Sharing the same scope in Masstransit mediator produces error: The ConsumeContext was already set

Question

I'm trying to use MassTransit mediator on my Asp.Net web API. Currently I'm using Masstransit 7.3.0

I wanted for consumers to share the same scope. So I did everything step-by-step as in documentation.

Here I'm setting up the mediator in startup and adding the consumers, requestclients:

        services.AddHttpContextAccessor();

        services.AddMediator(cfg =>
        {
            cfg.ConfigureMediator((regContext, options) =>
            {
                options.UseHttpContextScopeFilter(regContext);
            });

            cfg.AddConsumer<BillingFile.Create>();
            cfg.AddRequestClient<BillingFile.Command.CreateCommand>();
            cfg.AddConsumer<Payment.CreateBasePayment>();
            cfg.AddRequestClient<Payment.Command.CreateBasePaymentCommand>();
        });

I'm using HttpContextScopeFilter directly from the documentation on the website.

When I try to send a message from one consumer to the other, an exception is thrown:

The ConsumeContext was already set

Here is my Create consumer:

public class Create : IConsumer<CreateCommand>
{
    private readonly IMediator mediator;

    public Create(IMediator mediator)
    {
        this.mediator = mediator;
    }

    public async Task Consume(ConsumeContext<CreateCommand> context)
    {
        var request = context.Message.Request;

        /* Create base payment <--- here be the exception */
        var basePaymentHandler = mediator.CreateRequestClient<CreateBasePaymentCommand>(context);
        var basePaymentResponse = await basePaymentHandler.GetResponse<CreateBasePaymentResponse>(new CreateBasePaymentCommand { Request = Request, CorrelationId = Guid.NewGuid()}, cancellationToken: context.CancellationToken); 
    ....

Is this not allowed by Masstransit mediator?

Answer 1

MassTransit won't let you dispatch multiple messages in the same container scope. It results in the very exception you are experiencing. You're also using an obsolete/unsupported version of MassTransit.