如何覆盖 MassTransit 默认交换和队列拓扑约定？

Question

正如[在我关于 SO 的一个问题] () 中指出的那样，RabbitMQ 的 MassTransit 会自动创建一定数量的队列并为给定的简单配置交换：

Exchanges, all fanouts:

ConsoleApp1:Program-YourMessage: Durable

VP0003748_dotnet_bus_6n9oyyfzxhyx9ybobdmpj8qeyt: Auto-delete and Durable?

test_queue: Durable

Queues:

VP0003748_dotnet_bus_6n9oyyfzxhyx9ybobdmpj8qeyt: x-expire 60000

test_queue: Durable

但是，我发现无法覆盖那些交换器和队列的命名有点令人沮丧。我可以做些什么来改变它吗？

例如，如果您重构某些类型或命名空间，您可能最终会用大量不再使用的交换污染您的 RabbitMQ 实例 =/

我理解 test_queue 因为这是我的决定，非常公平。类型很容易发生变化/重构。

Answer 1

这是一种简单有效的方法：https://bartwullems.blogspot.com/2018/09/masstransitchange-exchange-naming.html

但最好在此处放置一些 dotnet 核心代码，以帮助刚起步的任何人。

我们基于配置的自定义格式化程序：

public class BusEnvironmentNameFormatter : IEntityNameFormatter
{
    private readonly IEntityNameFormatter _original;
    private readonly string _prefix;

    public BusEnvironmentNameFormatter(IEntityNameFormatter original, SomeAppSettingsSection busSettings)
    {
        _original = original;
        _prefix = string.IsNullOrWhiteSpace(busSettings.Environment)
            ? string.Empty // no prefix
            : $"{busSettings.Environment}:"; // custom prefix
    }

    // Used to rename the exchanges
    public string FormatEntityName<T>()
    {
        var original = _original.FormatEntityName<T>();
        return Format(original);
    }

    // Use this one to rename the queue
    public string Format(string original)
    {
        return string.IsNullOrWhiteSpace(_prefix)
            ? original
            : $"{_prefix}{original}";
    }
}

然后要使用它，我们会做这样的事情：

var busSettings = busConfigSection.Get<SomeAppSettingsSection>();
var rabbitMqSettings = rabbitMqConfigSection.Get<SomeOtherAppSettingsSection>();

services.AddMassTransit(scConfig =>
{
    scConfig.AddConsumers(consumerAssemblies);

    scConfig.AddBus(provider => Bus.Factory.CreateUsingRabbitMq(rmqConfig =>
    {
        rmqConfig.UseExtensionsLogging(provider.GetRequiredService<ILoggerFactory>());

        // Force serialization of default values: null, false, etc
        rmqConfig.ConfigureJsonSerializer(jsonSettings =>
        {
            jsonSettings.DefaultValueHandling = DefaultValueHandling.Include;
            return jsonSettings;
        });

        var nameFormatter = new BusEnvironmentNameFormatter(rmqConfig.MessageTopology.EntityNameFormatter, busSettings);
        var host = rmqConfig.Host(new Uri(rabbitMqSettings.ConnectionString), hostConfig =>
        {
            hostConfig.Username(rabbitMqSettings.Username);
            hostConfig.Password(rabbitMqSettings.Password);
        });

        // Endpoint with custom naming
        rmqConfig.ReceiveEndpoint(host, nameFormatter.Format(busSettings.Endpoint), epConfig =>
        {
            epConfig.PrefetchCount = busSettings.MessagePrefetchCount;
            epConfig.UseMessageRetry(x => x.Interval(busSettings.MessageRetryCount, busSettings.MessageRetryInterval));
            epConfig.UseInMemoryOutbox();

            //TODO: Bind messages to this queue/endpoint
            epConfig.MapMessagesToConsumers(provider, busSettings);
        });

        // Custom naming for exchanges
        rmqConfig.MessageTopology.SetEntityNameFormatter(nameFormatter);
    }));
});

Answer 2

可以使用 IRabbitMqBusFactoryConfigurator 的 OverrideDefaultBusEndpointQueueName 方法按以下方式更改队列的名称

var bus = Bus.Factory.CreateUsingRabbitMq(sbc =>
{
    sbc.Host("rabbitmq://localhost/");

    sbc.OverrideDefaultBusEndpointQueueName("endpoint");
});

如何覆盖 MassTransit 默认交换和队列拓扑约定？

How to override MassTransit default exchange and queue topology convention?

c#

masstransit

rabbitmq

.net-core