// snapshot should snapshot the store and cut the persistent
func TestSnapshot(t *testing.T) {
	be, tmpPath := backend.NewDefaultTmpBackend()
	defer func() {
		os.RemoveAll(tmpPath)
	}()

	s := raft.NewMemoryStorage()
	s.Append([]raftpb.Entry{{Index: 1}})
	st := mockstore.NewRecorderStream()
	p := mockstorage.NewStorageRecorderStream("")
	srv := &EtcdServer{
		Cfg: &ServerConfig{},
		r: raftNode{
			Node:        newNodeNop(),
			raftStorage: s,
			storage:     p,
		},
		store: st,
	}
	srv.kv = mvcc.New(be, &lease.FakeLessor{}, &srv.consistIndex)
	srv.be = be

	ch := make(chan struct{}, 2)

	go func() {
		gaction, _ := p.Wait(1)
		defer func() { ch <- struct{}{} }()

		if len(gaction) != 1 {
			t.Fatalf("len(action) = %d, want 1", len(gaction))
		}
		if !reflect.DeepEqual(gaction[0], testutil.Action{Name: "SaveSnap"}) {
			t.Errorf("action = %s, want SaveSnap", gaction[0])
		}
	}()

	go func() {
		gaction, _ := st.Wait(2)
		defer func() { ch <- struct{}{} }()

		if len(gaction) != 2 {
			t.Fatalf("len(action) = %d, want 2", len(gaction))
		}
		if !reflect.DeepEqual(gaction[0], testutil.Action{Name: "Clone"}) {
			t.Errorf("action = %s, want Clone", gaction[0])
		}
		if !reflect.DeepEqual(gaction[1], testutil.Action{Name: "SaveNoCopy"}) {
			t.Errorf("action = %s, want SaveNoCopy", gaction[1])
		}
	}()

	srv.snapshot(1, raftpb.ConfState{Nodes: []uint64{1}})
	<-ch
	<-ch
}

// Applied > SnapCount should trigger a SaveSnap event
func TestTriggerSnap(t *testing.T) {
	be, tmpPath := backend.NewDefaultTmpBackend()
	defer func() {
		os.RemoveAll(tmpPath)
	}()

	snapc := 10
	st := mockstore.NewRecorder()
	p := mockstorage.NewStorageRecorderStream("")
	srv := &EtcdServer{
		cfg:       &ServerConfig{TickMs: 1},
		snapCount: uint64(snapc),
		r: raftNode{
			Node:        newNodeCommitter(),
			raftStorage: raft.NewMemoryStorage(),
			storage:     p,
			transport:   rafthttp.NewNopTransporter(),
		},
		store:    st,
		reqIDGen: idutil.NewGenerator(0, time.Time{}),
	}
	srv.applyV2 = &applierV2store{srv}

	srv.kv = mvcc.New(be, &lease.FakeLessor{}, &srv.consistIndex)
	srv.be = be

	srv.start()

	donec := make(chan struct{})
	go func() {
		wcnt := 2 + snapc
		gaction, _ := p.Wait(wcnt)

		// each operation is recorded as a Save
		// (SnapCount+1) * Puts + SaveSnap = (SnapCount+1) * Save + SaveSnap
		if len(gaction) != wcnt {
			t.Fatalf("len(action) = %d, want %d", len(gaction), wcnt)
		}
		if !reflect.DeepEqual(gaction[wcnt-1], testutil.Action{Name: "SaveSnap"}) {
			t.Errorf("action = %s, want SaveSnap", gaction[wcnt-1])
		}
		close(donec)
	}()

	for i := 0; i < snapc+1; i++ {
		srv.Do(context.Background(), pb.Request{Method: "PUT"})
	}

	srv.Stop()
	<-donec
}

func newEtcdStore(
	proposalc chan<- []byte,
	snapshotc <-chan raftpb.Snapshot,
	entryc <-chan raftpb.Entry,
	confentryc chan<- raftpb.Entry,
	logger mesh.Logger,
) *etcdStore {
	// It would be much better if we could have a proper in-memory backend. Alas:
	// backend.Backend is tightly coupled to bolt.DB, and both are tightly coupled
	// to os.Open &c. So we'd need to fork both Bolt and backend. A task for
	// another day.
	f, err := ioutil.TempFile(os.TempDir(), "mesh_etcd_backend_")
	if err != nil {
		panic(err)
	}
	dbPath := f.Name()
	f.Close()
	logger.Printf("etcd store: using %s", dbPath)

	b := backend.NewDefaultBackend(dbPath)
	lessor := lease.NewLessor(b)
	index := &consistentIndex{0}
	kv := mvcc.New(b, lessor, index)

	s := &etcdStore{
		proposalc:   proposalc,
		snapshotc:   snapshotc,
		entryc:      entryc,
		confentryc:  confentryc,
		actionc:     make(chan func()),
		quitc:       make(chan struct{}),
		terminatedc: make(chan struct{}),
		logger:      logger,

		dbPath: dbPath,
		kv:     kv,
		lessor: lessor,
		index:  index,

		idgen:   makeIDGen(),
		pending: map[uint64]responseChans{},
	}
	go s.loop()
	return s
}

// NewServer creates a new EtcdServer from the supplied configuration. The
// configuration is considered static for the lifetime of the EtcdServer.
func NewServer(cfg *ServerConfig) (srv *EtcdServer, err error) {
	st := store.New(StoreClusterPrefix, StoreKeysPrefix)

	var (
		w  *wal.WAL
		n  raft.Node
		s  *raft.MemoryStorage
		id types.ID
		cl *membership.RaftCluster
	)

	if terr := fileutil.TouchDirAll(cfg.DataDir); terr != nil {
		return nil, fmt.Errorf("cannot access data directory: %v", terr)
	}

	// Run the migrations.
	dataVer, err := version.DetectDataDir(cfg.DataDir)
	if err != nil {
		return nil, err
	}
	if err = upgradeDataDir(cfg.DataDir, cfg.Name, dataVer); err != nil {
		return nil, err
	}

	haveWAL := wal.Exist(cfg.WALDir())

	if err = os.MkdirAll(cfg.SnapDir(), privateDirMode); err != nil && !os.IsExist(err) {
		plog.Fatalf("create snapshot directory error: %v", err)
	}
	ss := snap.New(cfg.SnapDir())
	be := backend.NewDefaultBackend(path.Join(cfg.SnapDir(), databaseFilename))
	defer func() {
		if err != nil {
			be.Close()
		}
	}()

	prt, err := rafthttp.NewRoundTripper(cfg.PeerTLSInfo, cfg.peerDialTimeout())
	if err != nil {
		return nil, err
	}
	var remotes []*membership.Member
	switch {
	case !haveWAL && !cfg.NewCluster:
		if err = cfg.VerifyJoinExisting(); err != nil {
			return nil, err
		}
		cl, err = membership.NewClusterFromURLsMap(cfg.InitialClusterToken, cfg.InitialPeerURLsMap)
		if err != nil {
			return nil, err
		}
		existingCluster, gerr := GetClusterFromRemotePeers(getRemotePeerURLs(cl, cfg.Name), prt)
		if gerr != nil {
			return nil, fmt.Errorf("cannot fetch cluster info from peer urls: %v", gerr)
		}
		if err = membership.ValidateClusterAndAssignIDs(cl, existingCluster); err != nil {
			return nil, fmt.Errorf("error validating peerURLs %s: %v", existingCluster, err)
		}
		if !isCompatibleWithCluster(cl, cl.MemberByName(cfg.Name).ID, prt) {
			return nil, fmt.Errorf("incomptible with current running cluster")
		}

		remotes = existingCluster.Members()
		cl.SetID(existingCluster.ID())
		cl.SetStore(st)
		cl.SetBackend(be)
		cfg.Print()
		id, n, s, w = startNode(cfg, cl, nil)
	case !haveWAL && cfg.NewCluster:
		if err = cfg.VerifyBootstrap(); err != nil {
			return nil, err
		}
		cl, err = membership.NewClusterFromURLsMap(cfg.InitialClusterToken, cfg.InitialPeerURLsMap)
		if err != nil {
			return nil, err
		}
		m := cl.MemberByName(cfg.Name)
		if isMemberBootstrapped(cl, cfg.Name, prt, cfg.bootstrapTimeout()) {
			return nil, fmt.Errorf("member %s has already been bootstrapped", m.ID)
		}
		if cfg.ShouldDiscover() {
			var str string
			str, err = discovery.JoinCluster(cfg.DiscoveryURL, cfg.DiscoveryProxy, m.ID, cfg.InitialPeerURLsMap.String())
			if err != nil {
				return nil, &DiscoveryError{Op: "join", Err: err}
			}
			var urlsmap types.URLsMap
			urlsmap, err = types.NewURLsMap(str)
			if err != nil {
				return nil, err
			}
			if checkDuplicateURL(urlsmap) {
				return nil, fmt.Errorf("discovery cluster %s has duplicate url", urlsmap)
			}
			if cl, err = membership.NewClusterFromURLsMap(cfg.InitialClusterToken, urlsmap); err != nil {
				return nil, err
			}
		}
//.........这里部分代码省略.........

// NewServer creates a new EtcdServer from the supplied configuration. The
// configuration is considered static for the lifetime of the EtcdServer.
func NewServer(cfg *ServerConfig) (srv *EtcdServer, err error) {
	st := store.New(StoreClusterPrefix, StoreKeysPrefix)

	var (
		w  *wal.WAL
		n  raft.Node
		s  *raft.MemoryStorage
		id types.ID
		cl *membership.RaftCluster
	)

	if terr := fileutil.TouchDirAll(cfg.DataDir); terr != nil {
		return nil, fmt.Errorf("cannot access data directory: %v", terr)
	}

	haveWAL := wal.Exist(cfg.WALDir())

	if err = fileutil.TouchDirAll(cfg.SnapDir()); err != nil {
		plog.Fatalf("create snapshot directory error: %v", err)
	}
	ss := snap.New(cfg.SnapDir())

	bepath := path.Join(cfg.SnapDir(), databaseFilename)
	beExist := fileutil.Exist(bepath)

	var be backend.Backend
	beOpened := make(chan struct{})
	go func() {
		be = backend.NewDefaultBackend(bepath)
		beOpened <- struct{}{}
	}()

	select {
	case <-beOpened:
	case <-time.After(time.Second):
		plog.Warningf("another etcd process is running with the same data dir and holding the file lock.")
		plog.Warningf("waiting for it to exit before starting...")
		<-beOpened
	}

	defer func() {
		if err != nil {
			be.Close()
		}
	}()

	prt, err := rafthttp.NewRoundTripper(cfg.PeerTLSInfo, cfg.peerDialTimeout())
	if err != nil {
		return nil, err
	}
	var (
		remotes  []*membership.Member
		snapshot *raftpb.Snapshot
	)

	switch {
	case !haveWAL && !cfg.NewCluster:
		if err = cfg.VerifyJoinExisting(); err != nil {
			return nil, err
		}
		cl, err = membership.NewClusterFromURLsMap(cfg.InitialClusterToken, cfg.InitialPeerURLsMap)
		if err != nil {
			return nil, err
		}
		existingCluster, gerr := GetClusterFromRemotePeers(getRemotePeerURLs(cl, cfg.Name), prt)
		if gerr != nil {
			return nil, fmt.Errorf("cannot fetch cluster info from peer urls: %v", gerr)
		}
		if err = membership.ValidateClusterAndAssignIDs(cl, existingCluster); err != nil {
			return nil, fmt.Errorf("error validating peerURLs %s: %v", existingCluster, err)
		}
		if !isCompatibleWithCluster(cl, cl.MemberByName(cfg.Name).ID, prt) {
			return nil, fmt.Errorf("incompatible with current running cluster")
		}

		remotes = existingCluster.Members()
		cl.SetID(existingCluster.ID())
		cl.SetStore(st)
		cl.SetBackend(be)
		cfg.Print()
		id, n, s, w = startNode(cfg, cl, nil)
	case !haveWAL && cfg.NewCluster:
		if err = cfg.VerifyBootstrap(); err != nil {
			return nil, err
		}
		cl, err = membership.NewClusterFromURLsMap(cfg.InitialClusterToken, cfg.InitialPeerURLsMap)
		if err != nil {
			return nil, err
		}
		m := cl.MemberByName(cfg.Name)
		if isMemberBootstrapped(cl, cfg.Name, prt, cfg.bootstrapTimeout()) {
			return nil, fmt.Errorf("member %s has already been bootstrapped", m.ID)
		}
		if cfg.ShouldDiscover() {
			var str string
			str, err = discovery.JoinCluster(cfg.DiscoveryURL, cfg.DiscoveryProxy, m.ID, cfg.InitialPeerURLsMap.String())
			if err != nil {
				return nil, &DiscoveryError{Op: "join", Err: err}
//.........这里部分代码省略.........

// TestConcurrentApplyAndSnapshotV3 will send out snapshots concurrently with
// proposals.
func TestConcurrentApplyAndSnapshotV3(t *testing.T) {
	const (
		// snapshots that may queue up at once without dropping
		maxInFlightMsgSnap = 16
	)
	n := newNopReadyNode()
	st := store.New()
	cl := membership.NewCluster("abc")
	cl.SetStore(st)

	testdir, err := ioutil.TempDir(os.TempDir(), "testsnapdir")
	if err != nil {
		t.Fatalf("Couldn't open tempdir (%v)", err)
	}
	defer os.RemoveAll(testdir)
	if err := os.MkdirAll(testdir+"/member/snap", 0755); err != nil {
		t.Fatalf("Couldn't make snap dir (%v)", err)
	}

	rs := raft.NewMemoryStorage()
	tr, snapDoneC := rafthttp.NewSnapTransporter(testdir)
	s := &EtcdServer{
		cfg: &ServerConfig{
			DataDir: testdir,
		},
		r: raftNode{
			Node:        n,
			transport:   tr,
			storage:     mockstorage.NewStorageRecorder(testdir),
			raftStorage: rs,
		},
		store:    st,
		cluster:  cl,
		msgSnapC: make(chan raftpb.Message, maxInFlightMsgSnap),
	}
	s.applyV2 = &applierV2store{s}

	be, tmpPath := backend.NewDefaultTmpBackend()
	defer func() {
		os.RemoveAll(tmpPath)
	}()
	s.kv = mvcc.New(be, &lease.FakeLessor{}, &s.consistIndex)
	s.be = be

	s.start()
	defer s.Stop()

	// submit applied entries and snap entries
	idx := uint64(0)
	outdated := 0
	accepted := 0
	for k := 1; k <= 101; k++ {
		idx++
		ch := s.w.Register(uint64(idx))
		req := &pb.Request{Method: "QGET", ID: uint64(idx)}
		ent := raftpb.Entry{Index: uint64(idx), Data: pbutil.MustMarshal(req)}
		ready := raft.Ready{Entries: []raftpb.Entry{ent}}
		n.readyc <- ready

		ready = raft.Ready{CommittedEntries: []raftpb.Entry{ent}}
		n.readyc <- ready

		// "idx" applied
		<-ch

		// one snapshot for every two messages
		if k%2 != 0 {
			continue
		}

		n.readyc <- raft.Ready{Messages: []raftpb.Message{{Type: raftpb.MsgSnap}}}
		// get the snapshot sent by the transport
		snapMsg := <-snapDoneC
		// If the snapshot trails applied records, recovery will panic
		// since there's no allocated snapshot at the place of the
		// snapshot record. This only happens when the applier and the
		// snapshot sender get out of sync.
		if snapMsg.Snapshot.Metadata.Index == idx {
			idx++
			snapMsg.Snapshot.Metadata.Index = idx
			ready = raft.Ready{Snapshot: snapMsg.Snapshot}
			n.readyc <- ready
			accepted++
		} else {
			outdated++
		}
		// don't wait for the snapshot to complete, move to next message
	}
	if accepted != 50 {
		t.Errorf("accepted=%v, want 50", accepted)
	}
	if outdated != 0 {
		t.Errorf("outdated=%v, want 0", outdated)
	}
}