From 28f1fd9aae03f0baaacc79cac379772420370888 Mon Sep 17 00:00:00 2001
From: Igor Chubin <igor@chub.in>
Date: Fri, 2 Dec 2022 19:47:36 +0100
Subject: [PATCH] Move global transport to RequestProcessor

---
 cmd/processRequest.go | 39 ++++++++++++++++++++++++++++-----------
 cmd/srv.go            | 14 --------------
 2 files changed, 28 insertions(+), 25 deletions(-)

diff --git a/cmd/processRequest.go b/cmd/processRequest.go
index cb2ce69..8080115 100644
--- a/cmd/processRequest.go
+++ b/cmd/processRequest.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"fmt"
 	"io/ioutil"
 	"log"
@@ -27,11 +28,12 @@ type responseWithHeader struct {
 
 // RequestProcessor handles incoming requests.
 type RequestProcessor struct {
-	peakRequest30 sync.Map
-	peakRequest60 sync.Map
-	lruCache      *lru.Cache
-	stats         *Stats
-	router        routing.Router
+	peakRequest30     sync.Map
+	peakRequest60     sync.Map
+	lruCache          *lru.Cache
+	stats             *Stats
+	router            routing.Router
+	upstreamTransport *http.Transport
 }
 
 // NewRequestProcessor returns new RequestProcessor.
@@ -41,9 +43,22 @@ func NewRequestProcessor() (*RequestProcessor, error) {
 		return nil, err
 	}
 
+	dialer := &net.Dialer{
+		Timeout:   uplinkTimeout * time.Second,
+		KeepAlive: uplinkTimeout * time.Second,
+		DualStack: true,
+	}
+
+	transport := &http.Transport{
+		DialContext: func(ctx context.Context, network, _ string) (net.Conn, error) {
+			return dialer.DialContext(ctx, network, uplinkSrvAddr)
+		},
+	}
+
 	rp := &RequestProcessor{
-		lruCache: lruCache,
-		stats:    NewStats(),
+		lruCache:          lruCache,
+		stats:             NewStats(),
+		upstreamTransport: transport,
 	}
 
 	// Initialize routes.
@@ -80,7 +95,7 @@ func (rp *RequestProcessor) ProcessRequest(r *http.Request) (*responseWithHeader
 
 	if dontCache(r) {
 		rp.stats.Inc("uncached")
-		return get(r)
+		return get(r, rp.upstreamTransport)
 	}
 
 	cacheDigest := getCacheDigest(r)
@@ -127,7 +142,7 @@ func (rp *RequestProcessor) ProcessRequest(r *http.Request) (*responseWithHeader
 
 		rp.lruCache.Add(cacheDigest, responseWithHeader{InProgress: true})
 
-		response, err = get(r)
+		response, err = get(r, rp.upstreamTransport)
 		if err != nil {
 			return nil, err
 		}
@@ -141,9 +156,11 @@ func (rp *RequestProcessor) ProcessRequest(r *http.Request) (*responseWithHeader
 	return response, nil
 }
 
-func get(req *http.Request) (*responseWithHeader, error) {
+func get(req *http.Request, transport *http.Transport) (*responseWithHeader, error) {
 
-	client := &http.Client{}
+	client := &http.Client{
+		Transport: transport,
+	}
 
 	queryURL := fmt.Sprintf("http://%s%s", req.Host, req.RequestURI)
 
diff --git a/cmd/srv.go b/cmd/srv.go
index 0db5a9d..28bd2ce 100644
--- a/cmd/srv.go
+++ b/cmd/srv.go
@@ -1,12 +1,10 @@
 package main
 
 import (
-	"context"
 	"crypto/tls"
 	"fmt"
 	"io"
 	"log"
-	"net"
 	"net/http"
 	"time"
 
@@ -35,18 +33,6 @@ var plainTextAgents = []string{
 	"xh",
 }
 
-func init() {
-	dialer := &net.Dialer{
-		Timeout:   uplinkTimeout * time.Second,
-		KeepAlive: uplinkTimeout * time.Second,
-		DualStack: true,
-	}
-
-	http.DefaultTransport.(*http.Transport).DialContext = func(ctx context.Context, network, _ string) (net.Conn, error) {
-		return dialer.DialContext(ctx, network, uplinkSrvAddr)
-	}
-}
-
 func copyHeader(dst, src http.Header) {
 	for k, vv := range src {
 		for _, v := range vv {