https://github.com/crabzilla/crabzilla

Yet another Event Sourcing experiment. A project exploring Vert.x to develop Event Sourcing / CQRS applications.
https://github.com/crabzilla/crabzilla

cqrs cqrs-es event-sourcing kotlin postgresql vertx

Last synced: about 2 months ago
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Yet another Event Sourcing experiment. A project exploring Vert.x to develop Event Sourcing / CQRS applications.

• Host: GitHub
• URL: https://github.com/crabzilla/crabzilla
• Owner: crabzilla
• License: apache-2.0
• Created: 2017-05-19T05:32:04.000Z (over 7 years ago)
• Default Branch: main
• Last Pushed: 2024-02-23T02:50:02.000Z (7 months ago)
• Last Synced: 2024-06-19T03:12:08.433Z (3 months ago)
• Topics: cqrs, cqrs-es, event-sourcing, kotlin, postgresql, vertx
• Language: Kotlin
• Homepage:
• Size: 3.91 MB
• Stars: 71
• Watchers: 7
• Forks: 9
• Open Issues: 0
• Metadata Files:
  • Readme: README.adoc
  • License: LICENSE.TXT

Awesome Lists containing this project

• vertx-awesome - Crabzilla - Yet another Event Sourcing experiment. A project exploring Vert.x to develop Event Sourcing / CQRS applications. (Examples)

README

        
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https://www.oracle.com/java/[image:https://img.shields.io/badge/Java-17-purple.svg[Vertx]]

https://kotlinlang.org/[image:https://img.shields.io/badge/Kotlin-1.9.22-purple.svg[Vertx]]

https://vertx.io[image:https://img.shields.io/badge/vert.x-4.5.1-purple.svg[Vertx]]

https://github.com/crabzilla/crabzilla/actions/workflows/blank.yml[image:https://github.com/crabzilla/crabzilla/actions/workflows/blank.yml/badge.svg[CI]]

https://codecov.io/gh/crabzilla/crabzilla[image:https://codecov.io/gh/crabzilla/crabzilla/branch/main/graph/badge.svg[codecov]]

https://jitpack.io/#io.github.crabzilla/crabzilla[image:https://jitpack.io/v/io.github.crabzilla/crabzilla.svg[Jitpack]]

== Objectives

. Allows writing your testable `CQRS/ES` model with minimal dependencies.

. Allows consistently handling your commands and save resulting events into `Postgres`.

. Allows consistently and ordered projecting your events to your view models in `Postgres`.

. Allows consistently and ordered publishing your events to Vertx eventbus, so you can integrate with any message broker, database, cache, etc.

== Approach

* Using https://vertx.io/docs/vertx-pg-client/java/[Vertx] `non-blocking IO` Postgres driver.

* Using key `Postgres` features: json, notification and advisory locks.

* Trying to be idiomatic Kotlin: type safeness: immutability, pattern matching, honouring your constructors.

== crabzilla-core

To express your domain model.

* State transitions occurs after computing results of pure functions `(State, Event) -> State`.

* Tests in BDD way without any dependency to Vertx: only to `crabzilla-core`:

** given command, then assertion

** given events, when command, then assertion

** given commands or events in any order, then assertion

== WIP