server: store the updated labels into etcd

pkg/domain/infosync/info.go

@@ -405,6 +405,39 @@ func GetAllServerInfo(ctx context.Context) (map[string]*ServerInfo, error) {
 	return is.getAllServerInfo(ctx)
 }
 
+// UpdateServerLabel updates the server label for global info syncer.
+func UpdateServerLabel(ctx context.Context, labels map[string]string) error {
+	is, err := getGlobalInfoSyncer()
+	if err != nil {
+		return err
+	}
+	// when etcdCli is nil, the server infos are generated from the latest config, no need to update.
+	if is.etcdCli == nil {
+		return nil
+	}
+	selfInfo, err := is.getServerInfoByID(ctx, is.info.ID)
+	if err != nil {
+		return err
+	}
+	changed := false
+	for k, v := range labels {
+		if selfInfo.Labels[k] != v {
+			changed = true
+			selfInfo.Labels[k] = v
+		}
+	}
+	if !changed {
+		return nil
+	}
+	infoBuf, err := selfInfo.Marshal()
+	if err != nil {
+		return errors.Trace(err)
+	}
+	str := string(hack.String(infoBuf))
+	err = util.PutKVToEtcd(ctx, is.etcdCli, keyOpDefaultRetryCnt, is.serverInfoPath, str, clientv3.WithLease(is.session.Lease()))
+	return err
+}
+
 // DeleteTiFlashTableSyncProgress is used to delete the tiflash table replica sync progress.
 func DeleteTiFlashTableSyncProgress(tableInfo *model.TableInfo) error {
 	is, err := getGlobalInfoSyncer()

pkg/server/handler/tests/BUILD.bazel

@@ -9,7 +9,7 @@ go_test(
         "main_test.go",
     ],
     flaky = True,
-    shard_count = 36,
+    shard_count = 37,
     deps = [
         "//pkg/config",
         "//pkg/ddl",
@@ -54,6 +54,7 @@ go_test(
         "@com_github_pingcap_log//:log",
         "@com_github_stretchr_testify//require",
         "@com_github_tikv_client_go_v2//tikv",
+        "@io_etcd_go_etcd_tests_v3//integration",
         "@org_uber_go_goleak//:goleak",
         "@org_uber_go_zap//:zap",
     ],

pkg/server/handler/tests/http_handler_test.go

@@ -16,6 +16,7 @@ package tests
 
 import (
 	"bytes"
+	"context"
 	"crypto/tls"
 	"crypto/x509"
 	"crypto/x509/pkix"
@@ -66,6 +67,7 @@ import (
 	"github.com/pingcap/tidb/pkg/util/rowcodec"
 	"github.com/stretchr/testify/require"
 	"github.com/tikv/client-go/v2/tikv"
+	"go.etcd.io/etcd/tests/v3/integration"
 	"go.uber.org/zap"
 )
 
@@ -1202,6 +1204,64 @@ func TestSetLabels(t *testing.T) {
 	})
 }
 
+func TestSetLabelsWithEtcd(t *testing.T) {
+	ts := createBasicHTTPHandlerTestSuite()
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	ts.startServer(t)
+	defer ts.stopServer(t)
+
+	integration.BeforeTestExternal(t)
+	cluster := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 1})
+	defer cluster.Terminate(t)
+	client := cluster.RandClient()
+	infosync.SetEtcdClient(client)
+	ts.domain.InfoSyncer().Restart(ctx)
+
+	testUpdateLabels := func(labels, expected map[string]string) {
+		buffer := bytes.NewBuffer([]byte{})
+		require.Nil(t, json.NewEncoder(buffer).Encode(labels))
+		resp, err := ts.PostStatus("/labels", "application/json", buffer)
+		require.NoError(t, err)
+		require.NotNil(t, resp)
+		defer func() {
+			require.NoError(t, resp.Body.Close())
+		}()
+		require.Equal(t, http.StatusOK, resp.StatusCode)
+		newLabels := config.GetGlobalConfig().Labels
+		require.Equal(t, newLabels, expected)
+		servers, err := infosync.GetAllServerInfo(ctx)
+		require.NoError(t, err)
+		for _, server := range servers {
+			for k, expectV := range expected {
+				v, ok := server.Labels[k]
+				require.True(t, ok)
+				require.Equal(t, expectV, v)
+			}
+			return
+		}
+		require.Fail(t, "no server found")
+	}
+
+	labels := map[string]string{
+		"zone": "us-west-1",
+		"test": "123",
+	}
+	testUpdateLabels(labels, labels)
+
+	updated := map[string]string{
+		"zone": "bj-1",
+	}
+	labels["zone"] = "bj-1"
+	testUpdateLabels(updated, labels)
+
+	// reset the global variable
+	config.UpdateGlobal(func(conf *config.Config) {
+		conf.Labels = map[string]string{}
+	})
+}
+
 func TestSetLabelsConcurrentWithGetLabel(t *testing.T) {
 	ts := createBasicHTTPHandlerTestSuite()
 

pkg/server/handler/tikvhandler/tikv_handler.go

@@ -2000,6 +2000,11 @@ func (LabelHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 				}
 			}
 		}
+		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		if err := infosync.UpdateServerLabel(ctx, labels); err != nil {
+			logutil.BgLogger().Error("update etcd labels failed", zap.Any("labels", cfg.Labels), zap.Error(err))
+		}
+		cancel()
 		cfg.Labels = labels
 		config.StoreGlobalConfig(&cfg)
 		logutil.BgLogger().Info("update server labels", zap.Any("labels", cfg.Labels))