Feat: Configurable calendar refresh frequency

Some calendars have a limited number of times per day that the calendar
can be refreshed. Since the refresh was originally hard coded at no more
than once every 2 minutes this caused polling exhaustion for some users.

The configuration now supports a polling frequency between as often as
possible (roughly every 30 seconds because of the HA event machine) up
to once per day. This configuration is given as a number of minutes
between 0 and 1440.

Issue: #79
Signed-off-by: Andrew Grimberg <tykeal@bardicgrove.org>

custom_components/rental_control/__init__.py

@@ -28,15 +28,16 @@
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.aiohttp_client import async_get_clientsession
 from homeassistant.util import dt
-from homeassistant.util import Throttle
 
 from .const import CONF_CHECKIN
 from .const import CONF_CHECKOUT
 from .const import CONF_DAYS
 from .const import CONF_EVENT_PREFIX
 from .const import CONF_IGNORE_NON_RESERVED
 from .const import CONF_MAX_EVENTS
+from .const import CONF_REFRESH_FREQUENCY
 from .const import CONF_TIMEZONE
+from .const import DEFAULT_REFRESH_FREQUENCY
 from .const import DOMAIN
 from .const import PLATFORMS
 from .const import REQUEST_TIMEOUT
@@ -124,26 +125,25 @@ def __init__(self, hass, config):
         self.name = config.get(CONF_NAME)
         self.event_prefix = config.get(CONF_EVENT_PREFIX)
         self.url = config.get(CONF_URL)
-        # Early versions did not have this variable, as such it may not be
+        # Early versions did not have these variables, as such it may not be
         # set, this should guard against issues until we're certain we can
         # remove this guard.
         try:
             self.timezone = ZoneInfo(config.get(CONF_TIMEZONE))
         except TypeError:
             self.timezone = dt.DEFAULT_TIME_ZONE
+        self.refresh_frequency = config.get(CONF_REFRESH_FREQUENCY)
+        if self.refresh_frequency is None:
+            self.refresh_frequency = DEFAULT_REFRESH_FREQUENCY
+        # after initial setup our first refresh should happen ASAP
+        self.next_refresh = dt.now()
         # our config flow guarantees that checkin and checkout are valid times
         # just use cv.time to get the parsed time object
         self.checkin = cv.time(config.get(CONF_CHECKIN))
         self.checkout = cv.time(config.get(CONF_CHECKOUT))
         self.max_events = config.get(CONF_MAX_EVENTS)
         self.days = config.get(CONF_DAYS)
-        # Early versions did not have this variable, as such it may not be
-        # set, this should guard against issues until we're certain
-        # we can remove this guard.
-        try:
-            self.ignore_non_reserved = config.get(CONF_IGNORE_NON_RESERVED)
-        except NameError:
-            self.ignore_non_reserved = None
+        self.ignore_non_reserved = config.get(CONF_IGNORE_NON_RESERVED)
         self.verify_ssl = config.get(CONF_VERIFY_SSL)
         self.calendar = []
         self.event = None
@@ -171,24 +171,42 @@ async def async_get_events(
                     events.append(event)
         return events
 
-    @Throttle(MIN_TIME_BETWEEN_UPDATES)
     async def update(self):
         """Regularly update the calendar."""
         _LOGGER.debug("Running ICalEvents update for calendar %s", self.name)
 
-        await self._refresh_calendar()
+        now = dt.now()
+        _LOGGER.debug("Refresh frequency is: %d", self.refresh_frequency)
+        _LOGGER.debug("Current time is: %s", now)
+        _LOGGER.debug("Next refresh is: %s", self.next_refresh)
+        if now >= self.next_refresh:
+            # Update the next refresh time before doing the calendar update
+            # If refresh_frequency is 0, then set the refresh for a little in
+            # the future to avoid having multiple calls to the calendar refresh
+            # happen at the same time
+            if self.refresh_frequency == 0:
+                self.next_refresh = now + timedelta(seconds=10)
+            else:
+                self.next_refresh = now + timedelta(minutes=self.refresh_frequency)
+            _LOGGER.debug("Updating next refresh to %s", self.next_refresh)
+            await self._refresh_calendar()
 
     def update_config(self, config):
         """Update config entries."""
         self.name = config.get(CONF_NAME)
         self.url = config.get(CONF_URL)
-        # Early versions did not have this variable, as such it may not be
+        # Early versions did not have these variables, as such it may not be
         # set, this should guard against issues until we're certain
         # we can remove this guard.
         try:
             self.timezone = ZoneInfo(config.get(CONF_TIMEZONE))
         except TypeError:
             self.timezone = dt.DEFAULT_TIME_ZONE
+        self.refresh_frequency = config.get(CONF_REFRESH_FREQUENCY)
+        if self.refresh_frequency is None:
+            self.refresh_frequency = DEFAULT_REFRESH_FREQUENCY
+        # always do a refresh ASAP after a config change
+        self.next_refresh = dt.now()
         self.event_prefix = config.get(CONF_EVENT_PREFIX)
         # our config flow guarantees that checkin and checkout are valid times
         # just use cv.time to get the parsed time object

custom_components/rental_control/config_flow.py

@@ -28,13 +28,15 @@
 from .const import CONF_IGNORE_NON_RESERVED
 from .const import CONF_LOCK_ENTRY
 from .const import CONF_MAX_EVENTS
+from .const import CONF_REFRESH_FREQUENCY
 from .const import CONF_START_SLOT
 from .const import CONF_TIMEZONE
 from .const import DEFAULT_CHECKIN
 from .const import DEFAULT_CHECKOUT
 from .const import DEFAULT_DAYS
 from .const import DEFAULT_EVENT_PREFIX
 from .const import DEFAULT_MAX_EVENTS
+from .const import DEFAULT_REFRESH_FREQUENCY
 from .const import DEFAULT_START_SLOT
 from .const import DOMAIN
 from .const import LOCK_MANAGER
@@ -59,6 +61,7 @@ class RentalControlFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
         CONF_IGNORE_NON_RESERVED: True,
         CONF_EVENT_PREFIX: DEFAULT_EVENT_PREFIX,
         CONF_MAX_EVENTS: DEFAULT_MAX_EVENTS,
+        CONF_REFRESH_FREQUENCY: DEFAULT_REFRESH_FREQUENCY,
         CONF_TIMEZONE: str(dt.DEFAULT_TIME_ZONE),
         CONF_VERIFY_SSL: True,
     }
@@ -161,6 +164,10 @@ def _get_default(key: str, fallback_default: Any = None) -> None:
         {
             vol.Required(CONF_NAME, default=_get_default(CONF_NAME)): cv.string,
             vol.Required(CONF_URL, default=_get_default(CONF_URL)): cv.string,
+            vol.Optional(
+                CONF_REFRESH_FREQUENCY,
+                default=_get_default(CONF_REFRESH_FREQUENCY, DEFAULT_REFRESH_FREQUENCY),
+            ): cv.positive_int,
             vol.Optional(
                 CONF_TIMEZONE,
                 default=_get_default(CONF_TIMEZONE, str(dt.DEFAULT_TIME_ZONE)),
@@ -267,6 +274,9 @@ async def _start_config_flow(
             _LOGGER.exception(err.msg)
             errors["base"] = "invalid_url"
 
+        if user_input[CONF_REFRESH_FREQUENCY] > 1440:
+            errors["base"] = "bad_refresh"
+
         try:
             cv.time(user_input["checkin"])
             cv.time(user_input["checkout"])

custom_components/rental_control/const.py

@@ -27,6 +27,7 @@
 CONF_IGNORE_NON_RESERVED = "ignore_non_reserved"
 CONF_LOCK_ENTRY = "keymaster_entry_id"
 CONF_MAX_EVENTS = "max_events"
+CONF_REFRESH_FREQUENCY = "refresh_frequency"
 CONF_START_SLOT = "start_slot"
 CONF_TIMEZONE = "timezone"
 
@@ -37,6 +38,7 @@
 DEFAULT_EVENT_PREFIX = ""
 DEFAULT_MAX_EVENTS = 5
 DEFAULT_NAME = DOMAIN
+DEFAULT_REFRESH_FREQUENCY = 2
 DEFAULT_START_SLOT = 10
 
 STARTUP_MESSAGE = f"""

custom_components/rental_control/strings.json

@@ -2,6 +2,7 @@
   "config": {
     "error": {
       "bad_ics": "URL did not provide valid calendar",
+      "bad_refresh": "Refresh must be between 0 and 1440.",
       "bad_time": "Check-in/out time is invalid. Use 24 hour time",
       "invalid_url": "Only https URLs are supported",
       "same_name": "Name already in use",
@@ -18,6 +19,7 @@
           "keymaster_entry_id": "Keymaster configuration to manage",
           "max_events": "Number of event sensors to create",
           "name": "Calendar name",
+          "refresh_frequency": "Refresh calendar in minutes. 0 - 1440",
           "start_slot": "Starting lock slot for management",
           "timezone": "Calendar Timezone",
           "url": "Calendar URL",
@@ -30,6 +32,7 @@
     "error": {
       "bad_ics": "URL did not provide valid calendar",
       "bad_time": "Check-in/out time is invalid. Use 24 hour time",
+      "bad_refresh": "Refresh must be between 0 and 1440.",
       "invalid_url": "Only https URLs are supported",
       "same_name": "Name already in use",
       "unknown": "Unexpected error, check logs for more details"
@@ -45,6 +48,7 @@
           "keymaster_entry_id": "Keymaster configuration to manage",
           "max_events": "Number of event sensors to create",
           "name": "Calendar name",
+          "refresh_frequency": "Refresh calendar in minutes. 0 - 1440",
           "start_slot": "Starting lock slot for management",
           "timezone": "Calendar Timezone",
           "url": "Calendar URL",

custom_components/rental_control/translations/en.json

@@ -3,6 +3,7 @@
     "error": {
       "bad_ics": "URL did not provide valid calendar",
       "bad_time": "Check-in/out time is invalid. Use 24 hour time",
+      "bad_refresh": "Refresh must be between 0 and 1440.",
       "invalid_url": "Only https URLs are supported",
       "same_name": "Name already in use",
       "unknown": "Unexpected error, check logs for more details"
@@ -18,6 +19,7 @@
           "keymaster_entry_id": "Keymaster configuration to manage",
           "max_events": "Number of event sensors to create",
           "name": "Calendar name",
+          "refresh_frequency": "Refresh calendar in minutes. 0 - 1440",
           "start_slot": "Starting lock slot for management",
           "timezone": "Calendar Timezone",
           "url": "Calendar URL",
@@ -30,6 +32,7 @@
     "error": {
       "bad_ics": "URL did not provide valid calendar",
       "bad_time": "Check-in/out time is invalid. Use 24 hour time",
+      "bad_refresh": "Refresh must be between 0 and 1440.",
       "invalid_url": "Only https URLs are supported",
       "same_name": "Name already in use",
       "unknown": "Unexpected error, check logs for more details"
@@ -45,6 +48,7 @@
           "keymaster_entry_id": "Keymaster configuration to manage",
           "max_events": "Number of event sensors to create",
           "name": "Calendar name",
+          "refresh_frequency": "Refresh calendar in minutes. 0 - 1440",
           "start_slot": "Starting lock slot for management",
           "timezone": "Calendar Timezone",
           "url": "Calendar URL",