implement raft consensus in go

main.go
package main

import (
	"log"
	"net"
	"os"

	"github.com/golang/protobuf/proto"
	"golang.org/x/net/context"
	"google.golang.org/grpc"
)

type Node struct {
	ID         string
	State      string
	Term       int64
	VotedFor   string
	Log        []LogEntry
	CommitIdx  int64
	LastAppld  int64
	NumVotes   int64
	NextIndex  map[string]int64
	MatchIndex map[string]int64
}

type LogEntry struct {
	Term    int64
	Index   int64
	Command string
}

func main() {
	// Initialize Raft nodes
	n1 := &Node{ID: "node1"}
	n2 := &Node{ID: "node2"}
	n3 := &Node{ID: "node3"}

	// Set initial state
	n1.State = "FOLLOWER"
	n2.State = "FOLLOWER"
	n3.State = "FOLLOWER"

	// Create channels for communication
	appendChan := make(chan LogEntry)
	voteChan := make(chan bool)

	// Start the Raft nodes
	go startNode(n1, appendChan, voteChan)
	go startNode(n2, appendChan, voteChan)
	go startNode(n3, appendChan, voteChan)

	// Send a sample log entry to node 1
	l := LogEntry{Term: 1, Index: 1, Command: "Test Command"}
	appendChan <- l

	// Get the state of node 1
	log.Printf("%+v\n", n1)
}

func startNode(n *Node, appendChan chan LogEntry, voteChan chan bool) {
	// gRPC server initialization
	lis, err := net.Listen("tcp", ":"+n.ID[4:])
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}
	s := grpc.NewServer()
	RegisterNodeServer(s, &nodeServer{node: n})

	// Start the gRPC server
	go func() {
		if err := s.Serve(lis); err != nil {
			log.Fatalf("failed to serve: %v", err)
		}
	}()

	// Raft event loop
	for {
		switch n.State {
		case "FOLLOWER":
			// TODO: implement follower logic
		case "CANDIDATE":
			// TODO: implement candidate logic
		case "LEADER":
			// TODO: implement leader logic
		}
	}
}

type nodeServer struct {
	node *Node
}

func (s *nodeServer) RequestVote(ctx context.Context, in *RequestVoteRequest) (*RequestVoteResponse, error) {
	resp := &RequestVoteResponse{}
	resp.Term = s.node.Term
	if resp.Term < in.Term {
		s.node.State = "FOLLOWER"
		resp.Term = in.Term
		s.node.VotedFor = in.CandidateId
		resp.VoteGranted = true
	} else {
		resp.VoteGranted = false
	}
	return resp, nil
}

func (s *nodeServer) AppendEntries(ctx context.Context, in *AppendEntriesRequest) (*AppendEntriesResponse, error) {
	resp := &AppendEntriesResponse{}
	resp.Term = s.node.Term
	if resp.Term <= in.Term {
		s.node.State = "FOLLOWER"
		s.node.Term = in.Term
		for i, l := range in.Entries {
			if len(s.node.Log) <= int(l.Index) || s.node.Log[l.Index].Term != l.Term {
				s.node.Log[i] = l
			}
			s.node.CommitIdx = l.Index
			s.node.LastAppld = l.Index
		}
		resp.Success = true
	} else {
		resp.Success = false
	}
	return resp, nil
}

func requestVote(node *Node, peerId string) bool {
	conn, err := grpc.Dial("localhost:"+peerId[4:], grpc.WithInsecure())
	if err != nil {
		log.Fatalf("did not connect: %v", err)
	}
	defer conn.Close()

	c := NewNodeClient(conn)

	resp, err := c.RequestVote(context.Background(), &RequestVoteRequest{})
	if err != nil {
		log.Fatalf("could not greet: %v", err)
	}

	if resp.VoteGranted {
		return true
	}

	return false
}

func appendEntry(node *Node, peerId string, l *LogEntry) bool {
	conn, err := grpc.Dial("localhost:"+peerId[4:], grpc.WithInsecure())
	if err != nil {
		log.Fatalf("did not connect: %v", err)
	}
	defer conn.Close()

	c := NewNodeClient(conn)

	aeReq := &AppendEntriesRequest{}
	aeReq.Entries = []*LogEntry{l}
	aeReq.Term = node.Term

	resp, err := c.AppendEntries(context.Background(), aeReq)
	if err != nil {
		log.Fatalf("could not greet: %v", err)
	}

	if resp.Success {
		return true
	}

	return false
}
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