example_service.go

package main

import (
	"flag"
	"io"
	"log"
	"net"
	"net/http"
	"os"
)

func main() {
	if err := run(); err != nil {
		log.Fatal(err)
	}
}

func run() error {
	var (
		listenAddr = "0.0.0.0:8080"
	)

	fs := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
	fs.StringVar(&listenAddr, "listen-addr", listenAddr, "Address to listen for traffic on.")

	if err := fs.Parse(os.Args[1:]); err != nil {
		return err
	}

	lis, err := net.Listen("tcp", listenAddr)
	if err != nil {
		return err
	}
	defer func() {
		_ = lis.Close()
	}()

	mux := http.NewServeMux()

	mux.HandleFunc("/echo/stdout", func(w http.ResponseWriter, r *http.Request) {
		_, _ = io.Copy(os.Stdout, r.Body)
	})
	mux.HandleFunc("/echo/stderr", func(w http.ResponseWriter, r *http.Request) {
		_, _ = io.Copy(os.Stderr, r.Body)
	})
	mux.HandleFunc("/echo/response", func(w http.ResponseWriter, r *http.Request) {
		_, _ = io.Copy(w, r.Body)
	})

	srv := &http.Server{Handler: mux}
	_ = srv.Serve(lis)
	return nil
}