lua-resty-shell 多任务执行

已经写过一个openresty 使用lua-resty-shell 执行shell 脚本的demo，但是实际上我们可能是多节点运行，
同时需要负载均衡的机制。
lua-resty-shell 支持unix socket 以及tcp soket 的管理，但是在测试的时候发现tcp 有问题，所以只好
使用unix socket了，通过nginx 的stream 将unix 转为tcp，因为是测试，使用docker-compose 进行缩放
以及负载均衡的处理
说明： 可以同时参考 https://www.cnblogs.com/rongfengliang/p/10079432.html

环境准备

• docker-compose 文件

version: "3"
services:
  app:
   build: ./
   ports:
   - "8080:80"
   volumes:
   - "./app/:/opt/app/"
   - "./nginx.conf:/usr/local/openresty/nginx/conf/nginx.conf"
  backend:
   build: ./
   volumes:
   - "./nginx-back.conf:/usr/local/openresty/nginx/conf/nginx.conf"

• 代码说明
  dockerfile 主要是进行环境的准备，包括镜像的准备&&启动需要的服务

FROM openresty/openresty:alpine-fat
LABEL author="1141591465@qq.com"
WORKDIR /sockproc
COPY ./sockproc/ /sockproc/
RUN make sockproc
COPY entrypoint.sh /entrypoint.sh
COPY sockproc.sh /sockproc.sh
COPY shell.lua /usr/local/openresty/lualib/resty/shell.lua
ENTRYPOINT [ "/entrypoint.sh" ]

nginx 配置要两个，一个是调用端的，一个是后端真正执行服务的
调用端，很简单，就是使用shell.lua 的封装进行调用

worker_processes 1;
user root;
events {
    worker_connections 1024;
}
http {
    include mime.types;
    default_type application/octet-stream;
    sendfile on;
    keepalive_timeout 65;
    lua_code_cache off;
    gzip on;
   # resolver 127.0.0.11;
    real_ip_header X-Forwarded-For;
    real_ip_recursive on;
    lua_package_path '/opt/app/?.lua;;';
    server {
        listen 80;
        server_name localhost;
        charset utf-8;
        root html;
        default_type text/html;
        location / {
           default_type text/html;
           index index.html;

        }
        location /test {
          resolver 127.0.0.11;
          content_by_lua_block {
             require("app").call();
          }
       }
        location /loop {
          content_by_lua_block {
             require("app").loop();
           }
        }
        error_page 500 502 503 504 /50x.html;
        location = /50x.html {
            root html;
        }
    }
}

后端服务nginx配置，就是unix 转tcp 服务

worker_processes 1;
user root;
events {
    worker_connections 1024;
}
stream {
    server {
     listen 13000;
     proxy_connect_timeout 1s;
     proxy_timeout 3s;
     proxy_pass unix:/tmp/shell.sock;
    }
}
http {
    include mime.types;
    default_type application/octet-stream;
    sendfile on;
    keepalive_timeout 65;
    lua_code_cache off;
    gzip on;
    real_ip_header X-Forwarded-For;
    real_ip_recursive on;
    lua_package_path '/opt/app/?.lua;;';
    server {
        listen 80;
        server_name localhost;
        charset utf-8;
        root html;
        default_type text/html;
        location / {
           default_type text/html;
           index index.html;

        }
        error_page 500 502 503 504 /50x.html;
        location = /50x.html {
            root html;
        }
    }
}

• lua 调用代码
  app/app.lua

local shell = require("resty.shell")
local log = ngx.log
local ERR = ngx.ERR
local delay = 5
local handler
handler = function (premature,param)
    -- do some routine job in Lua just like a cron job
    if premature then
        return
    end
    log(ERR, "param is : ", param)
    ngx.timer.at(delay, handler,"again run... dalongrong")
end

local args = {
   socket = {
       host="backend",
       port=13000
   }
}

function call()
    local status, out, err = shell.execute("cat /proc/sys/kernel/random/uuid", args)
    ngx.say(out)
end

function loop()
    local ok, err = ngx.timer.at(delay, handler,"dalong demo timer init")
end

return {
    call=call,
    loop=loop
}

启动&&测试

• 启动

docker-compose up -d

• 测试
  http://localhost:8080/test
  
• 扩容
  通过内置的基于dns的服务发现机制

docker-compose scale backend=3

参考资料

https://www.cnblogs.com/rongfengliang/p/10079432.html
https://github.com/rongfengliang/lua-resty-shell-docker--multi-running
https://github.com/juce/lua-resty-shell