SimpleScheduler
    redis parameters will be read from environment variables:
    REDIS_HOST, REDIS_PORT, REDIS_DB, REDIS_KEY (password)

def main():
    """ SimpleScheduler
    redis parameters will be read from environment variables:
    REDIS_HOST, REDIS_PORT, REDIS_DB, REDIS_KEY (password)
    """
    args = parser.parse_args()

    scheduler = Scheduler()

    print 'Start %s' % scheduler.scheduler_id
    scheduler.interval = args.interval
    if args.keepalive:
        scheduler.run(once=True)
        keepalive = Job('simplescheduler.keepalive',
                        args=[0,
                              scheduler.get_running_scheduler_id(),
                              args.interval * 2])
        scheduler.schedule(keepalive, long(time.time() * 1000000))
    scheduler._run()