2023-03-25 14:40:31 +01:00
|
|
|
-- This script updates a token bucket rate limiter with dynamic rate and burst multipliers in Redis.
|
|
|
|
|
|
|
|
-- KEYS: Input parameters
|
|
|
|
-- KEYS[1] - prefix: The Redis key prefix used to store the bucket information.
|
|
|
|
-- KEYS[2] - now: The current time in milliseconds.
|
|
|
|
-- KEYS[3] - dynamic_rate_multiplier: A multiplier to adjust the rate limit dynamically.
|
|
|
|
-- KEYS[4] - dynamic_burst_multiplier: A multiplier to adjust the burst limit dynamically.
|
|
|
|
-- KEYS[5] - max_dyn_rate: The maximum allowed value for the dynamic rate multiplier.
|
|
|
|
-- KEYS[6] - max_burst_rate: The maximum allowed value for the dynamic burst multiplier.
|
|
|
|
-- KEYS[7] - expire: The expiration time for the Redis key storing the bucket information, in seconds.
|
|
|
|
-- KEYS[8] - number_of_recipients: The number of requests to be allowed (or the increase rate).
|
|
|
|
|
|
|
|
-- 1. Retrieve the last hit time and initialize variables
|
2023-03-25 14:19:35 +01:00
|
|
|
local prefix = KEYS[1]
|
|
|
|
local last = redis.call('HGET', prefix, 'l')
|
|
|
|
local now = tonumber(KEYS[2])
|
2023-03-25 13:40:15 +01:00
|
|
|
local nrcpt = tonumber(KEYS[8])
|
|
|
|
if not last then
|
2023-03-25 14:40:31 +01:00
|
|
|
-- 2. Initialize a new bucket if the last hit time is not found (must not happen)
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HMSET', prefix, 'l', tostring(now), 'b', tostring(nrcpt), 'dr', '10000', 'db', '10000', 'p', '0')
|
|
|
|
redis.call('EXPIRE', prefix, KEYS[7])
|
2023-08-07 12:41:28 +02:00
|
|
|
return { 1, 1, 1 }
|
2023-03-25 13:40:15 +01:00
|
|
|
end
|
|
|
|
|
2023-03-25 14:40:31 +01:00
|
|
|
-- 3. Update the dynamic rate multiplier based on input parameters
|
2023-03-25 13:40:15 +01:00
|
|
|
local dr, db = 1.0, 1.0
|
|
|
|
|
2023-03-25 14:19:35 +01:00
|
|
|
local max_dr = tonumber(KEYS[5])
|
|
|
|
|
|
|
|
if max_dr > 1 then
|
2023-03-25 13:40:15 +01:00
|
|
|
local rate_mult = tonumber(KEYS[3])
|
2023-03-25 14:19:35 +01:00
|
|
|
dr = tonumber(redis.call('HGET', prefix, 'dr')) / 10000
|
2023-03-25 13:40:15 +01:00
|
|
|
|
2023-03-25 14:19:35 +01:00
|
|
|
if rate_mult > 1.0 and dr < max_dr then
|
2023-03-25 13:40:15 +01:00
|
|
|
dr = dr * rate_mult
|
|
|
|
if dr > 0.0001 then
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HSET', prefix, 'dr', tostring(math.floor(dr * 10000)))
|
2023-03-25 13:40:15 +01:00
|
|
|
else
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HSET', prefix, 'dr', '1')
|
2023-03-25 13:40:15 +01:00
|
|
|
end
|
2023-03-25 14:19:35 +01:00
|
|
|
elseif rate_mult < 1.0 and dr > (1.0 / max_dr) then
|
2023-03-25 13:40:15 +01:00
|
|
|
dr = dr * rate_mult
|
|
|
|
if dr > 0.0001 then
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HSET', prefix, 'dr', tostring(math.floor(dr * 10000)))
|
2023-03-25 13:40:15 +01:00
|
|
|
else
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HSET', prefix, 'dr', '1')
|
2023-03-25 13:40:15 +01:00
|
|
|
end
|
|
|
|
end
|
|
|
|
end
|
|
|
|
|
2023-03-25 14:40:31 +01:00
|
|
|
-- 4. Update the dynamic burst multiplier based on input parameters
|
2023-03-25 14:19:35 +01:00
|
|
|
local max_db = tonumber(KEYS[6])
|
|
|
|
if max_db > 1 then
|
2023-03-25 13:40:15 +01:00
|
|
|
local rate_mult = tonumber(KEYS[4])
|
2023-03-25 14:19:35 +01:00
|
|
|
db = tonumber(redis.call('HGET', prefix, 'db')) / 10000
|
2023-03-25 13:40:15 +01:00
|
|
|
|
2023-03-25 14:19:35 +01:00
|
|
|
if rate_mult > 1.0 and db < max_db then
|
2023-03-25 13:40:15 +01:00
|
|
|
db = db * rate_mult
|
|
|
|
if db > 0.0001 then
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HSET', prefix, 'db', tostring(math.floor(db * 10000)))
|
2023-03-25 13:40:15 +01:00
|
|
|
else
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HSET', prefix, 'db', '1')
|
2023-03-25 13:40:15 +01:00
|
|
|
end
|
2023-03-25 14:19:35 +01:00
|
|
|
elseif rate_mult < 1.0 and db > (1.0 / max_db) then
|
2023-03-25 13:40:15 +01:00
|
|
|
db = db * rate_mult
|
|
|
|
if db > 0.0001 then
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HSET', prefix, 'db', tostring(math.floor(db * 10000)))
|
2023-03-25 13:40:15 +01:00
|
|
|
else
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HSET', prefix, 'db', '1')
|
2023-03-25 13:40:15 +01:00
|
|
|
end
|
|
|
|
end
|
|
|
|
end
|
|
|
|
|
2023-03-25 14:40:31 +01:00
|
|
|
-- 5. Update the burst and pending values based on the number of recipients (requests)
|
2023-08-07 12:41:28 +02:00
|
|
|
local burst, pending = unpack(redis.call('HMGET', prefix, 'b', 'p'))
|
|
|
|
burst, pending = tonumber(burst or '0'), tonumber(pending or '0')
|
|
|
|
if burst < 0 then
|
|
|
|
burst = nrcpt
|
|
|
|
else
|
|
|
|
burst = burst + nrcpt
|
|
|
|
end
|
|
|
|
if pending < nrcpt then
|
|
|
|
pending = 0
|
|
|
|
else
|
|
|
|
pending = pending - nrcpt
|
|
|
|
end
|
2023-03-25 13:40:15 +01:00
|
|
|
|
2023-03-25 14:40:31 +01:00
|
|
|
-- 6. Set the updated values back to Redis and update the expiration time for the bucket
|
2023-03-25 14:19:35 +01:00
|
|
|
redis.call('HMSET', prefix, 'b', tostring(burst), 'p', tostring(pending), 'l', KEYS[2])
|
|
|
|
redis.call('EXPIRE', prefix, KEYS[7])
|
2023-03-25 13:40:15 +01:00
|
|
|
|
2023-03-25 14:40:31 +01:00
|
|
|
-- 7. Return the updated burst value, dynamic rate multiplier, and dynamic burst multiplier
|
2023-08-07 12:41:28 +02:00
|
|
|
return { tostring(burst), tostring(dr), tostring(db) }
|