CODEWITHSUNDEEP
redisluanode-redis
Владимир Говорухин
Владимир Говорухин

Reputation: 523

How do I pass ...array to redis rpush inside Lua script?

I need to iterate ring any times in redis, I have this Lua script:

local result = redis.call('lrange','test',0,5)
redis.call('ltrim','test',5,-1)
redis.call('rpush','test',result)
return result

Here I lpop 5 elements, then I need to rpush them back.

redis.call('rpush','test',result)

throws error Lua redis() command arguments must be strings or integers, so I need JavaScript like ...result in Lua.

Upvotes: 1

Views: 1004

Answers (1)

Ersoy
Ersoy

Reputation: 9596

I think you may use unpack for this.

local result = redis.call('lrange','test',0,5)
redis.call('ltrim','test',5,-1)
redis.call('rpush','test',unpack(result))
return result

While calling lrange you (may) need to use 4 instead of 5 if you want to keep the list size same. Here is the sample demonstration when executing it with 4.

127.0.0.1:6379> rpush test a b c d e f
(integer) 6
127.0.0.1:6379> "EVAL" "local result = redis.call('lrange','test',0,4) redis.call('ltrim','test',5,-1) redis.call('rpush','test',unpack(result)) return result" "0"
1) "a"
2) "b"
3) "c"
4) "d"
5) "e"
127.0.0.1:6379> lrange test 0 -1
1) "f"
2) "a"
3) "b"
4) "c"
5) "d"
6) "e"

Upvotes: 1

Related Questions