local uidKey = KEYS[1]
local bindUidKey = KEYS[2]
local openID = ARGV[1]
local uid = redis.call('HGET', bindUidKey, openID)
if uid then
    return tonumber(uid)
else
    local new_uid = redis.call('INCR', uidKey)
    redis.call('HSET', bindUidKey, openID, new_uid)
    return tonumber(new_uid)
end