Handling Authentication Issues

Common Error Messages

1. gcloud/bq CLI:
   • ERROR: (bq) You do not currently have an active account selected.
   • No credentialed accounts.
   • Configuration error: No account is currently active.
2. Execution Failures (Python/Notebooks):
   • google.auth.exceptions.DefaultCredentialsError: Could not automatically determine credentials.
   • Forbidden: 403 Access Denied (when it's clearly an auth issue).

Verification Step

Before asking the user to log in, independently verify the authentication status by running: gcloud auth list * If the output contains No credentialed accounts., proceed to the Corrective Action steps below. * If an account is listed but the user still receives a 403 Access Denied error, the issue is likely IAM permissions (e.g., missing BigQuery roles) on their active account, rather than missing authentication. In this case, investigate the permissions rather than asking them to log in again.

Corrective Action

When missing credentials are confirmed, DO NOT attempt to fix the credentials via code or alternative tools. Credentials must be established by the user.

Stop and ask the user to run the following commands in their terminal:

1. To authenticate the gcloud CLI: gcloud auth login

2. To set up Application Default Credentials (ADC) (required for BQ CLI AND most libraries/notebooks): gcloud auth application-default login

Post-Login Verification

After the user confirms they have logged in, verify with: gcloud auth list Then proceed with the original task.