连接中断时重试Redis操作

Question

我想写一段代码，把数据插入到Redis这个数据库里。首先，它需要连接到Redis服务器，如果连接失败，就要尝试重新连接。一旦连接成功，就可以执行一些命令，比如 hset() 和 set()。如果连接中断了，我该怎么重新尝试这些命令呢？

这是我目前写的代码，它只处理了连接时的重试。

while cnt < 11:
    try:
        r.ping()
        break

    except redis.ConnectionError:
        time_sleep = cnt * 5
        time.sleep(time_sleep)
        r = redis.Redis(host='10.23.*.*', port=6379, db=0)
        cnt += 1
        print cnt
if cnt == 11:
     sys.exit(-1)
r.hset(field,keys,1)

Answer 1

你可以在最初的计数器想法基础上，扩展它，让它适用于任何操作。

max_retries = 10
count = 0

r = redis.Redis(host='10.23.*.*', port=6379, db=0)

def try_command(f, *args, **kwargs):
    while True:
        try:
            return f(*args, **kwargs)
        except redis.ConnectionError:
            count += 1

            # re-raise the ConnectionError if we've exceeded max_retries
            if count > max_retries:
                raise

            backoff = count * 5

            print('Retrying in {} seconds'.format(backoff)
            time.sleep(backoff)

            r = redis.Redis(host='10.23.*.*', port=6379, db=0)

# this will retry until a result is returned
# or will re-raise the final ConnectionError
try_command(r.hset, field, keys, 1)