nginx+lua+redis实现广告缓存 - 2021-09-17
一. 大致流程: client -- Openresty -- Nginx -- lua -- redis -- mysql:
二. 环境: linux虚拟机中安装: lua, openresty, nginx
1.lua
lua安装:
yum install -y gcc
yum install libtermcap-devel ncurses-devel libevent-devel readline-devel
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 install2. openresty
linux安装openresty:
1.添加仓库执行命令
yum install yum-utils
yum-config-manager --add-repo https://openresty.org/package/centos/openresty.repo
2.执行安装
yum install openresty
3.安装成功后 会在默认的目录如下：
/usr/local/openresty3. 默认已经安装好了nginx,在目录：/usr/local/openresty/nginx
三. 配置文件:
1. 修改/usr/local/openresty/nginx/conf/nginx.conf ,将配置文件使用的根设置为root, 使用lua脚本时 ，直接加载在root下的lua脚本
#user nobody; 配置文件第一行原来为这样, 现改为下面的配置
user root root;2. 配置/root目录下的lua脚本:
(1). 创建ad_load.lua ，实现连接mysql 查询数据 并存储到redis中
ngx.header.content_type="application/json;charset=utf8"
local cjson = require("cjson")
local mysql = require("resty.mysql")
local uri_args = ngx.req.get_uri_args()
local position = uri_args["position"]
local db = mysql:new()
db:set_timeout(1000)
local props = {
host = "192.168.200.128",
port = 3306,
database = "changgou_business",
user = "root",
password = "root"
}
local res = db:connect(props)
local select_sql = "select url,image from tb_ad where status ='1' and position='"..position.."' and start_time<= NOW() AND end_time>= NOW()"
res = db:query(select_sql)
db:close()
local redis = require("resty.redis")
local red = redis:new()
red:set_timeout(2000)
local ip ="192.168.200.128"
local port = 6379
red:connect(ip,port)
red:set("ad_"..position,cjson.encode(res))
red:close()
ngx.say("{\"flag\":true,\"position\":\""..position.."\"}")(2). 创建ad_read.lua, 通过lua脚本直接从redis中获取数据
--设置响应头类型
ngx.header.content_type="application/json;charset=utf8"
--获取请求中的参数ID
local uri_args = ngx.req.get_uri_args();
local position = uri_args["position"];
--获取本地缓存
local cache_ngx = ngx.shared.dis_cache;
--根据ID 获取本地缓存数据
local adCache = cache_ngx:get('ad_cache_'..position);
if adCache == "" or adCache == nil then
--引入redis库
local redis = require("resty.redis");
--创建redis对象
local red = redis:new()
--设置超时时间
red:set_timeout(2000)
--连接
local ok, err = red:connect("192.168.200.128", 6379)
--获取key的值
local rescontent=red:get("ad_"..position)
--输出到返回响应中
ngx.say(rescontent)
--关闭连接
red:close()
--将redis中获取到的数据存入nginx本地缓存
cache_ngx:set('ad_cache_'..position, rescontent, 10*60);
else
--nginx本地缓存中获取到数据直接输出
ngx.say(adCache)
end(3). 修改/usr/local/openresty/nginx/conf/nginx.conf\
#user nobody;
user root root;
worker_processes 1;
#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
#pid logs/nginx.pid;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
#包含redis初始化模块
lua_shared_dict dis_cache 5m; #共享内存开
#tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
#gzip on;
# 设置限流配置
limit_req_zone $binary_remote_addr zone=myRateLimit:10m rate=2r/s;
server {
listen 80;
server_name localhost;
charset utf-8;
#access_log logs/host.access.log main;
# 添加
location /ad_update {
content_by_lua_file /root/lua/ad_update.lua;
}
# 读取
location /ad_read {
content_by_lua_file /root/lua/ad_read.lua;
}
# redirect server error pages to the static page /50x.html
#
#error_page 500 502 503 504 /50x.html;
location = / {
limit_req zone=myRateLimit burst=5 nodelay;
root html;
index index.html index.htm;
}
}
}四. 报错: redis读取不到缓存
原因: 没有缓存预热, 预加载数据
测试: 先访问连接缓存预热 http://host/ad_update?position=web_index_lb
请求： /ad_update
参数： position --指定广告位置
返回值：json