Storefront
Synchronously calls the order service to create an order.
Synthetic Technical Case
Order Events: Requests, Ownership, and Delivery
Arrows indicate layer grouping only. Node text defines specific dependencies, event routes, and data ownership.
Entry
Payment Platform
Synchronously calls the callback service with a callback ID.
Layer grouping only
Services
Order State and Event Publishing
Order service: writes Order DB; publishes OrderCreated asynchronously; consumes PaymentConfirmed, committing payment status and consumed event ID together.
Callback Deduplication and Events
Callback service: writes Callback DB; acknowledges after commit; deduplicates by callback ID; publishes PaymentConfirmed asynchronously.
Inventory Reservation and Deduplication
Inventory consumer: receives OrderCreated asynchronously; commits reservation and consumed event ID together.
Layer grouping only
Resources
Order DB
PostgreSQL; only the order service reads and writes it. Order and outbox commit together; stores consumed event IDs.
Callback DB
Separate PostgreSQL; only the callback service reads and writes it. Callback ID and outbox commit together.
Inventory DB
Separate PostgreSQL; only the inventory consumer reads and writes it. Stores reservations and consumed event IDs.
Business Event Queue
At-least-once delivery. OrderCreated → inventory consumer; PaymentConfirmed → order service.