如何通过 Autofac 模块配置 Masstransit 消费者

Question

How to register Masstransit consumers in Autofac modules.

I have this code:

 builder.AddMassTransit(configurator =>
        {
            configurator.AddConsumers(ThisAssembly);
            //Bus
            configurator.AddBus(c => c.Resolve<IBusFactory>().CreateBus());
        });

And in another Module I have this code:

public class AutofacModule: Module
{
    public override void Load(ContainerBuilder builder)
    {    
        builder.RegisterConsumers(ThisAssembly);
    }
}

But the Consumers located in Modue assembly is not found by Masstransit. Please help

EDIT: I have multiple assemblies (modules) that are not directly referenced by the starting project. The assemblies are loaded at the application startup using MEF from a /Modules subfolder. The consumers are located in those modules. I use Autofac integration with MEF to load Autofac Modules into Autofac configuration. When I say that Mass transit can't find consumers, I mean this: when I put a breakpoint ate the line

configurator.AddBus(...)

and inspect the configurator._consumerRegistrations field, there are none in it, only the ones from the starting application. Also when I publish events, none of the consumers located in those modules are consuming it. The events are only consumed in the starting application.

Answer 1

After the Autofac modules are loaded, and all of the consumers are registered in the container, you can use the following to register the consumers (and sagas).

    public static void AddConsumersFromContainer(this IRegistrationConfigurator configurator, IComponentContext context)
    {
        var consumerTypes = context.FindTypes(IsConsumerOrDefinition);
        configurator.AddConsumers(consumerTypes);
    }

    public static void AddSagasFromContainer(this IRegistrationConfigurator configurator, IComponentContext context)
    {
        var sagaTypes = context.FindTypes(IsSagaOrDefinition);
        configurator.AddSagas(sagaTypes);
    }

    static Type[] FindTypes(this IComponentContext context, Func<Type, bool> filter)
    {
        return context.ComponentRegistry.Registrations
            .SelectMany(r => r.Services.OfType<IServiceWithType>(), (r, s) => (r, s))
            .Where(rs => filter(rs.s.ServiceType))
            .Select(rs => rs.s.ServiceType)
            .ToArray();
    }

    /// <summary>
    /// Returns true if the type is a consumer, or a consumer definition
    /// </summary>
    /// <param name="type"></param>
    /// <returns></returns>
    public static bool IsConsumerOrDefinition(Type type)
    {
        Type[] interfaces = type.GetTypeInfo().GetInterfaces();

        return interfaces.Any(t => t.HasInterface(typeof(IConsumer<>)) || t.HasInterface(typeof(IConsumerDefinition<>)));
    }

    /// <summary>
    /// Returns true if the type is a saga, or a saga definition
    /// </summary>
    /// <param name="type"></param>
    /// <returns></returns>
    public static bool IsSagaOrDefinition(Type type)
    {
        Type[] interfaces = type.GetTypeInfo().GetInterfaces();

        if (interfaces.Contains(typeof(ISaga)))
            return true;

        return interfaces.Any(t => t.HasInterface(typeof(InitiatedBy<>))
            || t.HasInterface(typeof(Orchestrates<>))
            || t.HasInterface(typeof(Observes<,>))
            || t.HasInterface(typeof(ISagaDefinition<>)));
    }