Fix config reload that failed because of Gateways

Although Gateways reload is not supported at the moment, I had
to add the trap in the switch statement because it would find
a difference. The reason is the TLSConfig object that is likely
to not pass the reflect.DeepEqual test. So for now, I exclude this
from the deep equal test and fail the reload only if the user
has explicitly changed the configuration.

Signed-off-by: Ivan Kozlovic <ivan@synadia.com>

server/reload.go

@@ -637,6 +637,22 @@ func (s *Server) diffOptions(newOpts *Options) ([]option, error) {
 			diffOpts = append(diffOpts, &clientAdvertiseOption{newValue: cliAdv})
 		case "accounts":
 			diffOpts = append(diffOpts, &accountsOption{})
+		case "gateway":
+			// Not supported for now, but report warning if configuration of gateway
+			// is actually changed so that user knows that it won't take effect.
+
+			// Any deep-equal is likely to fail for when there is a TLSConfig. so
+			// remove for the test.
+			tmpOld := oldValue.(GatewayOpts)
+			tmpNew := newValue.(GatewayOpts)
+			tmpOld.TLSConfig = nil
+			tmpNew.TLSConfig = nil
+			// If there is really a change prevents reload.
+			if !reflect.DeepEqual(tmpOld, tmpNew) {
+				// See TODO(ik) note below about printing old/new values.
+				return nil, fmt.Errorf("Config reload not supported for %s: old=%v, new=%v",
+					field.Name, oldValue, newValue)
+			}
 		case "nolog", "nosigs":
 			// Ignore NoLog and NoSigs options since they are not parsed and only used in
 			// testing.
@@ -649,6 +665,11 @@ func (s *Server) diffOptions(newOpts *Options) ([]option, error) {
 			}
 			fallthrough
 		default:
+			// TODO(ik): Implement String() on those options to have a nice print.
+			// %v is difficult to figure what's what, %+v print private fields and
+			// would print passwords. Tried json.Marshal but it is too verbose for
+			// the URL array.
+
 			// Bail out if attempting to reload any unsupported options.
 			return nil, fmt.Errorf("Config reload not supported for %s: old=%v, new=%v",
 				field.Name, oldValue, newValue)

server/reload_test.go

@@ -3186,8 +3186,6 @@ func TestConfigReloadAccountServicesImportExport(t *testing.T) {
 // As of now, config reload does not support changes for gateways.
 // However, ensure that if a gateway is defined, one can still
 // do reload as long as we don't change the gateway spec.
-// There was an issue with the initialization of default TLS timeout
-// that caused the reload to fail.
 func TestConfigReloadNotPreventedByGateways(t *testing.T) {
 	confTemplate := `
 		listen: "127.0.0.1:-1"
@@ -3198,14 +3196,27 @@ func TestConfigReloadNotPreventedByGateways(t *testing.T) {
 			tls {
 				cert_file: "configs/certs/server.pem"
 				key_file: "configs/certs/key.pem"
+				timeout: %s
 			}
+			gateways [
+				{
+					name: "B"
+					url: "nats://localhost:8888"
+				}
+			]
 		}
 	`
-	conf := createConfFile(t, []byte(fmt.Sprintf(confTemplate, "")))
+	conf := createConfFile(t, []byte(fmt.Sprintf(confTemplate, "", "5")))
 	defer os.Remove(conf)
 	s, _ := RunServerWithConfig(conf)
 	defer s.Shutdown()
 
 	// Cause reload with adding a param that is supported
-	reloadUpdateConfig(t, s, conf, fmt.Sprintf(confTemplate, "max_payload: 100000"))
+	reloadUpdateConfig(t, s, conf, fmt.Sprintf(confTemplate, "max_payload: 100000", "5"))
+
+	// Now update gateway, should fail to reload.
+	changeCurrentConfigContentWithNewContent(t, conf, []byte(fmt.Sprintf(confTemplate, "max_payload: 100000", "3")))
+	if err := s.Reload(); err == nil || !strings.Contains(err.Error(), "not supported for Gateway") {
+		t.Fatalf("Expected Reload to return a not supported error, got %v", err)
+	}
 }