check if sysconfig.toml is really a file

entrypoint.py

@@ -29,6 +29,10 @@ class SystemConfigurator:
         self.config_path = path
 
     def _parse_config(self):
+        if not os.path.isfile(self.config_path):
+            raise RuntimeError(
+                f"{self.config_path}: is not a file. Mount a valid config."
+            )
         with open(self.config_path, "rb") as f:
             self.config = tomllib.load(f)