Added the EX_UNAVAILABLE to the daemon when no hardware and the service file now does not restart if there is no hardware

Author: darrylb123

rpm/usbrelay.spec

@@ -1,5 +1,5 @@
 Name:           usbrelay
-Version:        1.1.1
+Version:        1.1.2
 Release:        %autorelease
 Summary:        A library and command line tool to control USB-connected relays based on hidapi
 License:        GPL-2.0-or-later

usbrelayd

@@ -87,7 +87,8 @@ count = usbrelay_py.board_count()
 
 if(count < 1):
     print("No usbrelay modules connected",flush=True)
-    exit()
+    # exit with EX_UNAVAILABLE
+    exit(69)
 else:
     print("Modules Connected: ",count,flush=True)
 

usbrelayd.service

@@ -6,7 +6,9 @@ StartLimitIntervalSec=10
 
 [Service]
 Type=simple
-Restart=always
+# Daemon exits with EX_UNAVAILABLE (69) when there is no compatible hardware plugged in 
+Restart=on-failure
+RestartPreventExitStatus=69 
 RestartSec=1
 DynamicUser=yes
 # SupplementaryGroups should match the group used in udev rules