relay mqtt to clients

frigate/app.py

@@ -137,7 +137,7 @@ def init_stats(self):
  self.stats_tracking = stats_init(self.camera_metrics, self.detectors)
 
  def init_web_server(self):
- self.flask_app = create_app(self.config, self.db, self.stats_tracking, self.detected_frames_processor)
+ self.flask_app = create_app(self.config, self.db, self.stats_tracking, self.detected_frames_processor, self.mqtt_client)
 
  def init_mqtt(self):
  self.mqtt_client = create_mqtt_client(self.config, self.camera_metrics)

frigate/http.py

@@ -1,11 +1,13 @@
 import base64
 import datetime
+import json
 import logging
 import os
 import time
 from functools import reduce
 
 import cv2
+import gevent
 import numpy as np
 from flask import (Blueprint, Flask, Response, current_app, jsonify,
  make_response, request)
@@ -24,7 +26,37 @@
 bp = Blueprint('frigate', __name__)
 ws = Blueprint('ws', __name__)
 
-def create_app(frigate_config, database: SqliteDatabase, stats_tracking, detected_frames_processor):
+class MqttBackend():
+ """Interface for registering and updating WebSocket clients."""
+
+ def __init__(self, mqtt_client, topic_prefix):
+ self.clients = list()
+ self.mqtt_client = mqtt_client
+ self.topic_prefix = topic_prefix
+
+ def register(self, client):
+ """Register a WebSocket connection for Mqtt updates."""
+ self.clients.append(client)
+
+ def run(self):
+ def send(client, userdata, message):
+ """Sends mqtt messages to clients."""
+ logger.info(f"Sending mqtt to ws clients {len(self.clients)}")
+ ws_message = json.dumps({
+ 'topic': message.topic,
+ 'payload': message.payload.decode()
+ })
+ for client in self.clients:
+ client.send(ws_message)
+
+ logger.info(f"Subscribing to {self.topic_prefix}/#")
+ self.mqtt_client.message_callback_add(f"{self.topic_prefix}/#", send)
+
+ def start(self):
+ """Maintains mqtt subscription in the background."""
+ gevent.spawn(self.run)
+
+def create_app(frigate_config, database: SqliteDatabase, stats_tracking, detected_frames_processor, mqtt_client):
  app = Flask(__name__)
  sockets = Sockets(app)
 
@@ -44,6 +76,9 @@ def _db_close(exc):
  app.register_blueprint(bp)
  sockets.register_blueprint(ws)
 
+ app.mqtt_backend = MqttBackend(mqtt_client, frigate_config.mqtt.topic_prefix)
+ app.mqtt_backend.start()
+
  return app
 
 @bp.route('/')
@@ -311,6 +346,8 @@ def imagestream(detected_frames_processor, camera_name, fps, height, draw_option
 
 @ws.route('/ws')
 def echo_socket(socket):
+ current_app.mqtt_backend.register(socket)
+
  while not socket.closed:
- message = socket.receive()
- socket.send(message)
+ # Context switch while `ChatBackend.start` is running in the background.
+ gevent.sleep(0.1)