refactored the credential checking logic into a shared helper function to reduce code duplication

auth/google_auth.py

@@ -232,6 +232,19 @@ def load_client_secrets(client_secrets_path: str) -> Dict[str, Any]:
     except (IOError, json.JSONDecodeError) as e:
         logger.error(f"Error loading client secrets file {client_secrets_path}: {e}")
         raise
+def check_client_secrets() -> Optional[str]:
+    """
+    Checks for the presence of OAuth client secrets, either as environment
+    variables or as a file.
+
+    Returns:
+        An error message string if secrets are not found, otherwise None.
+    """
+    env_config = load_client_secrets_from_env()
+    if not env_config and not os.path.exists(CONFIG_CLIENT_SECRETS_PATH):
+        logger.error(f"OAuth client credentials not found. No environment variables set and no file at {CONFIG_CLIENT_SECRETS_PATH}")
+        return "OAuth client credentials not found. Please set GOOGLE_OAUTH_CLIENT_ID and GOOGLE_OAUTH_CLIENT_SECRET environment variables or provide client_secret.json file."
+    return None
 
 def create_oauth_flow(scopes: List[str], redirect_uri: str, state: Optional[str] = None) -> Flow:
     """Creates an OAuth flow using environment variables or client secrets file."""

auth/oauth_callback_server.py

@@ -15,7 +15,7 @@ import socket
 from fastapi import FastAPI, Request
 import uvicorn
 
-from auth.google_auth import handle_auth_callback, CONFIG_CLIENT_SECRETS_PATH
+from auth.google_auth import handle_auth_callback, check_client_secrets
 from auth.scopes import OAUTH_STATE_TO_SESSION_ID_MAP, SCOPES
 from auth.oauth_responses import create_error_response, create_success_response, create_server_error_response
 
@@ -60,11 +60,9 @@ class MinimalOAuthServer:
 
             try:
                 # Check if we have credentials available (environment variables or file)
-                from auth.google_auth import load_client_secrets_from_env
-                env_config = load_client_secrets_from_env()
-                if not env_config and not os.path.exists(CONFIG_CLIENT_SECRETS_PATH):
-                    logger.error(f"OAuth client credentials not found. No environment variables set and no file at {CONFIG_CLIENT_SECRETS_PATH}")
-                    return create_server_error_response("OAuth client credentials not found. Please set GOOGLE_OAUTH_CLIENT_ID and GOOGLE_OAUTH_CLIENT_SECRET environment variables or provide client_secret.json file.")
+                error_message = check_client_secrets()
+                if error_message:
+                    return create_server_error_response(error_message)
 
                 logger.info(f"OAuth callback: Received code (state: {state}). Attempting to exchange for tokens.")