Nginx+Lua+Redis实例

lua加入到nginx中，相当于让nginx拥有了处理业务逻辑的能力。

例如：对IP进行封禁

在站点遇到攻击且无明显攻击特征，造成站点访问慢，nginx不断返回502等错误时，可利用nginx+lua+redis实现在指定的时间段内，若单IP的请求量达到指定的数量后对该IP进行封禁，nginx返回403禁止访问。利用redis的expire命令设置封禁IP的过期时间达到在指定的封禁时间后实行自动解封的目的。

例如：灰度发布

灰度发布是指在黑与白之间，能够平滑过渡的一种发布方式。AB
test就是一种灰度发布方式，让一部分用户继续用A，一部分用户开始用B，如果用户对B没有什么反对意见，那么逐步扩大范围，把所有用户都迁移到B上面 来。灰度发布可以保证整体系统的稳定，在初始灰度的时候就可以发现、调整问题，以保证其影响度。

下面是一个nginx+lua+redis实例，在此基础上可以扩展nginx业务能力

test.conf

server {
listen       80;
server_name  test.geetest.com;
location @client{
proxy_pass http://www.baidu.com; }
location / {
set $variable 23;

lua_code_cache off;
default_type text/html;
content_by_lua_file /usr/local/openresty/nginx/conf/sites-avaliable/test_content.lua;
access_by_lua_file /usr/local/openresty/nginx/conf/sites-avaliable/test_access.lua;
rewrite_by_lua_file /usr/local/openresty/nginx/conf/sites-avaliable/test_rewrite.lua;

}

}

test.lua

local redis = require "resty.redis"
local red = redis:new()

red:set_timeout(1000) -- 1 sec

-- or connect to a unix domain socket file listened
-- by a redis server:
--     local ok, err = red:connect("unix:/path/to/redis.sock")

local ok, err = red:connect("127.0.0.1", 6379)
if not ok then
ngx.say("failed to connect: ", err)
return
end

ok, err = red:set("dog", "an animal")
if not ok then
ngx.say("failed to set dog: ", err)
return
end

ngx.say("set result: ", ok)

local res, err = red:get("dog")
if not res then
ngx.say("failed to get dog: ", err)
return
end

if res == ngx.null then
ngx.say("dog not found.")
return
end

ngx.say("dog: ", res)

red:init_pipeline()
red:set("cat", "Marry")
red:set("horse", "Bob")
red:get("cat")
red:get("horse")
local results, err = red:commit_pipeline()
if not results then
ngx.say("failed to commit the pipelined requests: ", err)
return
end

for i, res in ipairs(results) do
if type(res) == "table" then
if not res[1] then
ngx.say("failed to run command ", i, ": ", res[2])
else
-- process the table value
end
else
-- process the scalar value
end
end

-- put it into the connection pool of size 100,
-- with 10 seconds max idle time
local ok, err = red:set_keepalive(10000, 100)
if not ok then
ngx.say("failed to set keepalive: ", err)
return
end