Many Servers in One, with Go.

I’m still fiddling with a web server idea, currently trying my umpteenth version of it in Go. One of the things I want to do is serve a bunch of different things from one binary; they would usually live behind Nginx anyway, and I like the simplicity of serving a bunch of (somewhat) dynamic, small sites from a single program.

So, how does one do it? Why, one does it with Goroutines!

I had expected that to be the answer, but even then I was surprised at the simplicity of this solution. You don’t even need channels, since http.ListenAndServe is a blocking call if it’s not in a Goroutine.

Here’s the code, which should be self-explanatory.

	// multiserve - serve multiple web sites from one Go binary.
	// ----------
	// Just a demo for now. (C) Kevin Frost, github: biztos;
	// MIT license if you like.
	package main
	import (
	"fmt"
	"log"
	"net/http"
	)
	type Server struct {
	Name string
	Mux *http.ServeMux
	Port int
	}
	func (s *Server) Serve() {
	fmt.Printf("%s server listening on port %d.\n", s.Name, s.Port)
	portStr := fmt.Sprintf(":%d", s.Port)
	http.ListenAndServe(portStr, s.Mux)
	}
	func NewServer(name string, port int) *Server {
	homeHandler := func(w http.ResponseWriter, r *http.Request) {
	log.Printf("%s shall serve!\n", name)
	msg := fmt.Sprintf("Hello %s World!\n", name)
	w.Write([]byte(msg))
	}
	mux := http.NewServeMux()
	mux.HandleFunc("/", homeHandler)
	return &Server{
	Name: name,
	Port: port,
	Mux: mux,
	}
	}
	func main() {
	// Set up a router for each server. Here we just use two but
	// you could probably have lots and lots.
	servers := []*Server{
	NewServer("Foo", 8001),
	NewServer("Bar", 8002),
	}
	// Start them using goroutines, but *not* for the last one:
	final := len(servers) - 1
	for i, s := range servers {
	if i == final {
	s.Serve()
	} else {
	go s.Serve()
	}
	}
	}

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