devproxy.go

package main

import (
  "log"
  "net/http"
  "net/http/httputil"
  "net/url"
  "os"
)


type SingleRequestTransport struct {
  bottleneck chan bool
}

func (s *SingleRequestTransport) RoundTrip(req *http.Request) (*http.Response, error) {
  s.bottleneck <- true
  response, err := http.DefaultTransport.RoundTrip(req)
  <- s.bottleneck
  return response, err;
}


func main() {
  if len(os.Args) != 3 {
    log.Fatal("Usage: go run ./devproxy.go [listen host and port] [to host and port]")
  }

  hostAndPort := os.Args[1]
  proxyHost := os.Args[2]

  proxy := httputil.NewSingleHostReverseProxy(&url.URL{Scheme: "http", Host: proxyHost, Path: "/"})
  proxy.Transport = &SingleRequestTransport{bottleneck: make(chan bool, 1)}

  server := &http.Server{
    Addr:           hostAndPort,
    Handler:        proxy,
  }

  log.Print("Dev proxy listening on: ", hostAndPort, " redirecting to: ", proxyHost)
  err := server.ListenAndServe()
  if (err != nil) {
    log.Fatal(err)
  }
}

This is a simple reverse proxy that makes requests to the backend happen sequentially. This is for development use when your development server sucks at handling concurrent requests. (I'm looking at you, Django.)