Gera Tools

Message Queue / Topic Specification Builder

Document a message queue topic with schema, producers, and consumers

Builds a message queue topic specification — topic name, JSON payload schema, producer services, consumer services, retry policy, and dead-letter queue configuration — exported as clean Markdown for your architecture docs.

Why document a topic at all?

A topic is a contract between teams. Producers and consumers deploy independently, so a written schema, retry policy, and dead-letter rule prevent silent breakages when one side changes a field or assumes a delivery guarantee the other does not provide.

Turn a message topic into a clear contract

Event-driven systems break quietly: a producer renames a field, a consumer assumes at-least-once delivery, a poison message loops forever. The fix is a written contract for every topic. This builder generates a complete, broker-agnostic Markdown spec — payload schema, producers, consumers, retry policy, and dead-letter rules — so both sides of the queue agree before they ship.

How it works

You describe the topic and the builder assembles a structured Markdown document with these sections:

  • Topic — the name and a one-line purpose, plus delivery semantics (at-least-once, at-most-once, or exactly-once).
  • Payload schema — your fields rendered as a typed JSON example and a field table, so consumers know exactly what to parse.
  • Producers — the services that publish to the topic, making ownership explicit.
  • Consumers — the services that subscribe, each effectively a separate contract.
  • Retry policy — strategy (exponential backoff), max attempts, and base delay.
  • Dead-letter queue — the target queue name and the condition that routes a message there.

The payload table infers a JSON type from each field’s declared type, and the example object shows a representative value per field so the document doubles as a quick reference.

Tips and notes

  • Name topics for the event that happened, in the past tense (orders.created, payment.failed). Consumers subscribe to facts, not commands.
  • State delivery semantics explicitly. Most brokers give at-least-once, which means consumers must be idempotent — process the same message twice without side effects.
  • Size the dead-letter queue’s alerting, not just its existence: a message landing there is an incident signal, not a place data goes to be forgotten.
  • Version the payload (schemaVersion field or a topic suffix) so you can evolve the schema without breaking older consumers.