80 lines
2.9 KiB
Go
80 lines
2.9 KiB
Go
// Copyright 2015 The etcd Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package raft
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import (
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"errors"
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pb "go.etcd.io/etcd/raft/raftpb"
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)
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// Bootstrap initializes the RawNode for first use by appending configuration
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// changes for the supplied peers. This method returns an error if the Storage
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// is nonempty.
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//
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// It is recommended that instead of calling this method, applications bootstrap
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// their state manually by setting up a Storage that has a first index > 1 and
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// which stores the desired ConfState as its InitialState.
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func (rn *RawNode) Bootstrap(peers []Peer) error {
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if len(peers) == 0 {
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return errors.New("must provide at least one peer to Bootstrap")
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}
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lastIndex, err := rn.raft.raftLog.storage.LastIndex()
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if err != nil {
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return err
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}
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if lastIndex != 0 {
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return errors.New("can't bootstrap a nonempty Storage")
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}
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// We've faked out initial entries above, but nothing has been
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// persisted. Start with an empty HardState (thus the first Ready will
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// emit a HardState update for the app to persist).
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rn.prevHardSt = emptyState
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// TODO(tbg): remove StartNode and give the application the right tools to
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// bootstrap the initial membership in a cleaner way.
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rn.raft.becomeFollower(1, None)
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ents := make([]pb.Entry, len(peers))
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for i, peer := range peers {
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cc := pb.ConfChange{Type: pb.ConfChangeAddNode, NodeID: peer.ID, Context: peer.Context}
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data, err := cc.Marshal()
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if err != nil {
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return err
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}
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ents[i] = pb.Entry{Type: pb.EntryConfChange, Term: 1, Index: uint64(i + 1), Data: data}
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}
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rn.raft.raftLog.append(ents...)
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// Now apply them, mainly so that the application can call Campaign
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// immediately after StartNode in tests. Note that these nodes will
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// be added to raft twice: here and when the application's Ready
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// loop calls ApplyConfChange. The calls to addNode must come after
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// all calls to raftLog.append so progress.next is set after these
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// bootstrapping entries (it is an error if we try to append these
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// entries since they have already been committed).
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// We do not set raftLog.applied so the application will be able
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// to observe all conf changes via Ready.CommittedEntries.
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//
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// TODO(bdarnell): These entries are still unstable; do we need to preserve
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// the invariant that committed < unstable?
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rn.raft.raftLog.committed = uint64(len(ents))
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for _, peer := range peers {
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rn.raft.applyConfChange(pb.ConfChange{NodeID: peer.ID, Type: pb.ConfChangeAddNode}.AsV2())
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}
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return nil
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}
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