cChat

A minimal messenger application that supports direct (1-to-1) messages and group chats.
The system is split into two Spring Boot microservices connected via Apache Kafka:

• Ingress (Auth & Send) Service – handles user authentication/authorization and accepts outgoing messages from clients; publishes them to Kafka.
• Receive Service – consumes messages from Kafka, persists them, and exposes read/subscribe APIs (REST / WebSocket/STOMP) to clients.

This project is intentionally small and pragmatic: it focuses on clear separation of concerns, message-broker decoupling, and a working end-to-end flow.

---

Architecture

+---------------+           REST                       +-----------------+
|   Web / CLI   |  --------------------------------->  |  Ingress Service|
|   Client      |   (Auth, Send Message)               | (Auth & Send)   |
+-------+-------+                                      +-----------------+
        |                                                   |
        |                                                 Kafka
        |                                                   v
        |                                         +---------+-----------+
		| -----------------REST-------------->    |   Receive Service   |
		|           (Group management)            |                     |
        |  <----------- REST / WS/STOMP ----------| (Persist & Deliver) |
        |         (Fetch history, subscribe)      +---------+-----------+
        |                                                   |
        |                                         +---------v-----------+
        |                                         |   PostgreSQL        |
        |                                         +---------------------+

Tech Stack

• Java / Spring Boot
  • Spring Web, Spring Security, Spring Messaging (STOMP over WebSocket), Spring Data JPA
  • Spring for Apache Kafka
• Apache Kafka (broker + topic for messages)
• PostgreSQL
• Maven
• Docker / Docker Compose