config: fix precheck blocking the change of other PD configurations (#10132)

close #10114

Signed-off-by: Ryan Leung <rleungx@gmail.com>

Author: rleungx

server/server.go

@@ -1289,22 +1289,24 @@ func (s *Server) GetPDServerConfig() *config.PDServerConfig {
 
 // SetPDServerConfig sets the server config.
 func (s *Server) SetPDServerConfig(cfg config.PDServerConfig) error {
-	switch cfg.DashboardAddress {
-	case "auto":
-	case "none":
-	default:
-		if !strings.HasPrefix(cfg.DashboardAddress, "http") {
-			cfg.DashboardAddress = fmt.Sprintf("%s://%s", s.GetClientScheme(), cfg.DashboardAddress)
-		}
-		if !cluster.IsClientURL(cfg.DashboardAddress, s.client) {
-			return errors.Errorf("%s is not the client url of any member", cfg.DashboardAddress)
-		}
-	}
 	if err := cfg.Validate(); err != nil {
 		return err
 	}
-
 	old := s.persistOptions.GetPDServerConfig()
+	// See https://github.com/tikv/pd/issues/10114 for more details
+	if old.DashboardAddress != cfg.DashboardAddress {
+		switch cfg.DashboardAddress {
+		case "auto":
+		case "none":
+		default:
+			if !strings.HasPrefix(cfg.DashboardAddress, "http") {
+				cfg.DashboardAddress = fmt.Sprintf("%s://%s", s.GetClientScheme(), cfg.DashboardAddress)
+			}
+			if !cluster.IsClientURL(cfg.DashboardAddress, s.client) {
+				return errors.Errorf("dashboard address %s is not the client url of any member", cfg.DashboardAddress)
+			}
+		}
+	}
 	s.persistOptions.SetPDServerConfig(&cfg)
 	if err := s.persistOptions.Persist(s.storage); err != nil {
 		s.persistOptions.SetPDServerConfig(old)

tests/server/server_test.go

@@ -581,3 +581,40 @@ func TestMeteringWriter(t *testing.T) {
 	re.True(ok)
 	re.Equal(rmserver.ResourceManagerCategory, ruCollector.Category())
 }
+
+func TestSetPDServerConfigWithDashboard(t *testing.T) {
+	re := require.New(t)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	cluster, err := tests.NewTestCluster(ctx, 1)
+	defer cluster.Destroy()
+	re.NoError(err)
+
+	err = cluster.RunInitialServers()
+	re.NoError(err)
+
+	leader := cluster.WaitLeader()
+	re.NotEmpty(leader)
+	svr := cluster.GetServer(leader).GetServer()
+
+	// Test updating config without changing dashboard address
+	cfg := svr.GetPDServerConfig()
+	originalDashboard := cfg.DashboardAddress
+	originalUseRegionStorage := cfg.UseRegionStorage
+
+	// Change some other field but keep dashboard the same
+	cfg.UseRegionStorage = !cfg.UseRegionStorage
+	err = svr.SetPDServerConfig(*cfg)
+	re.NoError(err)
+
+	newCfg := svr.GetPDServerConfig()
+	re.Equal(originalDashboard, newCfg.DashboardAddress)
+	re.NotEqual(originalUseRegionStorage, newCfg.UseRegionStorage)
+
+	// Change both other field and dashboard
+	cfg.UseRegionStorage = !cfg.UseRegionStorage
+	cfg.DashboardAddress = "https://new-dashboard-address:1234"
+	err = svr.SetPDServerConfig(*cfg)
+	re.ErrorContains(err, "is not the client url of any member")
+}