draft of fix for issue #447. allows advertising separate host:ports to client.

server/opts.go

@@ -30,6 +30,7 @@ type ClusterOpts struct {
 	TLSTimeout     float64     `json:"-"`
 	TLSConfig      *tls.Config `json:"-"`
 	ListenStr      string      `json:"-"`
+	AdvertiseStr   string      `json:"-"`
 	NoAdvertise    bool        `json:"-"`
 	ConnectRetries int         `json:"-"`
 }
@@ -387,6 +388,8 @@ func parseCluster(cm map[string]interface{}, opts *Options) error {
 			opts.Cluster.TLSConfig.ClientAuth = tls.RequireAndVerifyClientCert
 			opts.Cluster.TLSConfig.RootCAs = opts.Cluster.TLSConfig.ClientCAs
 			opts.Cluster.TLSTimeout = tc.Timeout
+		case "cluster_advertise":
+			opts.Cluster.AdvertiseStr = mv.(string)
 		case "no_advertise":
 			opts.Cluster.NoAdvertise = mv.(bool)
 		case "connect_retries":
@@ -753,6 +756,9 @@ func MergeOptions(fileOpts, flagOpts *Options) *Options {
 	if flagOpts.Cluster.ListenStr != "" {
 		opts.Cluster.ListenStr = flagOpts.Cluster.ListenStr
 	}
+	if flagOpts.Cluster.AdvertiseStr != "" {
+		opts.Cluster.AdvertiseStr = flagOpts.Cluster.AdvertiseStr
+	}
 	if flagOpts.Cluster.NoAdvertise {
 		opts.Cluster.NoAdvertise = true
 	}
@@ -974,6 +980,7 @@ func ConfigureOptions(fs *flag.FlagSet, args []string, printVersion, printHelp,
 	fs.StringVar(&opts.RoutesStr, "routes", "", "Routes to actively solicit a connection.")
 	fs.StringVar(&opts.Cluster.ListenStr, "cluster", "", "Cluster url from which members can solicit routes.")
 	fs.StringVar(&opts.Cluster.ListenStr, "cluster_listen", "", "Cluster url from which members can solicit routes.")
+	fs.StringVar(&opts.Cluster.AdvertiseStr, "cluster_advertise", "", "Cluster URL sent on info for use with proxied connections.")
 	fs.BoolVar(&opts.Cluster.NoAdvertise, "no_advertise", false, "Advertise known cluster IPs to clients.")
 	fs.IntVar(&opts.Cluster.ConnectRetries, "connect_retries", 0, "For implicit routes, number of connect retries")
 	fs.BoolVar(&showTLSHelp, "help_tls", false, "TLS help.")
@@ -1171,6 +1178,7 @@ func overrideCluster(opts *Options) error {
 		opts.Cluster.Username = ""
 		opts.Cluster.Password = ""
 	}
+
 	return nil
 }
 

server/server.go

@@ -1002,42 +1002,62 @@ func (s *Server) getClientConnectURLs() []string {
 	sPort := strconv.Itoa(opts.Port)
 	urls := make([]string, 0, 1)
 
-	ipAddr, err := net.ResolveIPAddr("ip", opts.Host)
-	// If the host is "any" (0.0.0.0 or ::), get specific IPs from available
-	// interfaces.
-	if err == nil && ipAddr.IP.IsUnspecified() {
-		var ip net.IP
-		ifaces, _ := net.Interfaces()
-		for _, i := range ifaces {
-			addrs, _ := i.Addrs()
-			for _, addr := range addrs {
-				switch v := addr.(type) {
-				case *net.IPNet:
-					ip = v.IP
-				case *net.IPAddr:
-					ip = v.IP
+	// short circuit if cluster-advertise is set
+	if opts.Cluster.AdvertiseStr != "" {
+		hosts := strings.Split(opts.Cluster.AdvertiseStr, ",")
+
+		for _, i := range hosts {
+			hostPort := strings.Split(i, ":")
+			host := strings.TrimSpace(hostPort[0])
+
+			if len(hostPort) > 1 {
+				port := strings.TrimSpace(hostPort[1])
+				// if a separate advertise port is set, use that. Otherwise, use the main listen port.
+				if port != "" {
+					sPort = port
 				}
-				// Skip non global unicast addresses
-				if !ip.IsGlobalUnicast() || ip.IsUnspecified() {
-					ip = nil
-					continue
+			}
+			urls = append(urls, net.JoinHostPort(host, sPort))
+		}
+	} else {
+		ipAddr, err := net.ResolveIPAddr("ip", opts.Host)
+		// If the host is "any" (0.0.0.0 or ::), get specific IPs from available
+		// interfaces.
+		if err == nil && ipAddr.IP.IsUnspecified() {
+			var ip net.IP
+			ifaces, _ := net.Interfaces()
+			for _, i := range ifaces {
+				addrs, _ := i.Addrs()
+				for _, addr := range addrs {
+					switch v := addr.(type) {
+					case *net.IPNet:
+						ip = v.IP
+					case *net.IPAddr:
+						ip = v.IP
+					}
+					// Skip non global unicast addresses
+					if !ip.IsGlobalUnicast() || ip.IsUnspecified() {
+						ip = nil
+						continue
+					}
+					urls = append(urls, net.JoinHostPort(ip.String(), sPort))
 				}
-				urls = append(urls, net.JoinHostPort(ip.String(), sPort))
+			}
+		}
+		if err != nil || len(urls) == 0 {
+			// We are here if s.opts.Host is not "0.0.0.0" nor "::", or if for some
+			// reason we could not add any URL in the loop above.
+			// We had a case where a Windows VM was hosed and would have err == nil
+			// and not add any address in the array in the loop above, and we
+			// ended-up returning 0.0.0.0, which is problematic for Windows clients.
+			// Check for 0.0.0.0 or :: specifically, and ignore if that's the case.
+			if opts.Host == "0.0.0.0" || opts.Host == "::" {
+				s.Errorf("Address %q can not be resolved properly", opts.Host)
+			} else {
+				urls = append(urls, net.JoinHostPort(opts.Host, sPort))
 			}
 		}
 	}
-	if err != nil || len(urls) == 0 {
-		// We are here if s.opts.Host is not "0.0.0.0" nor "::", or if for some
-		// reason we could not add any URL in the loop above.
-		// We had a case where a Windows VM was hosed and would have err == nil
-		// and not add any address in the array in the loop above, and we
-		// ended-up returning 0.0.0.0, which is problematic for Windows clients.
-		// Check for 0.0.0.0 or :: specifically, and ignore if that's the case.
-		if opts.Host == "0.0.0.0" || opts.Host == "::" {
-			s.Errorf("Address %q can not be resolved properly", opts.Host)
-		} else {
-			urls = append(urls, net.JoinHostPort(opts.Host, sPort))
-		}
-	}
+
 	return urls
 }

server/server_test.go

@@ -213,6 +213,46 @@ func TestGetConnectURLs(t *testing.T) {
 	}
 }
 
+func TestClusterAdvertiseConnectURL(t *testing.T) {
+	opts := DefaultOptions()
+	opts.Port = 4222
+	opts.Cluster.AdvertiseStr = "nats.example.com"
+
+	s := New(opts)
+
+	urls := s.getClientConnectURLs()
+
+	if len(urls) != 1 {
+		t.Fatalf("Expected to get one url, got none: %v with Cluster.AdvertiseStr %v",
+			opts.Host, opts.Cluster.AdvertiseStr)
+	}
+
+	if urls[0] != "nats.example.com:4222" {
+		t.Fatalf("Expected to get '%s', got: '%v'", "nats.example.com:4222", urls[0])
+	}
+	s.Shutdown()
+
+	opts.Cluster.AdvertiseStr = "nats.example.com, nats2.example.com:7777"
+
+	s = New(opts)
+
+	urls = s.getClientConnectURLs()
+
+	if len(urls) != 2 {
+		t.Fatalf("Expected to get two urls, got %d: %v", len(urls), opts.Cluster.AdvertiseStr)
+	}
+
+	if urls[0] != "nats.example.com:4222" {
+		t.Fatalf("Expected 'nats.example.com:4222', got: '%v'", urls[0])
+	}
+
+	if urls[1] != "nats2.example.com:7777" {
+		t.Fatalf("Expected 'nats2.example.com:7777', got: '%v'", urls[1])
+	}
+
+	s.Shutdown()
+}
+
 func TestNoDeadlockOnStartFailure(t *testing.T) {
 	opts := DefaultOptions()
 	opts.Host = "x.x.x.x" // bad host