OpenResty+nginx+lua+redis实现二级缓存

下载OpenResty镜像

docker pull openresty/openresty

运行镜像

docker run -d -p 880:80 --name openresty --restart always -v /etc/localtime:/etc/localtime openresty/openresty

进入容器

docker exec -it openresty /bin/bash

安装lua

apt-get update -y
apt-get install -y gcc
apt-get install -y curl
apt-get install -y make
apt-get install -y vim
apt-get install libreadline-dev -y
curl -R -O http://www.lua.org/ftp/lua-5.3.5.tar.gz
tar -zxf lua-5.3.5.tar.gz
cd lua-5.3.5
make linux test
make install

编写lua脚本并上传到服务器

ngx.header.content_type = "application/json;charset=utf8"

--获取本地缓存
local cache_ngx = ngx.shared.dis_cache;
-- 获取本地缓存数据
local ngCache = cache_ngx:get('lua:application-data')
if ngCache == "" or ngCache == nil then
    --引入redis库
    local cjson = require("cjson")
    local redis = require("resty.redis")
    local red = redis:new()
    red:set_timeout(2000)

    local ip = "127.0.0.1"
    local port = 6379
    red:connect(ip, port)
    red:auth("123456")

    local redCache = red:get("lua:application-data")
    if redCache == ngx.null or redCache == "" or redCache == nil then
        --引入mysql库
        local mysql = require("resty.mysql")
        local db = mysql:new()
        db:set_timeout(3000)
        local props = {
            host = "127.0.0.1",
            port = 3306,
            database = "test",
            user = "root",
            password = "root"
        }

        local res = db:connect(props)
        local select_sql = "SELECT xxx from tb_level where xxx"
        res = db:query(select_sql)
        db:close()
        red:set("lua:application-data", cjson.encode(res))
        red:close()
        --将redis中获取到的数据存入nginx本地缓存10分钟 测试阶段先1分钟
        cache_ngx:set('lua:application-data', cjson.encode(res), 1 * 60)
        ngx.say("{\"code\":0,\"message\":\"sql success\",\"data\":" .. cjson.encode(res) .. "}")
    else
        --将redis中获取到的数据存入nginx本地缓存10分钟 测试阶段先1分钟
        cache_ngx:set('lua:application-data', redCache, 1 * 60)
        ngx.say("{\"code\":0,\"message\":\"redis success\",\"data\":" .. redCache .. "}")
    end
else
    ngx.say("{\"code\":0,\"message\":\"nginx success\",\"data\":" .. ngCache .. "}")
end

• 特别说明

  lua读取redis数据返回结果为空时，返回的结果不是nil而是userdata类型的ngx.null
  

在http节点下开启nginx共享内存

vim /usr/local/openresty/nginx/conf/nginx.conf

lua_shared_dict dis_cache 10m;

在server节点添加lua配置

location /lua {
    content_by_lua_file /opt/lua/cache.lua;
    add_header Access-Control-Allow-Origin *;
    add_header Access-Control-Allow-Methods 'GET, POST, OPTIONS';
    add_header Access-Control-Allow-Headers '*';
}