_auth.py 文件源码

def default_credentials():
    """Returns Application Default Credentials."""
    if HAS_GOOGLE_AUTH:
        credentials, _ = google.auth.default()
        return credentials
    elif HAS_OAUTH2CLIENT:
        return oauth2client.client.GoogleCredentials.get_application_default()
    else:
        raise EnvironmentError(
            'No authentication library is available. Please install either '
            'google-auth or oauth2client.')