Refined request_rate_limiter.lua.

spring-cloud-gateway-server/src/main/resources/META-INF/scripts/request_rate_limiter.lua

@@ -2,59 +2,26 @@ redis.replicate_commands()
 
 local tokens_key = KEYS[1]
 local timestamp_key = KEYS[2]
---redis.log(redis.LOG_WARNING, "tokens_key " .. tokens_key)
 
 local rate = tonumber(ARGV[1])
 local capacity = tonumber(ARGV[2])
-local now = tonumber(ARGV[3])
+local now = tonumber(ARGV[3]) or redis.call('TIME')[1]
 local requested = tonumber(ARGV[4])
 
 local fill_time = capacity / rate
 local ttl = math.floor(fill_time * 2)
 
--- for testing, it should use redis system time in production
-if now == nil then
-  now = redis.call('TIME')[1]
-end
-
---redis.log(redis.LOG_WARNING, "rate " .. ARGV[1])
---redis.log(redis.LOG_WARNING, "capacity " .. ARGV[2])
---redis.log(redis.LOG_WARNING, "now " .. now)
---redis.log(redis.LOG_WARNING, "requested " .. ARGV[4])
---redis.log(redis.LOG_WARNING, "filltime " .. fill_time)
---redis.log(redis.LOG_WARNING, "ttl " .. ttl)
-
-local last_tokens = tonumber(redis.call("get", tokens_key))
-if last_tokens == nil then
-  last_tokens = capacity
-end
---redis.log(redis.LOG_WARNING, "last_tokens " .. last_tokens)
-
-local last_refreshed = tonumber(redis.call("get", timestamp_key))
-if last_refreshed == nil then
-  last_refreshed = 0
-end
---redis.log(redis.LOG_WARNING, "last_refreshed " .. last_refreshed)
+local last_tokens = tonumber(redis.call("get", tokens_key)) or capacity
+local last_refreshed = tonumber(redis.call("get", timestamp_key)) or 0
 
 local delta = math.max(0, now-last_refreshed)
 local filled_tokens = math.min(capacity, last_tokens+(delta*rate))
 local allowed = filled_tokens >= requested
-local new_tokens = filled_tokens
-local allowed_num = 0
-if allowed then
-  new_tokens = filled_tokens - requested
-  allowed_num = 1
-end
-
---redis.log(redis.LOG_WARNING, "delta " .. delta)
---redis.log(redis.LOG_WARNING, "filled_tokens " .. filled_tokens)
---redis.log(redis.LOG_WARNING, "allowed_num " .. allowed_num)
---redis.log(redis.LOG_WARNING, "new_tokens " .. new_tokens)
+local new_tokens = allowed and filled_tokens - requested or filled_tokens
 
 if ttl > 0 then
   redis.call("setex", tokens_key, ttl, new_tokens)
   redis.call("setex", timestamp_key, ttl, now)
 end
 
--- return { allowed_num, new_tokens, capacity, filled_tokens, requested, new_tokens }
-return { allowed_num, new_tokens }
+return { allowed and 1 or 0, new_tokens }