request help: support http proxy

[GhangZh]

Issue description

I want to support the forward-auth , but how does go-pugin-runner support me to proxy the current request directly to the url, and then process the response and pass it on?
I wrote a version in lua, but our technology stack is unified with go, so I want to use go to implement

    local core = require("apisix.core")
    local http = require("resty.http")
    local http_new = http.new()
    local res, err = http_new:request_uri("https://forward-auth.xxx.com", {
        ssl_verify = false,
        method = "GET",
        headers = {
            ["X-Forwarded-User"] = core.request.header(ctx, "X-Forwarded-User"),
            ["X-Forwarded-UID"] = core.request.header(ctx, "X-Forwarded-UID"),
            ["Cookie"]=core.request.header(ctx,"Cookie")
        },
    })
    if err ~= nil then
        core.log.error("==== Serverless Request Error: ", err)
        return
    end
    if (res ~= nil) then
        for k, v in pairs(res.headers) do
            core.response.set_header(k, v)
        end
    end
    if res.status == 302 then
        core.response.set_header("Location", res.headers.location)
        core.response.exit(302)
        return
    end

Environment

• APISIX Go Plugin Runner's version:
• APISIX version:
• Go version:
• OS (cmd: uname -a):

[spacewander]

1. you can get/set the header via Request.Header, see https://pkg.go.dev/github.com/apache/apisix-go-plugin-runner@v0.2.0/pkg/http#Header
2. you can stop the request with headers, see

   apisix-go-plugin-runner/cmd/go-runner/plugins/say.go

   Line 61 in 195bd64

   w.Header().Add("X-Resp-A6-Runner", "Go")

3. currently, there is no way to set response header without stopping the request (the core.response.set_header(k, v) in your example). Maybe you can open an issue to track it?

[GhangZh]

1. you can get/set the header via Request.Header, see https://pkg.go.dev/github.com/apache/apisix-go-plugin-runner@v0.2.0/pkg/http#Header
2. you can stop the request with headers, see

   apisix-go-plugin-runner/cmd/go-runner/plugins/say.go

   Line 61 in 195bd64

   w.Header().Add("X-Resp-A6-Runner", "Go")

3. currently, there is no way to set response header without stopping the request (the core.response.set_header(k, v) in your example). Maybe you can open an issue to track it?

I want to proxy all the responses. Is there any way to do that?

[GhangZh]

I wrote a demo, but I found that the response body is empty ,For example, if I add this plugin to luacode.com, and I request a.com, the plugin will request b.com and do the processing, now the processing is successful but there is no response content from luacode.com.

package plugins

import (
	"encoding/json"
	"fmt"
	pkgHTTP "github.com/apache/apisix-go-plugin-runner/pkg/http"
	"github.com/apache/apisix-go-plugin-runner/pkg/log"
	"github.com/apache/apisix-go-plugin-runner/pkg/plugin"
	"github.com/sirupsen/logrus"
	"net/http"
	"time"
)

func init() {
	err := plugin.RegisterPlugin(&ForwardAuth{})
	if err != nil {
		log.Fatalf("failed to register plugin ForwardAuth: %s", err)
	}
}

// ForwardAuth is a demo to show how to return data directly instead of proxying
// it to the upstream.
type ForwardAuth struct {
}

type ForwardAuthConf struct {
	Body string `json:"body"`
}

func (p *ForwardAuth) Name() string {
	return "forward-auth"
}

func (p *ForwardAuth) ParseConf(in []byte) (interface{}, error) {
	conf := ForwardAuthConf{}
	err := json.Unmarshal(in, &conf)
	return conf, err
}
func (p *ForwardAuth) Filter(conf interface{}, w http.ResponseWriter, r pkgHTTP.Request) {
	req, err := http.NewRequest("GET", "http://b.com", nil)
	if err != nil {
		logrus.Errorf("send request failed err:%v", err)
		return
	}
	//req.Header.Set("Cookie", r.Header().Get("Cookie"))
	client := http.Client{
		Timeout: 5 * time.Second,
	}
	resp, err := client.Do(req)
	if err != nil {
		logrus.Errorf("get response failed err:%v", err)
		return
	}
	if resp == nil {
		logrus.Errorf("response is nil")
		return
	}
	defer resp.Body.Close()

	if len(resp.Header) > 0 {
		for k, v := range resp.Header {
			if v != nil {
				w.Header().Set(k, v[0])
			}
		}
	}

	w.Header().Add("X-Resp-A6-Runner", "Go")
	return

}

not use plugin

after use pulgin

[GhangZh]

1.I found that after I use core.response.set_header(k, v) then the response body of the service I requested was empty.
2.What do you mean by this? @spacewander

2. you can stop the request with headers, see

   apisix-go-plugin-runner/cmd/go-runner/plugins/say.go

   Line 61 in 195bd64

   w.Header().Add("X-Resp-A6-Runner", "Go")

3. currently, there is no way to set response header without stopping the request (the core.response.set_header(k, v) in your example). Maybe you can open an issue to track it?

[spacewander]

Currently, setting response data will mean stopping the current process and returning immediately without proxying the request to upstream.

[GhangZh]

Currently, setting response data will mean stopping the current process and returning immediately without proxying the request to upstream.

How should I change to proxy the request to upstream ?
I've tried both severless-plugin and go-plugin-runner plugins to support forward-auth,But none of these are currently met, And not having this plugin would cause all our services not being accessible

[shuaijinchao]

@GhangZh try w.Header().Add("X-Resp-A6-Runner", "Go") change to r.Header().Set("X-Resp-A6-Runner", "Go")

[GhangZh]

Thanks, change to r.Header().Set("X-Resp-A6-Runner", "Go") solved my problem