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Messaging & Events

Services communicate asynchronously through RabbitMQ using exactly two exchanges. Anything beyond these two patterns needs an architecture decision first.

os.rpc — synchronous request-reply (direct exchange)​

Used for one approved path only: the tickets service enriching tickets with organizational data owned by the auth service.

Routing keys: auth.department.get-by-id, auth.project.get-by-id, auth.pmo.get. The auth/user service remains the source of truth — RPC never transfers data ownership.

os.events — fire-and-forget domain events (durable topic exchange)​

The tickets service publishes events with routing key ticket.<eventtype>; the integration service consumes them via queue integration.notifications (bound to ticket.*, with a dead-letter queue) and turns them into in-app notifications.

Pinned event types: ASSIGNED, PARTICIPANT_ADDED, COMMENT_ADDED, INTERNAL_NOTE_ADDED, CLOSED_NEEDS_RESPONSE, SLA_BREACHED, RELATIVE_CREATED.

Envelope: includes eventId (for consumer idempotency), recipientUserIds, occurredAt, and an event-specific data payload. The contract is duplicated deliberately on both sides (os-tickets-service/src/events/ticket-event.types.ts and os-integration-service/src/notifications/notification-event.types.ts) — if you change one, change the other.

Rules of the road​

  • No Kafka, no service discovery (Eureka) — RabbitMQ and static Traefik routing only.
  • Publishing is fire-and-forget; never block a request on event delivery.
  • Consumers must tolerate duplicates (use eventId) and route poison messages to the DLQ.
  • New RPC paths require explicit approval in the design docs; default to synchronous HTTP through the gateway.

Where to look in code​

WhatWhere
Tickets RPC clientsos-tickets-service/src/messaging/*-lookup-client.service.ts
Auth RPC respondersos-auth-service/.../config/RabbitMqConfig.java + infrastructure/messaging listeners
Event publisheros-tickets-service/src/events/event-publisher.service.ts
Event consumeros-integration-service/src/notifications/ + src/messaging/messaging-config.ts