Proxy from faasd to gateway

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

pkg/proxy.go

@@ -2,7 +2,11 @@ package pkg
 
 import (
 	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
 	"net/http"
+	"strings"
 
 	"time"
 )
@@ -22,11 +26,72 @@ type Proxy struct {
 
 func (p *Proxy) Start() error {
 	tcp := 8080
+
+	time.Sleep(3 * time.Second)
+	log.Printf("Starting faasd proxy on %d\n", tcp)
+	data := struct{ host string }{
+		host: "",
+	}
+
+	fileData, fileErr := ioutil.ReadFile(p.Hosts)
+	if fileErr != nil {
+		return fileErr
+	}
+
+	lines := strings.Split(string(fileData), "\n")
+	for _, line := range lines {
+		if strings.Index(line, "gateway") > -1 {
+			data.host = line[:strings.Index(line, "\t")]
+		}
+	}
+	fmt.Printf("Gateway: %s\n", data.host)
+
 	s := &http.Server{
 		Addr:           fmt.Sprintf(":%d", tcp),
 		ReadTimeout:    p.Timeout,
 		WriteTimeout:   p.Timeout,
 		MaxHeaderBytes: 1 << 20, // Max header of 1MB
+		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+
+			query := ""
+			if len(r.URL.RawQuery) > 0 {
+				query = "?" + r.URL.RawQuery
+			}
+
+			upstream := fmt.Sprintf("http://%s:8080%s%s", data.host, r.URL.Path, query)
+			fmt.Printf("Forward to %s %s\n", upstream, data)
+
+			if r.Body != nil {
+				defer r.Body.Close()
+			}
+
+			wrapper := ioutil.NopCloser(r.Body)
+			upReq, upErr := http.NewRequest(r.Method, upstream, wrapper)
+
+			if upErr != nil {
+				log.Println(upErr)
+
+				http.Error(w, upErr.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			upRes, upResErr := http.DefaultClient.Do(upReq)
+
+			if upResErr != nil {
+				log.Println(upResErr)
+
+				http.Error(w, upResErr.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			for k, v := range upRes.Header {
+				w.Header().Set(k, v[0])
+			}
+
+			w.WriteHeader(upRes.StatusCode)
+			io.Copy(w, upRes.Body)
+
+		}),
 	}
 
 	return s.ListenAndServe()