improve config check

pyquarantine/modify.py

@@ -237,8 +237,12 @@ class AddDisclaimer:
             raise RuntimeError(e)
         body = html.find('body')
         self.html_template = body or html
-        self.action = action
+        self.action = action.lower()
-        self.error_policy = error_policy
+        assert self.action in ["prepend", "append"], \
+            f"invalid action '{action}'"
+        self.error_policy = error_policy.lower()
+        assert self.error_policy in ["ignore", "reject", "wrap"], \
+            f"invalid error_policy '{error_policy}'"
         self.pretend = pretend
 
     def patch_message_body(self, milter, logger):

pyquarantine/run.py

@@ -101,17 +101,12 @@ def main():
             if not rule["actions"]:
                 raise RuntimeError(
                     f"{rule['name']}: no actions configured")
+        ModifyMilter.set_config(cfg, args.debug)
 
     except (RuntimeError, AssertionError) as e:
         logger.error(f"config error: {e}")
         sys.exit(255)
 
-    try:
-        ModifyMilter.set_config(cfg, args.debug)
-    except RuntimeError as e:
-        logger.error(e)
-        sys.exit(254)
-
     if args.test:
         print("Configuration OK")
         sys.exit(0)