| // 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" |
| |
| pb "github.com/coreos/etcd/etcdserver/etcdserverpb" |
| "github.com/coreos/etcd/pkg/pbutil" |
| "github.com/coreos/etcd/pkg/types" |
| "github.com/coreos/etcd/raft/raftpb" |
| "github.com/coreos/etcd/snap" |
| "github.com/coreos/etcd/wal" |
| "github.com/coreos/etcd/wal/walpb" |
| ) |
| |
| type Storage interface { |
| // Save function saves ents and state to the underlying stable storage. |
| // Save MUST block until st and ents are on stable storage. |
| Save(st raftpb.HardState, ents []raftpb.Entry) error |
| // SaveSnap function saves snapshot to the underlying stable storage. |
| SaveSnap(snap raftpb.Snapshot) error |
| // Close closes the Storage and performs finalization. |
| Close() error |
| // Release releases the locked wal files older than the provided snapshot. |
| Release(snap raftpb.Snapshot) error |
| // Sync WAL |
| Sync() error |
| } |
| |
| type storage struct { |
| *wal.WAL |
| *snap.Snapshotter |
| } |
| |
| func NewStorage(w *wal.WAL, s *snap.Snapshotter) Storage { |
| return &storage{w, s} |
| } |
| |
| // SaveSnap saves the snapshot file to disk and writes the WAL snapshot entry. |
| func (st *storage) SaveSnap(snap raftpb.Snapshot) error { |
| walsnap := walpb.Snapshot{ |
| Index: snap.Metadata.Index, |
| Term: snap.Metadata.Term, |
| } |
| |
| // save the snapshot file before writing the snapshot to the wal. |
| // This makes it possible for the snapshot file to become orphaned, but prevents |
| // a WAL snapshot entry from having no corresponding snapshot file. |
| err := st.Snapshotter.SaveSnap(snap) |
| if err != nil { |
| return err |
| } |
| |
| return st.WAL.SaveSnapshot(walsnap) |
| } |
| |
| // Release releases resources older than the given snap and are no longer needed: |
| // - releases the locks to the wal files that are older than the provided wal for the given snap. |
| // - deletes any .snap.db files that are older than the given snap. |
| func (st *storage) Release(snap raftpb.Snapshot) error { |
| if err := st.WAL.ReleaseLockTo(snap.Metadata.Index); err != nil { |
| return err |
| } |
| return st.Snapshotter.ReleaseSnapDBs(snap) |
| } |
| |
| func readWAL(waldir string, snap walpb.Snapshot) (w *wal.WAL, id, cid types.ID, st raftpb.HardState, ents []raftpb.Entry) { |
| var ( |
| err error |
| wmetadata []byte |
| ) |
| |
| repaired := false |
| for { |
| if w, err = wal.Open(waldir, snap); err != nil { |
| plog.Fatalf("open wal error: %v", err) |
| } |
| if wmetadata, st, ents, err = w.ReadAll(); err != nil { |
| w.Close() |
| // we can only repair ErrUnexpectedEOF and we never repair twice. |
| if repaired || err != io.ErrUnexpectedEOF { |
| plog.Fatalf("read wal error (%v) and cannot be repaired", err) |
| } |
| if !wal.Repair(waldir) { |
| plog.Fatalf("WAL error (%v) cannot be repaired", err) |
| } else { |
| plog.Infof("repaired WAL error (%v)", err) |
| repaired = true |
| } |
| continue |
| } |
| break |
| } |
| var metadata pb.Metadata |
| pbutil.MustUnmarshal(&metadata, wmetadata) |
| id = types.ID(metadata.NodeID) |
| cid = types.ID(metadata.ClusterID) |
| return w, id, cid, st, ents |
| } |