服务限流demo（lua脚本）

古城微笑少年丶 2022-05-11 12:36 217阅读 0赞

本文提供了两种服务限流的demo，以开拓思路，仅供参考。

# 1. 基于漏统原理 #

local function close\_redis(red)

if not red then

return

end

local ok, err = red:close()

if not ok then

ngx.say("close redis error : ", err)

end

local function lua\_string\_split(str)

local sub\_str\_tab = \{\};

local local\_server\_name;

for mu\_id in string.gmatch(str, "(%w\*)/") do

table.insert(sub\_str\_tab, mu\_id)

end

if \#sub\_str\_tab >= 2 then

local\_server\_name = sub\_str\_tab\[2\]

else

local\_server\_name = nil

end

return local\_server\_name;

end

local redis = require("resty.redis")

\--创建实例

local red = redis:new()

\--设置超时（毫秒）

red:set\_timeout(1000)

\--建立连接

local ip = "127.0.0.1"

local port = 6379

local ok, err = [red:connect][red_connect](ip, port)

if not ok then

ngx.say("connect to redis error : ", err)

return close\_redis(red)

end

\-- 获取当前请求的uri

local uri = ngx.var.uri

\--解析服务名称

local server\_name = lua\_string\_split(uri)

\--define time\_distance to check unit:s

local time\_distance = 60

\--assume rate value red redis and config by ui unit: r/s

\--this rate get by server\_name

\--code sample: server\_rate = red:get(server\_name)

local server\_rate = 2

\--读取远程地址，限制的对象或者从request里获取

local remoteAdd = ngx.var.remote\_addr

local key = server\_name..remoteAdd

\--请求量

local server\_reqs = server\_rate \* time\_distance

\--set key expire

local ok,err = [red:expire][red_expire](key, time\_distance)

if not ok then

ngx.log(ngx.WARN, "redis set expire error: ", err)

close\_redis(red)

return nil

end

\--push list value

local ok, err = [red:rpush][red_rpush](key, ngx.time())

if not ok then

ngx.log(ngx.WARN, "redis rpush error: ", err)

close\_redis(red)

return nil

end

\--lrange key list value

local res, err = [red:lrange][red_lrange](key, -server\_reqs, -1)

if not ok then

ngx.log(ngx.WARN, "redis lrange error: ", err)

close\_redis(red)

return nil

end

\--finally

close\_redis(red)

if \#res >= server\_reqs or res\[\#res\] - res\[1\] >= time\_distance then

ngx.exit(ngx.HTTP\_FORBIDDEN)

end

ngx.say(server\_name.." status is  ok!")

# 2. 基于计数器 #

local function close\_redis(red)

if not red then

return

end

local ok, err = red:close()

if not ok then

ngx.say("close redis error : ", err)

end

local function wait()

ngx.sleep(1)

end

local function lua\_string\_split(str)

local sub\_str\_tab = \{\};

local local\_server\_name;

for mu\_id in string.gmatch(str, "(%w\*)/") do

table.insert(sub\_str\_tab, mu\_id)

end

if \#sub\_str\_tab >= 2 then

local\_server\_name = sub\_str\_tab\[2\]

else

local\_server\_name = nil

end

return local\_server\_name;

end

local redis = require "resty.redis"

local red = redis:new()

red:set\_timeout(1000)

local ip = "127.0.0.1"

local port = 6379

local ok, err = red:connect(ip,port)

if not ok then

return close\_redis(red)

end

-- 获取当前请求的uri

local uri = ngx.var.uri

\--解析服务名称

local server\_name = lua\_string\_split(uri)

\--define time\_distance to check unit:s

local time\_distance = 60

\--assume rate value red redis and config by ui unit: r/s

\--this rate get by server\_name

\--code sample: server\_rate = red:get(server\_name)

local server\_rate = 100

\--读取远程地址，限制的对象或者从request里获取

local remoteAdd = ngx.var.remote\_addr

local key = server\_name..remoteAdd

\--请求量

local server\_reqs = server\_rate \* time\_distance

local res, err = [red:eval][red_eval]("local res, err = redis.call('incr',KEYS\[1\]) if res == 1 then local resexpire, err = redis.call('expire',KEYS\[1\],KEYS\[2\]) end return (res)",2,key,time\_distance)

if not ok then

ngx.log(ngx.WARN, "redis lrange error: ", err)

close\_redis(red)

return nil

end

\--finally   
close\_redis(red)

\--判断总请求量

if res >= server\_reqs then

ngx.exit(ngx.HTTP\_FORBIDDEN)

end

ngx.say(server\_name.." status is  ok!")

[red_connect]: http://redconnect/
[red_expire]: http://redexpire/
[red_rpush]: http://redrpush/
[red_lrange]: http://redlrange/
[red_eval]: http://redeval/