added code for persisting and unmarshalling the log, updated cleanup file

assignment3/src/clean.sh

 #! /bin/bash
-rm {1..5} currentTerm* votedFor*
+rm {1..5} currentTerm* votedFor* log*

assignment3/src/raft/raft.go

 package raft
 
 import (
+	"encoding/json"
 	"io/ioutil"
 	"log"
 	"math/rand"
@@ -24,6 +25,7 @@ const (
 	FOLLOWER          = 30
 	VOTED_FOR         = "votedFor"
 	CURRENT_TERM      = "currentTerm"
+	LOG_PERSIST       = "log"
 	FILE_WRITTEN      = 0
 	FILE_ERR          = -1
 	NULL_VOTE         = 0
@@ -126,11 +128,41 @@ type LogEntryData struct {
 }
 
 func (rft *Raft) persistLog() {
-
+	if file, err := os.OpenFile(LOG_PERSIST+strconv.Itoa(rft.id), os.O_CREATE|os.O_RDWR|os.O_TRUNC, 0666); err != nil {
+		rft.Info.Println("error opening log persist file", err.Error())
+	} else {
+		defer file.Close()
+		enc := json.NewEncoder(file)
+		for _, e := range rft.LogArray {
+			if err := enc.Encode(e); err != nil {
+				rft.Info.Println("error persisting log entry", err.Error())
+			}
+		}
+		if err := file.Sync(); err != nil {
+			rft.Info.Println("error synching log persist file", err.Error())
+		} else {
+			rft.Info.Println("log persist success!")
+		}
+	}
 }
 
 func (rft *Raft) readLogFromDisk() {
-
+	if file, err := os.OpenFile(LOG_PERSIST+strconv.Itoa(rft.id), os.O_RDONLY, 0666); err != nil {
+		rft.Info.Println("error reading log persist file")
+	} else {
+		defer file.Close()
+		dec := json.NewDecoder(file)
+		for {
+			d := LogEntryData{}
+			if err := dec.Decode(d); err != nil {
+				rft.Info.Println("done reading log from file")
+				break
+			} else {
+				rft.LogArray = []*LogEntryData{}
+				rft.LogArray = append(rft.LogArray, &d)
+			}
+		}
+	}
 }
 
 func getSingleDataFromFile(name string, serverId int, info *log.Logger) int {
@@ -432,6 +464,9 @@ func (rft *Raft) follower() int {
 					}
 				}
 				rafts[req.leaderId].replyAppendRPC(reply, rft.currentTerm, rft.id)
+				if reply {
+					rft.persistLog()
+				}
 				rft.Info.Println("F: log is size", len(rft.LogArray))
 			}
 		}
@@ -520,6 +555,7 @@ func (rft *Raft) leader() int {
 	heartbeatReq := new(AppendRPC)
 	heartbeatReq.entries = []*LogEntryData{}
 	heartbeatReq.leaderId = rft.id
+	rft.currentTerm++
 
 	rft.LogArray = append(
 		rft.LogArray,
@@ -527,11 +563,13 @@ func (rft *Raft) leader() int {
 			Id:        1,
 			Data:      []byte("hello"),
 			Committed: false,
+			Term:      rft.currentTerm,
 		},
 		&LogEntryData{
 			Id:        2,
 			Data:      []byte("world"),
 			Committed: false,
+			Term:      rft.currentTerm,
 		})
 
 	//build nextIndex and matchIndex