Event architecture
On this page 9 topics
Overview
Topics
- Event ownership
- event catalogs
- schemas
- compatibility
Learn first
3 h of practice (estimate)
Learning outcomes
- Define event ownership across systems and organizations.
- Set up an event catalog with schemas, owners, and consumers.
- Define compatibility rules and an evolution process for event schemas.
- Decide when an event backbone (broker or streaming platform) is justified for an enterprise.
Lessons
Lab and exercises
Lab
ARC-026-LAB1 · Event catalog
Outcomes: 1–4 · Time: ~3 h
- List Larkspur's business events: order placed, stock changed, shipment dispatched, return received, plus any others you find.
- Assign one owner per event with the reason.
- Write schemas, examples, and the consumer list for each event.
- Write compatibility rules and an evolution process with a retirement policy.
- Score the need for an event backbone and record the decision.
- Defend the catalog in a catalog review.
Acceptance: no event has two owners; evolution process documented.
Exercises (case-based; five exercises)
| ID | Outcome | Task |
|---|---|---|
| ARC-026-EX01 | 1 | Both the platform and the ERP publish "OrderConfirmed". Decide the owner and fix the situation. |
| ARC-026-EX02 | 2 | Write a catalog entry for ShipmentDispatched with schema, owner, consumers, and delivery guarantee. |
| ARC-026-EX03 | 3 | Classify seven schema changes as compatible or breaking and give the migration path for the breaking ones. |
| ARC-026-EX04 | 4 | A department with three systems and ten messages a day asks for a streaming platform. Write your recommendation. |
| ARC-026-EX05 | 1, 2 | Review an event "CustomerTableChanged" mirroring a CRM table; redesign it as business events. |
Show solutions
- EX01 The system that decides the confirmation (platform) owns it; the ERP publishes its own fact such as OrderAccepted, or consumes the platform event.
- EX02 Fields: shipmentId, orderId, carrier, trackingNumber, dispatchedAt, lines; owner fulfillment; consumers platform, CRM, customer notifications; at-least-once, so consumers deduplicate by shipmentId.
- EX03 Compatible: add optional field, add enum value tolerated by readers, widen documentation. Breaking: remove, rename, retype, change meaning of a field, add required field. Use add-then-deprecate or a v2 event with overlap and retirement date.
- EX04 Not justified: low volume and few consumers; use APIs or a managed queue; revisit when producers, consumers, or replay needs grow.
- EX05 Table mirrors leak the CRM schema; publish CustomerRegistered, ConsentChanged, and AddressChanged with business fields.
Outcomes 3 and 4 are also covered by the quiz and the lab rules.
Workplace evidence: an event catalog or event standard you established.
Quiz
Outcomes: O1 event ownership · O2 event catalog and schemas · O3 compatibility and evolution · O4 event backbone decision.
A self-check for you: nothing is graded, saved or sent anywhere. Choose an answer, then check it. You can try again as often as you like.
Practical part
Catalog review of the Larkspur event catalog: the reviewer checks one owner per event and the documented evolution process. Pass: quiz at least 8/10, all five exercises correct, and a catalog with no shared ownership.
Common mistakes
Events that mirror database tables; no owner for shared events.
Assessment
Catalog review.
Workplace evidence
An event catalog or event standard you established.
Career relevance
Event architecture decisions shape integration for years.