[minor] Add dial timeout option

config/config.go

@@ -287,6 +287,7 @@ type Log struct {
 
 // Transport exposes a subset of Transport parameters. reference: https://github.com/golang/go/blob/master/src/net/http/transport.go#L95
 type Transport struct {
+	DialContext            DialContext   `yaml:"dialContext,omitempty"`
 	TLSHandshakeTimeout    time.Duration `yaml:"tlsHandshakeTimeout,omitempty"`
 	DisableKeepAlives      bool          `yaml:"disableKeepAlives,omitempty"`
 	DisableCompression     bool          `yaml:"disableCompression,omitempty"`
@@ -302,6 +303,11 @@ type Transport struct {
 	ForceAttemptHTTP2      bool          `yaml:"forceAttemptHTTP2,omitempty"`
 }
 
+// DialContext exposes a subset of DialContext parameters. reference: https://github.com/golang/go/blob/master/src/net/http/transport.go#L318
+type DialContext struct {
+	Timeout time.Duration `yaml:"timeout"`
+}
+
 // OriginLog represents log configuration from origin
 type OriginLog struct {
 	StatusCode StatusCode `yaml:"statusCode"`

config/config_test.go

@@ -140,6 +140,9 @@ func TestNew(t *testing.T) {
 						WriteBufferSize:        0,
 						ReadBufferSize:         0,
 						ForceAttemptHTTP2:      true,
+						DialContext: DialContext{
+							Timeout: 1 * time.Second,
+						},
 					},
 					OriginLog: OriginLog{
 						StatusCode: StatusCode{

handler/handler.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"net"
 	"net/http"
 	"net/http/httputil"
 	"strings"
@@ -88,14 +89,23 @@ func New(cfg config.Proxy, bp httputil.BufferPool, prov service.Authorizationd)
 		ModifyResponse: modifyResponse,
 		Transport: &transport{
 			prov:         prov,
-			RoundTripper: transportFromCfg(cfg.Transport),
+			RoundTripper: updateDialContext(transportFromCfg(cfg.Transport), cfg.Transport.DialContext.Timeout),
 			cfg:          cfg,
 			noAuthPaths:  mapPathToAssertion(cfg.NoAuthPaths),
 		},
 		ErrorHandler: handleError,
 	}
 }
 
+func updateDialContext(t *http.Transport, dialTimeout time.Duration) *http.Transport {
+	if dialTimeout != time.Duration(0) {
+		t.DialContext = (&net.Dialer{
+			Timeout: dialTimeout,
+		}).DialContext
+	}
+	return t
+}
+
 func transportFromCfg(cfg config.Transport) *http.Transport {
 	isZero := func(v interface{}) bool {
 		switch v.(type) {

handler/handler_test.go

@@ -5,6 +5,8 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"math"
+	"net"
 	"net/http"
 	"net/http/httptest"
 	"net/http/httputil"
@@ -565,6 +567,61 @@ func TestNew(t *testing.T) {
 	}
 }
 
+func Test_updateDialContext(t *testing.T) {
+	type args struct {
+		cfg         *http.Transport
+		dialTimeout time.Duration
+	}
+	tests := []struct {
+		name string
+		args args
+		want *http.Transport
+	}{
+		{
+			name: "check dialContext.timeout == 0 is not used",
+			args: args{
+				cfg:         &http.Transport{},
+				dialTimeout: 0,
+			},
+			want: &http.Transport{},
+		},
+		{
+			name: "check dialContext.timeout != 0 is used",
+			args: args{
+				cfg:         &http.Transport{},
+				dialTimeout: 10 * time.Second,
+			},
+			want: &http.Transport{
+				DialContext: (&net.Dialer{
+					Timeout: 10 * time.Second,
+				}).DialContext,
+			},
+		},
+		{
+			name: "check if dialContext.timeout is negative, timeout is math.MaxInt64",
+			args: args{
+				cfg:         &http.Transport{},
+				dialTimeout: -1,
+			},
+			want: &http.Transport{
+				DialContext: (&net.Dialer{
+					Timeout: math.MaxInt64,
+				}).DialContext,
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := updateDialContext(tt.args.cfg, tt.args.dialTimeout)
+			p1 := reflect.ValueOf(got.DialContext).Pointer()
+			p2 := reflect.ValueOf(tt.want.DialContext).Pointer()
+			if p1 != p2 {
+				t.Errorf("updateDialContext() = %+v, want %+v", p1, p2)
+			}
+		})
+	}
+}
+
 func Test_transportFromCfg(t *testing.T) {
 	type args struct {
 		cfg config.Transport

test/data/example_config.yaml

@@ -56,6 +56,8 @@ proxy:
     writeBufferSize: 0
     readBufferSize: 0
     forceAttemptHTTP2: true
+    dialContext:
+      timeout: "1s"
   originLog:
     statusCode:
       enable: true