communicate publication delta option in no history case

broker.go

@@ -35,7 +35,7 @@ type ClientInfo struct {
 // BrokerEventHandler can handle messages received from PUB/SUB system.
 type BrokerEventHandler interface {
 	// HandlePublication to handle received Publications.
-	HandlePublication(ch string, pub *Publication, sp StreamPosition, prevPub *Publication) error
+	HandlePublication(ch string, pub *Publication, sp StreamPosition, useDelta bool, prevPub *Publication) error
 	// HandleJoin to handle received Join messages.
 	HandleJoin(ch string, info *ClientInfo) error
 	// HandleLeave to handle received Leave messages.

broker_memory.go

@@ -121,7 +121,7 @@ func (b *MemoryBroker) Publish(ch string, data []byte, opts PublishOptions) (Str
 			}
 			b.saveResultToCache(ch, opts.IdempotencyKey, streamTop, resultExpireSeconds)
 		}
-		return streamTop, false, b.eventHandler.HandlePublication(ch, pub, streamTop, prevPub)
+		return streamTop, false, b.eventHandler.HandlePublication(ch, pub, streamTop, opts.UseDelta, prevPub)
 	}
 	streamPosition := StreamPosition{}
 	if opts.IdempotencyKey != "" {
@@ -131,7 +131,7 @@ func (b *MemoryBroker) Publish(ch string, data []byte, opts PublishOptions) (Str
 		}
 		b.saveResultToCache(ch, opts.IdempotencyKey, streamPosition, resultExpireSeconds)
 	}
-	return streamPosition, false, b.eventHandler.HandlePublication(ch, pub, StreamPosition{}, prevPub)
+	return streamPosition, false, b.eventHandler.HandlePublication(ch, pub, StreamPosition{}, opts.UseDelta, prevPub)
 }
 
 func (b *MemoryBroker) getResultFromCache(ch string, key string) (StreamPosition, bool) {

broker_memory_test.go

@@ -141,7 +141,7 @@ func TestMemoryBrokerPublishIdempotent(t *testing.T) {
 	numPubs := 0
 
 	e.eventHandler = &testBrokerEventHandler{
-		HandlePublicationFunc: func(ch string, pub *Publication, sp StreamPosition, prevPub *Publication) error {
+		HandlePublicationFunc: func(ch string, pub *Publication, sp StreamPosition, delta bool, prevPub *Publication) error {
 			numPubs++
 			return nil
 		},
@@ -169,7 +169,7 @@ func TestMemoryBrokerPublishIdempotentWithHistory(t *testing.T) {
 	numPubs := 0
 
 	e.eventHandler = &testBrokerEventHandler{
-		HandlePublicationFunc: func(ch string, pub *Publication, sp StreamPosition, prevPub *Publication) error {
+		HandlePublicationFunc: func(ch string, pub *Publication, sp StreamPosition, delta bool, prevPub *Publication) error {
 			numPubs++
 			return nil
 		},

broker_redis.go

@@ -614,6 +614,12 @@ func (b *RedisBroker) publish(s *shardWrapper, ch string, data []byte, opts Publ
 		Info: infoToProto(opts.ClientInfo),
 		Tags: opts.Tags,
 	}
+	if opts.HistorySize <= 0 || opts.HistoryTTL <= 0 {
+		// In no history case we communicate delta flag over Publication field. This field is then
+		// cleaned up before passing to the Node layer when handling Redis message.
+		protoPub.Delta = opts.UseDelta
+	}
+
 	byteMessage, err := protoPub.MarshalVT()
 	if err != nil {
 		return StreamPosition{}, false, err
@@ -1019,15 +1025,21 @@ func (b *RedisBroker) handleRedisClientMessage(eventHandler BrokerEventHandler,
 			// it to unmarshalled Publication.
 			pub.Offset = sp.Offset
 		}
+		if pub.Delta {
+			// In at most once scenario we are passing delta in Publication itself. But need to clean it
+			// before passing further.
+			delta = true
+			pub.Delta = false
+		}
 		if delta && len(prevPayload) > 0 {
 			var prevPub protocol.Publication
 			err = prevPub.UnmarshalVT(prevPayload)
 			if err != nil {
 				return err
 			}
-			_ = eventHandler.HandlePublication(channel, pubFromProto(&pub), sp, pubFromProto(&prevPub))
+			_ = eventHandler.HandlePublication(channel, pubFromProto(&pub), sp, true, pubFromProto(&prevPub))
 		} else {
-			_ = eventHandler.HandlePublication(channel, pubFromProto(&pub), sp, nil)
+			_ = eventHandler.HandlePublication(channel, pubFromProto(&pub), sp, delta, nil)
 		}
 	} else if pushType == joinPushType {
 		var info protocol.ClientInfo

channel_medium.go

@@ -97,13 +97,14 @@ type queuedPub struct {
 	pub                 *Publication
 	sp                  StreamPosition
 	prevPub             *Publication
+	delta               bool
 	isInsufficientState bool
 }
 
 const defaultChannelLayerQueueMaxSize = 16 * 1024 * 1024
 
-func (c *channelMedium) broadcastPublication(pub *Publication, sp StreamPosition, prevPub *Publication) {
-	bp := queuedPub{pub: pub, sp: sp, prevPub: prevPub}
+func (c *channelMedium) broadcastPublication(pub *Publication, sp StreamPosition, delta bool, prevPub *Publication) {
+	bp := queuedPub{pub: pub, sp: sp, prevPub: prevPub, delta: delta}
 	c.mu.Lock()
 	c.positionCheckTime = channelMediumTimeNow().UnixNano()
 	c.mu.Unlock()
@@ -151,7 +152,7 @@ func (c *channelMedium) broadcast(qp queuedPub) {
 	prevPub := qp.prevPub
 	var localPrevPub *Publication
 	useLocalLatestPub := c.options.KeepLatestPublication && !qp.isInsufficientState
-	if useLocalLatestPub {
+	if useLocalLatestPub && qp.delta {
 		localPrevPub = c.latestPublication
 	}
 	if c.options.broadcastDelay > 0 && !c.options.KeepLatestPublication {

channel_medium_test.go

@@ -77,7 +77,7 @@ func TestChannelMediumHandlePublication(t *testing.T) {
 			pub := &Publication{Data: []byte("test data")}
 			sp := StreamPosition{Offset: 1}
 
-			cache.broadcastPublication(pub, sp, nil)
+			cache.broadcastPublication(pub, sp, false, nil)
 
 			select {
 			case <-doneCh:

client_test.go

@@ -1545,7 +1545,7 @@ func TestClientPublishNotAvailable(t *testing.T) {
 
 type testBrokerEventHandler struct {
 	// Publication must register callback func to handle Publications received.
-	HandlePublicationFunc func(ch string, pub *Publication, sp StreamPosition, prevPub *Publication) error
+	HandlePublicationFunc func(ch string, pub *Publication, sp StreamPosition, delta bool, prevPub *Publication) error
 	// Join must register callback func to handle Join messages received.
 	HandleJoinFunc func(ch string, info *ClientInfo) error
 	// Leave must register callback func to handle Leave messages received.
@@ -1554,9 +1554,9 @@ type testBrokerEventHandler struct {
 	HandleControlFunc func([]byte) error
 }
 
-func (b *testBrokerEventHandler) HandlePublication(ch string, pub *Publication, sp StreamPosition, prevPub *Publication) error {
+func (b *testBrokerEventHandler) HandlePublication(ch string, pub *Publication, sp StreamPosition, delta bool, prevPub *Publication) error {
 	if b.HandlePublicationFunc != nil {
-		return b.HandlePublicationFunc(ch, pub, sp, prevPub)
+		return b.HandlePublicationFunc(ch, pub, sp, delta, prevPub)
 	}
 	return nil
 }
@@ -1602,7 +1602,7 @@ func TestClientPublishHandler(t *testing.T) {
 	connectClientV2(t, client)
 
 	node.broker.(*MemoryBroker).eventHandler = &testBrokerEventHandler{
-		HandlePublicationFunc: func(ch string, pub *Publication, sp StreamPosition, prevPub *Publication) error {
+		HandlePublicationFunc: func(ch string, pub *Publication, sp StreamPosition, delta bool, prevPub *Publication) error {
 			var msg testClientMessage
 			err := json.Unmarshal(pub.Data, &msg)
 			require.NoError(t, err)

node.go

@@ -1594,7 +1594,7 @@ type brokerEventHandler struct {
 }
 
 // HandlePublication coming from Broker.
-func (h *brokerEventHandler) HandlePublication(ch string, pub *Publication, sp StreamPosition, prevPub *Publication) error {
+func (h *brokerEventHandler) HandlePublication(ch string, pub *Publication, sp StreamPosition, delta bool, prevPub *Publication) error {
 	if pub == nil {
 		panic("nil Publication received, this must never happen")
 	}
@@ -1604,7 +1604,7 @@ func (h *brokerEventHandler) HandlePublication(ch string, pub *Publication, sp S
 		medium, ok := h.node.mediums[ch]
 		mu.Unlock()
 		if ok {
-			medium.broadcastPublication(pub, sp, prevPub)
+			medium.broadcastPublication(pub, sp, delta, prevPub)
 			return nil
 		}
 	}

node_test.go

@@ -1175,7 +1175,7 @@ func TestBrokerEventHandler_PanicsOnNil(t *testing.T) {
 	defer func() { _ = node.Shutdown(context.Background()) }()
 	handler := &brokerEventHandler{node: node}
 	require.Panics(t, func() {
-		_ = handler.HandlePublication("test", nil, StreamPosition{}, nil)
+		_ = handler.HandlePublication("test", nil, StreamPosition{}, false, nil)
 	})
 	require.Panics(t, func() {
 		_ = handler.HandleJoin("test", nil)