pkg/transport: pass dial timeout to NewTransport

So we could set dial timeout for new transport, which makes it
customizable according to max RTT.

etcdctl/command/util.go

@@ -23,6 +23,7 @@ import (
 	"net/url"
 	"os"
 	"strings"
+	"time"
 
 	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/bgentry/speakeasy"
 	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/codegangsta/cli"
@@ -33,6 +34,10 @@ import (
 
 var (
 	ErrNoAvailSrc = errors.New("no available argument and stdin")
+
+	// the maximum amount of time a dial will wait for a connection to setup.
+	// 30s is long enough for most of the network conditions.
+	defaultDialTimeout = 30 * time.Second
 )
 
 // trimsplit slices s into all substrings separated by sep and returns a
@@ -153,7 +158,7 @@ func getTransport(c *cli.Context) (*http.Transport, error) {
 		CertFile: certfile,
 		KeyFile:  keyfile,
 	}
-	return transport.NewTransport(tls)
+	return transport.NewTransport(tls, defaultDialTimeout)
 }
 
 func getUsernamePasswordFromFlag(usernameFlag string) (username string, password string, err error) {

pkg/transport/listener.go

@@ -46,18 +46,19 @@ func NewListener(addr string, scheme string, info TLSInfo) (net.Listener, error)
 	return l, nil
 }
 
-func NewTransport(info TLSInfo) (*http.Transport, error) {
+func NewTransport(info TLSInfo, dialtimeoutd time.Duration) (*http.Transport, error) {
 	cfg, err := info.ClientConfig()
 	if err != nil {
 		return nil, err
 	}
 
 	t := &http.Transport{
-		// timeouts taken from http.DefaultTransport
 		Dial: (&net.Dialer{
-			Timeout:   30 * time.Second,
+			Timeout: dialtimeoutd,
+			// value taken from http.DefaultTransport
 			KeepAlive: 30 * time.Second,
 		}).Dial,
+		// value taken from http.DefaultTransport
 		TLSHandshakeTimeout: 10 * time.Second,
 		TLSClientConfig:     cfg,
 	}

pkg/transport/listener_test.go

@@ -21,6 +21,7 @@ import (
 	"net/http"
 	"os"
 	"testing"
+	"time"
 )
 
 func createTempFile(b []byte) (string, error) {
@@ -115,7 +116,7 @@ func TestNewTransportTLSInfo(t *testing.T) {
 
 	for i, tt := range tests {
 		tt.parseFunc = fakeCertificateParserFunc(tls.Certificate{}, nil)
-		trans, err := NewTransport(tt)
+		trans, err := NewTransport(tt, time.Second)
 		if err != nil {
 			t.Fatalf("Received unexpected error from NewTransport: %v", err)
 		}

pkg/transport/timeout_transport.go

@@ -24,7 +24,7 @@ import (
 // If read/write on the created connection blocks longer than its time limit,
 // it will return timeout error.
 func NewTimeoutTransport(info TLSInfo, dialtimeoutd, rdtimeoutd, wtimeoutd time.Duration) (*http.Transport, error) {
-	tr, err := NewTransport(info)
+	tr, err := NewTransport(info, dialtimeoutd)
 	if err != nil {
 		return nil, err
 	}