Search/node-master.go

package main

import (
	"log"
	"sync"
	"time"
)

var (
	isMaster      bool
	masterNode    string
	masterNodeMux sync.RWMutex
)

const (
	heartbeatInterval = 5 * time.Second
	heartbeatTimeout  = 15 * time.Second
	electionTimeout   = 10 * time.Second
)

func sendHeartbeats() {
	for {
		if !isMaster {
			return
		}
		for _, node := range peers {
			msg := Message{
				ID:      hostID.Pretty(),
				Type:    "heartbeat",
				Content: authCode,
			}
			err := sendMessage(node, msg)
			if err != nil {
				log.Printf("Error sending heartbeat to %s: %v", node, err)
			}
		}
		time.Sleep(heartbeatInterval)
	}
}

func checkMasterHeartbeat() {
	for {
		time.Sleep(heartbeatTimeout)
		masterNodeMux.RLock()
		if masterNode == authCode || masterNode == "" {
			masterNodeMux.RUnlock()
			continue
		}
		masterNodeMux.RUnlock()

		masterNodeMux.Lock()
		masterNode = ""
		masterNodeMux.Unlock()
		startElection()
	}
}

func startElection() {
	masterNodeMux.Lock()
	defer masterNodeMux.Unlock()

	for _, node := range peers {
		msg := Message{
			ID:      hostID.Pretty(),
			Type:    "election",
			Content: authCode,
		}
		err := sendMessage(node, msg)
		if err != nil {
			log.Printf("Error sending election message to %s: %v", node, err)
		}
	}

	isMaster = true
	go sendHeartbeats()
}

func handleHeartbeat(content string) {
	masterNodeMux.Lock()
	defer masterNodeMux.Unlock()
	masterNode = content
}

func handleElection(content string) {
	masterNodeMux.Lock()
	defer masterNodeMux.Unlock()

	if content < authCode {
		masterNode = content
	}
}