CODEWITHSUNDEEP
redis
Dave Mateer
Dave Mateer

Reputation: 17956

Redis atomic GET and EXPIRE

Is there an atomic GET + EXPIRE command available for Redis? This would act as a sliding expiration value: attempt to get the value specified by the key, and then only if the key was found with this request, set the time to live for X seconds.

Upvotes: 3

Views: 3660

Answers (2)

Pavel Francírek
Pavel Francírek

Reputation: 188

Or, I use simple Lua script:

local val, err = redis.pcall('GET', KEYS[1])
if err then
    return err
end
redis.call('EXPIRE', KEYS[1], ARGV[1])
return {val}

In Golang you can do:

import "github.com/go-redis/redis"

const lua = `
local val, err = redis.pcall('GET', KEYS[1])
if err then
    return err
end
redis.call('EXPIRE', KEYS[1], ARGV[1])
return {val}
    `

redisGetEx = redis.NewScript(lua)
result, err = redisGetEx.Run(redisClient, []string{"key"}, 1800).Result()

Upvotes: 2

Itamar Haber
Itamar Haber

Reputation: 50112

No, there isn't, but there's nothing preventing you from sending the two commands one after the other in a MULTI/EXEC block or using a Lua script. Using EXPIRE on a non-existent key does nothing.

Upvotes: 5

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