Golang reverse proxy with multiple apps

Question

I want to serve two or more web applications running in a VM (different ports and some time in different directory under the same port) from the host machine and because I need the user to be logged before he can access those apps I can not use a static proxy like Nginx or Apache.

So here is my situation :

192.168.1.1 : is the host ip
192.168.1.2 : is the VM ip

Inside the VM I have this :

192.168.1.2/owncloud : owncloud address
192.168.1.2:8080 : an other app
192.168.1.2:8888 : 3rd app

I want to have this :

192.168.1.1/app1 --> 192.168.1.2/owncloud
192.168.1.1/app2 --> 192.168.1.2:8080
192.168.1.1/app2 --> 192.168.1.2:8888

I have tried to use golang httputil.ReverseProxy to achieve this routing but with no much success: my code is based on this work : gist

package main

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

func main() {
    remote, err := url.Parse("http://192.168.1.2:8080")
    if err != nil {
            panic(err)
    }

    proxy := httputil.NewSingleHostReverseProxy(remote)
    http.HandleFunc("/app2", handler(proxy))
    err = http.ListenAndServe(":80", nil)
    if err != nil {
            panic(err)
    }
}

func handler(p *httputil.ReverseProxy) func(http.ResponseWriter, *http.Request) {
    return func(w http.ResponseWriter, r *http.Request) {
        log.Println(r.URL)
        r.URL.Path = "/"                
            p.ServeHTTP(w, r)
    }
}

Edit :
I have changed the vm ip address: 192.168.1.2 not 192.168.1.1

Answer 1

Make a map like this

hostTarget = map[string]string{
    "app1.domain.com": "http://192.168.1.2/owncloud",
    "app2.domain.com": "http://192.168.1.2:8080",
    "app3.domain.com": "http://192.168.1.2:8888",
}

Use httputil.ReverseProxy build your handler

type baseHandle struct{}

func (h *baseHandle) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    host := r.Host

    if target, ok := hostTarget[host]; ok {
        remoteUrl, err := url.Parse(target)
        if err != nil {
            log.Println("target parse fail:", err)
            return
        }

        proxy := httputil.NewSingleHostReverseProxy(remoteUrl)
        proxy.ServeHTTP(w, r)
        return
    }
    w.Write([]byte("403: Host forbidden " + host))
}

ListenAndServe

h := &baseHandle{}
http.Handle("/", h)

server := &http.Server{
    Addr:    ":8080",
    Handler: h,
}
log.Fatal(server.ListenAndServe())

You can cached httputil.ReverseProxy in global map, all in file above.

Here is a SSLDocker project seen to match with you best.