blob: 928aa95b6b1623f1701dece4bdf7b0abc8f6991e [file] [log] [blame]
// 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 etcdserver
import (
"io"
"github.com/coreos/etcd/mvcc/backend"
"github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/snap"
)
// createMergedSnapshotMessage creates a snapshot message that contains: raft status (term, conf),
// a snapshot of v2 store inside raft.Snapshot as []byte, a snapshot of v3 KV in the top level message
// as ReadCloser.
func (s *EtcdServer) createMergedSnapshotMessage(m raftpb.Message, snapt, snapi uint64, confState raftpb.ConfState) snap.Message {
// get a snapshot of v2 store as []byte
clone := s.store.Clone()
d, err := clone.SaveNoCopy()
if err != nil {
plog.Panicf("store save should never fail: %v", err)
}
// commit kv to write metadata(for example: consistent index).
s.KV().Commit()
dbsnap := s.be.Snapshot()
// get a snapshot of v3 KV as readCloser
rc := newSnapshotReaderCloser(dbsnap)
// put the []byte snapshot of store into raft snapshot and return the merged snapshot with
// KV readCloser snapshot.
snapshot := raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{
Index: snapi,
Term: snapt,
ConfState: confState,
},
Data: d,
}
m.Snapshot = snapshot
return *snap.NewMessage(m, rc, dbsnap.Size())
}
func newSnapshotReaderCloser(snapshot backend.Snapshot) io.ReadCloser {
pr, pw := io.Pipe()
go func() {
n, err := snapshot.WriteTo(pw)
if err == nil {
plog.Infof("wrote database snapshot out [total bytes: %d]", n)
} else {
plog.Warningf("failed to write database snapshot out [written bytes: %d]: %v", n, err)
}
pw.CloseWithError(err)
err = snapshot.Close()
if err != nil {
plog.Panicf("failed to close database snapshot: %v", err)
}
}()
return pr
}