move mqtt motion publishing into separate thread

detect_objects.py

@@ -120,23 +120,41 @@ class ObjectParser(threading.Thread):
                     })
                     object_index += 6
             DETECTED_OBJECTS = detected_objects
+
+class MqttMotionPublisher(threading.Thread):
+    def __init__(self, client, topic_prefix, motion_changed, motion_flags):
+        threading.Thread.__init__(self)
+        self.client = client
+        self.topic_prefix = topic_prefix
+        self.motion_changed = motion_changed
+        self.motion_flags = motion_flags
+
+    def run(self):
+        last_sent_motion = ""
+        while True:
+            with self.motion_changed:
+                self.motion_changed.wait()
+            
+            # send message for motion
+            motion_status = 'OFF'
+            if any(obj.is_set() for obj in self.motion_flags):
+                motion_status = 'ON'
+                
+            if last_sent_motion != motion_status:
+                last_sent_motion = motion_status
+                self.client.publish(self.topic_prefix+'/motion', motion_status, retain=False)
+
 class MqttPublisher(threading.Thread):
-    def __init__(self, host, topic_prefix, object_classes, motion_flags):
+    def __init__(self, client, topic_prefix, object_classes):
         threading.Thread.__init__(self)
-        self.client = mqtt.Client()
-        self.client.will_set(topic_prefix+'/available', payload='offline', qos=1, retain=True)
-        self.client.connect(host, 1883, 60)
-        self.client.loop_start()
-        self.client.publish(topic_prefix+'/available', 'online', retain=True)
+        self.client = client
         self.topic_prefix = topic_prefix
         self.object_classes = object_classes
-        self.motion_flags = motion_flags
 
     def run(self):
         global DETECTED_OBJECTS
 
         last_sent_payload = ""
-        last_motion = ""
         while True:
             # initialize the payload
             payload = {}
@@ -154,15 +172,6 @@ class MqttPublisher(threading.Thread):
             if new_payload != last_sent_payload:
                 last_sent_payload = new_payload
                 self.client.publish(self.topic_prefix+'/objects', new_payload, retain=False)
-            
-            # send message for motion
-            motion_status = 'OFF'
-            if any(obj.is_set() for obj in self.motion_flags):
-                motion_status = 'ON'
-            
-            if motion_status != last_motion:
-                last_motion = motion_status
-                self.client.publish(self.topic_prefix+'/motion', motion_status, retain=False)
 
             time.sleep(0.1)
 
@@ -205,6 +214,8 @@ def main():
     frame_lock = mp.Lock()
     # Condition for notifying that a new frame is ready
     frame_ready = mp.Condition()
+    # Condition for notifying that motion status changed globally
+    motion_changed = mp.Condition()
     # Condition for notifying that object detection ran
     objects_changed = mp.Condition()
     # shape current frame so it can be treated as an image
@@ -232,6 +243,7 @@ def main():
             shared_frame_time,
             frame_lock, frame_ready,
             region['motion_detected'],
+            motion_changed,
             frame_shape, 
             region['size'], region['x_offset'], region['y_offset'],
             region['min_object_size'],
@@ -242,11 +254,20 @@ def main():
     object_parser = ObjectParser(objects_changed, [region['output_array'] for region in regions])
     object_parser.start()
 
-    mqtt_publisher = MqttPublisher(MQTT_HOST, MQTT_TOPIC_PREFIX, 
-        MQTT_OBJECT_CLASSES.split(','), 
-        [region['motion_detected'] for region in regions])
+    client = mqtt.Client()
+    client.will_set(MQTT_TOPIC_PREFIX+'/available', payload='offline', qos=1, retain=True)
+    client.connect(MQTT_HOST, 1883, 60)
+    client.loop_start()
+    client.publish(MQTT_TOPIC_PREFIX+'/available', 'online', retain=True)
+
+    mqtt_publisher = MqttPublisher(client, MQTT_TOPIC_PREFIX, 
+        MQTT_OBJECT_CLASSES.split(','))
     mqtt_publisher.start()
 
+    mqtt_motion_publisher = MqttMotionPublisher(client, MQTT_TOPIC_PREFIX, motion_changed,
+        [region['motion_detected'] for region in regions])
+    mqtt_motion_publisher.start()
+
     capture_process.start()
     print("capture_process pid ", capture_process.pid)
     for detection_process in detection_processes:
@@ -392,7 +413,8 @@ def process_frames(shared_arr, shared_output_arr, shared_frame_time, frame_lock,
             objects_changed.notify_all()
 
 # do the actual motion detection
-def detect_motion(shared_arr, shared_frame_time, frame_lock, frame_ready, motion_detected, frame_shape, region_size, region_x_offset, region_y_offset, min_motion_area, debug):
+def detect_motion(shared_arr, shared_frame_time, frame_lock, frame_ready, motion_detected, motion_changed,
+                  frame_shape, region_size, region_x_offset, region_y_offset, min_motion_area, debug):
     # shape shared input array into frame for processing
     arr = tonumpyarray(shared_arr).reshape(frame_shape)
 
@@ -406,6 +428,8 @@ def detect_motion(shared_arr, shared_frame_time, frame_lock, frame_ready, motion
         if last_motion > 0 and (now - last_motion) > 2:
             last_motion = -1
             motion_detected.clear()
+            with motion_changed:
+                motion_changed.notify_all()
         
         with frame_ready:
             # if there isnt a frame ready for processing or it is old, wait for a signal
@@ -464,6 +488,8 @@ def detect_motion(shared_arr, shared_frame_time, frame_lock, frame_ready, motion
             # if there have been enough consecutive motion frames, report motion
             if motion_frames >= 3:
                 motion_detected.set()
+                with motion_changed:
+                    motion_changed.notify_all()
                 last_motion = now
         else:
             motion_frames = 0