(doc) Clearify glossary terms.

[hastebrot]

We use a Message Broker as building block of our message-oriented middleware, which is an architectural software pattern.

It uses publish/subscribe and can be responsible for aggregration, decomposing and recomposing, validation, transformation, routing of messages, and can be extended for storage and transaction.

We want a message store for message record and replay. There should be no CQRS or ES needed for message replay.

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• Message Broker
  • https://en.wikipedia.org/wiki/Message_broker
  • http://www.enterpriseintegrationpatterns.com/ramblings/03_hubandspoke.html
• CQRS (Command and Query Responsibility Segregation), Greg Young 2010
  • https://martinfowler.com/bliki/CQRS.html
• ES (Event Sourcing), Martin Fowler 2005
  • https://martinfowler.com/eaaDev/EventSourcing.html
• DDD (Domain-driven Design), Eric Evans 2004

More:

• https://gist.github.com/jaceklaskowski/d267bf4176822293e95e

[hastebrot]

Inspiration for architecture:

• https://www.http4k.org/, https://twitter.github.io/finagle/
• Typesafe contracts using lenses: https://www.http4k.org/guide/modules/contracts/

For our purposes, we needed something that:

• Starts/stops ultra quickly.
• Easily testable outside of an HTTP container, and testing should require little to no custom infrastructure.
• Provides typesafe HTTP message deconstruction/construction (in this case via Lenses).
• Automatically deals with contract breaches (missing/invalid params etc) to remove boilerplate.
• Absolutely no magic involved: No reflection. No annotations.
• Minimal dependencies (apart from the Kotlin StdLib, http4k-core has zero).
• Automatic generation of OpenApi/Swagger documentation (including JSON Schema models).
• Has a symmetric server/client API (HttpHandler should just be Request -> Response).
• Has immutable Request/Response objects.