背景
来水一篇文章，其实官网都有，论如何在apisix上实现四层转发
什么是apisix
apisix是动态、实时、高性能的 API 网关，构建于 OpenResty 之上，支持热加载配置、灰度发布、蓝绿部署等功能，同时具有良好的可扩展性和易用性。
管理接口参考
参考：（以2.4版本为例）
https://625a57e513f19e48ae3a4468--old-docs-apache-apisix.netlify.app/zh/docs/apisix/2.4/admin-api/#route
基于tcp协议动态代理
参考：（以2.4版本为例）
https://625a57e513f19e48ae3a4468--old-docs-apache-apisix.netlify.app/zh/docs/apisix/2.4/stream-proxy/
步骤1：激活stream_routes模块
在 conf/config.yaml 配置文件设置 stream_proxy 选项，默认是开启的
apisix:stream_proxy: # TCP/UDP proxytcp: # TCP proxy address list- 9100
重启服务，使其配置生效
验证模块是否生效：
curl http://xxx.xxx.xxx.xxx:xxx/apisix/admin/stream_routes -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1'
步骤2：添加配置
例如：
配置多节点代理，启动本机的1302端口，tcp协议，代理"172.16.10.251:1301"，"172.16.10.252:1301"
（请求打到本机的1302端口，轮询策略roundrobin，转发到后端的两个节点的1301端口上）
配置如下：
curl 'http://xxx.xxx.xxx.xxx:xxx/apisix/admin/stream_routes/1' \-H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' \-H 'Content-Type: application/json;charset=UTF-8' \-X PUT \-d '{"server_port":1302,"upstream":{"nodes":{"172.16.10.251:1301":1,"172.16.10.252:1301":1},"type":"roundrobin"},"plugins":{},"desc":"tcp1301"}' \--compressed \--insecure
响应报文：
{"node":{"createdIndex":121,"value":{"desc":"tcp1301","upstream":{"type":"roundrobin","hash_on":"vars","nodes":{"172.16.10.251:1301":1,"172.16.10.252:1301":1}},"server_port":1302,"id":"1","plugins":{}},"modifiedIndex":121,"key":"\/apisix\/stream_routes\/1"},"action":"set"}
查看配置：
curl 'http://xxx.xxx.xxx.xxx:xxx/apisix/admin/stream_routes/1' -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1'
响应报文：
{"node":{"createdIndex":121,"value":{"desc":"tcp1301","upstream":{"type":"roundrobin","hash_on":"vars","nodes":{"172.16.10.251:1301":1,"172.16.10.252:1301":1}},"server_port":1302,"id":"1","plugins":{}},"modifiedIndex":121,"key":"\/apisix\/stream_routes\/1"},"action":"get"}
如果添加错了，删除配置：
curl 'http://xxx.xxx.xxx.xxx:xxx/apisix/admin/stream_routes/1' -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X DELETE
备注
1.修改（和创建一样，指定id=1，PUT正确的报文就行）
2.还有一种创建可以用POST,不指定id，随机生产id。
总结
Restful API 大法好啊
