Use dict to forward error

Author: EppO

prometrix/auth.py

@@ -63,8 +63,10 @@ def _post_azure_token_endpoint(cls, config: PrometheusConfig):
         # Fallback to Azure Service Principal
         if not token:
             if config.azure_use_workload_id:
-                logging.error(f"Could not open token file from {token_file}")
-                return {}
+                return {
+                    "ok": False,
+                    "reason": f"Could not open token file from {token_file}",
+                }
             data = {
                 "grant_type": "client_credentials",
                 "client_id": config.azure_client_id,