@cats-cradle/messaging-schemas

This contains Pub/Sub message schemas. These help provide loose coupling during async communication between microservices.

• SNS topics are deployed with the message broker.
• SQS deployments should be owned by consumer.

Naming Convention

CONTEXT - VERB - CATEGORY

e.g.

• EmailSendCommand
• UserPasswordResetEvent
• PlayerDisconnectedEvent
• CharacterRankRequest

Message Categories

Command Command send a idempotent request to a topic asking subscribers to perform task. The consumer of a command does not inform or provide a response to the publisher. The publisher expects something to occur as a result of the request.

Publisher -> SNS -> SQS -> Consumer

Event Publish to a SNS topic informing any subscribers that something occurred within a given system. Events published may be significant events that were published only for the purpose of data retention and analytic purposes.

Publisher -> SNS -> SQS -> Consumer

Request Publish an async message to a single queue letting them know which queue to send a reply to.

Publisher -> SQS -> Consumer -> (SQS -> Publisher)

Reply In response to a request publish an message to a single queue as request.

(Publisher -> SQS) -> Consumer -> SQS -> Publisher

References

• Pub/Sub Messaging Schema
• Microservice Async Message Based Communication
• Message Queue Pattern
• Request Reply Pattern
• CQRS
• Event Driven Schemas