From 0dad9bc393ee237f46a5bd3fba6914c17a2f3ff5 Mon Sep 17 00:00:00 2001
From: Blake Blackshear <blakeb@blakeshome.com>
Date: Tue, 24 Nov 2020 07:27:51 -0600
Subject: [PATCH] add event cleanup thread

---
 frigate/app.py    |  8 ++++++-
 frigate/events.py | 58 ++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/frigate/app.py b/frigate/app.py
index 4b0748a41..c15fd16df 100644
--- a/frigate/app.py
+++ b/frigate/app.py
@@ -10,7 +10,7 @@ from playhouse.sqlite_ext import SqliteExtDatabase
 
 from frigate.config import FrigateConfig
 from frigate.edgetpu import EdgeTPUProcess
-from frigate.events import EventProcessor
+from frigate.events import EventProcessor, EventCleanup
 from frigate.http import create_app
 from frigate.log import log_process, root_configurer
 from frigate.models import Event
@@ -115,6 +115,10 @@ class FrigateApp():
         self.event_processor = EventProcessor(self.config, self.camera_metrics, self.event_queue, self.stop_event)
         self.event_processor.start()
 
+    def start_event_cleanup(self):
+        self.event_cleanup = EventCleanup(self.config, self.stop_event)
+        self.event_cleanup.start()
+
     def start_watchdog(self):
         self.frigate_watchdog = FrigateWatchdog(self.detectors, self.stop_event)
         self.frigate_watchdog.start()
@@ -132,6 +136,7 @@ class FrigateApp():
         self.start_camera_capture_processes()
         self.init_web_server()
         self.start_event_processor()
+        self.start_event_cleanup()
         self.start_watchdog()
         self.flask_app.run(host='127.0.0.1', port=5001, debug=False)
         self.stop()
@@ -142,6 +147,7 @@ class FrigateApp():
 
         self.detected_frames_processor.join()
         self.event_processor.join()
+        self.event_cleanup.join()
         self.frigate_watchdog.join()
 
         for detector in self.detectors.values():
diff --git a/frigate/events.py b/frigate/events.py
index f98348347..1d469e5b8 100644
--- a/frigate/events.py
+++ b/frigate/events.py
@@ -7,9 +7,11 @@ import subprocess as sp
 import threading
 import time
 from collections import defaultdict
+from pathlib import Path
 
 import psutil
 
+from frigate.config import FrigateConfig
 from frigate.models import Event
 
 logger = logging.getLogger(__name__)
@@ -187,4 +189,58 @@ class EventProcessor(threading.Thread):
                     )
                 del self.events_in_process[event_data['id']]
 
-                
\ No newline at end of file
+class EventCleanup(threading.Thread):
+    def __init__(self, config: FrigateConfig, stop_event):
+        threading.Thread.__init__(self)
+        self.name = 'event_cleanup'
+        self.config = config
+        self.clips_dir = self.config.save_clips.clips_dir
+        self.stop_event = stop_event
+
+    def run(self):
+        counter = 0
+        while(True):
+            if self.stop_event.is_set():
+                logger.info(f"Exiting event cleanup...")
+                break
+
+            for name, camera in self.config.cameras.items():
+                retain_config = camera.save_clips.retain
+                # get distinct objects in database for this camera
+                distinct_labels = (Event.select(Event.label)
+                        .where(Event.camera == name)
+                        .distinct())
+
+                # loop over object types in db
+                for l in distinct_labels:
+                    # get expiration time for this label
+                    expire_days = retain_config.objects.get(l.label, retain_config.default)
+                    expire_after = datetime.datetime.now() - datetime.timedelta(days=expire_days)
+                    # grab all events after specific time
+                    expired_events = (
+                        Event.select()
+                            .where( Event.camera == name, 
+                                Event.start_time < expire_after, 
+                                Event.label == l.label)
+                    )
+                    # delete the grabbed clips from disk
+                    for event in expired_events:
+                        clip_name = f"{event.camera}-{event.id}"
+                        clip = Path(f"{os.path.join(self.clips_dir, clip_name)}.mp4")
+                        clip.unlink(missing_ok=True)
+                    # delete the event for this type from the db
+                    delete_query = (
+                        Event.delete()
+                            .where( Event.camera == name, 
+                                Event.start_time < expire_after, 
+                                Event.label == l.label)
+                    )
+                    delete_query.execute()
+            
+            time.sleep(10)
+
+            # only expire events every 10 minutes, but check for stop events every 10 seconds
+            counter += 1
+            if counter < 60:
+                continue
+            counter = 0