ensure bare AckNxt requesting >1 is supported

Signed-off-by: R.I.Pienaar <rip@devco.net>

server/consumer.go

@@ -158,6 +158,8 @@ var (
 	AckNext = []byte("+NXT")
 	// Terminate delivery of the message.
 	AckTerm = []byte("+TERM")
+
+	ackNextCnt = "+NXT %d+"
 )
 
 // Consumer is a jetstream consumer.
@@ -718,7 +720,7 @@ func (o *Consumer) processAck(_ *subscription, _ *client, subject, reply string,
 	switch {
 	case len(msg) == 0, bytes.Equal(msg, AckAck), bytes.Equal(msg, AckOK):
 		o.ackMsg(sseq, dseq, dcount)
-	case bytes.Equal(msg, AckNext):
+	case bytes.HasPrefix(msg, AckNext):
 		o.ackMsg(sseq, dseq, dcount)
 		o.processNextMsgReq(nil, nil, subject, reply, msg)
 		skipAckReply = true
@@ -1070,11 +1072,20 @@ func nextReqFromMsg(msg []byte) (time.Time, int, bool, error) {
 		}
 		return cr.Expires, cr.Batch, cr.NoWait, nil
 	}
-	// Naked batch size here for backward compatibility.
+
 	bs := 1
-	if n, err := strconv.Atoi(req); err == nil {
-		bs = n
+	// Naked batch size here for backward compatibility.
+	switch {
+	case bytes.HasPrefix(msg, AckNext):
+		if n, _ := fmt.Sscanf(string(msg), ackNextCnt, &bs); n == 0 {
+			bs = 1
+		}
+	default:
+		if n, err := strconv.Atoi(req); err == nil {
+			bs = n
+		}
 	}
+
 	return time.Time{}, bs, false, nil
 }
 

test/jetstream_test.go

@@ -15,6 +15,7 @@ package test
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -82,6 +83,7 @@ func RunBasicJetStreamServer() *server.Server {
 	opts := DefaultTestOptions
 	opts.Port = -1
 	opts.JetStream = true
+	opts.NoLog = true
 	return RunServer(&opts)
 }
 
@@ -2988,14 +2990,14 @@ func TestJetStreamConsumerAckAck(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Expected no error with registered interest, got %v", err)
 	}
-	rqn := o.RequestNextMsgSubject()
 	defer o.Delete()
+	rqn := o.RequestNextMsgSubject()
 
 	nc := clientConnectToServer(t, s)
 	defer nc.Close()
 
-	// 5 for number of ack protocols to test them all.
-	for i := 0; i < 5; i++ {
+	// 4 for number of ack protocols to test them all.
+	for i := 0; i < 4; i++ {
 		sendStreamMsg(t, nc, mname, "Hello World!")
 	}
 
@@ -3013,10 +3015,92 @@ func TestJetStreamConsumerAckAck(t *testing.T) {
 	testAck(server.AckAck)
 	testAck(server.AckNak)
 	testAck(server.AckProgress)
-	testAck(server.AckNext)
 	testAck(server.AckTerm)
 }
 
+func TestJetStreamNack(t *testing.T) {
+	s := RunBasicJetStreamServer()
+	defer s.Shutdown()
+
+	if config := s.JetStreamConfig(); config != nil {
+		defer os.RemoveAll(config.StoreDir)
+	}
+
+	mname := "ACKNXT"
+	mset, err := s.GlobalAccount().AddStream(&server.StreamConfig{Name: mname, Storage: server.MemoryStorage})
+	if err != nil {
+		t.Fatalf("Unexpected error adding stream: %v", err)
+	}
+	defer mset.Delete()
+
+	o, err := mset.AddConsumer(&server.ConsumerConfig{Durable: "worker", AckPolicy: server.AckExplicit})
+	if err != nil {
+		t.Fatalf("Expected no error with registered interest, got %v", err)
+	}
+	defer o.Delete()
+
+	nc := clientConnectToServer(t, s)
+	defer nc.Close()
+
+	for i := 0; i < 10; i++ {
+		sendStreamMsg(t, nc, mname, fmt.Sprintf("msg %d", i))
+	}
+
+	q := make(chan *nats.Msg, 10)
+	sub, err := nc.ChanSubscribe(nats.NewInbox(), q)
+	if err != nil {
+		t.Fatalf("SubscribeSync failed: %s", err)
+	}
+
+	nc.PublishRequest(o.RequestNextMsgSubject(), sub.Subject, []byte("1"))
+
+	// normal next should imply 1
+	msg := <-q
+	err = msg.RespondMsg(&nats.Msg{Reply: sub.Subject, Subject: msg.Reply, Data: server.AckNext})
+	if err != nil {
+		t.Fatalf("RespondMsg failed: %s", err)
+	}
+
+	// read 1 message and check ack was done etc
+	msg = <-q
+	if len(q) != 0 {
+		t.Fatalf("Expected empty q got %d", len(q))
+	}
+	if o.Info().AckFloor.StreamSeq != 1 {
+		t.Fatalf("First message was not acknowledged")
+	}
+	if !bytes.Equal(msg.Data, []byte("msg 1")) {
+		t.Fatalf("wrong message received, expected: msg 1 got %q", msg.Data)
+	}
+
+	// now ack and request 5 more
+	err = msg.RespondMsg(&nats.Msg{Reply: sub.Subject, Subject: msg.Reply, Data: append(server.AckNext, []byte(" 5")...)})
+	if err != nil {
+		t.Fatalf("RespondMsg failed: %s", err)
+	}
+
+	// check next+cnt worked and got the right amount of messages, use ctx to avoid
+	// sleeps when all is working
+	ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
+	defer cancel()
+
+	for i := 1; i < 6; i++ {
+		select {
+		case msg := <-q:
+			expect := fmt.Sprintf("msg %d", i+1)
+			if !bytes.Equal(msg.Data, []byte(expect)) {
+				t.Fatalf("wrong message received, expected: %s", expect)
+			}
+		case <-ctx.Done():
+			t.Fatalf("did not receive all messages")
+		}
+	}
+
+	if o.Info().AckFloor.StreamSeq != 2 {
+		t.Fatalf("second message was not acknowledged")
+	}
+}
+
 func TestJetStreamPublishDeDupe(t *testing.T) {
 	s := RunBasicJetStreamServer()
 	defer s.Shutdown()