Orleans.KafkaStreamProvider.KafkaQueue.KafkaQueueAdapterReceiver.GetQueueMessagesAsync C# (CSharp) Method

        public async Task<IList<IBatchContainer>> GetQueueMessagesAsync(int maxCount)
        {
            try
            {
                Task<IEnumerable<Message>> fetchingTask;
                IList<IBatchContainer> batches = new List<IBatchContainer>();

                using (TimerTimeToGetMessageFromKafka.NewContext(Id.ToString()))
                {
                    fetchingTask = _consumer.FetchMessages(maxCount, CurrentOffset);

                    await Task.WhenAny(fetchingTask, Task.Delay(_options.ReceiveWaitTimeInMs));
                }

                // Checking that the task completed successfully
                if (!fetchingTask.IsCompleted)
                {
                    _logger.Warn((int)KafkaErrorCodes.KafkaStreamProviderBase,
                        "KafkaQueueAdapterReceiver - Fetching operation was not completed, tried to fetch {0} messages from offest {1}",
                        maxCount, CurrentOffset);
                    return batches;
                }
                if (fetchingTask.IsFaulted && fetchingTask.Exception != null)
                {
                    _logger.Warn((int)KafkaErrorCodes.KafkaStreamProviderBase,
                        "KafkaQueueAdapterReceiver - Fetching messages from kafka failed, tried to fetch {0} messages from offest {1}",
                        maxCount, CurrentOffset);
                    throw fetchingTask.Exception;
                }
                if (fetchingTask.Result == null)
                {
                    return batches;
                }

                var messages = fetchingTask.Result.ToList();
                batches = messages.Select(m => _factory.FromKafkaMessage(m, m.Meta.Offset)).ToList();

                // No batches, we are done here..
                if (batches.Count <= 0) return batches;

                _logger.Verbose("KafkaQueueAdapterReceiver - Pulled {0} messages for queue number {1}", batches.Count, Id.GetNumericId());
                CurrentOffset += batches.Count;

                // Taking a bit of metrics
                MeterConsumedMessagesPerSecond.Mark(Id.ToString(), 1);
                HistogramConsumedMessagesPerFetch.Update(batches.Count, Id.ToString());

                return batches;
            }
            catch (BufferUnderRunException)
            {
                // This case the next message in the queue is too big for us to read, so we skip it
                _logger.Error((int)KafkaErrorCodes.KafkaStreamProviderBase, $"KafkaQueueAdapterReceiver - A message in the Kafka queue was too big to pull, skipping over it. offset was {CurrentOffset}");
                CurrentOffset++;

                return new List<IBatchContainer>();
            }
        }

        public async Task GetMessageFailGotNull()
        {
            Mock<IManualConsumer> consumerMock = new Mock<IManualConsumer>();

            consumerMock.Setup(x => x.FetchMessages(It.IsAny<int>(), It.IsAny<long>())).ReturnsAsync(null);

            Mock<IKafkaBatchFactory> factoryMock = new Mock<IKafkaBatchFactory>();

            KafkaQueueAdapterReceiver adapterReceiverMock = new KafkaQueueAdapterReceiver(_id, consumerMock.Object, _options, factoryMock.Object, _logger);

            int numToTake = 3;

            var result = await adapterReceiverMock.GetQueueMessagesAsync(numToTake);

            Assert.AreEqual(0, result.Count);
        }