populate.py 文件源码

def _resolve_data_source(value, default, param, must_exist=False):
    if must_exist:
        val_exists = os.path.isdir(value) if value else False
        default_exists = os.path.isdir(default)

        if val_exists:
            path_to_use = value
        elif default_exists:
            click.echo('==> No source provided')
            click.echo('==> Folder {} exists. Assuming that is our {}'
                       ' folder...'.format(default, param))
            path_to_use = default
        else:
            raise click.BadParameter('Cannot find a suitable {} '
                                     'directory.'.format(param))
    else:
        path_to_use = value if value else default

    return os.path.realpath(path_to_use)