clearcache.lua

local shard_id = tonumber(ARGV[3])
local shard_count = tonumber(ARGV[2])
local prefix = 'cache:' .. ARGV[1] .. ':'

local keys = redis.call('keys', prefix .. '*')
local deleted = 0

for i,v in pairs(keys) do
  local key = keys[i]
  local guild_id = string.sub(key, #prefix + 1)

  local guild_shard_id = math.floor((guild_id / 2^22) % shard_count)

  if shard_id == guild_shard_id then
    deleted = deleted + 1
    redis.call('del', key)
  end
end

return deleted