makcon / employees

Tech stack

• Kotlin
• Maven
• Spring boot
• MongoDB (embedded)

Architecture

• Monolith with maven modules
  • employees manages employees CRUD operations. Later it can be converted to a separate service
    • It based on hexagonal architecture.
      • domain package is the center part and responsible for the business logic
      • adapter is the right part that communicates with DB
      • client is the left part, it receives requests
    • All communications with the module go via EmployeesClient interface. Currently there is internal implementation because it's a module of the same artifact. After moving to a separate service need to implement an http/websockets client
    • Document versioning pattern to prevent concurrent update
    • For each modification a related event is created and stored in DB in the same transaction. This way we solve atomic issue between storing an object and sending an event. An event's structure is simple for this exercise, just contains an object id
  • app is the application runner. It also has all needed configuration and execute acceptance (integration) tests for the whole app
  • admin-api exposes API endpoints for an admin backoffice
  • commons has common logic/objects. It should be split and stored in artifactory storage e.q. Nexus
  • messaging a library contains common logic for sending/receiving events. It has a runner that constantly reads events collection and send events (for this example locally). Should be in Nexus as well
• Testing
  • Mother pattern to create valid random objects
  • Acceptance testing to test end-to-end (in scope of the service) logic
  • Unit testing using Junit 5 and Kotest lib for assertion