mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
127 lines
3.3 KiB
Go
127 lines
3.3 KiB
Go
// 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 raft snapshot
|
|
// snapshotStore will receive from the chan immediately after it sends empty to reqsnapc
|
|
raftsnapc chan raftpb.Snapshot
|
|
|
|
snap *snapshot
|
|
}
|
|
|
|
func newSnapshotStore(dir string, kv dstorage.KV) *snapshotStore {
|
|
return &snapshotStore{
|
|
dir: dir,
|
|
kv: kv,
|
|
reqsnapc: make(chan struct{}),
|
|
raftsnapc: 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.raftsnapc
|
|
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")
|
|
}
|