cleaner handling of SIGINT

main.py

@@ -3,6 +3,7 @@ import requests
 import os
 from dotenv import load_dotenv
 import logging
+import signal
 
 load_dotenv()
 
@@ -21,34 +22,59 @@ ch.setLevel(loglevel)
 formatter = logging.Formatter('[%(asctime)s] [%(levelname)s] %(message)s')
 formatter.default_msec_format = None
 ch.setFormatter(formatter)
-logger.addHandler(ch)
+if not logger.handlers:
+    logger.addHandler(ch)
 ##########################################
 
 ntfy_token = os.environ['NTFY_Token']
 device_name = os.environ['device_name']
 shutdown_timer = int(os.environ['shutdown_timer'])
 
-try:
+running = True
+
+def handle_shutdown(signum, frame):
+    global running
+    logger.info("Received shutdown signal, exiting...")
+    running = False
+
+signal.signal(signal.SIGTERM, handle_shutdown)
+signal.signal(signal.SIGINT, handle_shutdown)
+
+
+def main():
     with serial.Serial(device_name, 115200, timeout=1) as ser:
         inverter_offline_counter = 0
-        while True:
+        shutdown_triggered = False
-            if ser.readline().decode().strip() == "0":
+        while running:
+            line = ser.readline().decode(errors="ignore").strip()
+
+            if line == "0":
                 logger.debug("Inverter Online")
                 inverter_offline_counter = 0
             elif inverter_offline_counter >= shutdown_timer:
+                shutdown_triggered = True
                 break
             else:
                 inverter_offline_counter += 1
                 logger.info(f"Running on UPS reserve, offline for {inverter_offline_counter}s")
+
+        if shutdown_triggered:
             logger.info(f"Inverter offline for {shutdown_timer} seconds")
-        requests.post("https://ntfy.fieryeagle.org/Internet-Alerts",
+            try:
-                    data="Inverter offline, shutting down".encode(encoding='utf-8'),
+                requests.post(
+                    "https://ntfy.fieryeagle.org/Internet-Alerts",
+                    data="Inverter offline, shutting down".encode("utf-8"),
                     headers={
                         "Title": "Hydrogen running on reserve power",
                         "Authorization": f"Bearer {ntfy_token}"
-                        }
+                    },
+                    timeout=5
                 )
+            except Exception as e:
+                logger.error(f"Failed to send notification: {e}")
             os.system("shutdown now")
-except KeyboardInterrupt:
+        else:
-    logger.info("Exiting gracefully")
+            logger.info("Exited cleanly (service stop)")
-    exit()
+
+if __name__ == "__main__":
+    main()