feat: add API gateway to reverse proxy requests in front of two different services

1 files changed, 46 insertions, 2 deletions

diff --git a/cmd/gtwy/main.go b/cmd/gtwy/main.go
index eb6a1b5d..986741b0 100644
--- a/cmd/gtwy/main.go
+++ b/cmd/gtwy/main.go
@@ -1,7 +1,51 @@
 package main
 
-import "fmt"
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"net/http/httputil"
+	"strings"
+	"time"
+)
+
+func NewProxy(from, to string) http.Handler {
+	director := func(r *http.Request) {
+		log.Printf("%v (from: %v to: %v)\n", r.URL, from, to)
+		r.URL.Scheme = "http"
+		r.Host = to
+		r.URL.Host = to
+		r.URL.Path = strings.TrimPrefix(r.URL.Path, strings.TrimSuffix(from, "/*"))
+		r.URL.RawPath = strings.TrimPrefix(r.URL.RawPath, strings.TrimSuffix(from, "/*"))
+	}
+	return &httputil.ReverseProxy{
+		Director:      director,
+		Transport:     http.DefaultTransport,
+		FlushInterval: -1,
+		ErrorLog:      nil,
+		ModifyResponse: func(r *http.Response) error {
+			r.Header.Add("Via", fmt.Sprintf("%v gateway", r.Proto))
+			return nil
+		},
+		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
+			log.Println(err)
+		},
+	}
+}
 
 func main() {
-	fmt.Println("hello, world!")
+	mux := http.NewServeMux()
+	mux.Handle("/idp/", NewProxy("/idp", "localhost:8282"))
+	mux.Handle("/sp/", NewProxy("/sp", "localhost:8283"))
+
+	srv := &http.Server{
+		Addr:              ":8080",
+		Handler:           mux,
+		ReadHeaderTimeout: 10 * time.Second,
+		ReadTimeout:       30 * time.Second,
+		WriteTimeout:      2 * time.Minute,
+		IdleTimeout:       5 * time.Minute,
+		ErrorLog:          log.Default(),
+	}
+	log.Fatal(srv.ListenAndServe())
 }