Lab 2C

lab2c主要是实现persist，也就是持久化。

根据lab assignment，只需要完成几个函数即可：

func (rf *Raft) persist() {
	// Your code here (2C).
	// Example:
	w := new(bytes.Buffer)
	e := labgob.NewEncoder(w)
	e.Encode(rf.currentTerm)
	e.Encode(rf.votedFor)
	e.Encode(rf.log)
	data := w.Bytes()
	rf.persister.SaveRaftState(data)
}

func (rf *Raft) readPersist(data []byte) {
	if data == nil || len(data) < 1 { // bootstrap without any state?
		return
	}
	// Your code here (2C).
	// Example:
	r := bytes.NewBuffer(data)
	d := labgob.NewDecoder(r)
	var currentTerm int
	var votedFor int
	var log []Entry
	if d.Decode(&currentTerm) != nil ||
		d.Decode(&votedFor) != nil ||
		d.Decode(&log) != nil {
		DPrintf("readPersist 发生错误：%v %v %v\n", currentTerm, votedFor, log)
	} else {
		rf.currentTerm = currentTerm
		rf.votedFor = votedFor
		rf.log = log
	}
}

然后根据图二：需要持久化的有：

votedFor

currentTerm

log

在上述三个字段改变的地方加上 rf.persist() 即可。

easy lab