Remove Golang reverseproxy and use http Client

Signed-off-by: Alex Ellis <alexellis2@gmail.com>

gateway/handlers/forwarding_proxy.go

@@ -1,9 +1,9 @@
 package handlers
 
 import (
+	"io"
 	"log"
 	"net/http"
-	"net/http/httputil"
 	"strconv"
 	"strings"
 	"time"
@@ -14,36 +14,66 @@ import (
 )
 
 // MakeForwardingProxyHandler create a handler which forwards HTTP requests
-func MakeForwardingProxyHandler(proxy *httputil.ReverseProxy, metrics *metrics.MetricOptions) http.HandlerFunc {
-	return func(w http.ResponseWriter, r *http.Request) {
-		uri := r.URL.String()
+func MakeForwardingProxyHandler(proxy *types.HttpClientReverseProxy, metrics *metrics.MetricOptions) http.HandlerFunc {
+	baseURL := proxy.BaseURL.String()
+	if strings.HasSuffix(baseURL, "/") {
+		baseURL = baseURL[0 : len(baseURL)-1]
+	}
 
-		log.Printf("> Forwarding [%s] to %s", r.Method, r.URL.String())
+	return func(w http.ResponseWriter, r *http.Request) {
+
+		requestURL := r.URL.String()
+
+		log.Printf("> Forwarding [%s] to %s", r.Method, requestURL)
 		start := time.Now()
 
-		writeAdapter := types.NewWriteAdapter(w)
-		proxy.ServeHTTP(writeAdapter, r)
+		upstreamReq, _ := http.NewRequest(r.Method, baseURL+requestURL, nil)
+
+		upstreamReq.Header["X-Forwarded-For"] = []string{r.RequestURI}
+
+		if r.Body != nil {
+			defer r.Body.Close()
+			upstreamReq.Body = r.Body
+
+		}
+
+		res, resErr := proxy.Client.Do(upstreamReq)
+		if resErr != nil {
+			log.Printf("upstream client error: %s\n", resErr)
+			return
+		}
+
+		if res.Body != nil {
+			defer res.Body.Close()
+		}
+
+		for k, v := range res.Header {
+			w.Header()[k] = v
+		}
+
+		io.CopyBuffer(w, res.Body, nil)
 
 		seconds := time.Since(start).Seconds()
 		log.Printf("< [%s] - %d took %f seconds\n", r.URL.String(),
-			writeAdapter.GetHeaderCode(), seconds)
+			res.StatusCode, seconds)
 
 		forward := "/function/"
-		if startsWith(uri, forward) {
+		if startsWith(requestURL, forward) {
 			// log.Printf("function=%s", uri[len(forward):])
 
-			service := uri[len(forward):]
+			service := requestURL[len(forward):]
 
 			metrics.GatewayFunctionsHistogram.
 				WithLabelValues(service).
 				Observe(seconds)
 
-			code := strconv.Itoa(writeAdapter.GetHeaderCode())
+			code := strconv.Itoa(res.StatusCode)
 
 			metrics.GatewayFunctionInvocation.
 				With(prometheus.Labels{"function_name": service, "code": code}).
 				Inc()
 		}
+
 	}
 }
 

gateway/metrics/add_metrics.go

@@ -48,7 +48,7 @@ func AddMetricsHandler(handler http.HandlerFunc, prometheusQuery PrometheusQuery
 		err := json.Unmarshal(upstreamBody, &functions)
 
 		if err != nil {
-			log.Println(err)
+			log.Printf("Metrics upstream error: %s", err)
 
 			w.Header().Set("Content-Type", "text/plain")
 			w.WriteHeader(http.StatusInternalServerError)

gateway/server.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"log"
 	"net/http"
-	"net/http/httputil"
 	"time"
 
 	"github.com/gorilla/mux"
@@ -41,7 +40,7 @@ func main() {
 
 	servicePollInterval := time.Second * 5
 
-	reverseProxy := httputil.NewSingleHostReverseProxy(config.FunctionsProviderURL)
+	reverseProxy := types.NewHttpClientReverseProxy(config.FunctionsProviderURL, config.ReadTimeout)
 
 	faasHandlers.Proxy = internalHandlers.MakeForwardingProxyHandler(reverseProxy, &metricsOptions)
 	faasHandlers.RoutelessProxy = internalHandlers.MakeForwardingProxyHandler(reverseProxy, &metricsOptions)

gateway/types/http_adapter.go

@@ -1,48 +0,0 @@
-// Copyright (c) Alex Ellis 2017. All rights reserved.
-// Licensed under the MIT license. See LICENSE file in the project root for full license information.
-
-package types
-
-import (
-	"log"
-	"net/http"
-)
-
-// WriteAdapter adapts a ResponseWriter
-type WriteAdapter struct {
-	Writer     http.ResponseWriter
-	HTTPResult *HTTPResult
-}
-
-// HTTPResult captures data from forwarded HTTP call
-type HTTPResult struct {
-	HeaderCode int // HeaderCode is the result of WriteHeader(int)
-}
-
-//NewWriteAdapter create a new NewWriteAdapter
-func NewWriteAdapter(w http.ResponseWriter) WriteAdapter {
-	return WriteAdapter{Writer: w, HTTPResult: &HTTPResult{}}
-}
-
-//Header adapts Header
-func (w WriteAdapter) Header() http.Header {
-	return w.Writer.Header()
-}
-
-// Write adapts Write for a straight pass-through
-func (w WriteAdapter) Write(data []byte) (int, error) {
-	return w.Writer.Write(data)
-}
-
-// WriteHeader adapts WriteHeader
-func (w WriteAdapter) WriteHeader(statusCode int) {
-	w.Writer.WriteHeader(statusCode)
-	w.HTTPResult.HeaderCode = statusCode
-
-	log.Printf("GetHeaderCode %d", w.HTTPResult.HeaderCode)
-}
-
-// GetHeaderCode result from WriteHeader
-func (w *WriteAdapter) GetHeaderCode() int {
-	return w.HTTPResult.HeaderCode
-}

gateway/types/proxy_client.go

@@ -0,0 +1,32 @@
+package types
+
+import (
+	"net"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+func NewHttpClientReverseProxy(baseURL *url.URL, timeout time.Duration) *HttpClientReverseProxy {
+	h := HttpClientReverseProxy{
+		BaseURL: baseURL,
+	}
+
+	h.Client = &http.Client{
+		Transport: &http.Transport{
+			Proxy: http.ProxyFromEnvironment,
+			DialContext: (&net.Dialer{
+				Timeout:   timeout,
+				KeepAlive: 1 * time.Second,
+			}).DialContext,
+			IdleConnTimeout:       120 * time.Millisecond,
+			ExpectContinueTimeout: 1500 * time.Millisecond,
+		},
+	}
+	return &h
+}
+
+type HttpClientReverseProxy struct {
+	BaseURL *url.URL
+	Client  *http.Client
+}