Attempt to fix CPU utilisation bug by preventing the heartbeat callback leak in the SSE stream handlers and replacing Timer-based with Event-based threads. Also compiled regexes in advance for DXCC callsign lookups for efficiency, and fixed my misunderstanding of what Queue.empty() does

core/cleanup.py

@@ -1,6 +1,6 @@
 import logging
 from datetime import datetime
-from threading import Timer
+from threading import Timer, Event, Thread
 from time import sleep
 
 import pytz
@@ -18,17 +18,23 @@ class CleanupTimer:
         self.cleanup_timer = None
         self.last_cleanup_time = datetime.min.replace(tzinfo=pytz.UTC)
         self.status = "Starting"
+        self._stop_event = Event()
 
     # Start the cleanup timer
     def start(self):
-        self.cleanup()
+        self._thread = Thread(target=self._run, daemon=True)
+        self._thread.start()
 
     # Stop any threads and prepare for application shutdown
     def stop(self):
-        self.cleanup_timer.cancel()
+        self._stop_event.set()
+
+    def _run(self):
+        while not self._stop_event.wait(timeout=self.cleanup_interval):
+            self._cleanup()
 
     # Perform cleanup and reschedule next timer
-    def cleanup(self):
+    def _cleanup(self):
         try:
             # Perform cleanup via letting the data expire
             self.spots.expire()
@@ -61,7 +67,4 @@ class CleanupTimer:
         except Exception as e:
             self.status = "Error"
             logging.exception("Exception in Cleanup thread")
-            sleep(1)
-
-        self.cleanup_timer = Timer(self.cleanup_interval, self.cleanup)
-        self.cleanup_timer.start()
+            self._stop_event.wait(timeout=1)