diff --git a/vendor/go.etcd.io/etcd/etcdserver/api/snap/snapshotter.go b/vendor/go.etcd.io/etcd/etcdserver/api/snap/snapshotter.go
new file mode 100644
index 0000000..7e79333
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/etcdserver/api/snap/snapshotter.go
@@ -0,0 +1,255 @@
+// Copyright 2015 The etcd 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 snap
+
+import (
+	"errors"
+	"fmt"
+	"hash/crc32"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+
+	"go.etcd.io/etcd/etcdserver/api/snap/snappb"
+	pioutil "go.etcd.io/etcd/pkg/ioutil"
+	"go.etcd.io/etcd/pkg/pbutil"
+	"go.etcd.io/etcd/raft"
+	"go.etcd.io/etcd/raft/raftpb"
+
+	"github.com/coreos/pkg/capnslog"
+	"go.uber.org/zap"
+)
+
+const snapSuffix = ".snap"
+
+var (
+	plog = capnslog.NewPackageLogger("go.etcd.io/etcd/v3", "snap")
+
+	ErrNoSnapshot    = errors.New("snap: no available snapshot")
+	ErrEmptySnapshot = errors.New("snap: empty snapshot")
+	ErrCRCMismatch   = errors.New("snap: crc mismatch")
+	crcTable         = crc32.MakeTable(crc32.Castagnoli)
+
+	// A map of valid files that can be present in the snap folder.
+	validFiles = map[string]bool{
+		"db": true,
+	}
+)
+
+type Snapshotter struct {
+	lg  *zap.Logger
+	dir string
+}
+
+func New(lg *zap.Logger, dir string) *Snapshotter {
+	return &Snapshotter{
+		lg:  lg,
+		dir: dir,
+	}
+}
+
+func (s *Snapshotter) SaveSnap(snapshot raftpb.Snapshot) error {
+	if raft.IsEmptySnap(snapshot) {
+		return nil
+	}
+	return s.save(&snapshot)
+}
+
+func (s *Snapshotter) save(snapshot *raftpb.Snapshot) error {
+	start := time.Now()
+
+	fname := fmt.Sprintf("%016x-%016x%s", snapshot.Metadata.Term, snapshot.Metadata.Index, snapSuffix)
+	b := pbutil.MustMarshal(snapshot)
+	crc := crc32.Update(0, crcTable, b)
+	snap := snappb.Snapshot{Crc: crc, Data: b}
+	d, err := snap.Marshal()
+	if err != nil {
+		return err
+	}
+	snapMarshallingSec.Observe(time.Since(start).Seconds())
+
+	spath := filepath.Join(s.dir, fname)
+
+	fsyncStart := time.Now()
+	err = pioutil.WriteAndSyncFile(spath, d, 0666)
+	snapFsyncSec.Observe(time.Since(fsyncStart).Seconds())
+
+	if err != nil {
+		if s.lg != nil {
+			s.lg.Warn("failed to write a snap file", zap.String("path", spath), zap.Error(err))
+		}
+		rerr := os.Remove(spath)
+		if rerr != nil {
+			if s.lg != nil {
+				s.lg.Warn("failed to remove a broken snap file", zap.String("path", spath), zap.Error(err))
+			} else {
+				plog.Errorf("failed to remove broken snapshot file %s", spath)
+			}
+		}
+		return err
+	}
+
+	snapSaveSec.Observe(time.Since(start).Seconds())
+	return nil
+}
+
+func (s *Snapshotter) Load() (*raftpb.Snapshot, error) {
+	names, err := s.snapNames()
+	if err != nil {
+		return nil, err
+	}
+	var snap *raftpb.Snapshot
+	for _, name := range names {
+		if snap, err = loadSnap(s.lg, s.dir, name); err == nil {
+			break
+		}
+	}
+	if err != nil {
+		return nil, ErrNoSnapshot
+	}
+	return snap, nil
+}
+
+func loadSnap(lg *zap.Logger, dir, name string) (*raftpb.Snapshot, error) {
+	fpath := filepath.Join(dir, name)
+	snap, err := Read(lg, fpath)
+	if err != nil {
+		brokenPath := fpath + ".broken"
+		if lg != nil {
+			lg.Warn("failed to read a snap file", zap.String("path", fpath), zap.Error(err))
+		}
+		if rerr := os.Rename(fpath, brokenPath); rerr != nil {
+			if lg != nil {
+				lg.Warn("failed to rename a broken snap file", zap.String("path", fpath), zap.String("broken-path", brokenPath), zap.Error(rerr))
+			} else {
+				plog.Warningf("cannot rename broken snapshot file %v to %v: %v", fpath, brokenPath, rerr)
+			}
+		} else {
+			if lg != nil {
+				lg.Warn("renamed to a broken snap file", zap.String("path", fpath), zap.String("broken-path", brokenPath))
+			}
+		}
+	}
+	return snap, err
+}
+
+// Read reads the snapshot named by snapname and returns the snapshot.
+func Read(lg *zap.Logger, snapname string) (*raftpb.Snapshot, error) {
+	b, err := ioutil.ReadFile(snapname)
+	if err != nil {
+		if lg != nil {
+			lg.Warn("failed to read a snap file", zap.String("path", snapname), zap.Error(err))
+		} else {
+			plog.Errorf("cannot read file %v: %v", snapname, err)
+		}
+		return nil, err
+	}
+
+	if len(b) == 0 {
+		if lg != nil {
+			lg.Warn("failed to read empty snapshot file", zap.String("path", snapname))
+		} else {
+			plog.Errorf("unexpected empty snapshot")
+		}
+		return nil, ErrEmptySnapshot
+	}
+
+	var serializedSnap snappb.Snapshot
+	if err = serializedSnap.Unmarshal(b); err != nil {
+		if lg != nil {
+			lg.Warn("failed to unmarshal snappb.Snapshot", zap.String("path", snapname), zap.Error(err))
+		} else {
+			plog.Errorf("corrupted snapshot file %v: %v", snapname, err)
+		}
+		return nil, err
+	}
+
+	if len(serializedSnap.Data) == 0 || serializedSnap.Crc == 0 {
+		if lg != nil {
+			lg.Warn("failed to read empty snapshot data", zap.String("path", snapname))
+		} else {
+			plog.Errorf("unexpected empty snapshot")
+		}
+		return nil, ErrEmptySnapshot
+	}
+
+	crc := crc32.Update(0, crcTable, serializedSnap.Data)
+	if crc != serializedSnap.Crc {
+		if lg != nil {
+			lg.Warn("snap file is corrupt",
+				zap.String("path", snapname),
+				zap.Uint32("prev-crc", serializedSnap.Crc),
+				zap.Uint32("new-crc", crc),
+			)
+		} else {
+			plog.Errorf("corrupted snapshot file %v: crc mismatch", snapname)
+		}
+		return nil, ErrCRCMismatch
+	}
+
+	var snap raftpb.Snapshot
+	if err = snap.Unmarshal(serializedSnap.Data); err != nil {
+		if lg != nil {
+			lg.Warn("failed to unmarshal raftpb.Snapshot", zap.String("path", snapname), zap.Error(err))
+		} else {
+			plog.Errorf("corrupted snapshot file %v: %v", snapname, err)
+		}
+		return nil, err
+	}
+	return &snap, nil
+}
+
+// snapNames returns the filename of the snapshots in logical time order (from newest to oldest).
+// If there is no available snapshots, an ErrNoSnapshot will be returned.
+func (s *Snapshotter) snapNames() ([]string, error) {
+	dir, err := os.Open(s.dir)
+	if err != nil {
+		return nil, err
+	}
+	defer dir.Close()
+	names, err := dir.Readdirnames(-1)
+	if err != nil {
+		return nil, err
+	}
+	snaps := checkSuffix(s.lg, names)
+	if len(snaps) == 0 {
+		return nil, ErrNoSnapshot
+	}
+	sort.Sort(sort.Reverse(sort.StringSlice(snaps)))
+	return snaps, nil
+}
+
+func checkSuffix(lg *zap.Logger, names []string) []string {
+	snaps := []string{}
+	for i := range names {
+		if strings.HasSuffix(names[i], snapSuffix) {
+			snaps = append(snaps, names[i])
+		} else {
+			// If we find a file which is not a snapshot then check if it's
+			// a vaild file. If not throw out a warning.
+			if _, ok := validFiles[names[i]]; !ok {
+				if lg != nil {
+					lg.Warn("found unexpected non-snap file; skipping", zap.String("path", names[i]))
+				} else {
+					plog.Warningf("skipped unexpected non snapshot file %v", names[i])
+				}
+			}
+		}
+	}
+	return snaps
+}