contrib/raftexample: save snapshot to WAL first
Save the snapshot index to the WAL before saving the snapshot to the
filesystem. This ensures that we'll only ever call wal.Open with a
snapshot that was previously saved to the WAL.
@@ -107,9 +107,9 @@ func newRaftNode(id int, peers []string, join bool, getSnapshot func() ([]byte,
}
func (rc *raftNode) saveSnap(snap raftpb.Snapshot) error {
- if err := rc.snapshotter.SaveSnap(snap); err != nil {
- return err
- }
+ // must save the snapshot index to the WAL before saving the
+ // snapshot to maintain the invariant that we only Open the
+ // wal at previously-saved snapshot indexes.
walSnap := walpb.Snapshot{
Index: snap.Metadata.Index,
Term: snap.Metadata.Term,
@@ -117,6 +117,9 @@ func (rc *raftNode) saveSnap(snap raftpb.Snapshot) error {
if err := rc.wal.SaveSnapshot(walSnap); err != nil {
return err
}
+ if err := rc.snapshotter.SaveSnap(snap); err != nil {
+ return err
+ }
return rc.wal.ReleaseLockTo(snap.Metadata.Index)
}
