Use _stop_event consistently across all threads as the way to signal that it should stop. Add thread joins with timeouts to allow the program to exit cleanly

telnetserver/telnetserver.py

@@ -49,6 +49,7 @@ class TelnetServer:
         self._running = False
         self._clients = set()
         self._loop = None
+        self._thread = None
         self._shutdown_event = asyncio.Event()
 
     def start(self, port=7373):
@@ -58,8 +59,10 @@ class TelnetServer:
 
         # Start the telnet server. asyncio.run() needs a coroutine, and threading.Thread needs a plain callable, so
         # hand Thread the bridge between the two directly rather than writing a one-line wrapper method for it.
-        t = threading.Thread(target=asyncio.run, args=(self._start_internal(),), name="TelnetServer", daemon=True)
-        t.start()
+        self._thread = threading.Thread(
+            target=asyncio.run, args=(self._start_internal(),), name="TelnetServer", daemon=True
+        )
+        self._thread.start()
         logger.debug("Telnet server background thread spawned")
 
         # Listen for new spots and alerts being added to the cache, so we can notify SSE clients immediately
@@ -135,6 +138,10 @@ class TelnetServer:
         if self._loop and self._loop.is_running():
             logger.debug("Stopping telnet server...")
             self._loop.call_soon_threadsafe(self._shutdown_event.set)
+        if self._thread:
+            self._thread.join(timeout=15)
+            if self._thread.is_alive():
+                logger.warning("Telnet server background thread did not exit on time and will be killed.")
 
     @property
     def client_count(self) -> int: