Golang HardState.Commit方法代碼示例

// InitialState implements the raft.Storage interface.
func (r *Range) InitialState() (raftpb.HardState, raftpb.ConfState, error) {
	var hs raftpb.HardState
	found, err := engine.MVCCGetProto(r.rm.Engine(), keys.RaftHardStateKey(r.Desc().RaftID),
		proto.ZeroTimestamp, true, nil, &hs)
	if err != nil {
		return raftpb.HardState{}, raftpb.ConfState{}, err
	}
	if !found {
		// We don't have a saved HardState, so set up the defaults.
		if r.isInitialized() {
			// Set the initial log term.
			hs.Term = raftInitialLogTerm
			hs.Commit = raftInitialLogIndex

			atomic.StoreUint64(&r.lastIndex, raftInitialLogIndex)
		} else {
			// This is a new range we are receiving from another node. Start
			// from zero so we will receive a snapshot.
			atomic.StoreUint64(&r.lastIndex, 0)
		}
	}

	var cs raftpb.ConfState
	// For uninitalized ranges, membership is unknown at this point.
	if found || r.isInitialized() {
		for _, rep := range r.Desc().Replicas {
			cs.Nodes = append(cs.Nodes, uint64(proto.MakeRaftNodeID(rep.NodeID, rep.StoreID)))
		}
	}

	return hs, cs, nil
}

func updateHardState(eng engine.ReadWriter, s storagebase.ReplicaState) error {
	// Load a potentially existing HardState as we may need to preserve
	// information about cast votes. For example, during a Split for which
	// another node's new right-hand side has contacted us before our left-hand
	// side called in here to create the group.
	rangeID := s.Desc.RangeID
	oldHS, err := loadHardState(eng, rangeID)
	if err != nil {
		return err
	}

	newHS := raftpb.HardState{
		Term:   s.TruncatedState.Term,
		Commit: s.RaftAppliedIndex,
	}

	if !raft.IsEmptyHardState(oldHS) {
		if oldHS.Commit > newHS.Commit {
			newHS.Commit = oldHS.Commit
		}
		if oldHS.Term > newHS.Term {
			newHS.Term = oldHS.Term
		}
		newHS.Vote = oldHS.Vote
	}

	return setHardState(eng, rangeID, newHS)
}

// writeInitialState bootstraps a new Raft group (i.e. it is called when we
// bootstrap a Range, or when setting up the right hand side of a split).
// Its main task is to persist a consistent Raft (and associated Replica) state
// which does not start from zero but presupposes a few entries already having
// applied.
// The supplied MVCCStats are used for the Stats field after adjusting for
// persisting the state itself, and the updated stats are returned.
func writeInitialState(
	eng engine.ReadWriter, ms enginepb.MVCCStats, desc roachpb.RangeDescriptor,
) (enginepb.MVCCStats, error) {
	rangeID := desc.RangeID
	var s storagebase.ReplicaState

	s.TruncatedState = &roachpb.RaftTruncatedState{
		Term:  raftInitialLogTerm,
		Index: raftInitialLogIndex,
	}
	s.RaftAppliedIndex = s.TruncatedState.Index
	s.Desc = &roachpb.RangeDescriptor{
		RangeID: rangeID,
	}
	s.Stats = ms

	newMS, err := saveState(eng, s)
	if err != nil {
		return enginepb.MVCCStats{}, err
	}

	// Load a potentially existing HardState as we may need to preserve
	// information about cast votes. For example, during a Split for which
	// another node's new right-hand side has contacted us before our left-hand
	// side called in here to create the group.
	oldHS, err := loadHardState(eng, rangeID)
	if err != nil {
		return enginepb.MVCCStats{}, err
	}

	newHS := raftpb.HardState{
		Term:   s.TruncatedState.Term,
		Commit: s.TruncatedState.Index,
	}

	if !raft.IsEmptyHardState(oldHS) {
		if oldHS.Commit > newHS.Commit {
			newHS.Commit = oldHS.Commit
		}
		if oldHS.Term > newHS.Term {
			newHS.Term = oldHS.Term
		}
		newHS.Vote = oldHS.Vote
	}

	if err := setHardState(eng, rangeID, newHS); err != nil {
		return enginepb.MVCCStats{}, err
	}

	if err := setLastIndex(eng, rangeID, s.TruncatedState.Index); err != nil {
		return enginepb.MVCCStats{}, err
	}

	return newMS, nil
}

// InitialState implements the raft.Storage interface.
func (r *Replica) InitialState() (raftpb.HardState, raftpb.ConfState, error) {
	var hs raftpb.HardState
	desc := r.Desc()
	found, err := engine.MVCCGetProto(r.store.Engine(), keys.RaftHardStateKey(desc.RangeID),
		roachpb.ZeroTimestamp, true, nil, &hs)
	if err != nil {
		return raftpb.HardState{}, raftpb.ConfState{}, err
	}
	initialized := r.isInitialized()
	if !found {
		// We don't have a saved HardState, so set up the defaults.
		if initialized {
			// Set the initial log term.
			hs.Term = raftInitialLogTerm
			hs.Commit = raftInitialLogIndex

			atomic.StoreUint64(&r.lastIndex, raftInitialLogIndex)
		} else {
			// This is a new range we are receiving from another node. Start
			// from zero so we will receive a snapshot.
			atomic.StoreUint64(&r.lastIndex, 0)
		}
	} else if initialized && hs.Commit == 0 {
		// Normally, when the commit index changes, raft gives us a new
		// commit index to persist, however, during initialization, which
		// occurs entirely in cockroach, raft has no knowledge of this.
		// By setting this to the initial log index, we avoid a panic in
		// raft caused by this inconsistency.
		hs.Commit = raftInitialLogIndex
	}

	var cs raftpb.ConfState
	// For uninitalized ranges, membership is unknown at this point.
	if found || initialized {
		for _, rep := range desc.Replicas {
			cs.Nodes = append(cs.Nodes, uint64(rep.ReplicaID))
		}
	}

	return hs, cs, nil
}

func (n *Node) readWAL(ctx context.Context, snapshot *raftpb.Snapshot, forceNewCluster bool) (err error) {
	var (
		walsnap  walpb.Snapshot
		metadata []byte
		st       raftpb.HardState
		ents     []raftpb.Entry
	)

	if snapshot != nil {
		walsnap.Index = snapshot.Metadata.Index
		walsnap.Term = snapshot.Metadata.Term
	}

	repaired := false
	for {
		if n.wal, err = wal.Open(n.walDir(), walsnap); err != nil {
			return fmt.Errorf("open wal error: %v", err)
		}
		if metadata, st, ents, err = n.wal.ReadAll(); err != nil {
			if err := n.wal.Close(); err != nil {
				return err
			}
			// we can only repair ErrUnexpectedEOF and we never repair twice.
			if repaired || err != io.ErrUnexpectedEOF {
				return fmt.Errorf("read wal error (%v) and cannot be repaired", err)
			}
			if !wal.Repair(n.walDir()) {
				return fmt.Errorf("WAL error (%v) cannot be repaired", err)
			}
			log.G(ctx).Infof("repaired WAL error (%v)", err)
			repaired = true
			continue
		}
		break
	}

	defer func() {
		if err != nil {
			if walErr := n.wal.Close(); walErr != nil {
				n.Config.Logger.Errorf("error closing raft WAL: %v", walErr)
			}
		}
	}()

	var raftNode api.RaftMember
	if err := raftNode.Unmarshal(metadata); err != nil {
		return fmt.Errorf("error unmarshalling wal metadata: %v", err)
	}
	n.Config.ID = raftNode.RaftID

	if forceNewCluster {
		// discard the previously uncommitted entries
		for i, ent := range ents {
			if ent.Index > st.Commit {
				log.G(context.Background()).Infof("discarding %d uncommitted WAL entries ", len(ents)-i)
				ents = ents[:i]
				break
			}
		}

		// force append the configuration change entries
		toAppEnts := createConfigChangeEnts(getIDs(snapshot, ents), uint64(n.Config.ID), st.Term, st.Commit)
		ents = append(ents, toAppEnts...)

		// force commit newly appended entries
		err := n.wal.Save(st, toAppEnts)
		if err != nil {
			log.G(context.Background()).Fatalf("%v", err)
		}
		if len(toAppEnts) != 0 {
			st.Commit = toAppEnts[len(toAppEnts)-1].Index
		}
	}

	if snapshot != nil {
		if err := n.raftStore.ApplySnapshot(*snapshot); err != nil {
			return err
		}
	}
	if err := n.raftStore.SetHardState(st); err != nil {
		return err
	}
	if err := n.raftStore.Append(ents); err != nil {
		return err
	}

	return nil
}