|
|
@@ -0,0 +1,126 @@
|
|
|
+// Copyright 2015 CoreOS, Inc.
|
|
|
+//
|
|
|
+// 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 etcdserver
|
|
|
+
|
|
|
+import (
|
|
|
+ "fmt"
|
|
|
+ "io"
|
|
|
+ "io/ioutil"
|
|
|
+ "os"
|
|
|
+ "path"
|
|
|
+
|
|
|
+ "github.com/coreos/etcd/pkg/fileutil"
|
|
|
+ "github.com/coreos/etcd/raft"
|
|
|
+ "github.com/coreos/etcd/raft/raftpb"
|
|
|
+ dstorage "github.com/coreos/etcd/storage"
|
|
|
+)
|
|
|
+
|
|
|
+type snapshot struct {
|
|
|
+ r raftpb.Snapshot
|
|
|
+}
|
|
|
+
|
|
|
+func (s *snapshot) raft() raftpb.Snapshot { return s.r }
|
|
|
+
|
|
|
+func (s *snapshot) size() uint64 { return 0 }
|
|
|
+
|
|
|
+func (s *snapshot) writeTo(w io.Writer) (n int64, err error) { return 0, nil }
|
|
|
+
|
|
|
+func (s *snapshot) close() {}
|
|
|
+
|
|
|
+type snapshotStore struct {
|
|
|
+ // dir to save snapshot data
|
|
|
+ dir string
|
|
|
+ kv dstorage.KV
|
|
|
+
|
|
|
+ // send empty to reqsnapc to notify the channel receiver to send back latest
|
|
|
+ // snapshot to snapc
|
|
|
+ reqsnapc chan struct{}
|
|
|
+ // a chan to receive the requested snapshot
|
|
|
+ // snapshotStore will receive from the chan immediately after it sends empty to reqsnapc
|
|
|
+ snapc chan raftpb.Snapshot
|
|
|
+
|
|
|
+ snap *snapshot
|
|
|
+}
|
|
|
+
|
|
|
+func newSnapshotStore(dir string, kv dstorage.KV) *snapshotStore {
|
|
|
+ return &snapshotStore{
|
|
|
+ dir: dir,
|
|
|
+ kv: kv,
|
|
|
+ reqsnapc: make(chan struct{}),
|
|
|
+ snapc: make(chan raftpb.Snapshot),
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+// getSnap returns a snapshot.
|
|
|
+// If there is no available snapshot, ErrSnapshotTemporarilyUnavaliable will be returned.
|
|
|
+func (ss *snapshotStore) getSnap() (*snapshot, error) {
|
|
|
+ if ss.snap != nil {
|
|
|
+ return nil, raft.ErrSnapshotTemporarilyUnavailable
|
|
|
+ }
|
|
|
+
|
|
|
+ // ask to generate v2 snapshot
|
|
|
+ ss.reqsnapc <- struct{}{}
|
|
|
+ // TODO: generate v3 snapshot at here
|
|
|
+ raftsnap := <-ss.snapc
|
|
|
+ ss.snap = &snapshot{
|
|
|
+ r: raftsnap,
|
|
|
+ }
|
|
|
+ return ss.snap, nil
|
|
|
+}
|
|
|
+
|
|
|
+// saveSnap saves snapshot into disk.
|
|
|
+//
|
|
|
+// If snapshot has existed in disk, it keeps the original snapshot and returns error.
|
|
|
+// The function guarantees that it always saves either complete snapshot or no snapshot,
|
|
|
+// even if the call is aborted because program is hard killed.
|
|
|
+func (ss *snapshotStore) saveSnap(s *snapshot) error {
|
|
|
+ f, err := ioutil.TempFile(ss.dir, "tmp")
|
|
|
+ if err != nil {
|
|
|
+ return err
|
|
|
+ }
|
|
|
+ _, err = s.writeTo(f)
|
|
|
+ f.Close()
|
|
|
+ if err != nil {
|
|
|
+ os.Remove(f.Name())
|
|
|
+ return err
|
|
|
+ }
|
|
|
+ fn := path.Join(ss.dir, fmt.Sprintf("%016x.db", s.raft().Metadata.Index))
|
|
|
+ if fileutil.Exist(fn) {
|
|
|
+ os.Remove(f.Name())
|
|
|
+ return fmt.Errorf("snapshot to save has existed")
|
|
|
+ }
|
|
|
+ err = os.Rename(f.Name(), fn)
|
|
|
+ if err != nil {
|
|
|
+ os.Remove(f.Name())
|
|
|
+ return err
|
|
|
+ }
|
|
|
+ return nil
|
|
|
+}
|
|
|
+
|
|
|
+// getSnapFilePath returns the file path for the snapshot with given index.
|
|
|
+// If the snapshot does not exist, it returns error.
|
|
|
+func (ss *snapshotStore) getSnapFilePath(index uint64) (string, error) {
|
|
|
+ fns, err := fileutil.ReadDir(ss.dir)
|
|
|
+ if err != nil {
|
|
|
+ return "", err
|
|
|
+ }
|
|
|
+ wfn := fmt.Sprintf("%016x.db", index)
|
|
|
+ for _, fn := range fns {
|
|
|
+ if fn == wfn {
|
|
|
+ return path.Join(ss.dir, fn), nil
|
|
|
+ }
|
|
|
+ }
|
|
|
+ return "", fmt.Errorf("snapshot file doesn't exist")
|
|
|
+}
|
Yicheng Qin