Allow batching in JetStreamConsumer (#2686)

This allows us to receive more than one message from NATS at a time if we want.

federationapi/consumers/keychange.go

@@ -67,14 +67,15 @@ func NewKeyChangeConsumer(
 // Start consuming from key servers
 func (t *KeyChangeConsumer) Start() error {
 	return jetstream.JetStreamConsumer(
-		t.ctx, t.jetstream, t.topic, t.durable, t.onMessage,
-		nats.DeliverAll(), nats.ManualAck(),
+		t.ctx, t.jetstream, t.topic, t.durable, 1,
+		t.onMessage, nats.DeliverAll(), nats.ManualAck(),
 	)
 }
 
 // onMessage is called in response to a message received on the
 // key change events topic from the key server.
-func (t *KeyChangeConsumer) onMessage(ctx context.Context, msg *nats.Msg) bool {
+func (t *KeyChangeConsumer) onMessage(ctx context.Context, msgs []*nats.Msg) bool {
+	msg := msgs[0] // Guaranteed to exist if onMessage is called
 	var m api.DeviceMessage
 	if err := json.Unmarshal(msg.Data, &m); err != nil {
 		logrus.WithError(err).Errorf("failed to read device message from key change topic")

federationapi/consumers/presence.go

@@ -69,14 +69,15 @@ func (t *OutputPresenceConsumer) Start() error {
 		return nil
 	}
 	return jetstream.JetStreamConsumer(
-		t.ctx, t.jetstream, t.topic, t.durable, t.onMessage,
+		t.ctx, t.jetstream, t.topic, t.durable, 1, t.onMessage,
 		nats.DeliverAll(), nats.ManualAck(), nats.HeadersOnly(),
 	)
 }
 
 // onMessage is called in response to a message received on the presence
 // events topic from the client api.
-func (t *OutputPresenceConsumer) onMessage(ctx context.Context, msg *nats.Msg) bool {
+func (t *OutputPresenceConsumer) onMessage(ctx context.Context, msgs []*nats.Msg) bool {
+	msg := msgs[0] // Guaranteed to exist if onMessage is called
 	// only send presence events which originated from us
 	userID := msg.Header.Get(jetstream.UserID)
 	_, serverName, err := gomatrixserverlib.SplitID('@', userID)

federationapi/consumers/receipts.go

@@ -65,14 +65,15 @@ func NewOutputReceiptConsumer(
 // Start consuming from the clientapi
 func (t *OutputReceiptConsumer) Start() error {
 	return jetstream.JetStreamConsumer(
-		t.ctx, t.jetstream, t.topic, t.durable, t.onMessage,
+		t.ctx, t.jetstream, t.topic, t.durable, 1, t.onMessage,
 		nats.DeliverAll(), nats.ManualAck(), nats.HeadersOnly(),
 	)
 }
 
 // onMessage is called in response to a message received on the receipt
 // events topic from the client api.
-func (t *OutputReceiptConsumer) onMessage(ctx context.Context, msg *nats.Msg) bool {
+func (t *OutputReceiptConsumer) onMessage(ctx context.Context, msgs []*nats.Msg) bool {
+	msg := msgs[0] // Guaranteed to exist if onMessage is called
 	receipt := syncTypes.OutputReceiptEvent{
 		UserID:  msg.Header.Get(jetstream.UserID),
 		RoomID:  msg.Header.Get(jetstream.RoomID),

federationapi/consumers/roomserver.go

@@ -68,8 +68,8 @@ func NewOutputRoomEventConsumer(
 // Start consuming from room servers
 func (s *OutputRoomEventConsumer) Start() error {
 	return jetstream.JetStreamConsumer(
-		s.ctx, s.jetstream, s.topic, s.durable, s.onMessage,
-		nats.DeliverAll(), nats.ManualAck(),
+		s.ctx, s.jetstream, s.topic, s.durable, 1,
+		s.onMessage, nats.DeliverAll(), nats.ManualAck(),
 	)
 }
 
@@ -77,7 +77,8 @@ func (s *OutputRoomEventConsumer) Start() error {
 // It is unsafe to call this with messages for the same room in multiple gorountines
 // because updates it will likely fail with a types.EventIDMismatchError when it
 // realises that it cannot update the room state using the deltas.
-func (s *OutputRoomEventConsumer) onMessage(ctx context.Context, msg *nats.Msg) bool {
+func (s *OutputRoomEventConsumer) onMessage(ctx context.Context, msgs []*nats.Msg) bool {
+	msg := msgs[0] // Guaranteed to exist if onMessage is called
 	// Parse out the event JSON
 	var output api.OutputEvent
 	if err := json.Unmarshal(msg.Data, &output); err != nil {

federationapi/consumers/sendtodevice.go

@@ -63,14 +63,15 @@ func NewOutputSendToDeviceConsumer(
 // Start consuming from the client api
 func (t *OutputSendToDeviceConsumer) Start() error {
 	return jetstream.JetStreamConsumer(
-		t.ctx, t.jetstream, t.topic, t.durable, t.onMessage,
-		nats.DeliverAll(), nats.ManualAck(),
+		t.ctx, t.jetstream, t.topic, t.durable, 1,
+		t.onMessage, nats.DeliverAll(), nats.ManualAck(),
 	)
 }
 
 // onMessage is called in response to a message received on the
 // send-to-device events topic from the client api.
-func (t *OutputSendToDeviceConsumer) onMessage(ctx context.Context, msg *nats.Msg) bool {
+func (t *OutputSendToDeviceConsumer) onMessage(ctx context.Context, msgs []*nats.Msg) bool {
+	msg := msgs[0] // Guaranteed to exist if onMessage is called
 	// only send send-to-device events which originated from us
 	sender := msg.Header.Get("sender")
 	_, originServerName, err := gomatrixserverlib.SplitID('@', sender)

federationapi/consumers/typing.go

@@ -62,14 +62,15 @@ func NewOutputTypingConsumer(
 // Start consuming from the clientapi
 func (t *OutputTypingConsumer) Start() error {
 	return jetstream.JetStreamConsumer(
-		t.ctx, t.jetstream, t.topic, t.durable, t.onMessage,
+		t.ctx, t.jetstream, t.topic, t.durable, 1, t.onMessage,
 		nats.DeliverAll(), nats.ManualAck(), nats.HeadersOnly(),
 	)
 }
 
 // onMessage is called in response to a message received on the typing
 // events topic from the client api.
-func (t *OutputTypingConsumer) onMessage(ctx context.Context, msg *nats.Msg) bool {
+func (t *OutputTypingConsumer) onMessage(ctx context.Context, msgs []*nats.Msg) bool {
+	msg := msgs[0] // Guaranteed to exist if onMessage is called
 	// Extract the typing event from msg.
 	roomID := msg.Header.Get(jetstream.RoomID)
 	userID := msg.Header.Get(jetstream.UserID)