Goldpath.Messaging 0.1.0-preview.8

Goldpath.Messaging

Message-path floor of the Goldpath enterprise asset, composed on the MassTransit 8.x OSS line (v9 went commercial — the golden path carries no commercial-license surprise; exit strategy documented in docs/rfc/goldpath-messaging.md D1).

Getting started

builder.AddGoldpathMessaging(bus =>
{
    bus.AddConsumer<OrderConfirmedConsumer>();
    bus.AddGoldpathOutbox<OrdersDbContext>(o => o.UsePostgres());   // features.outbox — template wires the lock provider

    bus.UsingRabbitMq((context, cfg) =>                        // transport from manifest providers.broker
    {
        cfg.Host(connectionString);
        cfg.ConfigureGoldpathEndpoints(context);                    // guard + propagation + retry + conventions
    });
});

Consuming through the seam (ADR-0013)

public sealed class OrderConfirmedHandler(OrdersDbContext db) : IIntegrationEventHandler<OrderConfirmed>
{
    public async Task HandleAsync(OrderConfirmed e, IntegrationEventContext context, CancellationToken ct)
    {
        // context: MessageId (the inbox key), CorrelationId, Tenant, RetryAttempt, Headers — no library type.
        ...
    }
}

builder.AddGoldpathMessaging(bus =>
{
    bus.AddGoldpathHandler<OrderConfirmed, OrderConfirmedHandler>();   // or bus.AddGoldpathHandlers(typeof(Program).Assembly)
    ...
});

A handler drains the SAME queue the consumer of that name drained (OrderConfirmedHandler and OrderConfirmedConsumer → order-confirmed), so moving to the seam changes no wire. Retry, redelivery, the inbox and tenant restoration are the pipeline's — a throw is a retry, then the error queue. IConsumer<T> still works (analyzer GP0405 says so, Info until the templates adopt the seam at the next train; Warning from then on).

Configuration

Bound from Goldpath:Messaging:

{ "Goldpath": { "Messaging": { "Retry": { "ImmediateCount": 3 } } } }

Redelivery defaults: 5m/15m/30m, then the error queue — messages are never silently dropped.

Advanced

The event boundary (the rule everything hangs on):

public record OrderConfirmed(Guid OrderId) : IIntegrationEvent;   // broker-bound — marker REQUIRED
public record OrderTotalsChanged(...) : INotification;            // in-process — Mediant, never the bus

Publishing an unmarked type throws (runtime guard; analyzer GP0401 will catch it at build). A Mediant notification must never carry IIntegrationEvent (GP0402) — one world only.

• Outbox (AddGoldpathOutbox<TContext>): publish commits atomically with business data; consumer-side inbox dedup included; 30m duplicate-detection window default.
• Propagation: X-Goldpath-Tenant and X-Correlation-Id flow through publish/consume automatically; on consume the tenant is restored into the message-scoped GoldpathMessageTenantContext (ITenantContext in golden-path services).
• Kebab-case endpoint naming; OTel tracing flows via MassTransit's built-in instrumentation.

Providers

Transport chosen in the manifest (providers.broker): rabbitmq, kafka, inmemory (tests/dev). Transport packages and the outbox lock provider are wired by the template; this package references only MassTransit core + EF outbox.