如何指定要與 MassTransit 一起使用的 Azure 服務總線主題

Question

我嘗試使用 MassTransit 將消息發布到 Azure 服務總線中名為events的主題。 我在配置 MassTransit 以使用我預定義的主題events遇到問題，而是為消息類型創建了一個由命名空間/類名命名的新主題。 所以我想知道如何指定使用哪個主題而不是創建一個新主題。

這是我測試過的代碼：

using System;
using System.Threading.Tasks;
using MassTransit;
using MassTransit.AzureServiceBusTransport;
using Microsoft.ServiceBus;

namespace PublisherNameSpace
{
    public class Publisher
    {
        public static async Task PublishMessage()
        {
            var topic = "events";
            var bus = Bus.Factory.CreateUsingAzureServiceBus(
                cfg =>
                {
                    var azureServiceBusHost = cfg.Host(new Uri("sb://<busname>.servicebus.windows.net"), host =>
                    {
                        host.OperationTimeout = TimeSpan.FromSeconds(5);
                        host.TokenProvider =
                            TokenProvider.CreateSharedAccessSignatureTokenProvider(
                                "RootManageSharedAccessKey",
                                "<key>"
                            );
                    });

                    cfg.ReceiveEndpoint(azureServiceBusHost, topic, e =>
                    {
                        e.Consumer<TestConsumer>();
                    });
                });

            await bus.Publish<TestConsumer>(new TestMessage { TestString = "testing" });
        }
    }

    public class TestConsumer : IConsumer<TestMessage>
    {
        public Task Consume(ConsumeContext<TestMessage> context)
        {
            return Console.Out.WriteAsync("Consuming message");
        }
    }

    public class TestMessage
    {
        public string TestString { get; set; }
    }
}

Answer 1

接受的答案清除了訂閱方：

cfg.SubscriptionEndpoint(
    host,
    "sub-1",
    "my-topic-1",
    e =>
    {
        e.ConfigureConsumer<TestConsumer>(provider);
    });

對於那些想知道如何在發布端正確獲取總線配置的人，它應該如下所示：

cfg.Message<TestMessage>(x =>
{
    x.SetEntityName("my-topic-1");
});

然后你可以在總線上調用發布：

await bus.Publish<TestMessage>(message);

感謝@ChrisPatterson 向我指出這一點！

Answer 2

如果要從特定主題消費，請創建訂閱端點而不是接收端點，並在配置中指定主題和訂閱名稱。

單元測試中顯示了最簡單的形式：

https://github.com/MassTransit/MassTransit/blob/develop/tests/MassTransit.Azure.ServiceBus.Core.Tests/Subscription_Specs.cs

Answer 3

我能夠使用_sendEndpointProvider.GetSendEndpoint(new Uri("topic:shape"));發送到 Azure 服務總線主題。 其中...“形狀”是主題名稱。

public class MassTransitController : ControllerBase
{
    private readonly ILogger<MassTransitController> _logger;
    private readonly ISendEndpointProvider _sendEndpointProvider;

    public MassTransitController(ILogger<MassTransitController> logger, ISendEndpointProvider sendEndpointProvider)
    {
        _logger = logger;
        _sendEndpointProvider = sendEndpointProvider;
    }

    [HttpGet]
    public async Task<IActionResult> Get()
    {
        try
        {
            var randomType = new Random();
            var randomColor = new Random();

            var shape = new Shape();
            shape.ShapeId = Guid.NewGuid();
            shape.Color = ShapeType.ShapeColors[randomColor.Next(ShapeType.ShapeColors.Count)];
            shape.Type = ShapeType.ShapeTypes[randomType.Next(ShapeType.ShapeTypes.Count)];

            var endpoint = await _sendEndpointProvider.GetSendEndpoint(new Uri("topic:shape"));
            await endpoint.Send(shape);

            return Ok(shape);
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }
}

我還能夠讓 .NET 5 Worker Consumer 使用這樣的代碼……其中訂閱“sub-all”將捕獲所有形狀……我將為此寫一篇博文/git repo。

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureServices((hostContext, services) =>
            {
                services.AddMassTransit(x =>
                {
                    x.UsingAzureServiceBus((context, cfg) =>
                    {
                        cfg.Host("Endpoint=sb://******");

                        cfg.SubscriptionEndpoint(
                            "sub-all",
                            "shape",
                            e =>
                        {
                            e.Handler<Shape>(async context =>
                            {
                                await Console.Out.WriteLineAsync($"Shape Received: {context.Message.Type}");
                            });

                            e.MaxDeliveryCount = 15;
                        });
                    });
                });

                services.AddMassTransitHostedService();
            });