Add a method to export membership info to v2 store from RaftCluster

Signed-off-by: Geeta Gharpure <geetagh@amazon.com>

etcdutl/etcdutl/backup_command.go

@@ -28,9 +28,9 @@ import (
 	"go.etcd.io/etcd/client/pkg/v3/types"
 	"go.etcd.io/etcd/pkg/v3/idutil"
 	"go.etcd.io/etcd/pkg/v3/pbutil"
+	"go.etcd.io/etcd/server/v3/etcdserver"
 	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
 	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
-	"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
 	"go.etcd.io/etcd/server/v3/storage/backend"
 	"go.etcd.io/etcd/server/v3/storage/datadir"
 	"go.etcd.io/etcd/server/v3/storage/schema"
@@ -178,21 +178,10 @@ func saveSnap(lg *zap.Logger, destSnap, srcSnap string, desired *desiredCluster)
 // mustTranslateV2store processes storeData such that they match 'desiredCluster'.
 // In particular the method overrides membership information.
 func mustTranslateV2store(lg *zap.Logger, storeData []byte, desired *desiredCluster) []byte {
-	st := v2store.New()
-	if err := st.Recovery(storeData); err != nil {
-		lg.Panic("cannot translate v2store", zap.Error(err))
-	}
-
 	raftCluster := membership.NewClusterFromMembers(lg, desired.clusterId, desired.members)
 	raftCluster.SetID(desired.nodeId, desired.clusterId)
-	raftCluster.SetStore(st)
-	raftCluster.PushMembershipToStorage()
-
-	outputData, err := st.Save()
-	if err != nil {
-		lg.Panic("cannot save v2store", zap.Error(err))
-	}
-	return outputData
+	d := etcdserver.GetMembershipInfoInV2Format(lg, raftCluster)
+	return d
 }
 
 func translateWAL(lg *zap.Logger, srcWAL string, walsnap walpb.Snapshot) (etcdserverpb.Metadata, raftpb.HardState, []raftpb.Entry) {

server/etcdserver/api/membership/cluster.go

@@ -854,3 +854,26 @@ func ValidateMaxLearnerConfig(maxLearners int, members []*Member, scaleUpLearner
 
 	return nil
 }
+
+func (c *RaftCluster) Store(store v2store.Store) {
+	c.Lock()
+	defer c.Unlock()
+	for _, m := range c.members {
+		mustSaveMemberToStore(c.lg, store, m)
+		if m.ClientURLs != nil {
+			mustUpdateMemberAttrInStore(c.lg, store, m)
+		}
+		c.lg.Info(
+			"snapshot storing member",
+			zap.String("id", m.ID.String()),
+			zap.Strings("peer-urls", m.PeerURLs),
+			zap.Bool("is-learner", m.IsLearner),
+		)
+	}
+	for id, _ := range c.removed {
+		mustDeleteMemberFromStore(c.lg, store, id)
+	}
+	if c.version != nil {
+		mustSaveClusterVersionToStore(c.lg, store, c.version)
+	}
+}

server/etcdserver/api/membership/cluster_test.go

@@ -21,6 +21,7 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
 	"go.uber.org/zap/zaptest"
 
 	"go.etcd.io/etcd/client/pkg/v3/testutil"
@@ -975,3 +976,29 @@ func TestIsReadyToPromoteMember(t *testing.T) {
 		}
 	}
 }
+
+func TestClusterStore(t *testing.T) {
+	name := "etcd"
+	clientURLs := []string{"http://127.0.0.1:4001"}
+	tests := []struct {
+		mems    []*Member
+		removed map[types.ID]bool
+	}{
+		{
+			[]*Member{
+				newTestMember(1, nil, name, clientURLs),
+			},
+			map[types.ID]bool{types.ID(2): true},
+		},
+	}
+	for _, tt := range tests {
+		c := newTestCluster(t, tt.mems)
+		c.removed = tt.removed
+
+		st := v2store.New("/0", "/1")
+		c.Store(st)
+		mst, rst := membersFromStore(c.lg, st)
+		assert.Equal(t, mst[types.ID(1)], tt.mems[0])
+		assert.Equal(t, rst, tt.removed)
+	}
+}

server/etcdserver/api/membership/storev2.go

@@ -94,7 +94,7 @@ func mustSaveMemberToStore(lg *zap.Logger, s v2store.Store, m *Member) {
 }
 
 func mustDeleteMemberFromStore(lg *zap.Logger, s v2store.Store, id types.ID) {
-	if _, err := s.Delete(MemberStoreKey(id), true, true); err != nil {
+	if _, err := s.Delete(MemberStoreKey(id), true, true); err != nil && !isKeyNotFound(err) {
 		lg.Panic(
 			"failed to delete member from store",
 			zap.String("path", MemberStoreKey(id)),

server/etcdserver/cluster_util.go

@@ -28,6 +28,7 @@ import (
 	"go.etcd.io/etcd/api/v3/version"
 	"go.etcd.io/etcd/client/pkg/v3/types"
 	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
 	"go.etcd.io/etcd/server/v3/etcdserver/errors"
 
 	"github.com/coreos/go-semver/semver"
@@ -416,3 +417,14 @@ func convertToClusterVersion(v string) (*semver.Version, error) {
 	ver = &semver.Version{Major: ver.Major, Minor: ver.Minor}
 	return ver, nil
 }
+
+func GetMembershipInfoInV2Format(lg *zap.Logger, cl *membership.RaftCluster) []byte {
+	var st v2store.Store
+	st = v2store.New(StoreClusterPrefix, StoreKeysPrefix)
+	cl.Store(st)
+	d, err := st.SaveNoCopy()
+	if err != nil {
+		lg.Panic("failed to save v2 store", zap.Error(err))
+	}
+	return d
+}