Nginx通过LUA脚本访问RabbitMQ消息队列

发现了一个Nginx的LUA脚本：lua-resty-rabbitmqstomp，可以让Nginx通过LUA脚本访问RabbitMQ消息队列，这个脚本是通过stomp协议连接RabbitMQ的stomp适配器，来pub/sub消息的

关于RabbitMQ-STOMP安装使用相关内容可以参见：RabbitMQ STOMP Adapter

关于Nginx-LUA模块安装使用参见：LAMP架构演进到LAMPGC，再演进到LNMLGC

关于STOMP协议相关资料参见这里：

STOMP官方英文协议1.1版

STOMP协议学习与实战-1.1版

STOMP官方英文协议1.2版

STOMP协议说明书-1.2版

nginx配置：

        location /rabbitmq {
            lua_code_cache off;
            content_by_lua_file conf/rabbitmq.lua;
        }

rabbitmq.lua源码如下，该脚本简单的实现pub一个消息然后再sub该消息，set_timeout(60000)表示sub消息如果没有消息时等待60S超时

local strlen =  string.len
local json = require "json"
local rabbitmq = require "rabbitmqstomp"

local mq, err = rabbitmq:new()
if not mq then
      return
end

mq:set_timeout(60000)

local ok, err = mq:connect {
                    host = "127.0.0.1",
                    port = 61613,
                    username = "guest",
                    password = "guest",
                    vhost = "/"
                }
if not ok then
    return
end
ngx.log(ngx.INFO, "Connect: " .. "OK")

local msg = {key="value1", key2="value2"}
local headers = {}
headers["destination"] = "/queue/my_queue"
headers["receipt"] = "msg#1"
headers["app-id"] = "luaresty"
headers["persistent"] = "true"
headers["content-type"] = "application/json"

local ok, err = mq:send(json.encode(msg), headers)
if not ok then
    return
end
ngx.log(ngx.INFO, "Published: " .. json.encode(msg))

local headers = {}
headers["destination"] = "/queue/my_queue"
headers["persistent"] = "true"
headers["id"] = "123"

local ok, err = mq:subscribe(headers)
if not ok then
    return
end

local data, err = mq:receive()
if not data then
    return
end
ngx.log(ngx.INFO, "Consumed: " .. data)
ngx.header.content_type = "text/plain";
ngx.say(data);

local headers = {}
headers["persistent"] = "true"
headers["id"] = "123"

local ok, err = mq:unsubscribe(headers)

local ok, err = mq:set_keepalive(10000, 10000)
if not ok then
    return
end

具体扩展一下，可以实现推送功能：发送方调用send将消息pub到RabbitMQ，接收方设置一个超时调用subscribe订阅消息（就类似于long polling）