 
-GET_STATUS = None
+MIN_TIME_BETWEEN_UPDATES = timedelta(seconds=60)
+
+DATA = None
 
 _LOGGER = logging.getLogger(__name__)
 
 
 def setup(hass, config):
     """ Use config values to set up a function enabling status retrieval. """
-    global GET_STATUS
-    from apcaccess import status
+    global DATA
 
     host = config[DOMAIN].get(CONF_HOST, DEFAULT_HOST)
     port = config[DOMAIN].get(CONF_PORT, DEFAULT_PORT)
 
-    def get_status():
-        """ Get the status from APCUPSd and parse it into a dict. """
-        return status.parse(status.get(host=host, port=port))
-
-    GET_STATUS = get_status
+    DATA = APCUPSdData(host, port)
 
     # It doesn't really matter why we're not able to get the status, just that
     # we can't.
     # pylint: disable=broad-except
     try:
-        GET_STATUS()
+        DATA.update(no_throttle=True)
     except Exception:
         _LOGGER.exception("Failure while testing APCUPSd status retrieval.")
         return False
     return True
+
+
+class APCUPSdData(object):
+    """
+    Stores the data retrieved from APCUPSd for each entity to use, acts as the
+    single point responsible for fetching updates from the server.
+    """
+    def __init__(self, host, port):
+        from apcaccess import status
+        self._host = host
+        self._port = port
+        self._status = None
+        self._get = status.get
+        self._parse = status.parse
+
+    @property
+    def status(self):
+        """ Get latest update if throttle allows. Return status. """
+        self.update()
+        return self._status
+
+    def _get_status(self):
+        """ Get the status from APCUPSd and parse it into a dict. """
+        return self._parse(self._get(host=self._host, port=self._port))
+
+    @Throttle(MIN_TIME_BETWEEN_UPDATES)
+    def update(self, **kwargs):
+        """
+        Fetch the latest status from APCUPSd and store it in self._status.
+        """
+        self._status = self._get_status()

homeassistant/components/binary_sensor/apcupsd.py

@@ -3,7 +3,6 @@ homeassistant.components.binary_sensor.apcupsd
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Provides a binary sensor to track online status of a UPS.
 """
-from homeassistant.core import JobPriority
 from homeassistant.components.binary_sensor import BinarySensorDevice
 from homeassistant.components import apcupsd
 
@@ -15,17 +14,16 @@ DEFAULT_NAME = "UPS Online Status"
 
 def setup_platform(hass, config, add_entities, discovery_info=None):
     """ Instantiate an OnlineStatus binary sensor entity and add it to HA. """
-    add_entities((OnlineStatus(hass, config),))
+    add_entities((OnlineStatus(config, apcupsd.DATA),))
 
 
 class OnlineStatus(BinarySensorDevice):
     """ Binary sensor to represent UPS online status. """
-    def __init__(self, hass, config):
+    def __init__(self, config, data):
         self._config = config
+        self._data = data
         self._state = None
-        # Get initial state
-        hass.pool.add_job(
-            JobPriority.EVENT_STATE, (self.update_ha_state, True))
+        self.update()
 
     @property
     def name(self):
@@ -39,8 +37,7 @@ class OnlineStatus(BinarySensorDevice):
 
     def update(self):
         """
-        Get the latest status report from APCUPSd and establish whether the
-        UPS is online.
+        Get the status report from APCUPSd (or cache) and set this entity's
+        state.
         """
-        status = apcupsd.GET_STATUS()
-        self._state = status[apcupsd.KEY_STATUS]
+        self._state = self._data.status[apcupsd.KEY_STATUS]

homeassistant/components/sensor/apcupsd.py

@@ -5,7 +5,6 @@ Provides a sensor to track various status aspects of a UPS.
 """
 import logging
 
-from homeassistant.core import JobPriority
 from homeassistant.const import TEMP_CELCIUS
 from homeassistant.helpers.entity import Entity
 from homeassistant.components import apcupsd
@@ -32,28 +31,17 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
         _LOGGER.error(
             "You must include a '%s' when configuring an APCUPSd sensor.",
             apcupsd.CONF_TYPE)
-        return
+        return False
     typ = typ.upper()
 
-    # Get a status reading from APCUPSd and check whether the user provided
-    # 'type' is present in the output. If we're not able to check, then assume
-    # the user knows what they're doing.
-    # pylint: disable=broad-except
-    status = None
-    try:
-        status = apcupsd.GET_STATUS()
-        if typ not in status:
+    if typ not in apcupsd.DATA.status:
         _LOGGER.error(
             "Specified '%s' of '%s' does not appear in the APCUPSd status "
             "output.", apcupsd.CONF_TYPE, typ)
-            return
-    except Exception as exc:
-        _LOGGER.warning(
-            "Unable to fetch initial value from ACPUPSd to check that '%s' is "
-            "a supported '%s': %s", typ, apcupsd.CONF_TYPE, exc)
-    unit = SPECIFIC_UNITS.get(typ)
+        return False
+
     add_entities((
-        Sensor(hass, config, unit=unit, initial_status=status),
+        Sensor(config, apcupsd.DATA, unit=SPECIFIC_UNITS.get(typ)),
     ))
 
 
@@ -72,16 +60,12 @@ def infer_unit(value):
 
 class Sensor(Entity):
     """ Generic sensor entity for APCUPSd status values. """
-    def __init__(self, hass, config, unit=None, initial_status=None):
+    def __init__(self, config, data, unit=None):
         self._config = config
         self._unit = unit
-        self._state = None
+        self._data = data
         self._inferred_unit = None
-        if initial_status is None:
-            hass.pool.add_job(
-                JobPriority.EVENT_STATE, (self.update_ha_state, True))
-        else:
-            self._update_from_status(initial_status)
+        self.update()
 
     @property
     def name(self):
@@ -99,9 +83,5 @@ class Sensor(Entity):
 
     def update(self):
         """ Get the latest status and use it to update our sensor state. """
-        self._update_from_status(apcupsd.GET_STATUS())
-
-    def _update_from_status(self, status):
-        """ Set state and infer unit from status. """
         key = self._config[apcupsd.CONF_TYPE].upper()
-        self._state, self._inferred_unit = infer_unit(status[key])
+        self._state, self._inferred_unit = infer_unit(self._data.status[key])