C#实现kafka消息队列-Confluent.Kafka

一、本文是C#引用Confluent.Kafka.dll实现kafka消息队列的实际开发例子。在实际开发中遇到9094端口始终消息生产和消费超时的问题，需要对网络白名单进行配置或者直接使用9092端口。大部分Time Out情况与代码无关，跟kafka的安装配置有关。

二、、Nuget中添加引用Confluent.Kafka

三、消费

public class KafkaConsumer
    {
        public static string brokerUrl = ConfigurationManager.AppSettings["Broker"];
        public static string topic = ConfigurationManager.AppSettings["ConsumeTopic"];
        public static string groupid = ConfigurationManager.AppSettings["GroupID"];
        public static string consumercount = ConfigurationManager.AppSettings["ConsumerCount"];
        public static void Consume()
        {
            var mode = "consume";
            var brokerList = brokerUrl;
            List topics = new List(topic.Split(','));

            try
            {
                CancellationTokenSource cts = new CancellationTokenSource();
                Console.CancelKeyPress += (_, e) =>
                {
                    e.Cancel = true; // prevent the process from terminating.
                    cts.Cancel();
                };

                switch (mode)
                {
                    case "consume":
                        Run_Consume(brokerList, topics, cts.Token);
                        break;
                    case "manual":
                        Run_ManualAssign(brokerList, topics, cts.Token);
                        break;
                    default:
                        PrintUsage();
                        break;
                }
            }
            catch (Exception ex)
            {
                LogHelper.WriteProgramLog(DateTime.Now.ToString() + ex.Message);
            }

        }
        /// 

        ///     In this example
        ///         - offsets are manually committed.
        ///         - no extra thread is created for the Poll (Consume) loop.
        /// 
        public static void Run_Consume(string brokerList, List topics, CancellationToken cancellationToken)
        {
            var config = new ConsumerConfig
            {
                BootstrapServers = brokerList,
                GroupId = groupid,
                EnableAutoCommit = false,
                StatisticsIntervalMs = 5000,
                SessionTimeoutMs = 6000,
                AutoOffsetReset = AutoOffsetResetType.Earliest
            };

            const int commitPeriod = 5;

            using (var consumer = new Consumer(config))
            {
                consumer.Subscribe(topics);

                while (!cancellationToken.IsCancellationRequested)
                {
                    try
                    {
                        var consumeResult = consumer.Consume(cancellationToken);
                        if (consumeResult.Offset % commitPeriod == 0)
                        {
                            // The Commit method sends a "commit offsets" request to the Kafka
                            // cluster and synchronously waits for the response. This is very
                            // slow compared to the rate at which the consumer is capable of
                            // consuming messages. A high performance application will typically
                            // commit offsets relatively infrequently and be designed handle
                            // duplicate messages in the event of failure.
                            var committedOffsets = consumer.Commit(consumeResult);
                            Console.WriteLine(string.Format("Committed offset: {0}", committedOffsets));
                        }
                    }
                    catch (ConsumeException e)
                    {
                        Console.WriteLine(string.Format("Consume error: {0}", e.Error));
                    }
                }

                consumer.Close();
            }
        }
        /// 

        ///     In this example
        ///         - consumer group functionality (i.e. .Subscribe + offset commits) is not used.
        ///         - the consumer is manually assigned to a partition and always starts consumption
        ///           from a specific offset (0).
        /// 
        public static void Run_ManualAssign(string brokerList, List topics, CancellationToken cancellationToken)
        {
            var config = new ConsumerConfig
            {
                // the group.id property must be specified when creating a consumer, even 
                // if you do not intend to use any consumer group functionality.
                GroupId = new Guid().ToString(),
                BootstrapServers = brokerList,
                // partition offsets can be committed to a group even by consumers not
                // subscribed to the group. in this example, auto commit is disabled
                // to prevent this from occuring.
                EnableAutoCommit = true
            };

            using (var consumer = new Consumer(config))
            {
                consumer.Assign(topics.Select(topic => new TopicPartitionOffset(topic, 0, Offset.Beginning)).ToList());

                consumer.OnError += (_, e)
                    => Console.WriteLine(string.Format("Error: {0}", e.Reason));

                consumer.OnPartitionEOF += (_, topicPartitionOffset)
                    => Console.WriteLine(string.Format("End of partition: {0}", topicPartitionOffset));

                while (!cancellationToken.IsCancellationRequested)
                {
                    try
                    {
                        var consumeResult = consumer.Consume(cancellationToken);
                        Console.WriteLine(string.Format("Received message at {0}:${1}", consumeResult.TopicPartitionOffset, consumeResult.Message));
                    }
                    catch (ConsumeException e)
                    {
                        Console.WriteLine(string.Format("Consume error: {0}", e.Error));
                    }
                }

                consumer.Close();
            }
        }
        private static void PrintUsage()
        {
            Console.WriteLine("Usage: ..    [topic..]");
        }
    }

四、生产

/// 

    /// Kafka消息生产者
    /// 
    public class KafkaProducer
    {
        public static string brokerUrl = ConfigurationManager.AppSettings["Broker"];
        public static string topic = ConfigurationManager.AppSettings["ProduceTopic"];
        public static string groupid = ConfigurationManager.AppSettings["GroupID"];
        private static readonly object Locker = new object();
        private static Producer _producer;
        /// 

        /// 单例生产
        /// 
        public KafkaProducer()
        {
            if (_producer == null)
            {
                lock (Locker)
                {
                    if (_producer == null)
                    {
                        var config = new ProducerConfig
                        {
                            BootstrapServers = brokerUrl
                        };
                        _producer = new Producer(config);
                    }
                }
            }
        }

        /// 

        /// 生产消息并发送消息
        /// 
        /// key
        /// 需要传送的消息
        public static void Produce(string key, string message)
        {
            bool result = false;
            new KafkaProducer();
            if (string.IsNullOrEmpty(message) || string.IsNullOrWhiteSpace(message) || message.Length <= 0)
            {
                throw new ArgumentNullException("消息内容不能为空！");
            }
            var deliveryReport = _producer.ProduceAsync(topic, new Message { Key = key, Value = message });
            deliveryReport.ContinueWith(task =>
            {
                Console.WriteLine("Producer：" + _producer.Name + "\r\nTopic：" + topic + "\r\nPartition：" + task.Result.Partition + "\r\nOffset：" + task.Result.Offset + "\r\nMessage：" + task.Result.Value + "\r\nResult：" + result);
            });
            _producer.Flush(TimeSpan.FromSeconds(10));
        }
    }