How go-redis pipeline do atomically?

As the title, and the code like this:

    var stringSliceCmd *redis.StringSliceCmd   // stringSliceCmd is the result of Redis operation 
    _, err := RedisCli.Pipelined(ctx, func(pipe redis.Pipeliner) error {
        stringSliceCmd = pipe.LRange(ctx, "log-oss", 0, 1) // step one
        pipe.LTrim(ctx, "log-oss", 2, -1)                 // step two
        err := testHandleMessage(stringSliceCmd)         // step three
        if err != nil {
            log.Errorf("HandleMessage err: %v", err)
            return err
        }
        return nil
    })

Explanation:

Now I need to do three steps, and hopefully do it atomically. Step one can get the result stringSliceCmd from redis, step two is another redis operation, and step three is a function that need the result stringSliceCmd. And if one of three steps failed, then return error.

But if I code it as above, the result stringSliceCmd if nil. What should I do?