fix: jetstream switch to new API, discard buffer on close

internal/sub/jetstream.go

@@ -20,7 +20,7 @@ type (
 	}
 
 	JetStreamSub struct {
-		jsConsumer jetstream.Consumer
+		jsIter    jetstream.MessagesContext
 		logg      *slog.Logger
 		natsConn  *nats.Conn
 		router    *router.Router
@@ -33,7 +33,7 @@ const (
 	pullSubject = "TRACKER.*"
 )
 
-func NewJetStreamSub(o JetStreamOpts) (Sub, error) {
+func NewJetStreamSub(o JetStreamOpts) (*JetStreamSub, error) {
 	natsConn, err := nats.Connect(o.Endpoint)
 	if err != nil {
 		return nil, err
@@ -55,14 +55,23 @@ func NewJetStreamSub(o JetStreamOpts) (Sub, error) {
 	consumer, err := stream.CreateOrUpdateConsumer(ctx, jetstream.ConsumerConfig{
 		Durable:       o.JetStreamID,
 		AckPolicy:     jetstream.AckExplicitPolicy,
+		FilterSubject: pullSubject,
 	})
 	if err != nil {
 		return nil, err
 	}
 	o.Logg.Info("successfully connected to NATS server")
 
+	iter, err := consumer.Messages(
+		jetstream.WithMessagesErrOnMissingHeartbeat(false),
+		jetstream.PullMaxMessages(100),
+	)
+	if err != nil {
+		return nil, err
+	}
+
 	return &JetStreamSub{
-		jsConsumer: consumer,
+		jsIter:    iter,
 		router:    o.Router,
 		natsConn:  natsConn,
 		logg:      o.Logg,
@@ -71,34 +80,25 @@ func NewJetStreamSub(o JetStreamOpts) (Sub, error) {
 }
 
 func (s *JetStreamSub) Close() {
-	if s.natsConn != nil {
-		s.natsConn.Close()
-	}
+	s.jsIter.Stop()
 }
 
-func (s *JetStreamSub) Process() error {
-	iter, err := s.jsConsumer.Messages(jetstream.WithMessagesErrOnMissingHeartbeat(false))
-	if err != nil {
-		return err
-	}
-	defer iter.Stop()
-
+func (s *JetStreamSub) Process() {
 	for {
-		msg, err := iter.Next()
+		msg, err := s.jsIter.Next()
 		if err != nil {
-			if errors.Is(err, nats.ErrTimeout) {
-				s.logg.Error("jetstream: iter fetch timeout")
-				continue
-			} else if errors.Is(err, nats.ErrConnectionClosed) {
-				return nil
+			if errors.Is(err, jetstream.ErrMsgIteratorClosed) {
+				s.logg.Debug("jetstream: iterator closed")
+				return
 			} else {
-				return err
+				s.logg.Debug("jetstream: unknown iterator error", "error", err)
+				continue
 			}
 		}
 
-		s.logg.Info("processing nats message", "subject", msg.Subject())
+		s.logg.Debug("processing nats message", "subject", msg.Subject())
 		if err := s.router.Handle(context.Background(), msg); err != nil {
-			s.logg.Error("router: error processing nats message", "error", err)
+			s.logg.Error("jetstream: router: error processing nats message", "error", err)
 		}
 	}
 }

internal/sub/sub.go

@@ -1,6 +0,0 @@
-package sub
-
-type Sub interface {
-	Process() error
-	Close()
-}

internal/telegram/telegram.go

@@ -19,8 +19,7 @@ type (
 )
 
 const (
-	NOTIFY_LOW_BALANCE_ON_GAS_FAUCET = `
-		Gas faucet balance is low. Top is required soon!`
+	NOTIFY_LOW_BALANCE_ON_GAS_FAUCET = "Gas faucet balance is low. Top-up is required soon!"
 )
 
 func New(o TelegramOpts) *Telegram {