1// Copyright 2015 The etcd Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package etcdserver
16
17import (
18	"io"
19
20	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
21	"github.com/coreos/etcd/pkg/pbutil"
22	"github.com/coreos/etcd/pkg/types"
23	"github.com/coreos/etcd/raft/raftpb"
24	"github.com/coreos/etcd/snap"
25	"github.com/coreos/etcd/wal"
26	"github.com/coreos/etcd/wal/walpb"
27)
28
29type Storage interface {
30	// Save function saves ents and state to the underlying stable storage.
31	// Save MUST block until st and ents are on stable storage.
32	Save(st raftpb.HardState, ents []raftpb.Entry) error
33	// SaveSnap function saves snapshot to the underlying stable storage.
34	SaveSnap(snap raftpb.Snapshot) error
35	// Close closes the Storage and performs finalization.
36	Close() error
37}
38
39type storage struct {
40	*wal.WAL
41	*snap.Snapshotter
42}
43
44func NewStorage(w *wal.WAL, s *snap.Snapshotter) Storage {
45	return &storage{w, s}
46}
47
48// SaveSnap saves the snapshot to disk and release the locked
49// wal files since they will not be used.
50func (st *storage) SaveSnap(snap raftpb.Snapshot) error {
51	walsnap := walpb.Snapshot{
52		Index: snap.Metadata.Index,
53		Term:  snap.Metadata.Term,
54	}
55	err := st.WAL.SaveSnapshot(walsnap)
56	if err != nil {
57		return err
58	}
59	err = st.Snapshotter.SaveSnap(snap)
60	if err != nil {
61		return err
62	}
63	return st.WAL.ReleaseLockTo(snap.Metadata.Index)
64}
65
66func readWAL(waldir string, snap walpb.Snapshot) (w *wal.WAL, id, cid types.ID, st raftpb.HardState, ents []raftpb.Entry) {
67	var (
68		err       error
69		wmetadata []byte
70	)
71
72	repaired := false
73	for {
74		if w, err = wal.Open(waldir, snap); err != nil {
75			plog.Fatalf("open wal error: %v", err)
76		}
77		if wmetadata, st, ents, err = w.ReadAll(); err != nil {
78			w.Close()
79			// we can only repair ErrUnexpectedEOF and we never repair twice.
80			if repaired || err != io.ErrUnexpectedEOF {
81				plog.Fatalf("read wal error (%v) and cannot be repaired", err)
82			}
83			if !wal.Repair(waldir) {
84				plog.Fatalf("WAL error (%v) cannot be repaired", err)
85			} else {
86				plog.Infof("repaired WAL error (%v)", err)
87				repaired = true
88			}
89			continue
90		}
91		break
92	}
93	var metadata pb.Metadata
94	pbutil.MustUnmarshal(&metadata, wmetadata)
95	id = types.ID(metadata.NodeID)
96	cid = types.ID(metadata.ClusterID)
97	return w, id, cid, st, ents
98}
99