kalzu-value-store/cluster/bootstrap.go

package cluster

import (
	"bytes"
	"encoding/json"
	"fmt"
	"net/http"
	"time"

	"github.com/sirupsen/logrus"

	"kvs/types"
)

// BootstrapService handles cluster joining and initial synchronization
type BootstrapService struct {
	config        *types.Config
	gossipService *GossipService
	syncService   *SyncService
	logger        *logrus.Logger
	setMode       func(string) // Callback to set server mode
}

// NewBootstrapService creates a new bootstrap service
func NewBootstrapService(config *types.Config, gossipService *GossipService, syncService *SyncService, logger *logrus.Logger, setMode func(string)) *BootstrapService {
	return &BootstrapService{
		config:        config,
		gossipService: gossipService,
		syncService:   syncService,
		logger:        logger,
		setMode:       setMode,
	}
}

// Bootstrap joins cluster using seed nodes
func (s *BootstrapService) Bootstrap() {
	if len(s.config.SeedNodes) == 0 {
		s.logger.Info("No seed nodes configured, running as standalone")
		return
	}

	s.logger.Info("Starting bootstrap process")
	s.setMode("syncing")

	// Try to join cluster via each seed node
	joined := false
	for _, seedAddr := range s.config.SeedNodes {
		if s.attemptJoin(seedAddr) {
			joined = true
			break
		}
	}

	if !joined {
		s.logger.Warn("Failed to join cluster via seed nodes, running as standalone")
		s.setMode("normal")
		return
	}

	// Wait a bit for member discovery
	time.Sleep(2 * time.Second)

	// Perform gradual sync (now Merkle-based)
	s.performGradualSync()

	// Switch to normal mode
	s.setMode("normal")
	s.logger.Info("Bootstrap completed, entering normal mode")
}

// attemptJoin attempts to join cluster via a seed node
func (s *BootstrapService) attemptJoin(seedAddr string) bool {
	joinReq := types.JoinRequest{
		ID:              s.config.NodeID,
		Address:         fmt.Sprintf("%s:%d", s.config.BindAddress, s.config.Port),
		JoinedTimestamp: time.Now().UnixMilli(),
	}

	jsonData, err := json.Marshal(joinReq)
	if err != nil {
		s.logger.WithError(err).Error("Failed to marshal join request")
		return false
	}

	client := &http.Client{Timeout: 10 * time.Second}
	url := fmt.Sprintf("http://%s/members/join", seedAddr)

	resp, err := client.Post(url, "application/json", bytes.NewBuffer(jsonData))
	if err != nil {
		s.logger.WithFields(logrus.Fields{
			"seed":  seedAddr,
			"error": err.Error(),
		}).Warn("Failed to contact seed node")
		return false
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		s.logger.WithFields(logrus.Fields{
			"seed":   seedAddr,
			"status": resp.StatusCode,
		}).Warn("Seed node rejected join request")
		return false
	}

	// Process member list response
	var memberList []types.Member
	if err := json.NewDecoder(resp.Body).Decode(&memberList); err != nil {
		s.logger.WithError(err).Error("Failed to decode member list from seed")
		return false
	}

	// Add all members to our local list
	for _, member := range memberList {
		if member.ID != s.config.NodeID {
			s.gossipService.AddMember(&member)
		}
	}

	s.logger.WithFields(logrus.Fields{
		"seed":         seedAddr,
		"member_count": len(memberList),
	}).Info("Successfully joined cluster")

	return true
}

// performGradualSync performs gradual sync (Merkle-based version)
func (s *BootstrapService) performGradualSync() {
	s.logger.Info("Starting gradual sync (Merkle-based)")

	members := s.gossipService.GetHealthyMembers()
	if len(members) == 0 {
		s.logger.Info("No healthy members for gradual sync")
		return
	}

	// For now, just do a few rounds of Merkle sync
	for i := 0; i < 3; i++ {
		s.syncService.performMerkleSync()
		time.Sleep(time.Duration(s.config.ThrottleDelayMs) * time.Millisecond)
	}

	s.logger.Info("Gradual sync completed")
}