Add consumer Owner ID

Signed-off-by: Tomasz Pietrek <tomasz@nats.io>

server/consumer.go

@@ -109,6 +109,7 @@ type ConsumerConfig struct {
 
 	// PauseUntil is for suspending the consumer until the deadline.
 	PauseUntil *time.Time `json:"pause_until,omitempty"`
+	OwnerID    string     `json:"owner_id,omitempty"`
 }
 
 // SequenceInfo has both the consumer and the stream sequence and last activity.
@@ -2976,36 +2977,36 @@ func (o *consumer) needAck(sseq uint64, subj string) bool {
 }
 
 // Helper for the next message requests.
-func nextReqFromMsg(msg []byte) (time.Time, int, int, bool, time.Duration, time.Time, error) {
+func nextReqFromMsg(msg []byte) (time.Time, int, int, bool, time.Duration, time.Time, string, error) {
 	req := bytes.TrimSpace(msg)
 
 	switch {
 	case len(req) == 0:
-		return time.Time{}, 1, 0, false, 0, time.Time{}, nil
+		return time.Time{}, 1, 0, false, 0, time.Time{}, "", nil
 
 	case req[0] == '{':
 		var cr JSApiConsumerGetNextRequest
 		if err := json.Unmarshal(req, &cr); err != nil {
-			return time.Time{}, -1, 0, false, 0, time.Time{}, err
+			return time.Time{}, -1, 0, false, 0, time.Time{}, "", err
 		}
 		var hbt time.Time
 		if cr.Heartbeat > 0 {
 			if cr.Heartbeat*2 > cr.Expires {
-				return time.Time{}, 1, 0, false, 0, time.Time{}, errors.New("heartbeat value too large")
+				return time.Time{}, 1, 0, false, 0, time.Time{}, "", errors.New("heartbeat value too large")
 			}
 			hbt = time.Now().Add(cr.Heartbeat)
 		}
 		if cr.Expires == time.Duration(0) {
-			return time.Time{}, cr.Batch, cr.MaxBytes, cr.NoWait, cr.Heartbeat, hbt, nil
+			return time.Time{}, cr.Batch, cr.MaxBytes, cr.NoWait, cr.Heartbeat, hbt, cr.OwnerID, nil
 		}
-		return time.Now().Add(cr.Expires), cr.Batch, cr.MaxBytes, cr.NoWait, cr.Heartbeat, hbt, nil
+		return time.Now().Add(cr.Expires), cr.Batch, cr.MaxBytes, cr.NoWait, cr.Heartbeat, hbt, cr.OwnerID, nil
 	default:
 		if n, err := strconv.Atoi(string(req)); err == nil {
-			return time.Time{}, n, 0, false, 0, time.Time{}, nil
+			return time.Time{}, n, 0, false, 0, time.Time{}, "", nil
 		}
 	}
 
-	return time.Time{}, 1, 0, false, 0, time.Time{}, nil
+	return time.Time{}, 1, 0, false, 0, time.Time{}, "", nil
 }
 
 // Represents a request that is on the internal waiting queue
@@ -3321,12 +3322,18 @@ func (o *consumer) processNextMsgRequest(reply string, msg []byte) {
 	}
 
 	// Check payload here to see if they sent in batch size or a formal request.
-	expires, batchSize, maxBytes, noWait, hb, hbt, err := nextReqFromMsg(msg)
+	expires, batchSize, maxBytes, noWait, hb, hbt, ownerID, err := nextReqFromMsg(msg)
 	if err != nil {
 		sendErr(400, fmt.Sprintf("Bad Request - %v", err))
 		return
 	}
 
+	// Check the owner for exclusive consumer.
+	if o.cfg.OwnerID != _EMPTY_ && ownerID != o.cfg.OwnerID {
+		sendErr(409, "Consumer is owned by another client")
+		return
+	}
+
 	// Check for request limits
 	if o.cfg.MaxRequestBatch > 0 && batchSize > o.cfg.MaxRequestBatch {
 		sendErr(409, fmt.Sprintf("Exceeded MaxRequestBatch of %d", o.cfg.MaxRequestBatch))

server/jetstream_api.go

@@ -730,6 +730,7 @@ type JSApiConsumerGetNextRequest struct {
 	MaxBytes  int           `json:"max_bytes,omitempty"`
 	NoWait    bool          `json:"no_wait,omitempty"`
 	Heartbeat time.Duration `json:"idle_heartbeat,omitempty"`
+	OwnerID   string        `json:"owner_id,omitempty"`
 }
 
 // JSApiStreamTemplateCreateResponse for creating templates.

server/jetstream_consumer_test.go

@@ -31,6 +31,124 @@ import (
 	"github.com/nats-io/nuid"
 )
 
+func TestJetStreamConsumerExclusive(t *testing.T) {
+	s := RunBasicJetStreamServer(t)
+	defer s.Shutdown()
+
+	nc, js := jsClientConnect(t, s)
+	defer nc.Close()
+	acc := s.GlobalAccount()
+
+	mset, err := acc.addStream(&StreamConfig{
+		Name:      "TEST",
+		Retention: LimitsPolicy,
+		Subjects:  []string{"events.>"},
+		MaxAge:    time.Second * 90,
+	})
+	require_NoError(t, err)
+
+	_, err = mset.addConsumer(&ConsumerConfig{
+		Durable:       "consumer",
+		AckPolicy:     AckExplicit,
+		DeliverPolicy: DeliverAll,
+		FilterSubject: "events.>",
+		OwnerID:       "me",
+	})
+	require_NoError(t, err)
+
+	for i := 0; i < 10; i++ {
+		_, err = js.Publish("events.1", []byte("hello"))
+	}
+
+	// set ID that is not owned by us.
+	cr := JSApiConsumerGetNextRequest{
+		Batch:   1,
+		OwnerID: "notMe",
+	}
+	crBytes, err := json.Marshal(cr)
+	require_NoError(t, err)
+
+	inbox := nats.NewInbox()
+	err = nc.PublishRequest(fmt.Sprintf(JSApiRequestNextT, "TEST", "consumer"), inbox, crBytes)
+	require_NoError(t, err)
+
+	consumerSub, err := nc.SubscribeSync(inbox)
+	require_NoError(t, err)
+
+	msg, err := consumerSub.NextMsg(time.Second)
+	require_NoError(t, err)
+
+	// check if message header contains error "Consumer is owned by another client"
+	if !strings.Contains(string(msg.Header.Get("Description")), "Consumer is owned by another client") {
+		t.Fatalf("Expected exclusive consumer error, got %q", msg.Header.Get("Description"))
+	}
+
+	// now set our ID
+	cr = JSApiConsumerGetNextRequest{
+		Batch:   2,
+		OwnerID: "me",
+	}
+	crBytes, err = json.Marshal(cr)
+	require_NoError(t, err)
+
+	err = nc.PublishRequest(fmt.Sprintf(JSApiRequestNextT, "TEST", "consumer"), inbox, crBytes)
+	require_NoError(t, err)
+
+	msg, err = consumerSub.NextMsg(time.Second)
+	require_NoError(t, err)
+	require_Equal(t, string(msg.Data), "hello")
+
+	// update the consumer to different ID
+	_, err = mset.addConsumer(&ConsumerConfig{
+		Durable:       "consumer",
+		AckPolicy:     AckExplicit,
+		DeliverPolicy: DeliverAll,
+		FilterSubject: "events.>",
+		OwnerID:       "differentMe",
+	})
+
+	// we should still get messages from the pending pull requests
+	msg, err = consumerSub.NextMsg(time.Second)
+	require_NoError(t, err)
+	require_Equal(t, string(msg.Data), "hello")
+
+	// check if the previous ID works. It should not
+	cr = JSApiConsumerGetNextRequest{
+		Batch:   1,
+		OwnerID: "me",
+	}
+	crBytes, err = json.Marshal(cr)
+	require_NoError(t, err)
+
+	err = nc.PublishRequest(fmt.Sprintf(JSApiRequestNextT, "TEST", "consumer"), inbox, crBytes)
+	require_NoError(t, err)
+
+	msg, err = consumerSub.NextMsg(time.Second)
+	require_NoError(t, err)
+
+	// we should now get an error
+	if !strings.Contains(string(msg.Header.Get("Description")), "Consumer is owned by another client") {
+		t.Fatalf("Expected exclusive consumer error, got %q", msg.Header.Get("Description"))
+	}
+
+	// and this should work now
+
+	cr = JSApiConsumerGetNextRequest{
+		Batch:   1,
+		OwnerID: "differentMe",
+	}
+	crBytes, err = json.Marshal(cr)
+	require_NoError(t, err)
+
+	err = nc.PublishRequest(fmt.Sprintf(JSApiRequestNextT, "TEST", "consumer"), inbox, crBytes)
+	require_NoError(t, err)
+
+	msg, err = consumerSub.NextMsg(time.Second)
+	require_NoError(t, err)
+	require_Equal(t, string(msg.Data), "hello")
+
+}
+
 func TestJetStreamConsumerMultipleFiltersRemoveFilters(t *testing.T) {
 
 	s := RunBasicJetStreamServer(t)

server/jetstream_test.go

@@ -639,7 +639,7 @@ func TestJetStreamConsumerMaxDeliveries(t *testing.T) {
 
 func TestJetStreamNextReqFromMsg(t *testing.T) {
 	bef := time.Now()
-	expires, _, _, _, _, _, err := nextReqFromMsg([]byte(`{"expires":5000000000}`)) // nanoseconds
+	expires, _, _, _, _, _, _, err := nextReqFromMsg([]byte(`{"expires":5000000000}`)) // nanoseconds
 	require_NoError(t, err)
 	now := time.Now()
 	if expires.Before(bef.Add(5*time.Second)) || expires.After(now.Add(5*time.Second)) {