Configuration settings.

def configure(logstash_host=None, logstash_port=None, logdir=None):
    '''Configuration settings.'''

    if not (logstash_host or logstash_port or logdir):
        raise ValueError('you must specify at least one parameter')

    config.logstash.host = logstash_host or config.logstash.host
    config.logstash.port = logstash_port or config.logstash.port
    config.logdir = logdir or config.logdir

    create_logdir(config.logdir)