[scripts][execute] Cleanup user id handling

beat/backend/python/scripts/execute.py

@@ -207,12 +207,13 @@ def main():
         cfg = simplejson.load(f)
 
     # Create a new user with less privileges (if necessary)
-    if os.getuid() != cfg["uid"]:
+    user_id = cfg["uid"]
+    if os.getuid() != user_id:
         retcode = subprocess.call(  # nosec
             [
                 "adduser",
                 "--uid",
-                str(cfg["uid"]),
+                str(user_id),
                 "--no-create-home",
                 "--disabled-password",
                 "--disabled-login",
@@ -227,15 +228,15 @@ def main():
                 logger,
                 socket,
                 "sys",
-                "Failed to create an user with the UID %d" % cfg["uid"],
+                "Failed to create an user with the UID %d" % user_id,
             )
             close(logger, [socket, db_socket, loop_socket], context)
             return 1
 
         # Change to the user with less privileges
         try:
-            os.setgid(cfg["uid"])
-            os.setuid(cfg["uid"])
+            os.setgid(user_id)
+            os.setuid(user_id)
         except Exception:
             import traceback