用openresty实现动态upstream，openrestyupstream

用openresty实现动态upstream，openrestyupstream

前言：
此文的读者定义为对openresty有一定了解的读者。


openresty：
https://github.com/openresty/lua-nginx-module


此文要讲什么：
大家都知道openresty可以用ngx.location.capture和ngx.exec来实现内部跳转，
下面要讲怎么将ngx.location.capture和ngx.exec与upstream模块结合起来，实现一个动态的upstream。

下面的演示中：

80端口表示首次请求入口

8080端口表示upstream的出口

直接上配置和源码：

配置： conf/nginx.conf

worker_processes  1;
error_log logs/error.log;
events {
    worker_connections 1024;
}

http {

    log_format  main  '$msec $status $request $request_time '
                      '$http_referer $remote_addr [ $time_local ] '
                      '$upstream_response_time $host $bytes_sent '
                      '$request_length $upstream_addr';

    access_log  logs/access.log main buffer=32k flush=1s;


    upstream remote_hello {
        server 127.0.0.1:8080;
    }

    upstream remote_world {
        server 127.0.0.1:8080;
    }

    server {
        listen 80;

        location /capture {
            content_by_lua '
                local test = require "lua.test"
                test.capture_test()
            ';
        }

        location /exec {
            content_by_lua '
                local test = require "lua.test"
                test.exec_test()
            ';
        }

        location /upstream {
            internal;

            set $my_upstream $my_upstream;
            set $my_uri $my_uri;
            proxy_pass http://$my_upstream$my_uri;
        }
    }


    server {
        listen 8080;
        location /hello {
            echo "hello";
        }

        location /world {
            echo "world";
        }
    }
}

源码： lua/test.lua

local _M = { _VERSION = '1.0' }

function _M:capture_test()
    local res = ngx.location.capture("/upstream",
        {
             method = ngx.HTTP_GET,
             vars = {
                 my_upstream = "remote_hello",
                 my_uri = "/hello",
             },
        }
    )
    if res == nil or res.status ~= ngx.HTTP_OK then
        ngx.say("capture failed")
        return
    end
    ngx.print(res.body)
end

function _M:exec_test()
    ngx.var.my_upstream = "remote_world"
    ngx.var.my_uri = "/world"
    ngx.exec("/upstream")
end

return _M

运行效果：

原文出自：http://blog.csdn.net/daiyudong2020/article/details/53027934

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