Add setting to debounce MQTT state updates

Adds a setting that delays state updates from being sent until an update hasn't occurred for a configurable threshold

Implements #615

docs/openapi.yaml

@@ -889,6 +889,10 @@ components:
           type: integer
           description: Controls how many miliseconds must pass between MQTT state updates.  Set to 0 to disable throttling.
           default: 500
+        mqtt_debounce_delay:
+          type: integer
+          description: Controls how much time has to pass after the last status update was queued.
+          default: 500
         packet_repeat_throttle_threshold:
           type: integer
           description:

lib/MQTT/BulbStateUpdater.cpp

@@ -5,6 +5,7 @@ BulbStateUpdater::BulbStateUpdater(Settings& settings, MqttClient& mqttClient, G
     mqttClient(mqttClient),
     stateStore(stateStore),
     lastFlush(0),
+    lastQueue(0),
     enabled(true)
 { }
 
@@ -17,12 +18,10 @@ void BulbStateUpdater::disable() {
 }
 
 void BulbStateUpdater::enqueueUpdate(BulbId bulbId, GroupState& groupState) {
-  // If can flush immediately, do so (avoids lookup of group state later).
-  if (canFlush()) {
-    flushGroup(bulbId, groupState);
-  } else {
-    staleGroups.push(bulbId);
-  }
+  staleGroups.push(bulbId);
+  //Remember time, when queue was added for debounce delay
+  lastQueue = millis();
+
 }
 
 void BulbStateUpdater::loop() {
@@ -56,5 +55,5 @@ inline void BulbStateUpdater::flushGroup(BulbId bulbId, GroupState& state) {
 }
 
 inline bool BulbStateUpdater::canFlush() const {
-  return enabled && (millis() > (lastFlush + settings.mqttStateRateLimit));
+  return enabled && (millis() > (lastFlush + settings.mqttStateRateLimit) && millis() > (lastQueue + settings.mqttDebounceDelay));
 }

lib/MQTT/BulbStateUpdater.h

@@ -25,6 +25,7 @@ class BulbStateUpdater {
   GroupStateStore& stateStore;
   CircularBuffer<BulbId, MILIGHT_MAX_STALE_MQTT_GROUPS> staleGroups;
   unsigned long lastFlush;
+  unsigned long lastQueue;
   bool enabled;
 
   inline void flushGroup(BulbId bulbId, GroupState& state);

lib/Settings/Settings.cpp

@@ -88,6 +88,7 @@ void Settings::patch(JsonObject parsedSettings) {
   this->setIfPresent(parsedSettings, "listen_repeats", listenRepeats);
   this->setIfPresent(parsedSettings, "state_flush_interval", stateFlushInterval);
   this->setIfPresent(parsedSettings, "mqtt_state_rate_limit", mqttStateRateLimit);
+  this->setIfPresent(parsedSettings, "mqtt_debounce_delay", mqttDebounceDelay);
   this->setIfPresent(parsedSettings, "packet_repeat_throttle_threshold", packetRepeatThrottleThreshold);
   this->setIfPresent(parsedSettings, "packet_repeat_throttle_sensitivity", packetRepeatThrottleSensitivity);
   this->setIfPresent(parsedSettings, "packet_repeat_minimum", packetRepeatMinimum);
@@ -271,6 +272,7 @@ void Settings::serialize(Print& stream, const bool prettyPrint) {
   root["listen_repeats"] = this->listenRepeats;
   root["state_flush_interval"] = this->stateFlushInterval;
   root["mqtt_state_rate_limit"] = this->mqttStateRateLimit;
+  root["mqtt_debounce_delay"] = this->mqttDebounceDelay;
   root["packet_repeat_throttle_sensitivity"] = this->packetRepeatThrottleSensitivity;
   root["packet_repeat_throttle_threshold"] = this->packetRepeatThrottleThreshold;
   root["packet_repeat_minimum"] = this->packetRepeatMinimum;

lib/Settings/Settings.h

@@ -102,6 +102,7 @@ class Settings {
     simpleMqttClientStatus(false),
     stateFlushInterval(10000),
     mqttStateRateLimit(500),
+    mqttDebounceDelay(500),
     packetRepeatThrottleThreshold(200),
     packetRepeatThrottleSensitivity(0),
     packetRepeatMinimum(3),
@@ -168,6 +169,7 @@ class Settings {
   bool simpleMqttClientStatus;
   size_t stateFlushInterval;
   size_t mqttStateRateLimit;
+  size_t mqttDebounceDelay;
   size_t packetRepeatThrottleThreshold;
   size_t packetRepeatThrottleSensitivity;
   size_t packetRepeatMinimum;

test/remote/settings.json.example

@@ -13,6 +13,7 @@
   "listen_repeats": 3,
   "state_flush_interval": 2000,
   "mqtt_state_rate_limit": 1000,
+  "mqtt_debounce_delay": 0,
   "packet_repeat_throttle_sensitivity": 0,
   "packet_repeat_throttle_threshold": 200,
   "packet_repeat_minimum": 3,

test/remote/spec/mqtt_spec.rb

@@ -193,6 +193,58 @@
       expect(update_timestamp_gaps.length).to be >= 3
       expect((avg - 0.5).abs).to be < 0.15, "Should be within margin of error of rate limit"
     end
+
+    it 'should respect the update debouce interval' do
+      @client.put(
+        '/settings',
+        mqtt_debounce_delay: 1000,
+        packet_repeats: 1
+      )
+
+      start_time = Time.now
+
+      @mqtt_client.on_state(@id_params) do |id, message|
+        true
+      end
+
+      # Set initial state
+      @client.patch_state({status: 'ON', level: 0}, @id_params)
+      @mqtt_client.wait_for_listeners
+
+      expect(Time.now - start_time).to be >= 1
+    end
+
+    it 'should only send one state update for many commands if debounce interval is enabled' do
+      @client.put(
+        '/settings',
+        mqtt_update_topic_pattern: '',
+        mqtt_debounce_delay: 1000,
+        packet_repeats: 1
+      )
+
+      # Set initial state
+      @client.patch_state({status: 'ON', level: 0}, @id_params)
+
+      num_updates = 10
+      seen_updates = 0
+      last_level_value = 0
+
+      @mqtt_client.on_state(@id_params) do |id, message|
+        seen_updates += 1
+        last_level_value = message['level']
+        last_level_value == num_updates
+      end
+
+      (1..num_updates).each do |i|
+        @mqtt_client.patch_state(@id_params, level: i)
+        sleep 0.5
+      end
+
+      @mqtt_client.wait_for_listeners
+
+      expect(seen_updates).to eq(1)
+      expect(last_level_value).to eq(num_updates)
+    end
   end
 
   context ':device_id token for command topic' do

test/remote/spec/udp_spec.rb

@@ -48,6 +48,7 @@
 
   context 'on/off commands' do
     it 'should result in state changes' do
+      @client.delete_state(@id_params)
       @udp_client.group(@id_params[:group_id]).on
 
       # Wait for packet to be processed
@@ -66,6 +67,7 @@
     end
 
     it 'should result in an MQTT update' do
+      @client.delete_state(@id_params)
       desired_state = {
         'status' => 'ON',
         'level' => 48

web/src/js/script.js

@@ -273,6 +273,12 @@ var UI_FIELDS = [ {
     help: "Minimum number of milliseconds between MQTT updates of bulb state (defaults to 500)",
     type: "string",
     tab: "tab-mqtt"
+  }, {
+    tag:   "mqtt_debounce_delay",
+    friendly: "MQTT debounce delay",
+    help: "Minimum number of milliseconds delay for MQTT state updates after change (defaults to 500)",
+    type: "string",
+    tab: "tab-mqtt"
   }, {
     tag:   "packet_repeat_throttle_threshold",
     friendly: "Packet repeat throttle threshold",