etcdutil: support multi backends client

client/base_client.go

@@ -143,7 +143,7 @@ func (c *baseClient) memberLoop() {
 			failpoint.Continue()
 		})
 		if err := c.updateMember(); err != nil {
-			log.Error("[pd] failed updateMember", errs.ZapError(err))
+			log.Error("[pd] failed to update member", errs.ZapError(err))
 		}
 	}
 }
@@ -303,7 +303,7 @@ func (c *baseClient) updateMember() error {
 			errTSO = c.switchTSOAllocatorLeader(members.GetTsoAllocatorLeaders())
 		}
 
-		// Failed to get PD leader
+		// Failed to get members
 		if err != nil {
 			log.Info("[pd] cannot update member from this address",
 				zap.String("address", u),
@@ -327,7 +327,7 @@ func (c *baseClient) updateMember() error {
 		// the error of `switchTSOAllocatorLeader` will be returned.
 		return errTSO
 	}
-	return errs.ErrClientGetLeader.FastGenByArgs(c.GetURLs())
+	return errs.ErrClientGetMember.FastGenByArgs(c.GetURLs())
 }
 
 func (c *baseClient) getMembers(ctx context.Context, url string, timeout time.Duration) (*pdpb.GetMembersResponse, error) {

pkg/mcs/resource_manager/server/server.go

@@ -151,7 +151,6 @@ func (s *Server) AddServiceReadyCallback(callbacks ...func(context.Context)) {
 }
 
 func (s *Server) initClient() error {
-	// TODO: We need to keep all backend endpoints and keep updating them to the latest. Once one of them failed, need to try another one.
 	tlsConfig, err := s.cfg.Security.ToTLSConfig()
 	if err != nil {
 		return err

pkg/utils/etcdutil/etcdutil.go

@@ -17,21 +17,18 @@ package etcdutil
 import (
 	"context"
 	"crypto/tls"
-	"fmt"
 	"math/rand"
 	"net/http"
 	"net/url"
-	"testing"
 	"time"
 
 	"github.com/gogo/protobuf/proto"
 	"github.com/pingcap/errors"
+	"github.com/pingcap/failpoint"
 	"github.com/pingcap/log"
 	"github.com/tikv/pd/pkg/errs"
-	"github.com/tikv/pd/pkg/utils/tempurl"
 	"github.com/tikv/pd/pkg/utils/typeutil"
 	"go.etcd.io/etcd/clientv3"
-	"go.etcd.io/etcd/embed"
 	"go.etcd.io/etcd/etcdserver"
 	"go.etcd.io/etcd/pkg/types"
 	"go.uber.org/zap"
@@ -41,6 +38,9 @@ const (
 	// defaultEtcdClientTimeout is the default timeout for etcd client.
 	defaultEtcdClientTimeout = 3 * time.Second
 
+	// defaultAutoSyncInterval is the interval to sync etcd cluster.
+	defaultAutoSyncInterval = 60 * time.Second
+
 	// DefaultDialTimeout is the maximum amount of time a dial will wait for a
 	// connection to setup. 30s is long enough for most of the network conditions.
 	DefaultDialTimeout = 30 * time.Second
@@ -186,53 +186,48 @@ func EtcdKVPutWithTTL(ctx context.Context, c *clientv3.Client, key string, value
 	return kv.Put(ctx, key, value, clientv3.WithLease(grantResp.ID))
 }
 
-// NewTestSingleConfig is used to create a etcd config for the unit test purpose.
-func NewTestSingleConfig(t *testing.T) *embed.Config {
-	cfg := embed.NewConfig()
-	cfg.Name = "test_etcd"
-	cfg.Dir = t.TempDir()
-	cfg.WalDir = ""
-	cfg.Logger = "zap"
-	cfg.LogOutputs = []string{"stdout"}
-
-	pu, _ := url.Parse(tempurl.Alloc())
-	cfg.LPUrls = []url.URL{*pu}
-	cfg.APUrls = cfg.LPUrls
-	cu, _ := url.Parse(tempurl.Alloc())
-	cfg.LCUrls = []url.URL{*cu}
-	cfg.ACUrls = cfg.LCUrls
-
-	cfg.StrictReconfigCheck = false
-	cfg.InitialCluster = fmt.Sprintf("%s=%s", cfg.Name, &cfg.LPUrls[0])
-	cfg.ClusterState = embed.ClusterStateFlagNew
-	return cfg
-}
-
 // CreateClients creates etcd v3 client and http client.
 func CreateClients(tlsConfig *tls.Config, acUrls []url.URL) (*clientv3.Client, *http.Client, error) {
-	endpoints := []string{acUrls[0].String()}
-	lgc := zap.NewProductionConfig()
-	lgc.Encoding = log.ZapEncodingName
-	client, err := clientv3.New(clientv3.Config{
-		Endpoints:   endpoints,
-		DialTimeout: defaultEtcdClientTimeout,
-		TLS:         tlsConfig,
-		LogConfig:   &lgc,
-	})
+	client, err := createEtcdClient(tlsConfig, acUrls)
 	if err != nil {
 		return nil, nil, errs.ErrNewEtcdClient.Wrap(err).GenWithStackByCause()
 	}
-
 	httpClient := &http.Client{
 		Transport: &http.Transport{
 			DisableKeepAlives: true,
 			TLSClientConfig:   tlsConfig,
 		},
 	}
-	log.Info("create etcd v3 client", zap.Strings("endpoints", endpoints))
 	return client, httpClient, nil
 }
 
+func createEtcdClient(tlsConfig *tls.Config, acUrls []url.URL) (*clientv3.Client, error) {
+	if len(acUrls) == 0 {
+		return nil, errs.ErrNewEtcdClient.FastGenByArgs("no available etcd address")
+	}
+	endpoints := make([]string, 0, len(acUrls))
+	for _, u := range acUrls {
+		endpoints = append(endpoints, u.String())
+	}
+	lgc := zap.NewProductionConfig()
+	lgc.Encoding = log.ZapEncodingName
+	autoSyncInterval := defaultAutoSyncInterval
+	failpoint.Inject("autoSyncInterval", func() {
+		autoSyncInterval = 10 * time.Millisecond
+	})
+	client, err := clientv3.New(clientv3.Config{
+		Endpoints:        endpoints,
+		DialTimeout:      defaultEtcdClientTimeout,
+		AutoSyncInterval: autoSyncInterval,
+		TLS:              tlsConfig,
+		LogConfig:        &lgc,
+	})
+	if err != nil {
+		log.Info("create etcd v3 client", zap.Strings("endpoints", endpoints))
+	}
+	return client, err
+}
+
 // InitClusterID creates a cluster ID for the given key if it hasn't existed.
 // This function assumes the cluster ID has already existed and always use a
 // cheaper read to retrieve it; if it doesn't exist, invoke the more expensive

pkg/utils/etcdutil/etcdutil_test.go

@@ -21,6 +21,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/pingcap/failpoint"
 	"github.com/stretchr/testify/require"
 	"go.etcd.io/etcd/clientv3"
 	"go.etcd.io/etcd/embed"
@@ -78,7 +79,6 @@ func TestMemberHelpers(t *testing.T) {
 	re.NoError(err)
 
 	<-etcd2.Server.ReadyNotify()
-	re.NoError(err)
 
 	listResp2, err := ListEtcdMembers(client2)
 	re.NoError(err)
@@ -232,3 +232,65 @@ func TestInitClusterID(t *testing.T) {
 	re.NoError(err)
 	re.Equal(clusterID, clusterID1)
 }
+
+func TestEtcdClientSync(t *testing.T) {
+	t.Parallel()
+	re := require.New(t)
+	re.NoError(failpoint.Enable("github.com/tikv/pd/pkg/utils/etcdutil/autoSyncInterval", "return(true)"))
+
+	// Start a etcd server.
+	cfg1 := NewTestSingleConfig(t)
+	etcd1, err := embed.StartEtcd(cfg1)
+	re.NoError(err)
+
+	// Create a etcd client with etcd1 as endpoint.
+	ep1 := cfg1.LCUrls[0].String()
+	urls, err := types.NewURLs([]string{ep1})
+	re.NoError(err)
+	client1, err := createEtcdClient(nil, urls)
+	re.NoError(err)
+	<-etcd1.Server.ReadyNotify()
+
+	// Add a new member.
+	cfg2 := NewTestSingleConfig(t)
+	cfg2.Name = "etcd2"
+	cfg2.InitialCluster = cfg1.InitialCluster + fmt.Sprintf(",%s=%s", cfg2.Name, &cfg2.LPUrls[0])
+	cfg2.ClusterState = embed.ClusterStateFlagExisting
+	peerURL := cfg2.LPUrls[0].String()
+	addResp, err := AddEtcdMember(client1, []string{peerURL})
+	re.NoError(err)
+	etcd2, err := embed.StartEtcd(cfg2)
+	defer func() {
+		etcd2.Close()
+	}()
+	re.NoError(err)
+	re.Equal(uint64(etcd2.Server.ID()), addResp.Member.ID)
+	<-etcd2.Server.ReadyNotify()
+
+	// Check the client can get the new member.
+	listResp2, err := ListEtcdMembers(client1)
+	re.NoError(err)
+	re.Len(listResp2.Members, 2)
+	for _, m := range listResp2.Members {
+		switch m.ID {
+		case uint64(etcd1.Server.ID()):
+		case uint64(etcd2.Server.ID()):
+		default:
+			t.Fatalf("unknown member: %v", m)
+		}
+	}
+
+	// Remove the first member and close the etcd1.
+	_, err = RemoveEtcdMember(client1, uint64(etcd1.Server.ID()))
+	re.NoError(err)
+	time.Sleep(20 * time.Millisecond) // wait for etcd client sync endpoints and client will be connected to etcd2
+	etcd1.Close()
+
+	// Check the client can get the new member with the new endpoints.
+	listResp3, err := ListEtcdMembers(client1)
+	re.NoError(err)
+	re.Len(listResp3.Members, 1)
+	re.Equal(uint64(etcd2.Server.ID()), listResp3.Members[0].ID)
+
+	require.NoError(t, failpoint.Disable("github.com/tikv/pd/pkg/utils/etcdutil/autoSyncInterval"))
+}

pkg/utils/etcdutil/testutil.go

@@ -0,0 +1,46 @@
+// Copyright 2023 TiKV Project Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdutil
+
+import (
+	"fmt"
+	"net/url"
+	"testing"
+
+	"github.com/tikv/pd/pkg/utils/tempurl"
+	"go.etcd.io/etcd/embed"
+)
+
+// NewTestSingleConfig is used to create a etcd config for the unit test purpose.
+func NewTestSingleConfig(t *testing.T) *embed.Config {
+	cfg := embed.NewConfig()
+	cfg.Name = "test_etcd"
+	cfg.Dir = t.TempDir()
+	cfg.WalDir = ""
+	cfg.Logger = "zap"
+	cfg.LogOutputs = []string{"stdout"}
+
+	pu, _ := url.Parse(tempurl.Alloc())
+	cfg.LPUrls = []url.URL{*pu}
+	cfg.APUrls = cfg.LPUrls
+	cu, _ := url.Parse(tempurl.Alloc())
+	cfg.LCUrls = []url.URL{*cu}
+	cfg.ACUrls = cfg.LCUrls
+
+	cfg.StrictReconfigCheck = false
+	cfg.InitialCluster = fmt.Sprintf("%s=%s", cfg.Name, &cfg.LPUrls[0])
+	cfg.ClusterState = embed.ClusterStateFlagNew
+	return cfg
+}

tests/client/client_test.go

@@ -91,7 +91,7 @@ func TestClientClusterIDCheck(t *testing.T) {
 		pd.SecurityOption{}, pd.WithMaxErrorRetry(1),
 	)
 	re.Error(err)
-	re.Contains(err.Error(), "ErrClientGetLeader")
+	re.Contains(err.Error(), "ErrClientGetMember")
 	re.NoError(failpoint.Disable("github.com/tikv/pd/client/skipFirstUpdateMember"))
 	re.NoError(failpoint.Disable("github.com/tikv/pd/client/skipClusterIDCheck"))
 }