help request: How to Customize Load Balancing for TCP Requests

[haydn-yang]

Description

I now need to do custom load balancing of content based on TCP requests, I tried to implement it in the balance phase of the plugin, but it never worked.

Plugin core code
`
local balancer = require("ngx.balancer")
local plugin_name = "xm-plugin"
……
function _M.balancer(conf, ctx)
core.log.warm("balance-log: IP: ", ctx.balancer_ip, ", Port: ", ctx.balancer_port)
-- Fake data, the host will actually be obtained through the interface
local host = {"127.0.0.1:10000", "127.0.0.1:20000"}

local backend = host[1]

local ok, err = balancer.set_current_peer(backend, ngx.var.server_port)
if not ok then
    -- ngx.log(ngx.ERR, "failed to set the current peer: ", err)
     return 500, {error_msg = "set server fail"}
end

end
……
`

Add route
`
curl http://127.0.0.1:9180/apisix/admin/stream_routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
"plugins": {
"xm-plugin":{
}
},
"upstream": {
"scheme": "tcp",
"nodes": {
},
"type": "roundrobin"
},
"server_port": 8000
}'

`

Environment

All components are started via docker on mac (m1)

• APISIX version (run apisix version): 3.0.0-debian
• Operating system (run uname -a): Darwin Kernel Version 21.6.0
• OpenResty / Nginx version (run openresty -V or nginx -V):1.19.10-alpine
• etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info): v3.4.15-arm64
• APISIX Dashboard version, if relevant: 2.13-alpine
• Plugin runner version, for issues related to plugin runners:
• LuaRocks version, for installation issues (run luarocks --version):

[tzssangglass]

function _M.balancer(conf, ctx)

try to hook before_proxy phase, read more: https://github.com/apache/apisix/blob/8b14c68840a9fd1bae6718a57f158cc117a12acf/docs/en/latest/plugins/serverless.md#attributes