import time


def get_signature(user_agent, query_string, client_ip_address, lang):
    """
    Get cache signature based on `user_agent`, `url_string`,
    `lang`, and `client_ip_address`
    """

    timestamp = int(time.time()) / 1000
    signature = "%s:%s:%s:%s:%s" % \
        (user_agent, query_string, client_ip_address, lang, timestamp)
    return signature