func snapshot(fsm raft.FSM, fss raft.SnapshotStore, numLogs uint64) error {
snapshot, err := fsm.Snapshot()
if err != nil {
return fmt.Errorf("Unexpected error in fsm.Snapshot(): %v", err)
}
robustsnap, ok := snapshot.(*robustSnapshot)
if !ok {
return fmt.Errorf("fsm.Snapshot() return value is not a robustSnapshot")
}
if robustsnap.lastIndex != numLogs {
return fmt.Errorf("snapshot does not retain the last message, got: %d, want: %d", robustsnap.lastIndex, numLogs)
}
sink, err := fss.Create(numLogs, 1, []byte{})
if err != nil {
return fmt.Errorf("fss.Create: %v", err)
}
if err := snapshot.Persist(sink); err != nil {
return fmt.Errorf("Unexpected error in snapshot.Persist(): %v", err)
}
sink.Close()
return nil
}
func restore(fsm raft.FSM, fss raft.SnapshotStore, numLogs uint64) error {
snapshots, err := fss.List()
if err != nil {
return fmt.Errorf("fss.List(): %v", err)
}
// snapshots[0] is the most recent snapshot
snapshotId := snapshots[0].ID
_, readcloser, err := fss.Open(snapshotId)
if err != nil {
return fmt.Errorf("fss.Open(%s): %v", snapshotId, err)
}
if err := fsm.Restore(readcloser); err != nil {
return fmt.Errorf("fsm.Restore(): %v", err)
}
first, _ := fsm.(*FSM).ircstore.FirstIndex()
last, _ := fsm.(*FSM).ircstore.LastIndex()
if last-first >= numLogs {
return fmt.Errorf("Compaction did not decrease log size. got: %d, want: < %d", last-first, numLogs)
}
return nil
}