I am storing strings and numbers in Redis.

I use basic key value stores to keep track of the current color value.

DATA:color:ID1 = red
DATA:color:ID2 = red
DATA:color:ID3 = red
DATA:color:ID4 = blue

I use SETs to allow for quick lookup of colors and corresponding IDs.

INDEX:color:red = {ID1, ID2, ID3}
INDEX:color:blue = {ID4}

How should I go about updating these values? If ID1 becomes blue, we will need to run the following commands:

SADD INDEX:color:blue ID1
SREM INDEX:color:red ID1
SET DATA:color:ID1 blue

The issue though is I do not know which SET ID1 is inside at the time of updating the value to blue. I can achieve this using a lua script, but this violates the rules about generating dynamic keys. The lua script would look like:

-- ARGV[1] is the index key
-- ARGV[2] is the ID
-- ARGV[3] is the new value

local k = redis.call('GET', KEYS[1])
redis.call('SREM', ARGV[1] .. ":" .. k, ARGV[2])
redis.call('SADD', ARGV[1] .. ":" .. ARGV[3], ARGV[2])
redis.call('SET', KEYS[1], ARGV[3])

Example usage would look like:

EVALSHA <SHA> 1 DATA:color:ID1 INDEX:color ID1 blue

If I were storing numbers, this is trivial as I can use sorted sets.

Is there a way to achieve this without violating the guidelines?