ITLab.Template.DevPack.Messaging

Provides outcome contracts for message handlers integrated with external brokers (Azure Service Bus and similar). Independent of the in-process CQRS area in Mediator/ — this namespace is exclusively about broker-side settlement (complete, abandon, dead-letter).

Componentes

Tipo	Nome	Responsabilidade
Enum	EMessageDisposition	Settlement disposition for a processed broker message: Complete, Abandon, DeadLetter
Record	MessageHandlingResult	Outcome of processing a single broker message, carrying disposition, optional Error, transient flag and retry delay
Static Class	MessagingErrors	Catalog of well-known errors produced by the messaging infrastructure layer (InvalidPayload, ProcessingFailed)

Como usar

public async Task<MessageHandlingResult> HandleAsync(OrderShippedMessage msg, CancellationToken ct)
{
    if (!msg.IsValid())
    {
        return MessageHandlingResult.DeadLettered(MessagingErrors.InvalidPayload(msg.RawPayload));
    }

    try
    {
        await _handler.ProcessAsync(msg, ct);
        return MessageHandlingResult.Completed();
    }
    catch (TransientServiceUnavailableException ex)
    {
        return MessageHandlingResult.Abandoned(
            MessagingErrors.ProcessingFailed(ex.Message),
            isTransient: true,
            retryDelay: TimeSpan.FromSeconds(30));
    }
}

O que não fazer

• Do not use this namespace for in-process CQRS commands or queries — those live in Mediator/.
• Do not invent custom dispositions outside EMessageDisposition — broker semantics are fixed.
• Do not retry forever inside a handler — use MessageHandlingResult.Abandoned(..., retryDelay: ...) and let the broker honor its own redelivery policy.

Extensão pelo produto

• Products implement broker-specific adapters that translate MessageHandlingResult into the broker's settlement API (e.g., ServiceBusMessageActions.CompleteMessageAsync).
• Products extend the error catalog with product-specific failures, following the Infrastructure.Messaging.{Code} prefix convention.