canal 環境搭建 canal 與kafka通信（三）

canal 占用了生產者

.net core端 使用消費者獲取canal 消息

安裝 Confluent.Kafka  demo使用 1.3.0

 public static void Consumer()
        {
            var conf = new ConsumerConfig
            {
                GroupId = "canal-group",
                BootstrapServers = "192.168.1.26:9092",
                // Note: The AutoOffsetReset property determines the start offset in the event
                // there are not yet any committed offsets for the consumer group for the
                // topic/partitions of interest. By default, offsets are committed
                // automatically, so in this example, consumption will only start from the
                // earliest message in the topic 'my-topic' the first time you run the program.
                AutoOffsetReset = AutoOffsetReset.Earliest,
                EnableAutoCommit = true //是否自動提交  默認為true


            };

            using (var c = new ConsumerBuilder<Ignore, string>(conf).Build())
            {
                //指定 消費那個分區
                //c.Assign(new TopicPartition ("flexmall13",new Partition ()))
                c.Subscribe("flexmall13");

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

                try
                {
                    while (true)
                    {
                        try
                        {
                            var cr = c.Consume(cts.Token);
                            Console.WriteLine($"Consumed message '{cr.Value}' at: '{cr.TopicPartitionOffset}'.");

                            //如果配置 自動提交為 否 需要手動提交

                            //c.Commit();
                            //c.Commit(new List<TopicPartitionOffset>() { cr.TopicPartitionOffset });
                        }
                        catch (ConsumeException e)
                        {
                            Console.WriteLine($"Error occured: {e.Error.Reason}");
                        }
                    }
                }
                catch (OperationCanceledException e)
                {
                    // Ensure the consumer leaves the group cleanly and final offsets are committed.

                    Console.WriteLine($"OperationCanceledException occured: {e.StackTrace}");
                    c.Close();
                }
            }
        }
    }

注意：

1. 在config項 中 有 EnableAutoCommit 設置是否自動應答提交，默認是 true，如果設置為否，需要在消費后，手動 commit。

2.消費者指定訂閱 分區，如果不指定使用Subscribe，指定需要使用Assign