Revert "Revert "Treat URLs have same IP address as same""

This reverts commit 3153e635d5.

Conflicts:
	etcdserver/config.go

pkg/netutil/netutil.go

@@ -19,6 +19,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"reflect"
 	"strings"
 
 	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/coreos/pkg/capnslog"
@@ -60,6 +61,51 @@ func ResolveTCPAddrs(urls ...[]url.URL) error {
 	return nil
 }
 
+// URLsEqual checks equality of url.URLS between two arrays.
+// This check pass even if an URL is in hostname and opposite is in IP address.
+func URLsEqual(a []url.URL, b []url.URL) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i, urlA := range a {
+		urlB := b[i]
+
+		if !reflect.DeepEqual(urlA, urlB) {
+			urls := []url.URL{urlA, urlB}
+			ResolveTCPAddrs(urls)
+			if !reflect.DeepEqual(urls[0], urls[1]) {
+				return false
+			}
+		}
+	}
+
+	return true
+}
+
+func URLStringsEqual(a []string, b []string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	urlsA := make([]url.URL, len(a))
+	for _, str := range a {
+		u, err := url.Parse(str)
+		if err != nil {
+			return false
+		}
+		urlsA = append(urlsA, *u)
+	}
+	urlsB := make([]url.URL, len(b))
+	for _, str := range b {
+		u, err := url.Parse(str)
+		if err != nil {
+			return false
+		}
+		urlsB = append(urlsB, *u)
+	}
+
+	return URLsEqual(urlsA, urlsB)
+}
+
 // BasicAuth returns the username and password provided in the request's
 // Authorization header, if the request uses HTTP Basic Authentication.
 // See RFC 2617, Section 2.