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Asset Outbox and Messaging Operations

Summary​

This page documents how the asset-service stages and relays domain events using a transactional outbox. Events are written to outbox rows in the same transaction as the domain change, then a background relay polls and publishes them to the shared RabbitMQ event bus. The relay is resilient — a publish failure leaves rows for re-processing and never blocks the writing request — but there is no retry ceiling, backoff, dead-letter, or cleanup. A read-only diagnostics endpoint exists for inspection only.

Audience​

  • DevOps engineers operating the messaging path.
  • Support and QA engineers investigating event delivery.
  • Solution architects assessing delivery guarantees.

Reference Content​

Outbox row shape​

FieldPurpose
Id, EventIdRow and event identity
EventTypeThe domain event type
PayloadJsonSerialized event payload
OccurredAtUtc, ProcessedOnUtcTiming of creation and processing
StatusPending / Processing / Processed / Failed
RetryCount, ErrorMessageFailure accounting
CorrelationId, TenantId, SourceServiceTraceability and tenancy

Relay behavior​

The relay is OutboxRelayHostedService, a background service that polls every 10 seconds with a batch size of 50 and resolves IOutboxProcessor per iteration in its own scope. A failure during relay simply leaves rows in Pending or Failed state and never blocks the request that wrote them.

Status transitions​

OutboxProcessor.GetPending returns rows in Pending or Failed state ordered by OccurredAtUtc, so failed rows are naturally retried on subsequent polls. Success marks the row Processed; failure marks it Failed with an incremented retry count and recorded error.

Delivery boundaries​

  • No retry ceiling and no backoff — failed rows are retried indefinitely on each poll.
  • No dead-letter path.
  • No cleanup or archival of processed rows.
  • Broker delivery depends on broker availability and configuration and is not verified here.

Safe diagnostics​

A read-only diagnostics endpoint (/asset/outbox?take=N) projects row metadata using AsNoTracking. It is for inspection only. This documentation intentionally provides no replay, edit, or manual-requeue instructions.

Source References​

  • microservices/src/asset-service/Messaging/OutboxRelayHostedService.cs
  • microservices/src/shared-kernel/Messaging/OutboxProcessor.cs
  • microservices/src/shared-kernel/Extensions/MessagingExtensions.cs

See Also​

Keywords​

asset outbox, event relay, messaging, unbounded retry, no dead-letter

Revision Information​

  • Status: Draft
  • Last reviewed: 2026-07-17
  • Review cycle: Quarterly