graceful exit of subprocesses

frigate/edgetpu.py

@@ -5,6 +5,7 @@ import multiprocessing as mp
 import os
 import queue
 import threading
+import signal
 from abc import ABC, abstractmethod
 from multiprocessing.connection import Connection
 from typing import Dict
@@ -109,6 +110,14 @@ def run_detector(name: str, detection_queue: mp.Queue, out_events: Dict[str, mp.
     threading.current_thread().name = f"detector:{name}"
     logging.info(f"Starting detection process: {os.getpid()}")
     listen()
+
+    stop_event = mp.Event()
+    def receiveSignal(signalNumber, frame):
+        stop_event.set()
+    
+    signal.signal(signal.SIGTERM, receiveSignal)
+    signal.signal(signal.SIGINT, receiveSignal)
+
     frame_manager = SharedMemoryFrameManager()
     object_detector = LocalObjectDetector(tf_device=tf_device)
 
@@ -122,7 +131,13 @@ def run_detector(name: str, detection_queue: mp.Queue, out_events: Dict[str, mp.
         }
     
     while True:
-        connection_id = detection_queue.get()
+        if stop_event.is_set():
+            break
+
+        try:
+            connection_id = detection_queue.get(timeout=5)
+        except queue.Empty:
+            continue
         input_frame = frame_manager.get(connection_id, (1,300,300,3))
 
         if input_frame is None:

frigate/log.py

@@ -1,6 +1,8 @@
 # adapted from https://medium.com/@jonathonbao/python3-logging-with-multiprocessing-f51f460b8778
 import logging
 import threading
+import signal
+import multiprocessing as mp
 from logging import handlers
 
 
@@ -19,9 +21,21 @@ def root_configurer(queue):
     root.setLevel(logging.INFO)
 
 def log_process(queue):
+    stop_event = mp.Event()
+    def receiveSignal(signalNumber, frame):
+        stop_event.set()
+    
+    signal.signal(signal.SIGTERM, receiveSignal)
+    signal.signal(signal.SIGINT, receiveSignal)
+
     threading.current_thread().name = f"logger"
     listener_configurer()
     while True:
-        record = queue.get()
+        if stop_event.is_set() and queue.empty():
+            break
+        try:
+            record = queue.get(timeout=5)
+        except queue.Empty:
+            continue
         logger = logging.getLogger(record.name)
         logger.handle(record)

frigate/video.py

@@ -9,6 +9,7 @@ import multiprocessing as mp
 import os
 import queue
 import subprocess as sp
+import signal
 import threading
 import time
 from collections import defaultdict
@@ -72,8 +73,7 @@ def create_tensor_input(frame, region):
     # Expand dimensions since the model expects images to have shape: [1, 300, 300, 3]
     return np.expand_dims(cropped_frame, axis=0)
 
-def start_or_restart_ffmpeg(ffmpeg_cmd, frame_size=None, ffmpeg_process=None):
-    if not ffmpeg_process is None:
+def stop_ffmpeg(ffmpeg_process):
     logger.info("Terminating the existing ffmpeg process...")
     ffmpeg_process.terminate()
     try:
@@ -85,6 +85,10 @@ def start_or_restart_ffmpeg(ffmpeg_cmd, frame_size=None, ffmpeg_process=None):
         ffmpeg_process.communicate()
     ffmpeg_process = None
 
+def start_or_restart_ffmpeg(ffmpeg_cmd, frame_size=None, ffmpeg_process=None):
+    if not ffmpeg_process is None:
+        stop_ffmpeg(ffmpeg_process)
+
     if frame_size is None:
         process = sp.Popen(ffmpeg_cmd, stdout = sp.DEVNULL, stdin = sp.DEVNULL, start_new_session=True)
     else:
@@ -133,7 +137,7 @@ def capture_frames(ffmpeg_process, camera_name, frame_shape, frame_manager: Fram
         frame_queue.put(current_frame.value)
 
 class CameraWatchdog(threading.Thread):
-    def __init__(self, camera_name, config, frame_queue, camera_fps, ffmpeg_pid):
+    def __init__(self, camera_name, config, frame_queue, camera_fps, ffmpeg_pid, stop_event):
         threading.Thread.__init__(self)
         self.name = f"watchdog:{camera_name}"
         self.camera_name = camera_name
@@ -146,6 +150,7 @@ class CameraWatchdog(threading.Thread):
         self.frame_queue = frame_queue
         self.frame_shape = self.config.frame_shape_yuv
         self.frame_size = self.frame_shape[0] * self.frame_shape[1]
+        self.stop_event = stop_event
 
     def run(self):
         self.start_ffmpeg_detect()
@@ -160,6 +165,12 @@ class CameraWatchdog(threading.Thread):
         
         time.sleep(10)
         while True:
+            if self.stop_event.is_set():
+                stop_ffmpeg(self.ffmpeg_detect_process)
+                for p in self.ffmpeg_other_processes:
+                    stop_ffmpeg(p['process'])
+                break
+
             now = datetime.datetime.now().timestamp()
 
             if not self.capture_thread.is_alive():
@@ -212,12 +223,26 @@ class CameraCapture(threading.Thread):
             self.fps, self.skipped_fps, self.current_frame)
 
 def capture_camera(name, config: CameraConfig, process_info):
+    stop_event = mp.Event()
+    def receiveSignal(signalNumber, frame):
+        stop_event.set()
+    
+    signal.signal(signal.SIGTERM, receiveSignal)
+    signal.signal(signal.SIGINT, receiveSignal)
+
     frame_queue = process_info['frame_queue']
-    camera_watchdog = CameraWatchdog(name, config, frame_queue, process_info['camera_fps'], process_info['ffmpeg_pid'])
+    camera_watchdog = CameraWatchdog(name, config, frame_queue, process_info['camera_fps'], process_info['ffmpeg_pid'], stop_event)
     camera_watchdog.start()
     camera_watchdog.join()
 
 def track_camera(name, config: CameraConfig, detection_queue, result_connection, detected_objects_queue, process_info):
+    stop_event = mp.Event()
+    def receiveSignal(signalNumber, frame):
+        stop_event.set()
+    
+    signal.signal(signal.SIGTERM, receiveSignal)
+    signal.signal(signal.SIGINT, receiveSignal)
+
     threading.current_thread().name = f"process:{name}"
     listen()
 
@@ -236,7 +261,7 @@ def track_camera(name, config: CameraConfig, detection_queue, result_connection,
     frame_manager = SharedMemoryFrameManager()
 
     process_frames(name, frame_queue, frame_shape, frame_manager, motion_detector, object_detector,
-        object_tracker, detected_objects_queue, process_info, objects_to_track, object_filters, mask)
+        object_tracker, detected_objects_queue, process_info, objects_to_track, object_filters, mask, stop_event)
 
     logger.info(f"{name}: exiting subprocess")
 
@@ -273,7 +298,7 @@ def process_frames(camera_name: str, frame_queue: mp.Queue, frame_shape,
     frame_manager: FrameManager, motion_detector: MotionDetector, 
     object_detector: RemoteObjectDetector, object_tracker: ObjectTracker,
     detected_objects_queue: mp.Queue, process_info: Dict,
-    objects_to_track: List[str], object_filters, mask,
+    objects_to_track: List[str], object_filters, mask, stop_event,
     exit_on_empty: bool = False):
     
     fps = process_info['process_fps']
@@ -284,6 +309,9 @@ def process_frames(camera_name: str, frame_queue: mp.Queue, frame_shape,
     fps_tracker.start()
 
     while True:
+        if stop_event.is_set():
+            break
+
         if exit_on_empty and frame_queue.empty():
             logger.info(f"Exiting track_objects...")
             break