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271 lines
7.3 KiB
271 lines
7.3 KiB
package nodes
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import (
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"simple-kv-store/internal/logprovider"
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"sort"
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"strconv"
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"sync"
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"go.uber.org/zap"
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)
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type AppendEntriesArg struct {
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Term int
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LeaderId string
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PrevLogIndex int
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PrevLogTerm int
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Entries []RaftLogEntry
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LeaderCommit int
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}
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type AppendEntriesReply struct {
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Term int
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Success bool
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}
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// leader收到新内容要广播，以及心跳广播（同步自己的log)
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func (node *Node) BroadCastKV() {
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log.Sugar().Infof("leader[%s]广播消息", node.SelfId)
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defer logprovider.DebugTraceback("broadcast")
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failCount := 0
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// 这里增加一个锁，防止并发修改成功计数
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var failMutex sync.Mutex
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// 遍历所有节点
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for _, id := range node.Nodes {
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go func(id string) {
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defer logprovider.DebugTraceback("send")
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node.sendKV(id, &failCount, &failMutex)
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}(id)
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}
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}
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func (node *Node) sendKV(peerId string, failCount *int, failMutex *sync.Mutex) {
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node.Mu.Lock()
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selfId := node.SelfId
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node.Mu.Unlock()
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client, err := node.Transport.DialHTTPWithTimeout("tcp", selfId, peerId)
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if err != nil {
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node.Mu.Lock()
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log.Error("[" + node.SelfId + "]dialling [" + peerId + "] fail: ", zap.Error(err))
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failMutex.Lock()
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*failCount++
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if *failCount == len(node.Nodes) / 2 + 1 { // 无法联系超过半数：自己有问题，降级
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node.LeaderId = ""
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node.State = Follower
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node.ResetElectionTimer()
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}
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failMutex.Unlock()
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node.Mu.Unlock()
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return
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}
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defer func(client ClientInterface) {
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err := client.Close()
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if err != nil {
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log.Error("client close err: ", zap.Error(err))
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}
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}(client)
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node.Mu.Lock()
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NextIndex := node.NextIndex[peerId]
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// log.Info("NextIndex " + strconv.Itoa(NextIndex))
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for {
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if NextIndex < 0 {
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log.Fatal("assert >= 0 here")
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}
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sendEntries := node.Log[NextIndex:]
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arg := AppendEntriesArg{
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Term: node.CurrTerm,
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PrevLogIndex: NextIndex - 1,
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Entries: sendEntries,
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LeaderCommit: node.CommitIndex,
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LeaderId: node.SelfId,
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}
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if arg.PrevLogIndex >= 0 {
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arg.PrevLogTerm = node.Log[arg.PrevLogIndex].Term
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}
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// 记录关键数据后解锁
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currTerm := node.CurrTerm
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currState := node.State
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MaxLogId := node.MaxLogId
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var appendReply AppendEntriesReply
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appendReply.Success = false
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node.Mu.Unlock()
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callErr := node.Transport.CallWithTimeout(client, "Node.AppendEntries", &arg, &appendReply) // RPC
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node.Mu.Lock()
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if node.CurrTerm != currTerm || node.MaxLogId != MaxLogId || node.State != currState {
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node.Mu.Unlock()
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return
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}
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if callErr != nil {
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log.Error("[" + node.SelfId + "]calling [" + peerId + "] fail: ", zap.Error(callErr))
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failMutex.Lock()
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*failCount++
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if *failCount == len(node.Nodes) / 2 + 1 { // 无法联系超过半数：自己有问题，降级
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log.Info("term=" + strconv.Itoa(node.CurrTerm) + "的Leader[" + node.SelfId + "]无法联系到半数节点, 降级为 Follower")
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node.LeaderId = ""
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node.State = Follower
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node.ResetElectionTimer()
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}
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failMutex.Unlock()
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node.Mu.Unlock()
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return
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}
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if appendReply.Term != node.CurrTerm {
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log.Sugar().Infof("term=%s的leader[%s]因为[%s]收到更高的term=%s, 转换为follower",
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strconv.Itoa(node.CurrTerm), node.SelfId, peerId, strconv.Itoa(appendReply.Term))
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node.LeaderId = ""
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node.CurrTerm = appendReply.Term
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node.State = Follower
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node.VotedFor = ""
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node.Storage.SetTermAndVote(node.CurrTerm, node.VotedFor)
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node.ResetElectionTimer()
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node.Mu.Unlock()
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return
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}
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if appendReply.Success {
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break
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}
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NextIndex-- // 失败往前传一格
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}
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// 不变成follower情况下
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node.NextIndex[peerId] = node.MaxLogId + 1
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node.MatchIndex[peerId] = node.MaxLogId
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node.updateCommitIndex()
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node.Mu.Unlock()
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}
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func (node *Node) updateCommitIndex() {
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if node.Mu.TryLock() {
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log.Fatal("这里要保证有锁")
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}
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if node.IsFinish {
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return
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}
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totalNodes := len(node.Nodes)
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// 收集所有 MatchIndex 并排序
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MatchIndexes := make([]int, 0, totalNodes)
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for _, index := range node.MatchIndex {
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MatchIndexes = append(MatchIndexes, index)
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}
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sort.Ints(MatchIndexes) // 排序
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// 计算多数派 CommitIndex
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majorityIndex := MatchIndexes[totalNodes/2] // 取 N/2 位置上的索引（多数派）
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// 确保这个索引的日志条目属于当前 term，防止提交旧 term 的日志
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if majorityIndex > node.CommitIndex && majorityIndex < len(node.Log) && node.Log[majorityIndex].Term == node.CurrTerm {
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node.CommitIndex = majorityIndex
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log.Info("Leader[" + node.SelfId + "]更新 CommitIndex: " + strconv.Itoa(majorityIndex))
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// 应用日志到状态机
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node.applyCommittedLogs()
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}
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}
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// 应用日志到状态机
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func (node *Node) applyCommittedLogs() {
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for node.LastApplied < node.CommitIndex {
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node.LastApplied++
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logEntry := node.Log[node.LastApplied]
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log.Sugar().Infof("[%s]应用日志到状态机: " + logEntry.print(), node.SelfId)
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err := node.Db.Put([]byte(logEntry.LogE.Key), []byte(logEntry.LogE.Value), nil)
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if err != nil {
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log.Error(node.SelfId + "应用状态机失败: ", zap.Error(err))
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}
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}
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}
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// RPC call
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func (node *Node) AppendEntries(arg *AppendEntriesArg, reply *AppendEntriesReply) error {
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defer logprovider.DebugTraceback("append")
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node.Mu.Lock()
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defer node.Mu.Unlock()
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log.Sugar().Infof("[%s]在term=%d收到[%s]的AppendEntries", node.SelfId, node.CurrTerm, arg.LeaderId)
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// 如果 term 过期，拒绝接受日志
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if node.CurrTerm > arg.Term {
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reply.Term = node.CurrTerm
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reply.Success = false
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return nil
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}
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node.LeaderId = arg.LeaderId // 记录Leader
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// 如果term比自己高，或自己不是follower但收到相同term的心跳
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if node.CurrTerm < arg.Term || node.State != Follower {
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log.Sugar().Infof("[%s]发现更高 term(%s)", node.SelfId, strconv.Itoa(arg.Term))
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node.CurrTerm = arg.Term
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node.State = Follower
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node.VotedFor = ""
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// node.storage.SetTermAndVote(node.CurrTerm, node.VotedFor)
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}
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node.Storage.SetTermAndVote(node.CurrTerm, node.VotedFor)
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// 检查 prevLogIndex 是否有效
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if arg.PrevLogIndex >= len(node.Log) || (arg.PrevLogIndex >= 0 && node.Log[arg.PrevLogIndex].Term != arg.PrevLogTerm) {
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reply.Term = node.CurrTerm
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reply.Success = false
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return nil
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}
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// 处理日志冲突（如果存在不同 term，则截断日志）
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idx := arg.PrevLogIndex + 1
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for i := idx; i < len(node.Log) && i-idx < len(arg.Entries); i++ {
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if node.Log[i].Term != arg.Entries[i-idx].Term {
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node.Log = node.Log[:idx]
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break
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}
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}
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// log.Info(strconv.Itoa(idx) + strconv.Itoa(len(node.Log)))
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// 追加新的日志条目
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for _, raftLogEntry := range arg.Entries {
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log.Sugar().Infof("[%s]写入：" + raftLogEntry.print(), node.SelfId)
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if idx < len(node.Log) {
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node.Log[idx] = raftLogEntry
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} else {
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node.Log = append(node.Log, raftLogEntry)
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}
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idx++
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}
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// 暴力持久化
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node.Storage.WriteLog(node.Log)
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// 更新 MaxLogId
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node.MaxLogId = len(node.Log) - 1
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// 更新 CommitIndex
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if arg.LeaderCommit < node.MaxLogId {
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node.CommitIndex = arg.LeaderCommit
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} else {
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node.CommitIndex = node.MaxLogId
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}
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// 提交已提交的日志
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node.applyCommittedLogs()
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// 在成功接受日志或心跳后，重置选举超时
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node.ResetElectionTimer()
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reply.Term = node.CurrTerm
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reply.Success = true
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return nil
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}
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