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Creating a Proxy Server with Go

by jokeofweek on 9/22/13, 12:50 PM with 18 comments

• by tptacek on 9/22/13, 3:38 PM

  I know it's irrational, but it drives me a little nuts how the proxy idiom in go is "two goroutines implementing socket-to-socket copy". The inner handler loop of a proxy is a place where, to me, select/poll might actually make the code easier to follow; also, the idiom doubles the number of goroutines required to handle a given connection load, and while goroutines are cheap, they aren't free.

  I know it's possible to pull select() into Golang programs (I ended up having to, to write a fast port scanner), but Golang people look at you weirdly when you tell them you did that.

• by mcot2 on 9/22/13, 1:45 PM

  I'm not sure I agree with how channels are used here. What's the point of this spaces chan? Why couldn't a simple atomic counter solve this (see sync/atomic)? Why allocate a thousand bools?

      // The booleans representing the free active connection spaces.
      spaces := make(chan bool, *maxConnections)
      // Initialize the spaces
      for i := 0; i < *maxConnections; i++ {
          spaces <- true
      }

  }

  Is this really how people use go???

• by farslan on 9/22/13, 8:37 PM

  The inbuilt reverseproxy is also handy for small tasks:

      package main
  
      import (
      	"net/http"
      	"net/http/httputil"
      	"net/url"
      )
  
      func main() {
      	target, _ := url.Parse("http://127.0.0.1:8000")
      	http.ListenAndServe(":80", httputil.NewSingleHostReverseProxy(target))
      }
  

  This will http proxy :80 to :8000.