feat: enhance push notification handlers with context information

Author: ndyakov

internal/pool/conn.go

@@ -7,7 +7,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/redis/go-redis/v9/internal"
 	"github.com/redis/go-redis/v9/internal/proto"
 	"github.com/redis/go-redis/v9/internal/pushnotif"
 )
@@ -78,16 +77,8 @@ func (cn *Conn) RemoteAddr() net.Addr {
 func (cn *Conn) WithReader(
 	ctx context.Context, timeout time.Duration, fn func(rd *proto.Reader) error,
 ) error {
-	// Process any pending push notifications before executing the read function
-	// This ensures push notifications are handled as soon as they arrive
-	if cn.PushNotificationProcessor != nil {
-		// Type assert to the processor interface
-		if err := cn.PushNotificationProcessor.ProcessPendingNotifications(ctx, cn.rd); err != nil {
-			// Log the error but don't fail the read operation
-			// Push notification processing errors shouldn't break normal Redis operations
-			internal.Logger.Printf(ctx, "push: error processing pending notifications in WithReader: %v", err)
-		}
-	}
+	// Push notification processing is now handled by the client before calling WithReader
+	// This ensures proper context (client, connection pool, connection) is available to handlers
 
 	if timeout >= 0 {
 		if err := cn.netConn.SetReadDeadline(cn.deadline(ctx, timeout)); err != nil {

internal/pool/pool.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/redis/go-redis/v9/internal"
+	"github.com/redis/go-redis/v9/internal/proto"
 	"github.com/redis/go-redis/v9/internal/pushnotif"
 )
 
@@ -237,11 +238,6 @@ func (p *ConnPool) dialConn(ctx context.Context, pooled bool) (*Conn, error) {
 	cn := NewConn(netConn)
 	cn.pooled = pooled
 
-	// Set push notification processor if available
-	if p.cfg.PushNotificationProcessor != nil {
-		cn.PushNotificationProcessor = p.cfg.PushNotificationProcessor
-	}
-
 	return cn, nil
 }
 
@@ -392,23 +388,18 @@ func (p *ConnPool) popIdle() (*Conn, error) {
 func (p *ConnPool) Put(ctx context.Context, cn *Conn) {
 	if cn.rd.Buffered() > 0 {
 		// Check if this might be push notification data
-		if cn.PushNotificationProcessor != nil && p.cfg.Protocol == 3 {
-			// Only process for RESP3 clients (push notifications only available in RESP3)
-			err := cn.PushNotificationProcessor.ProcessPendingNotifications(ctx, cn.rd)
-			if err != nil {
-				internal.Logger.Printf(ctx, "push: error processing pending notifications: %v", err)
-			}
-			// Check again if there's still unread data after processing push notifications
-			if cn.rd.Buffered() > 0 {
-				internal.Logger.Printf(ctx, "Conn has unread data after processing push notifications")
-				p.Remove(ctx, cn, BadConnError{})
+		if p.cfg.Protocol == 3 {
+			if replyType, err := cn.rd.PeekReplyType(); err == nil && replyType == proto.RespPush {
+				// For push notifications, we allow some buffered data
+				// The client will process these notifications before using the connection
+				internal.Logger.Printf(ctx, "push: connection has buffered data, likely push notifications - will be processed by client")
 				return
 			}
-		} else {
-			internal.Logger.Printf(ctx, "Conn has unread data")
-			p.Remove(ctx, cn, BadConnError{})
-			return
 		}
+		// For non-RESP3 or data that is not a push notification, buffered data is unexpected
+		internal.Logger.Printf(ctx, "Conn has unread data")
+		p.Remove(ctx, cn, BadConnError{})
+		return
 	}
 
 	if !cn.pooled {
@@ -554,19 +545,17 @@ func (p *ConnPool) isHealthyConn(cn *Conn) bool {
 
 	// Check connection health, but be aware of push notifications
 	if err := connCheck(cn.netConn); err != nil {
-		// If there's unexpected data and we have push notification support,
-		// it might be push notifications (only for RESP3)
-		if err == errUnexpectedRead && cn.PushNotificationProcessor != nil && p.cfg.Protocol == 3 {
-			// Try to process any pending push notifications (only for RESP3)
-			ctx := context.Background()
-			if procErr := cn.PushNotificationProcessor.ProcessPendingNotifications(ctx, cn.rd); procErr != nil {
-				internal.Logger.Printf(ctx, "push: error processing pending notifications during health check: %v", procErr)
-				return false
-			}
-			// Check again after processing push notifications
-			if connCheck(cn.netConn) != nil {
-				return false
+		// If there's unexpected data, it might be push notifications (RESP3)
+		// However, push notification processing is now handled by the client
+		// before WithReader to ensure proper context is available to handlers
+		if err == errUnexpectedRead && p.cfg.Protocol == 3 {
+			if replyType, err := cn.rd.PeekReplyType(); err == nil && replyType == proto.RespPush {
+				// For RESP3 connections with push notifications, we allow some buffered data
+				// The client will process these notifications before using the connection
+				internal.Logger.Printf(context.Background(), "push: connection has buffered data, likely push notifications - will be processed by client")
+				return true // Connection is healthy, client will handle notifications
 			}
+			return false // Unexpected data, not push notifications, connection is unhealthy
 		} else {
 			return false
 		}

internal/pushnotif/processor.go

@@ -39,7 +39,8 @@ func (p *Processor) UnregisterHandler(pushNotificationName string) error {
 }
 
 // ProcessPendingNotifications checks for and processes any pending push notifications.
-func (p *Processor) ProcessPendingNotifications(ctx context.Context, rd *proto.Reader) error {
+// The handlerCtx provides context about the client, connection pool, and connection.
+func (p *Processor) ProcessPendingNotifications(ctx context.Context, handlerCtx *HandlerContext, rd *proto.Reader) error {
 	// Check for nil reader
 	if rd == nil {
 		return nil
@@ -98,8 +99,8 @@ func (p *Processor) ProcessPendingNotifications(ctx context.Context, rd *proto.R
 
 				// Get the handler for this notification type
 				if handler := p.registry.GetHandler(notificationType); handler != nil {
-					// Handle the notification
-					handler.HandlePushNotification(ctx, notification)
+					// Handle the notification with context
+					handler.HandlePushNotification(ctx, handlerCtx, notification)
 				}
 			}
 		}
@@ -176,10 +177,10 @@ func (v *VoidProcessor) UnregisterHandler(pushNotificationName string) error {
 }
 
 // ProcessPendingNotifications for VoidProcessor does nothing since push notifications
-// are only available in RESP3 and this processor is used when they're disabled.
+// are only available in RESP3 and this processor is used for RESP2 connections.
 // This avoids unnecessary buffer scanning overhead.
-func (v *VoidProcessor) ProcessPendingNotifications(ctx context.Context, rd *proto.Reader) error {
-	// VoidProcessor is used when push notifications are disabled (typically RESP2 or disabled RESP3).
+func (v *VoidProcessor) ProcessPendingNotifications(ctx context.Context, handlerCtx *HandlerContext, rd *proto.Reader) error {
+	// VoidProcessor is used for RESP2 connections where push notifications are not available.
 	// Since push notifications only exist in RESP3, we can safely skip all processing
 	// to avoid unnecessary buffer scanning overhead.
 	return nil

internal/pushnotif/pushnotif_test.go

@@ -25,8 +25,10 @@ func NewTestHandler(name string, returnValue bool) *TestHandler {
 	}
 }
 
-func (h *TestHandler) HandlePushNotification(ctx context.Context, notification []interface{}) bool {
+func (h *TestHandler) HandlePushNotification(ctx context.Context, handlerCtx *HandlerContext, notification []interface{}) bool {
 	h.handled = append(h.handled, notification)
+	// Store the handler context for testing if needed
+	_ = handlerCtx
 	return h.returnValue
 }
 
@@ -131,6 +133,13 @@ func testProcessPendingNotifications(processor *Processor, ctx context.Context,
 		return nil
 	}
 
+	// Create a test handler context
+	handlerCtx := &HandlerContext{
+		Client:   nil,
+		ConnPool: nil,
+		Conn:     nil,
+	}
+
 	for {
 		// Check if there are push notifications available
 		replyType, err := reader.PeekReplyType()
@@ -175,8 +184,8 @@ func testProcessPendingNotifications(processor *Processor, ctx context.Context,
 			if notificationType, ok := notification[0].(string); ok {
 				// Get the handler for this notification type
 				if handler := processor.registry.GetHandler(notificationType); handler != nil {
-					// Handle the notification
-					handler.HandlePushNotification(ctx, notification)
+					// Handle the notification with context
+					handler.HandlePushNotification(ctx, handlerCtx, notification)
 				}
 			}
 		}
@@ -420,14 +429,19 @@ func TestProcessor(t *testing.T) {
 		ctx := context.Background()
 
 		// Test with nil reader
-		err := processor.ProcessPendingNotifications(ctx, nil)
+		handlerCtx := &HandlerContext{
+			Client:   nil,
+			ConnPool: nil,
+			Conn:     nil,
+		}
+		err := processor.ProcessPendingNotifications(ctx, handlerCtx, nil)
 		if err != nil {
 			t.Errorf("ProcessPendingNotifications with nil reader should not error, got: %v", err)
 		}
 
 		// Test with empty reader (no buffered data)
 		reader := proto.NewReader(strings.NewReader(""))
-		err = processor.ProcessPendingNotifications(ctx, reader)
+		err = processor.ProcessPendingNotifications(ctx, handlerCtx, reader)
 		if err != nil {
 			t.Errorf("ProcessPendingNotifications with empty reader should not error, got: %v", err)
 		}
@@ -533,21 +547,21 @@ func TestProcessor(t *testing.T) {
 
 		// Test the actual ProcessPendingNotifications method with real proto.Reader
 		// Test with nil reader
-		err = processor.ProcessPendingNotifications(ctx, nil)
+		err = processor.ProcessPendingNotifications(ctx, handlerCtx, nil)
 		if err != nil {
 			t.Errorf("ProcessPendingNotifications with nil reader should not error, got: %v", err)
 		}
 
 		// Test with empty reader (no buffered data)
 		protoReader := proto.NewReader(strings.NewReader(""))
-		err = processor.ProcessPendingNotifications(ctx, protoReader)
+		err = processor.ProcessPendingNotifications(ctx, handlerCtx, protoReader)
 		if err != nil {
 			t.Errorf("ProcessPendingNotifications with empty reader should not error, got: %v", err)
 		}
 
 		// Test with reader that has some data but not push notifications
 		protoReader = proto.NewReader(strings.NewReader("+OK\r\n"))
-		err = processor.ProcessPendingNotifications(ctx, protoReader)
+		err = processor.ProcessPendingNotifications(ctx, handlerCtx, protoReader)
 		if err != nil {
 			t.Errorf("ProcessPendingNotifications with non-push data should not error, got: %v", err)
 		}
@@ -637,22 +651,27 @@ func TestVoidProcessor(t *testing.T) {
 	t.Run("ProcessPendingNotifications", func(t *testing.T) {
 		processor := NewVoidProcessor()
 		ctx := context.Background()
+		handlerCtx := &HandlerContext{
+			Client:   nil,
+			ConnPool: nil,
+			Conn:     nil,
+		}
 
 		// VoidProcessor should always succeed and do nothing
-		err := processor.ProcessPendingNotifications(ctx, nil)
+		err := processor.ProcessPendingNotifications(ctx, handlerCtx, nil)
 		if err != nil {
 			t.Errorf("VoidProcessor ProcessPendingNotifications should never error, got: %v", err)
 		}
 
 		// Test with various readers
 		reader := proto.NewReader(strings.NewReader(""))
-		err = processor.ProcessPendingNotifications(ctx, reader)
+		err = processor.ProcessPendingNotifications(ctx, handlerCtx, reader)
 		if err != nil {
 			t.Errorf("VoidProcessor ProcessPendingNotifications should never error, got: %v", err)
 		}
 
 		reader = proto.NewReader(strings.NewReader("some data"))
-		err = processor.ProcessPendingNotifications(ctx, reader)
+		err = processor.ProcessPendingNotifications(ctx, handlerCtx, reader)
 		if err != nil {
 			t.Errorf("VoidProcessor ProcessPendingNotifications should never error, got: %v", err)
 		}

internal/pushnotif/types.go

@@ -6,17 +6,32 @@ import (
 	"github.com/redis/go-redis/v9/internal/proto"
 )
 
+// HandlerContext provides context information about where a push notification was received.
+// This allows handlers to make informed decisions based on the source of the notification.
+type HandlerContext struct {
+	// Client is the Redis client instance that received the notification
+	Client interface{}
+
+	// ConnPool is the connection pool from which the connection was obtained
+	ConnPool interface{}
+
+	// Conn is the specific connection on which the notification was received
+	Conn interface{}
+}
+
 // Handler defines the interface for push notification handlers.
 type Handler interface {
-	// HandlePushNotification processes a push notification.
+	// HandlePushNotification processes a push notification with context information.
+	// The handlerCtx provides information about the client, connection pool, and connection
+	// on which the notification was received, allowing handlers to make informed decisions.
 	// Returns true if the notification was handled, false otherwise.
-	HandlePushNotification(ctx context.Context, notification []interface{}) bool
+	HandlePushNotification(ctx context.Context, handlerCtx *HandlerContext, notification []interface{}) bool
 }
 
 // ProcessorInterface defines the interface for push notification processors.
 type ProcessorInterface interface {
 	GetHandler(pushNotificationName string) Handler
-	ProcessPendingNotifications(ctx context.Context, rd *proto.Reader) error
+	ProcessPendingNotifications(ctx context.Context, handlerCtx *HandlerContext, rd *proto.Reader) error
 	RegisterHandler(pushNotificationName string, handler Handler, protected bool) error
 }
 

options.go

@@ -217,19 +217,11 @@ type Options struct {
 	// When unstable mode is enabled, the client will use RESP3 protocol and only be able to use RawResult
 	UnstableResp3 bool
 
-	// PushNotifications enables general push notification processing.
-	// When enabled, the client will process RESP3 push notifications and
-	// route them to registered handlers.
-	//
-	// For RESP3 connections (Protocol: 3), push notifications are always enabled
-	// and cannot be disabled. To avoid push notifications, use Protocol: 2 (RESP2).
-	// For RESP2 connections, push notifications are not available.
-	//
-	// default: always enabled for RESP3, disabled for RESP2
-	PushNotifications bool
+	// Push notifications are always enabled for RESP3 connections (Protocol: 3)
+	// and are not available for RESP2 connections. No configuration option is needed.
 
 	// PushNotificationProcessor is the processor for handling push notifications.
-	// If nil, a default processor will be created when PushNotifications is enabled.
+	// If nil, a default processor will be created for RESP3 connections.
 	PushNotificationProcessor PushNotificationProcessorInterface
 }
 

osscluster.go

@@ -1623,7 +1623,7 @@ func (c *ClusterClient) processTxPipelineNode(
 }
 
 func (c *ClusterClient) processTxPipelineNodeConn(
-	ctx context.Context, _ *clusterNode, cn *pool.Conn, cmds []Cmder, failedCmds *cmdsMap,
+	ctx context.Context, node *clusterNode, cn *pool.Conn, cmds []Cmder, failedCmds *cmdsMap,
 ) error {
 	if err := cn.WithWriter(c.context(ctx), c.opt.WriteTimeout, func(wr *proto.Writer) error {
 		return writeCmds(wr, cmds)
@@ -1641,7 +1641,7 @@ func (c *ClusterClient) processTxPipelineNodeConn(
 		trimmedCmds := cmds[1 : len(cmds)-1]
 
 		if err := c.txPipelineReadQueued(
-			ctx, rd, statusCmd, trimmedCmds, failedCmds,
+			ctx, node, cn, rd, statusCmd, trimmedCmds, failedCmds,
 		); err != nil {
 			setCmdsErr(cmds, err)
 
@@ -1653,30 +1653,50 @@ func (c *ClusterClient) processTxPipelineNodeConn(
 			return err
 		}
 
-		return pipelineReadCmds(rd, trimmedCmds)
+		return node.Client.pipelineReadCmds(ctx, cn, rd, trimmedCmds)
 	})
 }
 
 func (c *ClusterClient) txPipelineReadQueued(
 	ctx context.Context,
+	node *clusterNode,
+	cn *pool.Conn,
 	rd *proto.Reader,
 	statusCmd *StatusCmd,
 	cmds []Cmder,
 	failedCmds *cmdsMap,
 ) error {
 	// Parse queued replies.
+	// To be sure there are no buffered push notifications, we process them before reading the reply
+	if err := node.Client.processPendingPushNotificationWithReader(ctx, cn, rd); err != nil {
+		// Log the error but don't fail the command execution
+		// Push notification processing errors shouldn't break normal Redis operations
+		internal.Logger.Printf(ctx, "push: error processing pending notifications before reading reply: %v", err)
+	}
 	if err := statusCmd.readReply(rd); err != nil {
 		return err
 	}
 
 	for _, cmd := range cmds {
+		// To be sure there are no buffered push notifications, we process them before reading the reply
+		if err := node.Client.processPendingPushNotificationWithReader(ctx, cn, rd); err != nil {
+			// Log the error but don't fail the command execution
+			// Push notification processing errors shouldn't break normal Redis operations
+			internal.Logger.Printf(ctx, "push: error processing pending notifications before reading reply: %v", err)
+		}
 		err := statusCmd.readReply(rd)
 		if err == nil || c.checkMovedErr(ctx, cmd, err, failedCmds) || isRedisError(err) {
 			continue
 		}
 		return err
 	}
 
+	// To be sure there are no buffered push notifications, we process them before reading the reply
+	if err := node.Client.processPendingPushNotificationWithReader(ctx, cn, rd); err != nil {
+		// Log the error but don't fail the command execution
+		// Push notification processing errors shouldn't break normal Redis operations
+		internal.Logger.Printf(ctx, "push: error processing pending notifications before reading reply: %v", err)
+	}
 	// Parse number of replies.
 	line, err := rd.ReadLine()
 	if err != nil {