def bucket_uri(bucket, acceleration=False):
    """
    Convert a S3 bucket name string in to a S3 bucket uri.

    :param bucket: Bucket name
    :param acceleration: Use transfer acceleration if the endpoint is available
    :return: Bucket URI
    """
    return '{uri}://{bucket}'.format(uri='s3-accelerate' if acceleration else
        's3', bucket=bucket)
