redis限流

前提

redis+lua

 

滑动窗口

-- 滑动窗口
local key = KEYS[1]
local maxSize = ARGV[1]
local currentTime = ARGV[2]
local startTime = ARGV[3]
local uuid = ARGV[4]
local currentCount = redis.call('zcount',key,startTime,currentTime)
if (currentCount and tonumber(currentCount)>=tonumber(maxSize)) then
    return 0
end
-- 防止zset添加同一时间添加元素覆盖，添加后缀uuid
redis.call('zadd',key,currentTime,currentTime..uuid)
redis.call('expire',key,60*60*24)
-- 删除过期时间区间
redis.call('zremrangebyscore',key,0,startTime-10000)
return 1

 

漏桶

-- 漏桶
-- capacity：容量，passRate：漏水速率，addWater：每次请求加水量（默认为1），water：当前水量，lastTs：时间戳
local limitInfo = redis.call('hmget',KEYS[1],'capacity','passRate','water','lastTs')
local capacity = limitInfo[1]
local passRate = limitInfo[2]
local water = limitInfo[3]
local lastTs = limitInfo[4]
local addWater = 1
-- 初始化漏桶
if capacity == false or passRate==false then
    capacity = tonumber(ARGV[1])
    passRate = tonumber(ARGV[2])
    water = addWater
    lastTs = ARGV[3]
    redis.call('hmset',KEYS[1],'capacity',capacity,'passRate',passRate,'addWater',addWater,'water',water,'lastTs',lastTs)
    return 1
else
    local nowTs = ARGV[3]
    -- 当前距离上一次漏水量
    local waterPass = tonumber((tonumber(nowTs)-tonumber(lastTs))*tonumber(passRate)/1000)
    water = math.max(0,tonumber(water-waterPass))
    lastTs = nowTs
    if capacity-water>=addWater then
        water = water+addWater
        capacity = tonumber(ARGV[1])
        passRate = tonumber(ARGV[2])
        redis.call('hmset',KEYS[1],'capacity',capacity,'passRate',passRate,'water',water,'lastTs',lastTs)
        redis.call('expire',KEYS[1],60*60*24)
        return 1
    end
    return 0
end

 

令牌桶

-- 令牌桶
-- capacity：容量，rate：令牌生成速率，leftTokenNum：剩余令牌数，lastTs：时间戳
local limitInfo = redis.call('hmget',KEYS[1],'capacity','rate','leftTokenNum','lastTs')
local capacity = limitInfo[1]
local rate = limitInfo[2]
local leftTokenNum = limitInfo[3]
local lastTs = limitInfo[4]
-- 本次需要的令牌数
local need = 1
if capacity==false or rate==false or leftTokenNum==false then
    capacity = tonumber(ARGV[1])
    rate = tonumber(ARGV[2])
    lastTs = ARGV[3]
    leftTokenNum = capacity-need
    redis.call('hmset',KEYS[1],'capacity',capacity,'rate',rate,'leftTokenNum',leftTokenNum,'lastTs',lastTs)
    return 1
else
    local nowTs = ARGV[3]
    -- 距离上次产生的令牌数
    local createTokenNum = tonumber((tonumber(nowTs)-tonumber(lastTs))*tonumber(rate)/1000)
    -- 剩余的令牌数
    leftTokenNum = math.min(capacity,createTokenNum+leftTokenNum)
    lastTs = nowTs
    -- 判断是否还有令牌
    if leftTokenNum>=need then
        -- 减去需要的令牌
        leftTokenNum = leftTokenNum - need
        -- 更新
        capacity = tonumber(ARGV[1])
        rate = tonumber(ARGV[2])
        redis.call('hmset',KEYS[1],'capacity',capacity,'rate',rate,'leftTokenNum',leftTokenNum,'lastTs',lastTs)
        redis.call('expire',KEYS[1],60*60*24)
        return 1
    end
    return 0
end