fix offset of single active consumer reset to 0 (#336)

* fix consumer offset being reset to 0 when closing consumer when no messages have been consumed

pkg/stream/client.go

@@ -891,7 +891,9 @@ func (c *Client) DeclareSubscriber(streamName string,
 	// copy the option offset to the consumer offset
 	// the option.offset won't change ( in case we need to retrive the original configuration)
 	// consumer.current offset will be moved when reading
-	consumer.setCurrentOffset(options.Offset.offset)
+	if !options.IsSingleActiveConsumerEnabled() {
+		consumer.setCurrentOffset(options.Offset.offset)
+	}
 
 	/// define the consumerOptions
 	consumerProperties := make(map[string]string)

pkg/stream/consumer_sac_test.go

@@ -187,4 +187,64 @@ var _ = Describe("Streaming Single Active Consumer", func() {
 		Expect(c2.Close()).NotTo(HaveOccurred())
 	})
 
+	It("offset should not be overwritten by autocommit on consumer close when no messages have been consumed", func() {
+		producer, err := testEnvironment.NewProducer(streamName, nil)
+		Expect(err).NotTo(HaveOccurred())
+
+		consumerUpdate := func(streamName string, isActive bool) OffsetSpecification {
+			offset, err := testEnvironment.QueryOffset("my_consumer", streamName)
+			if err != nil {
+				return OffsetSpecification{}.First()
+			}
+
+			return OffsetSpecification{}.Offset(offset + 1)
+		}
+
+		var messagesReceived int32 = 0
+		consumerA, err := testEnvironment.NewConsumer(streamName,
+			func(consumerContext ConsumerContext, message *amqp.Message) {
+				atomic.AddInt32(&messagesReceived, 1)
+			}, NewConsumerOptions().
+				SetSingleActiveConsumer(NewSingleActiveConsumer(consumerUpdate)).
+				SetConsumerName("my_consumer").
+				SetAutoCommit(nil))
+		Expect(err).NotTo(HaveOccurred())
+
+		Expect(producer.BatchSend(CreateArrayMessagesForTesting(10))).NotTo(HaveOccurred())
+		Eventually(func() int32 {
+			return atomic.LoadInt32(&messagesReceived)
+		}, 5*time.Second).Should(Equal(int32(10)),
+			"consumer should receive only 10 messages")
+
+		Expect(consumerA.Close()).NotTo(HaveOccurred())
+		Expect(consumerA.GetLastStoredOffset()).To(Equal(int64(9)))
+
+		offset, err := testEnvironment.QueryOffset("my_consumer", streamName)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(offset).To(Equal(int64(9)))
+
+		messagesReceived = 0
+		consumerB, err := testEnvironment.NewConsumer(streamName,
+			func(consumerContext ConsumerContext, message *amqp.Message) {
+				atomic.AddInt32(&messagesReceived, 1)
+			}, NewConsumerOptions().
+				SetConsumerName("my_consumer").
+				SetSingleActiveConsumer(NewSingleActiveConsumer(consumerUpdate)).
+				SetAutoCommit(nil))
+		Expect(err).NotTo(HaveOccurred())
+
+		Expect(consumerB.Close()).NotTo(HaveOccurred())
+		time.Sleep(100 * time.Millisecond)
+		Eventually(func() int32 {
+			return atomic.LoadInt32(&messagesReceived)
+		}, 5*time.Second).Should(Equal(int32(0)),
+			"consumer should have received no messages")
+
+		offsetAfter, err := testEnvironment.QueryOffset("my_consumer", streamName)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(offsetAfter).To(Equal(int64(9)))
+
+		Expect(producer.Close()).NotTo(HaveOccurred())
+	})
+
 })

pkg/stream/coordinator.go

@@ -202,6 +202,7 @@ func (coordinator *Coordinator) NewConsumer(messagesHandler MessagesHandler,
 		status:             open,
 		mutex:              &sync.Mutex{},
 		MessagesHandler:    messagesHandler,
+		currentOffset:      -1, // currentOffset has to equal lastStoredOffset as the currentOffset 0 may otherwise be flushed to the server when the consumer is closed and auto commit is enabled
 		lastStoredOffset:   -1, // because 0 is a valid value for the offset
 		isPromotedAsActive: true,
 	}

pkg/stream/server_frame.go

@@ -603,6 +603,11 @@ func (c *Client) handleConsumerUpdate(readProtocol *ReaderProtocol, r *bufio.Rea
 	responseOff := consumer.options.SingleActiveConsumer.ConsumerUpdate(consumer.GetStreamName(),
 		isActive == 1)
 	consumer.options.SingleActiveConsumer.offsetSpecification = responseOff
+
+	if isActive == 1 {
+		consumer.setCurrentOffset(responseOff.offset)
+	}
+
 	err = consumer.writeConsumeUpdateOffsetToSocket(readProtocol.CorrelationId, responseOff)
 	logErrorCommand(err, "handleConsumerUpdate writeConsumeUpdateOffsetToSocket")
 }