redis分布式锁-自动超时锁

def acquire_lock_with_timeout（conn,lockname,acquire_timeout,lock_timeout)
    identifer=uuid.uuid4
    lockname=‘lock:‘+lockname
    repeat_end_time=current_time()+acquire_timeout
    
    while current_time<repeat_end_time
        if conn.setnx(lockname,identifer)
            conn.expire(lockname,lock_timeout)
            return identifer
        elif not conn.ttl(lockname)
            conn.expire(lockname,lock_timeout)
        time.sleep(0.001)
    return false

def release_loc(conn,lockname,identifer)
    pipe=conn.pipeline(true)
    lockname=‘lock:‘+lockname
    while True
        try:
            pipe.watch(lockname)
            if pipe.get(lockname) == identifer   // 检查进程是否仍然是有锁，若未持有锁，则返回false
                pipe.multi()
                pipe.delete(lockname)
                pipe.execute
                return true
            pipe.unwatch()
            break
        except redis.exceptions.WatchError
            pass    // 有其他客户端修改了锁，重试
    return False