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

spothole.py

@@ -15,17 +15,25 @@ from webserver.webserver import WEB_SERVER
 
 logger = logging.getLogger(__name__)
 
+_shutdown_in_progress = False
+
 
 def shutdown(_signum=None, _frame=None):
     """Shutdown function"""
 
+    # Check if this is the second time a shutdown was asked for, if so immediately kill the program.
+    global _shutdown_in_progress
+    if _shutdown_in_progress:
+        os._exit(1)
+    _shutdown_in_progress = True
+
     logger.info("Stopping program...")
     WEB_SERVER.stop()
     TELNET_SERVER.stop()
     DATA_PROVIDERS.stop()
     CLEANUP_TIMER.stop()
     DATA_STORE.close()
-    os._exit(0)
+    logger.info("Stopped.")
 
 
 # Main function
@@ -43,8 +51,9 @@ if __name__ == "__main__":
     logger.info("Starting...")
     logger.info(f"This is Spothole version {SOFTWARE_VERSION}. This instance is run by {SERVER_OWNER_CALLSIGN}.")
 
-    # Shut down gracefully on SIGINT
+    # Shut down gracefully on SIGINT or SIGTERM
     signal.signal(signal.SIGINT, shutdown)
+    signal.signal(signal.SIGTERM, shutdown)
 
     # Set up data store
     DATA_STORE.setup()
@@ -59,14 +68,16 @@ if __name__ == "__main__":
     status_reporter = StatusReporter(run_interval=5)
     status_reporter.start()
 
-    # Set up the web server
-    WEB_SERVER.setup()
-
     # Run the telnet server
     if TELNET_SERVER_ENABLED:
         TELNET_SERVER.start(port=TELNET_SERVER_PORT)
 
-    # Run the web server. This is the blocking call that keeps the application running in the main thread, so this must
-    # be the last thing we do. web_server.stop() triggers an await condition in the web server which finishes the main
-    # thread.
+    # Set up the web server
+    WEB_SERVER.setup()
+
+    # Run the web server
     WEB_SERVER.start()
+
+    # Block the main thread until a termination signal arrives and shutdown() is running.
+    while not _shutdown_in_progress:
+        signal.pause()