Notify of configuration update through redis.

    Arguments:
        state (_WaffleState): Object that contains reference to app and its
            configstore.

def _redis_notifier(state):
    """Notify of configuration update through redis.

    Arguments:
        state (_WaffleState): Object that contains reference to app and its
            configstore.
    """
    tstamp = time.time()
    state._tstamp = tstamp
    conf = state.app.config

    # Notify timestamp
    r = redis.client.StrictRedis()
    r.publish(conf.get('WAFFLE_REDIS_CHANNEL', 'waffleconf'), tstamp)