v1.1.0-20251130

Event-Driven Architectures and Microservices

• Event store technology example: Apache Kafka
  • "An open-source distributed event streaming platform" - watching together this video intro
  • Background and Context
  • Kafka Documentation
    • Architecture
  • Kafka Quick start
    • Setting up Kafka Using Docker
      • using Docker Compose with kafka-deplo.yaml config file
      • user guides: Kafka docs, Docker docs
  • Working with Kafka - Kafka clients
    • Kafka clients in Java
    • Simple examples in repo - sap.kafka package
  • Dashboard Tools for Kafka: Offset Explorer (formerly Kafka Tool)
    • Using Offset Explorer GUI tool as a simple dashboard for Kafka
      • setting the Bootstrap servers property to connect to the Kafka server to listen at port 9092 or 29092 (if using Docker) for the host machine
• Documenting API in Event-Driven Architectures: AsyncAPI initiative
  • Kafka case
    • tutorial from AsyncAPI
    • tutoria from Kafka
    • Terminology mapping
• TTT Game System case study
  • Focus on ttt-game-service microservice: making it event-driven, using Kafka
    • designing event channels - both static and dynamic, inspired by REST principles
      • static event channels, functioning as a single entry point (à-la-REST)
        • create-game-requests (input)
        • create-game-requests-approved (output)
        • create-game-requests-rejected (output)
        • new-game-created (output)
      • dynamic event channels
        • to join a game identified by <gameId>
          • game-<gameId>-join-requests (input)
          • game-<gameId>-join-requests-approved (output)
          • game-<gameId>-join-requests-rejected (output)
        • to make a move by a player session identified by <playerSessionId>
          • session-<playerSessionId>-move-requests (input)
          • session-<playerSessionId>-move-requests-approved (output)
          • session-<playerSessionId>-move-requests-rejected (output)
        • about the events of game identified by <gameId>
          • game-<gameId>-events (output)
    • adding an event-driven controller
    • [TODO] implementing event sourcing
  • TTT Game Service AsyncAPI spec
    • including some main fields
    • verified with AsyncAPI Studio
  • Creating new proxies in other services interacting with ttt-game-service
    • ttt-lobby-service
    • ttt-api-gateway
  • Running
    • simple interaction example with the single service:
      • running the broker docker run -p 9092:9092 apache/kafka:4.1.1
      • running the service: ttt_game_service_infrastructure.GameServiceNoDockerMain
      • running ttt_game_service_infrastructure.SimpleInteractionExample
    • full TTT Game System
      • setting up all services and broker with docker compose up
      • interacting with the API gateway as seen in previous labs
  • TTT Game