Event sourcing service cluster

This repository contains study project for distributed scalable service cluster that is based on the event sourcing pattern.

Event Sourcing is a persistence approach based on storing a stream of events instead of the current state of an object.

   +-------------------------------+    +---------------+    +-------------+
   |           Message             |---►|    Command    |---►|    Event    |
   ---------------------------------    -----------------    ---------------
   | Contains:                     |    | AddObject,    |    | Contains:   |
   | ClassName,                    |    | DeleteObject, |    | ClassState, |
   | ObjectType,                   |    | GetAllObjects |    | ClassEvent  |
   | ObjectActionType (ADD/DELETE) |    +---------------+    +-------------+
   +-------------------------------+

• Events from event sourcing pattern are messages informing about the change in the state of the object.
• RabbitMQListener parses received String to ObjectActionMessage and sends it to Service.
• Service operates the state of the object and sends action to Actor.
• Actor processes the messages in one thread via event handlers.
• Controller gets the current state of the classes.

                      +------------------------+     +----------------------+
                      |    RabbitMQListener    |◄----|    RabbitMQConfig    |          
                      +------------------------+     +----------------------+
                                 | 
                                 ▼
                      +---------------------+    +------------------+
                      |    Class Service    |---►|    Controller    |
                      +---------------------+    +------------------+
                                ▲
                                | 
                                ▼
+----------------+    +-------------------+     +------------------+
| Event Sourcing |---►|    Class Actor    |◄----|    AkkaConfig    |        
|   Properties   |    +-------------------+     +------------------+
+----------------+                             

Technologies:

1. Kotlin + Gradle 7.1.1
2. Spring Boot
3. Akka