为 MassTransit SQS 调用 ReceiveEndpoint 时如何防止 NullReferenceException？

Question

我使用 MassT运行在 .NET 核心 Web 应用程序 (web api) 中使用 SQS。发布消息工作正常。但是在我尝试添加消费者之后，我运行遇到了问题。

这是我的代码

    public static void UseMassTransit(this IServiceCollection services, MassTransitConfiguration massTransitConfiguration)
    {
        services.AddMassTransit(x =>
        {
            x.AddConsumer<CustomerChangeConsumer>();
            x.UsingAmazonSqs((context, cfg) =>
            {
                cfg.Host(massTransitConfiguration.Host, h =>
                {
                    h.AccessKey(massTransitConfiguration.AccessKey);
                    h.SecretKey(massTransitConfiguration.SecretKey);

                    cfg.ReceiveEndpoint("CustomerChangeConsumer", 
                        configurator =>
                    {
                        configurator.ConfigureConsumer<CustomerChangeConsumer>(context);
                    });

                    // scope topics as well
                    h.EnableScopedTopics();
                });
            });
        });
        services.AddMassTransitHostedService();
    }

问题是 ReceiveEndpoint 给出了 NullReferenceException。

这是 st运行ge，因为 ConfigureConsumer 是 executed.However，ReceiveEndpoint 如果不抛出此异常就无法完全完成。

这是堆栈跟踪：

MassTransit.AmazonSqsTransport.Configurators.ConfigurationHostSettings.FormatHostAddress()
System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
System.Lazy`1.CreateValue()
System.Lazy`1.Value
MassTransit.AmazonSqsTransport.Configurators.ConfigurationHostSettings.HostAddress
MassTransit.AmazonSqsTransport.Configuration.AmazonSqsHostConfiguration.HostAddress
MassTransit.AmazonSqsTransport.Configuration.AmazonSqsReceiveEndpointConfiguration.FormatInputAddress()
System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
System.Lazy`1.CreateValue()
System.Lazy`1.Value
MassTransit.AmazonSqsTransport.Configuration.AmazonSqsReceiveEndpointConfiguration.InputAddress
MassTransit.Monitoring.Health.EndpointHealth.EndpointConfigured(T configurator)
MassTransit.Monitoring.Health.BusHealth.MassTransit.EndpointConfigurators.IEndpointConfigurationObserver.EndpointConfigured[T](T configurator)
MassTransit.EndpointConfigurators.EndpointConfigurationObservable.<>c__DisplayClass0_0`1.<EndpointConfigured>b__0(IEndpointConfigurationObserver observer)
GreenPipes.Util.Connectable`1.All(Func`2 callback)
MassTransit.EndpointConfigurators.EndpointConfigurationObservable.EndpointConfigured(T configurator)
MassTransit.AmazonSqsTransport.Configuration.AmazonSqsHostConfiguration.CreateReceiveEndpointConfiguration(QueueReceiveSettings settings, IAmazonSqsEndpointConfiguration endpointConfiguration, Action`1 configure)
MassTransit.AmazonSqsTransport.Configuration.AmazonSqsHostConfiguration.CreateReceiveEndpointConfiguration(String queueName, Action`1 configure)
MassTransit.AmazonSqsTransport.Configuration.AmazonSqsHostConfiguration.ReceiveEndpoint(String queueName, Action`1 configureEndpoint)
MassTransit.AmazonSqsTransport.Configurators.AmazonSqsBusFactoryConfigurator.ReceiveEndpoint(String queueName, Action`1 configureEndpoint)
Kinley.SMPD.CustomerService.API.Extensions.MassTransitExtensions.<>c__DisplayClass0_1.<UseMassTransit>b__2(IAmazonSqsHostConfigurator h) in MassTransitExtensions.cs: line: 23

怎么会？以及如何解决？

Answer 1

您不应在主机配置闭包中配置接收端点。尝试将其移出 .Host() 方法，看看是否能解决您的问题。

为 MassTransit SQS 调用 ReceiveEndpoint 时如何防止 NullReferenceException？

How to prevent a NullReferenceException when calling ReceiveEndpoint for MassTransit SQS?

masstransit

amazon-sqs

asp.net-core-webapi