separate worker from pool hook

hitless/handoff_worker.go

@@ -0,0 +1,394 @@
+package hitless
+
+import (
+	"context"
+	"net"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/redis/go-redis/v9/internal"
+	"github.com/redis/go-redis/v9/internal/pool"
+)
+
+// handoffWorkerManager manages background workers and queue for connection handoffs
+type handoffWorkerManager struct {
+	// Event-driven handoff support
+	handoffQueue chan HandoffRequest // Queue for handoff requests
+	shutdown     chan struct{}       // Shutdown signal
+	shutdownOnce sync.Once           // Ensure clean shutdown
+	workerWg     sync.WaitGroup      // Track worker goroutines
+
+	// On-demand worker management
+	maxWorkers     int
+	activeWorkers  atomic.Int32
+	workerTimeout  time.Duration // How long workers wait for work before exiting
+	workersScaling atomic.Bool
+
+	// Simple state tracking
+	pending sync.Map // map[uint64]int64 (connID -> seqID)
+
+	// Configuration for the hitless upgrade
+	config *Config
+
+	// Pool hook reference for handoff processing
+	poolHook *PoolHook
+}
+
+// newHandoffWorkerManager creates a new handoff worker manager
+func newHandoffWorkerManager(config *Config, poolHook *PoolHook) *handoffWorkerManager {
+	return &handoffWorkerManager{
+		handoffQueue:  make(chan HandoffRequest, config.HandoffQueueSize),
+		shutdown:      make(chan struct{}),
+		maxWorkers:    config.MaxWorkers,
+		activeWorkers: atomic.Int32{}, // Start with no workers - create on demand
+		workerTimeout: 15 * time.Second, // Workers exit after 15s of inactivity
+		config:        config,
+		poolHook:      poolHook,
+	}
+}
+
+// getCurrentWorkers returns the current number of active workers (for testing)
+func (hwm *handoffWorkerManager) getCurrentWorkers() int {
+	return int(hwm.activeWorkers.Load())
+}
+
+// getPendingMap returns the pending map for testing purposes
+func (hwm *handoffWorkerManager) getPendingMap() *sync.Map {
+	return &hwm.pending
+}
+
+// getMaxWorkers returns the max workers for testing purposes
+func (hwm *handoffWorkerManager) getMaxWorkers() int {
+	return hwm.maxWorkers
+}
+
+// getHandoffQueue returns the handoff queue for testing purposes
+func (hwm *handoffWorkerManager) getHandoffQueue() chan HandoffRequest {
+	return hwm.handoffQueue
+}
+
+// isHandoffPending returns true if the given connection has a pending handoff
+func (hwm *handoffWorkerManager) isHandoffPending(conn *pool.Conn) bool {
+	_, pending := hwm.pending.Load(conn.GetID())
+	return pending
+}
+
+// ensureWorkerAvailable ensures at least one worker is available to process requests
+// Creates a new worker if needed and under the max limit
+func (hwm *handoffWorkerManager) ensureWorkerAvailable() {
+	select {
+	case <-hwm.shutdown:
+		return
+	default:
+		if hwm.workersScaling.CompareAndSwap(false, true) {
+			defer hwm.workersScaling.Store(false)
+			// Check if we need a new worker
+			currentWorkers := hwm.activeWorkers.Load()
+			workersWas := currentWorkers
+			for currentWorkers <= int32(hwm.maxWorkers) {
+				hwm.workerWg.Add(1)
+				go hwm.onDemandWorker()
+				currentWorkers++
+			}
+			// workersWas is always <= currentWorkers
+			// currentWorkers will be maxWorkers, but if we have a worker that was closed
+			// while we were creating new workers, just add the difference between
+			// the currentWorkers and the number of workers we observed initially (i.e. the number of workers we created)
+			hwm.activeWorkers.Add(currentWorkers - workersWas)
+		}
+	}
+}
+
+// onDemandWorker processes handoff requests and exits when idle
+func (hwm *handoffWorkerManager) onDemandWorker() {
+	defer func() {
+		// Decrement active worker count when exiting
+		hwm.activeWorkers.Add(-1)
+		hwm.workerWg.Done()
+	}()
+
+	for {
+		select {
+		case <-hwm.shutdown:
+			return
+		case <-time.After(hwm.workerTimeout):
+			// Worker has been idle for too long, exit to save resources
+			if hwm.config != nil && hwm.config.LogLevel.InfoOrAbove() { // Debug level
+				internal.Logger.Printf(context.Background(),
+					"hitless: worker exiting due to inactivity timeout (%v)", hwm.workerTimeout)
+			}
+			return
+		case request := <-hwm.handoffQueue:
+			// Check for shutdown before processing
+			select {
+			case <-hwm.shutdown:
+				// Clean up the request before exiting
+				hwm.pending.Delete(request.ConnID)
+				return
+			default:
+				// Process the request
+				hwm.processHandoffRequest(request)
+			}
+		}
+	}
+}
+
+// processHandoffRequest processes a single handoff request
+func (hwm *handoffWorkerManager) processHandoffRequest(request HandoffRequest) {
+	// Remove from pending map
+	defer hwm.pending.Delete(request.Conn.GetID())
+	internal.Logger.Printf(context.Background(), "hitless: conn[%d] Processing handoff request start", request.Conn.GetID())
+
+	// Create a context with handoff timeout from config
+	handoffTimeout := 15 * time.Second // Default timeout
+	if hwm.config != nil && hwm.config.HandoffTimeout > 0 {
+		handoffTimeout = hwm.config.HandoffTimeout
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), handoffTimeout)
+	defer cancel()
+
+	// Create a context that also respects the shutdown signal
+	shutdownCtx, shutdownCancel := context.WithCancel(ctx)
+	defer shutdownCancel()
+
+	// Monitor shutdown signal in a separate goroutine
+	go func() {
+		select {
+		case <-hwm.shutdown:
+			shutdownCancel()
+		case <-shutdownCtx.Done():
+		}
+	}()
+
+	// Perform the handoff with cancellable context
+	shouldRetry, err := hwm.performConnectionHandoff(shutdownCtx, request.Conn)
+	minRetryBackoff := 500 * time.Millisecond
+	if err != nil {
+		if shouldRetry {
+			now := time.Now()
+			deadline, ok := shutdownCtx.Deadline()
+			thirdOfTimeout := handoffTimeout / 3
+			if !ok || deadline.Before(now) {
+				// wait half the timeout before retrying if no deadline or deadline has passed
+				deadline = now.Add(thirdOfTimeout)
+			}
+			afterTime := deadline.Sub(now)
+			if afterTime < minRetryBackoff {
+				afterTime = minRetryBackoff
+			}
+
+			internal.Logger.Printf(context.Background(), "Handoff failed for conn[%d] WILL RETRY After %v: %v", request.ConnID, afterTime, err)
+			time.AfterFunc(afterTime, func() {
+				if err := hwm.queueHandoff(request.Conn); err != nil {
+					internal.Logger.Printf(context.Background(), "can't queue handoff for retry: %v", err)
+					hwm.closeConnFromRequest(context.Background(), request, err)
+				}
+			})
+			return
+		} else {
+			go hwm.closeConnFromRequest(ctx, request, err)
+		}
+
+		// Clear handoff state if not returned for retry
+		seqID := request.Conn.GetMovingSeqID()
+		connID := request.Conn.GetID()
+		if hwm.poolHook.hitlessManager != nil {
+			hwm.poolHook.hitlessManager.UntrackOperationWithConnID(seqID, connID)
+		}
+	}
+}
+
+// queueHandoff queues a handoff request for processing
+// if err is returned, connection will be removed from pool
+func (hwm *handoffWorkerManager) queueHandoff(conn *pool.Conn) error {
+	// Create handoff request
+	request := HandoffRequest{
+		Conn:     conn,
+		ConnID:   conn.GetID(),
+		Endpoint: conn.GetHandoffEndpoint(),
+		SeqID:    conn.GetMovingSeqID(),
+		Pool:     hwm.poolHook.pool, // Include pool for connection removal on failure
+	}
+
+	select {
+	// priority to shutdown
+	case <-hwm.shutdown:
+		return ErrShutdown
+	default:
+		select {
+		case <-hwm.shutdown:
+			return ErrShutdown
+		case hwm.handoffQueue <- request:
+			// Store in pending map
+			hwm.pending.Store(request.ConnID, request.SeqID)
+			// Ensure we have a worker to process this request
+			hwm.ensureWorkerAvailable()
+			return nil
+		default:
+			select {
+			case <-hwm.shutdown:
+				return ErrShutdown
+			case hwm.handoffQueue <- request:
+				// Store in pending map
+				hwm.pending.Store(request.ConnID, request.SeqID)
+				// Ensure we have a worker to process this request
+				hwm.ensureWorkerAvailable()
+				return nil
+			case <-time.After(100 * time.Millisecond): // give workers a chance to process
+				// Queue is full - log and attempt scaling
+				queueLen := len(hwm.handoffQueue)
+				queueCap := cap(hwm.handoffQueue)
+				if hwm.config != nil && hwm.config.LogLevel.WarnOrAbove() { // Warning level
+					internal.Logger.Printf(context.Background(),
+						"hitless: handoff queue is full (%d/%d), cannot queue new handoff requests - consider increasing HandoffQueueSize or MaxWorkers in configuration",
+						queueLen, queueCap)
+				}
+			}
+		}
+	}
+
+	// Ensure we have workers available to handle the load
+	hwm.ensureWorkerAvailable()
+	return ErrHandoffQueueFull
+}
+
+// shutdownWorkers gracefully shuts down the worker manager, waiting for workers to complete
+func (hwm *handoffWorkerManager) shutdownWorkers(ctx context.Context) error {
+	hwm.shutdownOnce.Do(func() {
+		close(hwm.shutdown)
+		// workers will exit when they finish their current request
+	})
+
+	// Wait for workers to complete
+	done := make(chan struct{})
+	go func() {
+		hwm.workerWg.Wait()
+		close(done)
+	}()
+
+	select {
+	case <-done:
+		return nil
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}
+
+// performConnectionHandoff performs the actual connection handoff
+// When error is returned, the connection handoff should be retried if err is not ErrMaxHandoffRetriesReached
+func (hwm *handoffWorkerManager) performConnectionHandoff(ctx context.Context, conn *pool.Conn) (shouldRetry bool, err error) {
+	// Clear handoff state after successful handoff
+	connID := conn.GetID()
+
+	newEndpoint := conn.GetHandoffEndpoint()
+	if newEndpoint == "" {
+		return false, ErrConnectionInvalidHandoffState
+	}
+
+	retries := conn.IncrementAndGetHandoffRetries(1)
+	internal.Logger.Printf(ctx, "hitless: conn[%d] Retry %d: Performing handoff to %s(was %s)", conn.GetID(), retries, newEndpoint, conn.RemoteAddr().String())
+	maxRetries := 3 // Default fallback
+	if hwm.config != nil {
+		maxRetries = hwm.config.MaxHandoffRetries
+	}
+
+	if retries > maxRetries {
+		if hwm.config != nil && hwm.config.LogLevel.WarnOrAbove() { // Warning level
+			internal.Logger.Printf(ctx,
+				"hitless: reached max retries (%d) for handoff of conn[%d] to %s",
+				maxRetries, conn.GetID(), conn.GetHandoffEndpoint())
+		}
+		// won't retry on ErrMaxHandoffRetriesReached
+		return false, ErrMaxHandoffRetriesReached
+	}
+
+	// Create endpoint-specific dialer
+	endpointDialer := hwm.createEndpointDialer(newEndpoint)
+
+	// Create new connection to the new endpoint
+	newNetConn, err := endpointDialer(ctx)
+	if err != nil {
+		internal.Logger.Printf(ctx, "hitless: conn[%d] Failed to dial new endpoint %s: %v", conn.GetID(), newEndpoint, err)
+		// hitless: will retry
+		// Maybe a network error - retry after a delay
+		return true, err
+	}
+
+	// Get the old connection
+	oldConn := conn.GetNetConn()
+
+	// Apply relaxed timeout to the new connection for the configured post-handoff duration
+	// This gives the new connection more time to handle operations during cluster transition
+	// Setting this here (before initing the connection) ensures that the connection is going
+	// to use the relaxed timeout for the first operation (auth/ACL select)
+	if hwm.config != nil && hwm.config.PostHandoffRelaxedDuration > 0 {
+		relaxedTimeout := hwm.config.RelaxedTimeout
+		// Set relaxed timeout with deadline - no background goroutine needed
+		deadline := time.Now().Add(hwm.config.PostHandoffRelaxedDuration)
+		conn.SetRelaxedTimeoutWithDeadline(relaxedTimeout, relaxedTimeout, deadline)
+
+		if hwm.config.LogLevel.InfoOrAbove() {
+			internal.Logger.Printf(context.Background(),
+				"hitless: conn[%d] applied post-handoff relaxed timeout (%v) until %v",
+				connID, relaxedTimeout, deadline.Format("15:04:05.000"))
+		}
+	}
+
+	// Replace the connection and execute initialization
+	err = conn.SetNetConnAndInitConn(ctx, newNetConn)
+	if err != nil {
+		// hitless: won't retry
+		// Initialization failed - remove the connection
+		return false, err
+	}
+	defer func() {
+		if oldConn != nil {
+			oldConn.Close()
+		}
+	}()
+
+	conn.ClearHandoffState()
+	internal.Logger.Printf(ctx, "hitless: conn[%d] Handoff to %s successful", conn.GetID(), newEndpoint)
+
+	return false, nil
+}
+
+// createEndpointDialer creates a dialer function that connects to a specific endpoint
+func (hwm *handoffWorkerManager) createEndpointDialer(endpoint string) func(context.Context) (net.Conn, error) {
+	return func(ctx context.Context) (net.Conn, error) {
+		// Parse endpoint to extract host and port
+		host, port, err := net.SplitHostPort(endpoint)
+		if err != nil {
+			// If no port specified, assume default Redis port
+			host = endpoint
+			if port == "" {
+				port = "6379"
+			}
+		}
+
+		// Use the base dialer to connect to the new endpoint
+		return hwm.poolHook.baseDialer(ctx, hwm.poolHook.network, net.JoinHostPort(host, port))
+	}
+}
+
+// closeConnFromRequest closes the connection and logs the reason
+func (hwm *handoffWorkerManager) closeConnFromRequest(ctx context.Context, request HandoffRequest, err error) {
+	pooler := request.Pool
+	conn := request.Conn
+	if pooler != nil {
+		pooler.Remove(ctx, conn, err)
+		if hwm.config != nil && hwm.config.LogLevel.WarnOrAbove() { // Warning level
+			internal.Logger.Printf(ctx,
+				"hitless: removed conn[%d] from pool due to max handoff retries reached: %v",
+				conn.GetID(), err)
+		}
+	} else {
+		conn.Close()
+		if hwm.config != nil && hwm.config.LogLevel.WarnOrAbove() { // Warning level
+			internal.Logger.Printf(ctx,
+				"hitless: no pool provided for conn[%d], cannot remove due to handoff initialization failure: %v",
+				conn.GetID(), err)
+		}
+	}
+}

hitless/pool_hook.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"net"
 	"sync"
-	"sync/atomic"
 	"time"
 
 	"github.com/redis/go-redis/v9/internal"
@@ -36,20 +35,8 @@ type PoolHook struct {
 	// Network type (e.g., "tcp", "unix")
 	network string
 
-	// Event-driven handoff support
-	handoffQueue chan HandoffRequest // Queue for handoff requests
-	shutdown     chan struct{}       // Shutdown signal
-	shutdownOnce sync.Once           // Ensure clean shutdown
-	workerWg     sync.WaitGroup      // Track worker goroutines
-
-	// On-demand worker management
-	maxWorkers     int
-	activeWorkers  atomic.Int32
-	workerTimeout  time.Duration // How long workers wait for work before exiting
-	workersScaling atomic.Bool
-
-	// Simple state tracking
-	pending sync.Map // map[uint64]int64 (connID -> seqID)
+	// Worker manager for background handoff processing
+	workerManager *handoffWorkerManager
 
 	// Configuration for the hitless upgrade
 	config *Config
@@ -77,18 +64,14 @@ func NewPoolHookWithPoolSize(baseDialer func(context.Context, string, string) (n
 		// baseDialer is used to create connections to new endpoints during handoffs
 		baseDialer: baseDialer,
 		network:    network,
-		// handoffQueue is a buffered channel for queuing handoff requests
-		handoffQueue: make(chan HandoffRequest, config.HandoffQueueSize),
-		// shutdown is a channel for signaling shutdown
-		shutdown:      make(chan struct{}),
-		maxWorkers:    config.MaxWorkers,
-		activeWorkers: atomic.Int32{}, // Start with no workers - create on demand
-		// NOTE: maybe we would like to make this configurable?
-		workerTimeout: 15 * time.Second, // Workers exit after 15s of inactivity
-		config:        config,
+		config:     config,
 		// Hitless manager for operation completion tracking
 		hitlessManager: hitlessManager,
 	}
+
+	// Create worker manager
+	ph.workerManager = newHandoffWorkerManager(config, ph)
+
 	return ph
 }
 
@@ -99,13 +82,27 @@ func (ph *PoolHook) SetPool(pooler pool.Pooler) {
 
 // GetCurrentWorkers returns the current number of active workers (for testing)
 func (ph *PoolHook) GetCurrentWorkers() int {
-	return int(ph.activeWorkers.Load())
+	return ph.workerManager.getCurrentWorkers()
 }
 
 // IsHandoffPending returns true if the given connection has a pending handoff
 func (ph *PoolHook) IsHandoffPending(conn *pool.Conn) bool {
-	_, pending := ph.pending.Load(conn.GetID())
-	return pending
+	return ph.workerManager.isHandoffPending(conn)
+}
+
+// GetPendingMap returns the pending map for testing purposes
+func (ph *PoolHook) GetPendingMap() *sync.Map {
+	return ph.workerManager.getPendingMap()
+}
+
+// GetMaxWorkers returns the max workers for testing purposes
+func (ph *PoolHook) GetMaxWorkers() int {
+	return ph.workerManager.getMaxWorkers()
+}
+
+// GetHandoffQueue returns the handoff queue for testing purposes
+func (ph *PoolHook) GetHandoffQueue() chan HandoffRequest {
+	return ph.workerManager.getHandoffQueue()
 }
 
 // OnGet is called when a connection is retrieved from the pool
@@ -136,13 +133,12 @@ func (ph *PoolHook) OnPut(ctx context.Context, conn *pool.Conn) (shouldPool bool
 	}
 
 	// check pending handoff to not queue the same connection twice
-	_, hasPendingHandoff := ph.pending.Load(conn.GetID())
-	if hasPendingHandoff {
+	if ph.workerManager.isHandoffPending(conn) {
 		// Default behavior (pending handoff): pool the connection
 		return true, false, nil
 	}
 
-	if err := ph.queueHandoff(conn); err != nil {
+	if err := ph.workerManager.queueHandoff(conn); err != nil {
 		// Failed to queue handoff, remove the connection
 		internal.Logger.Printf(ctx, "Failed to queue handoff: %v", err)
 		// Don't pool, remove connection, no error to caller
@@ -167,331 +163,7 @@ func (ph *PoolHook) OnPut(ctx context.Context, conn *pool.Conn) (shouldPool bool
 	return true, false, nil
 }
 
-// ensureWorkerAvailable ensures at least one worker is available to process requests
-// Creates a new worker if needed and under the max limit
-func (ph *PoolHook) ensureWorkerAvailable() {
-	select {
-	case <-ph.shutdown:
-		return
-	default:
-		if ph.workersScaling.CompareAndSwap(false, true) {
-			defer ph.workersScaling.Store(false)
-			// Check if we need a new worker
-			currentWorkers := ph.activeWorkers.Load()
-			workersWas := currentWorkers
-			for currentWorkers <= int32(ph.maxWorkers) {
-				ph.workerWg.Add(1)
-				go ph.onDemandWorker()
-				currentWorkers++
-			}
-			// workersWas is always <= currentWorkers
-			// currentWorkers will be maxWorkers, but if we have a worker that was closed
-			// while we were creating new workers, just add the difference between
-			// the currentWorkers and the number of workers we observed initially (i.e. the number of workers we created)
-			ph.activeWorkers.Add(currentWorkers - workersWas)
-		}
-	}
-}
-
-// onDemandWorker processes handoff requests and exits when idle
-func (ph *PoolHook) onDemandWorker() {
-	defer func() {
-		// Decrement active worker count when exiting
-		ph.activeWorkers.Add(-1)
-		ph.workerWg.Done()
-	}()
-
-	for {
-		select {
-		case <-ph.shutdown:
-			return
-		case <-time.After(ph.workerTimeout):
-			// Worker has been idle for too long, exit to save resources
-			if ph.config != nil && ph.config.LogLevel.InfoOrAbove() { // Debug level
-				internal.Logger.Printf(context.Background(),
-					"hitless: worker exiting due to inactivity timeout (%v)", ph.workerTimeout)
-			}
-			return
-		case request := <-ph.handoffQueue:
-			// Check for shutdown before processing
-			select {
-			case <-ph.shutdown:
-				// Clean up the request before exiting
-				ph.pending.Delete(request.ConnID)
-				return
-			default:
-				// Process the request
-				ph.processHandoffRequest(request)
-			}
-		}
-	}
-}
-
-// processHandoffRequest processes a single handoff request
-func (ph *PoolHook) processHandoffRequest(request HandoffRequest) {
-	// Remove from pending map
-	defer ph.pending.Delete(request.Conn.GetID())
-	internal.Logger.Printf(context.Background(), "hitless: conn[%d] Processing handoff request start", request.Conn.GetID())
-
-	// Create a context with handoff timeout from config
-	handoffTimeout := 30 * time.Second // Default fallback
-	if ph.config != nil && ph.config.HandoffTimeout > 0 {
-		handoffTimeout = ph.config.HandoffTimeout
-	}
-	ctx, cancel := context.WithTimeout(context.Background(), handoffTimeout)
-	defer cancel()
-
-	// Create a context that also respects the shutdown signal
-	shutdownCtx, shutdownCancel := context.WithCancel(ctx)
-	defer shutdownCancel()
-
-	// Monitor shutdown signal in a separate goroutine
-	go func() {
-		select {
-		case <-ph.shutdown:
-			shutdownCancel()
-		case <-shutdownCtx.Done():
-		}
-	}()
-
-	// Perform the handoff with cancellable context
-	shouldRetry, err := ph.performConnectionHandoff(shutdownCtx, request.Conn)
-	minRetryBackoff := 500 * time.Millisecond
-	if err != nil {
-		if shouldRetry {
-			now := time.Now()
-			deadline, ok := shutdownCtx.Deadline()
-			thirdOfTimeout := handoffTimeout / 3
-			if !ok || deadline.Before(now) {
-				// wait half the timeout before retrying if no deadline or deadline has passed
-				deadline = now.Add(thirdOfTimeout)
-			}
-
-			afterTime := deadline.Sub(now)
-			if afterTime > thirdOfTimeout {
-				afterTime = thirdOfTimeout
-			}
-			if afterTime < minRetryBackoff {
-				afterTime = minRetryBackoff
-			}
-
-			internal.Logger.Printf(context.Background(), "Handoff failed for conn[%d] WILL RETRY After %v: %v", request.ConnID, afterTime, err)
-			time.AfterFunc(afterTime, func() {
-				if err := ph.queueHandoff(request.Conn); err != nil {
-					internal.Logger.Printf(context.Background(), "can't queue handoff for retry: %v", err)
-					ph.closeConnFromRequest(context.Background(), request, err)
-				}
-			})
-			return
-		} else {
-			go ph.closeConnFromRequest(ctx, request, err)
-		}
-
-		// Clear handoff state if not returned for retry
-		seqID := request.Conn.GetMovingSeqID()
-		connID := request.Conn.GetID()
-		if ph.hitlessManager != nil {
-			ph.hitlessManager.UntrackOperationWithConnID(seqID, connID)
-		}
-	}
-}
-
-// closeConn closes the connection and logs the reason
-func (ph *PoolHook) closeConnFromRequest(ctx context.Context, request HandoffRequest, err error) {
-	pooler := request.Pool
-	conn := request.Conn
-	if pooler != nil {
-		pooler.Remove(ctx, conn, err)
-		if ph.config != nil && ph.config.LogLevel.WarnOrAbove() { // Warning level
-			internal.Logger.Printf(ctx,
-				"hitless: removed conn[%d] from pool due to max handoff retries reached: %v",
-				conn.GetID(), err)
-		}
-	} else {
-		conn.Close()
-		if ph.config != nil && ph.config.LogLevel.WarnOrAbove() { // Warning level
-			internal.Logger.Printf(ctx,
-				"hitless: no pool provided for conn[%d], cannot remove due to handoff initialization failure: %v",
-				conn.GetID(), err)
-		}
-	}
-}
-
-// queueHandoff queues a handoff request for processing
-// if err is returned, connection will be removed from pool
-func (ph *PoolHook) queueHandoff(conn *pool.Conn) error {
-	// Create handoff request
-	request := HandoffRequest{
-		Conn:     conn,
-		ConnID:   conn.GetID(),
-		Endpoint: conn.GetHandoffEndpoint(),
-		SeqID:    conn.GetMovingSeqID(),
-		Pool:     ph.pool, // Include pool for connection removal on failure
-	}
-
-	select {
-	// priority to shutdown
-	case <-ph.shutdown:
-		return ErrShutdown
-	default:
-		select {
-		case <-ph.shutdown:
-			return ErrShutdown
-		case ph.handoffQueue <- request:
-			// Store in pending map
-			ph.pending.Store(request.ConnID, request.SeqID)
-			// Ensure we have a worker to process this request
-			ph.ensureWorkerAvailable()
-			return nil
-		default:
-			select {
-			case <-ph.shutdown:
-				return ErrShutdown
-			case ph.handoffQueue <- request:
-				// Store in pending map
-				ph.pending.Store(request.ConnID, request.SeqID)
-				// Ensure we have a worker to process this request
-				ph.ensureWorkerAvailable()
-				return nil
-			case <-time.After(100 * time.Millisecond): // give workers a chance to process
-				// Queue is full - log and attempt scaling
-				queueLen := len(ph.handoffQueue)
-				queueCap := cap(ph.handoffQueue)
-				if ph.config != nil && ph.config.LogLevel.WarnOrAbove() { // Warning level
-					internal.Logger.Printf(context.Background(),
-						"hitless: handoff queue is full (%d/%d), cant queue handoff request for conn[%d] seqID[%d]",
-						queueLen, queueCap, request.ConnID, request.SeqID)
-					if ph.config.LogLevel.DebugOrAbove() { // Debug level
-						ph.pending.Range(func(k, v interface{}) bool {
-							internal.Logger.Printf(context.Background(), "hitless: pending handoff for conn[%d] seqID[%d]", k, v)
-							return true
-						})
-					}
-				}
-			}
-		}
-	}
-
-	// Ensure we have workers available to handle the load
-	ph.ensureWorkerAvailable()
-	return ErrHandoffQueueFull
-}
-
-// performConnectionHandoff performs the actual connection handoff
-// When error is returned, the connection handoff should be retried if err is not ErrMaxHandoffRetriesReached
-func (ph *PoolHook) performConnectionHandoff(ctx context.Context, conn *pool.Conn) (shouldRetry bool, err error) {
-	// Clear handoff state after successful handoff
-	connID := conn.GetID()
-
-	newEndpoint := conn.GetHandoffEndpoint()
-	if newEndpoint == "" {
-		return false, ErrConnectionInvalidHandoffState
-	}
-
-	retries := conn.IncrementAndGetHandoffRetries(1)
-	internal.Logger.Printf(ctx, "hitless: conn[%d] Retry %d: Performing handoff to %s(was %s)", conn.GetID(), retries, newEndpoint, conn.RemoteAddr().String())
-	maxRetries := 3 // Default fallback
-	if ph.config != nil {
-		maxRetries = ph.config.MaxHandoffRetries
-	}
-
-	if retries > maxRetries {
-		if ph.config != nil && ph.config.LogLevel.WarnOrAbove() { // Warning level
-			internal.Logger.Printf(ctx,
-				"hitless: reached max retries (%d) for handoff of conn[%d] to %s",
-				maxRetries, conn.GetID(), conn.GetHandoffEndpoint())
-		}
-		// won't retry on ErrMaxHandoffRetriesReached
-		return false, ErrMaxHandoffRetriesReached
-	}
-
-	// Create endpoint-specific dialer
-	endpointDialer := ph.createEndpointDialer(newEndpoint)
-
-	// Create new connection to the new endpoint
-	newNetConn, err := endpointDialer(ctx)
-	if err != nil {
-		internal.Logger.Printf(ctx, "hitless: conn[%d] Failed to dial new endpoint %s: %v", conn.GetID(), newEndpoint, err)
-		// hitless: will retry
-		// Maybe a network error - retry after a delay
-		return true, err
-	}
-
-	// Get the old connection
-	oldConn := conn.GetNetConn()
-
-	// Apply relaxed timeout to the new connection for the configured post-handoff duration
-	// This gives the new connection more time to handle operations during cluster transition
-	// Setting this here (before initing the connection) ensures that the connection is going
-	// to use the relaxed timeout for the first operation (auth/ACL select)
-	if ph.config != nil && ph.config.PostHandoffRelaxedDuration > 0 {
-		relaxedTimeout := ph.config.RelaxedTimeout
-		// Set relaxed timeout with deadline - no background goroutine needed
-		deadline := time.Now().Add(ph.config.PostHandoffRelaxedDuration)
-		conn.SetRelaxedTimeoutWithDeadline(relaxedTimeout, relaxedTimeout, deadline)
-
-		if ph.config.LogLevel.InfoOrAbove() {
-			internal.Logger.Printf(context.Background(),
-				"hitless: conn[%d] applied post-handoff relaxed timeout (%v) until %v",
-				connID, relaxedTimeout, deadline.Format("15:04:05.000"))
-		}
-	}
-
-	// Replace the connection and execute initialization
-	err = conn.SetNetConnAndInitConn(ctx, newNetConn)
-	if err != nil {
-		// hitless: won't retry
-		// Initialization failed - remove the connection
-		return false, err
-	}
-	defer func() {
-		if oldConn != nil {
-			oldConn.Close()
-		}
-	}()
-
-	conn.ClearHandoffState()
-	internal.Logger.Printf(ctx, "hitless: conn[%d] Handoff to %s successful", conn.GetID(), newEndpoint)
-
-	return false, nil
-}
-
-// createEndpointDialer creates a dialer function that connects to a specific endpoint
-func (ph *PoolHook) createEndpointDialer(endpoint string) func(context.Context) (net.Conn, error) {
-	return func(ctx context.Context) (net.Conn, error) {
-		// Parse endpoint to extract host and port
-		host, port, err := net.SplitHostPort(endpoint)
-		if err != nil {
-			// If no port specified, assume default Redis port
-			host = endpoint
-			if port == "" {
-				port = "6379"
-			}
-		}
-
-		// Use the base dialer to connect to the new endpoint
-		return ph.baseDialer(ctx, ph.network, net.JoinHostPort(host, port))
-	}
-}
-
 // Shutdown gracefully shuts down the processor, waiting for workers to complete
 func (ph *PoolHook) Shutdown(ctx context.Context) error {
-	ph.shutdownOnce.Do(func() {
-		close(ph.shutdown)
-		// workers will exit when they finish their current request
-	})
-
-	// Wait for workers to complete
-	done := make(chan struct{})
-	go func() {
-		ph.workerWg.Wait()
-		close(done)
-	}()
-
-	select {
-	case <-done:
-		return nil
-	case <-ctx.Done():
-		return ctx.Err()
-	}
+	return ph.workerManager.shutdownWorkers(ctx)
 }

hitless/pool_hook_test.go

@@ -169,7 +169,7 @@ func TestConnectionHook(t *testing.T) {
 		}
 
 		// Connection should be in pending map while initialization is blocked
-		if _, pending := processor.pending.Load(conn.GetID()); !pending {
+		if _, pending := processor.GetPendingMap().Load(conn.GetID()); !pending {
 			t.Error("Connection should be in pending handoffs map")
 		}
 
@@ -187,14 +187,14 @@ func TestConnectionHook(t *testing.T) {
 			case <-timeout:
 				t.Fatal("Timeout waiting for handoff to complete")
 			case <-ticker.C:
-				if _, pending := processor.pending.Load(conn); !pending {
+				if _, pending := processor.GetPendingMap().Load(conn); !pending {
 					handoffCompleted = true
 				}
 			}
 		}
 
 		// Verify handoff completed (removed from pending map)
-		if _, pending := processor.pending.Load(conn); pending {
+		if _, pending := processor.GetPendingMap().Load(conn); pending {
 			t.Error("Connection should be removed from pending map after handoff")
 		}
 
@@ -306,14 +306,14 @@ func TestConnectionHook(t *testing.T) {
 			case <-timeout:
 				t.Fatal("Timeout waiting for failed handoff to complete")
 			case <-ticker.C:
-				if _, pending := processor.pending.Load(conn.GetID()); !pending {
+				if _, pending := processor.GetPendingMap().Load(conn.GetID()); !pending {
 					handoffCompleted = true
 				}
 			}
 		}
 
 		// Connection should be removed from pending map after failed handoff
-		if _, pending := processor.pending.Load(conn.GetID()); pending {
+		if _, pending := processor.GetPendingMap().Load(conn.GetID()); pending {
 			t.Error("Connection should be removed from pending map after failed handoff")
 		}
 
@@ -380,8 +380,8 @@ func TestConnectionHook(t *testing.T) {
 
 		// Simulate a pending handoff by marking for handoff and queuing
 		conn.MarkForHandoff("new-endpoint:6379", 12345)
-		processor.pending.Store(conn.GetID(), int64(12345)) // Store connID -> seqID
-		conn.MarkQueuedForHandoff()                         // Mark as queued (sets usable=false)
+		processor.GetPendingMap().Store(conn.GetID(), int64(12345)) // Store connID -> seqID
+		conn.MarkQueuedForHandoff()                                 // Mark as queued (sets usable=false)
 
 		ctx := context.Background()
 		err := processor.OnGet(ctx, conn, false)
@@ -390,7 +390,7 @@ func TestConnectionHook(t *testing.T) {
 		}
 
 		// Clean up
-		processor.pending.Delete(conn)
+		processor.GetPendingMap().Delete(conn)
 	})
 
 	t.Run("EventDrivenStateManagement", func(t *testing.T) {
@@ -400,16 +400,16 @@ func TestConnectionHook(t *testing.T) {
 		conn := createMockPoolConnection()
 
 		// Test initial state - no pending handoffs
-		if _, pending := processor.pending.Load(conn); pending {
+		if _, pending := processor.GetPendingMap().Load(conn); pending {
 			t.Error("New connection should not have pending handoffs")
 		}
 
 		// Test adding to pending map
 		conn.MarkForHandoff("new-endpoint:6379", 12345)
-		processor.pending.Store(conn.GetID(), int64(12345)) // Store connID -> seqID
-		conn.MarkQueuedForHandoff()                         // Mark as queued (sets usable=false)
+		processor.GetPendingMap().Store(conn.GetID(), int64(12345)) // Store connID -> seqID
+		conn.MarkQueuedForHandoff()                                 // Mark as queued (sets usable=false)
 
-		if _, pending := processor.pending.Load(conn.GetID()); !pending {
+		if _, pending := processor.GetPendingMap().Load(conn.GetID()); !pending {
 			t.Error("Connection should be in pending map")
 		}
 
@@ -421,8 +421,8 @@ func TestConnectionHook(t *testing.T) {
 		}
 
 		// Test removing from pending map and clearing handoff state
-		processor.pending.Delete(conn)
-		if _, pending := processor.pending.Load(conn); pending {
+		processor.GetPendingMap().Delete(conn)
+		if _, pending := processor.GetPendingMap().Load(conn); pending {
 			t.Error("Connection should be removed from pending map")
 		}
 
@@ -510,14 +510,14 @@ func TestConnectionHook(t *testing.T) {
 		if processor.GetCurrentWorkers() != 0 {
 			t.Errorf("Expected 0 initial workers with on-demand system, got %d", processor.GetCurrentWorkers())
 		}
-		if processor.maxWorkers != 15 {
-			t.Errorf("Expected maxWorkers=15, got %d", processor.maxWorkers)
+		if processor.GetMaxWorkers() != 15 {
+			t.Errorf("Expected maxWorkers=15, got %d", processor.GetMaxWorkers())
 		}
 
 		// The on-demand worker behavior creates workers only when needed
 		// This test just verifies the basic configuration is correct
 		t.Logf("On-demand worker configuration verified - Max: %d, Current: %d",
-			processor.maxWorkers, processor.GetCurrentWorkers())
+			processor.GetMaxWorkers(), processor.GetCurrentWorkers())
 	})
 
 	t.Run("PassiveTimeoutRestoration", func(t *testing.T) {
@@ -567,7 +567,7 @@ func TestConnectionHook(t *testing.T) {
 			case <-timeout:
 				t.Fatal("Timeout waiting for handoff to complete")
 			case <-ticker.C:
-				if _, pending := processor.pending.Load(conn); !pending {
+				if _, pending := processor.GetPendingMap().Load(conn); !pending {
 					handoffCompleted = true
 				}
 			}
@@ -701,7 +701,7 @@ func TestConnectionHook(t *testing.T) {
 		defer processor.Shutdown(context.Background())
 
 		// Verify queue capacity matches configured size
-		queueCapacity := cap(processor.handoffQueue)
+		queueCapacity := cap(processor.GetHandoffQueue())
 		if queueCapacity != 50 {
 			t.Errorf("Expected queue capacity 50, got %d", queueCapacity)
 		}
@@ -734,7 +734,7 @@ func TestConnectionHook(t *testing.T) {
 		}
 
 		// Verify queue capacity remains static (the main purpose of this test)
-		finalCapacity := cap(processor.handoffQueue)
+		finalCapacity := cap(processor.GetHandoffQueue())
 
 		if finalCapacity != 50 {
 			t.Errorf("Queue capacity should remain static at 50, got %d", finalCapacity)
@@ -851,7 +851,7 @@ func TestConnectionHook(t *testing.T) {
 			case <-timeout:
 				t.Fatal("Timeout waiting for handoff to complete")
 			case <-ticker.C:
-				if _, pending := processor.pending.Load(conn); !pending {
+				if _, pending := processor.GetPendingMap().Load(conn); !pending {
 					handoffCompleted = true
 				}
 			}