Add time_throttle filter to sensor.filter (#20334)

* Added time_throttle filter

* Added time_throttle filter test

* Updated comments for time_throttle filter

homeassistant/components/sensor/filter.py

@@ -32,6 +32,7 @@ FILTER_NAME_RANGE = 'range'
 FILTER_NAME_LOWPASS = 'lowpass'
 FILTER_NAME_OUTLIER = 'outlier'
 FILTER_NAME_THROTTLE = 'throttle'
+FILTER_NAME_TIME_THROTTLE = 'time_throttle'
 FILTER_NAME_TIME_SMA = 'time_simple_moving_average'
 FILTERS = Registry()
 
@@ -101,6 +102,12 @@ FILTER_THROTTLE_SCHEMA = FILTER_SCHEMA.extend({
                  default=DEFAULT_WINDOW_SIZE): vol.Coerce(int),
 })
 
+FILTER_TIME_THROTTLE_SCHEMA = FILTER_SCHEMA.extend({
+    vol.Required(CONF_FILTER_NAME): FILTER_NAME_TIME_THROTTLE,
+    vol.Required(CONF_FILTER_WINDOW_SIZE): vol.All(cv.time_period,
+                                                   cv.positive_timedelta)
+})
+
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Required(CONF_ENTITY_ID): cv.entity_id,
     vol.Optional(CONF_NAME): cv.string,
@@ -109,6 +116,7 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
                                                  FILTER_LOWPASS_SCHEMA,
                                                  FILTER_TIME_SMA_SCHEMA,
                                                  FILTER_THROTTLE_SCHEMA,
+                                                 FILTER_TIME_THROTTLE_SCHEMA,
                                                  FILTER_RANGE_SCHEMA)])
 })
 
@@ -444,7 +452,7 @@ class TimeSMAFilter(Filter):
     The window_size is determined by time, and SMA is time weighted.
 
     Args:
-        variant (enum): type of argorithm used to connect discrete values
+        type (enum): type of algorithm used to connect discrete values
     """
 
     def __init__(self, window_size, precision, entity,
@@ -502,3 +510,29 @@ class ThrottleFilter(Filter):
             self._skip_processing = True
 
         return new_state
+
+
+@FILTERS.register(FILTER_NAME_TIME_THROTTLE)
+class TimeThrottleFilter(Filter):
+    """Time Throttle Filter.
+
+    One sample per time period.
+    """
+
+    def __init__(self, window_size, precision, entity):
+        """Initialize Filter."""
+        super().__init__(FILTER_NAME_TIME_THROTTLE,
+                         window_size, precision, entity)
+        self._time_window = window_size
+        self._last_emitted_at = None
+
+    def _filter_state(self, new_state):
+        """Implement the filter."""
+        window_start = new_state.timestamp - self._time_window
+        if not self._last_emitted_at or self._last_emitted_at <= window_start:
+            self._last_emitted_at = new_state.timestamp
+            self._skip_processing = False
+        else:
+            self._skip_processing = True
+
+        return new_state

tests/components/sensor/test_filter.py

@@ -5,7 +5,7 @@ from unittest.mock import patch
 
 from homeassistant.components.sensor.filter import (
     LowPassFilter, OutlierFilter, ThrottleFilter, TimeSMAFilter,
-    RangeFilter)
+    RangeFilter, TimeThrottleFilter)
 import homeassistant.util.dt as dt_util
 from homeassistant.setup import setup_component
 import homeassistant.core as ha
@@ -178,6 +178,18 @@ class TestFilterSensor(unittest.TestCase):
                 filtered.append(new_state)
         assert [20, 21] == [f.state for f in filtered]
 
+    def test_time_throttle(self):
+        """Test if lowpass filter works."""
+        filt = TimeThrottleFilter(window_size=timedelta(minutes=2),
+                                  precision=2,
+                                  entity=None)
+        filtered = []
+        for state in self.values:
+            new_state = filt.filter_state(state)
+            if not filt.skip_processing:
+                filtered.append(new_state)
+        assert [20, 18, 22] == [f.state for f in filtered]
+
     def test_time_sma(self):
         """Test if time_sma filter works."""
         filt = TimeSMAFilter(window_size=timedelta(minutes=2),