passthrough proxy

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: testproxy
  namespace: spi-system
  labels:
    app.kubernetes.io/name: testproxy
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: testproxy
  template:
    metadata:
      labels:
        app.kubernetes.io/name: testproxy
    spec:
      containers:
      - name: testproxy
        image: quay.io/mvala/testproxy:latest
        imagePullPolicy: Always
        command:
        - /main
        args: ["-upstream", "https://api.cluster-4fxm9.4fxm9.sandbox1216.opentlc.com:6443/"]
        ports:
        - containerPort: 8080
          name: testproxy-port
---
apiVersion: v1
kind: Service
metadata:
  name: testproxy
  namespace: spi-system
spec:
  selector:
    app.kubernetes.io/name: testproxy
  ports:
    - protocol: TCP
      port: 8080
      targetPort: 8080
      name: testproxy
---
apiVersion: route.openshift.io/v1
kind: Route
metadata:
  name: testproxy
  namespace: spi-system
spec:
  port:
    targetPort: 8080
  to:
    kind: Service
    name: testproxy
  tls:
    termination: edge

main.go

package main

import (
	"crypto/tls"
	"flag"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/url"
)

type conf struct {
	listen   string
	upstream string
}

func main() {
	conf := conf{}

	flag.StringVar(&conf.listen, "listen", ":8080", "")
	flag.StringVar(&conf.upstream, "upstream", "", "")

	flag.Parse()

	url, err := url.Parse(conf.upstream)
	if err != nil {
		panic(err)
	}

	client := &http.Client{
		Transport: &http.Transport{
			TLSClientConfig: &tls.Config{
				InsecureSkipVerify: true,
			},
		},
	}
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		log.Printf("REQ => %+v\n", r)

		r.RequestURI = ""
		r.URL, _ = url.Parse(fmt.Sprintf("%s://%s%s", url.Scheme, url.Host, r.URL.Path))
		response, err := client.Do(r)
		if err != nil {
			log.Fatal("failed doing request", err)
			w.Write([]byte(err.Error()))
			return
		}

		// log.Printf("RESP => %+v\n", response)

		for hk, hvl := range response.Header {
			for _, hv := range hvl {
				// log.Printf("HEADER => '%s' = '%s'\n", hk, hv)
				w.Header().Set(hk, hv)
			}
		}
		w.WriteHeader(response.StatusCode)
		io.Copy(w, response.Body)
		response.Body.Close()
	})
	server := &http.Server{
		Addr:      conf.listen,
		TLSConfig: &tls.Config{InsecureSkipVerify: true},
	}
	server.ListenAndServe()
}