无法连接kafka集群时无异常

Question

当程序无法连接到kafka集群时，我无法得到异常。代码在控制台日志中输出异常，但我需要它抛出异常。我正在使用这个 c# 库： https://github.com/confluentinc/confluent-kafka-dotnet

ProducerConfig _configKafka = new ProducerConfig { BootstrapServers ="localhost:9092/" };

ProducerBuilder<string, string> _kafkaProducer = new ProducerBuilder<string, string>(_configKafka);
using (var kafkaProducer = _kafkaProducer.Build())
{

    try
    {
        var dr = kafkaProducer.ProduceAsync("Kafka_Messages", new Message<string, string> { Key = null, Value = $"message {i++}" });
        dr.Wait(TimeSpan.FromSeconds(10));

        if(dr.Exception!=null)
        {
            Console.WriteLine($"Delivery failed:");
        }

        var status = dr.Status;

        //Console.WriteLine($"Delivered '{dr.Value}' to '{dr.TopicPartitionOffset}'");
    }

    catch (ProduceException<Null, string> e)
    {
        Console.WriteLine($"Delivery failed: {e.Error.Reason}");
    }
}

下面是confluent-kafka在控制台打印的错误：

%3|1565248275.024|FAIL|rdkafka#producer-1| [thrd:localhst:9092/bootstrap]: localhst:9092/bootstrap: Failed to resolve 'localhst:9092': No such host is known.  (after 2269ms in state CONNECT)
%3|1565248275.024|ERROR|rdkafka#producer-1| [thrd:localhst:9092/bootstrap]: localhst:9092/bootstrap: Failed to resolve 'localhst:9092': No such host is known.  (after 2269ms in state CONNECT)
%3|1565248275.025|ERROR|rdkafka#producer-1| [thrd:localhst:9092/bootstrap]: 1/1 brokers are down

Answer 1

要在您的应用程序中获取实际异常，您需要添加 .SetErrorHandler():

    ProducerBuilder<string, string> _kafkaProducer = new ProducerBuilder<string, string>(_configKafka);

    using (var kafkaProducer = _kafkaProducer.SetErrorHandler((producer, error) =>
                        {
                           //You can handle error right here

                        }).Build())

error.Reason包含错误信息

Answer 2

您可以在消费者和生产者代码中同时使用 .SetLogHandler 和 .SetErrorHandler。否则它会在不提供太多细节的情况下默默地失败。您可以在那里将消息转发给您的记录器。

无法连接kafka集群时无异常

No exception when unable to connect to kafka cluster

c#

error-handling

apache-kafka

.net-core

confluent-platform