CourseHunter — Online Learning Management Platform

An enterprise-grade, cloud-native microservices platform for online education. Built with Spring Boot 3.4+ / Java 21, event-driven architecture (Kafka), advanced resilience patterns (Saga, CQRS, Circuit Breaker), and deployed on Kubernetes.

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Services

Service	Responsibility
gateway-service	JWT validation, request routing, rate limiting
identity-service	OAuth2 token issuing (Keycloak or custom)
student-service	Student profiles, enrollment Saga orchestration
course-service	Course catalog with CQRS read/write separation
payment-service	Payment processing, compensating transactions
notification-service	Email/SMS via Kafka event listeners
gradebook-service	Async grade updates (CQRS write+read model)
audit-service	Compliance event recording
common-library	Shared DTOs, events, configs

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Architecture

              +----------------------+
              |     API Gateway      |
              | (JWT/OAuth2 + Routing)|
              +----------+-----------+
                         |
           +-------------+---------------+
           |                             |
    +------+-------+             +-------+------+
    | Student Svc  | ----REST----| Course Svc   |
    | (Saga Orches)|             | (CQRS Model) |
    +------+-------+             +-------+------+
           |                             |
     Kafka |                             | Kafka
           v                             v
    +-------------+               +--------------+
    | Payment Svc | <---> Kafka -->| Notification |
    | (Saga Step) |               |  & Gradebook |
    +-------------+               +--------------+

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Enterprise Patterns

1. Saga Pattern — Enrollment Flow (Choreography-based)

1. Student Service publishes EnrollmentCreatedEvent
2. Payment Service listens → processes payment → publishes PaymentCompletedEvent
3. Course Service listens → reserves seat → publishes SeatAllocatedEvent
4. Student Service listens for all success signals → marks enrollment COMPLETED
5. On failure → compensating transactions reverse each step (refund, seat release)

2. CQRS — Course Catalog & Gradebook

• Write model: handles CRUD and business logic via command handlers
• Read model: denormalized views stored in Elasticsearch or Postgres read replica for fast queries
• Gradebook follows the same pattern: writes via events, reads via a dedicated query service

3. Circuit Breaker — Inter-service Resilience

• Student Service → Course Service calls are wrapped with Resilience4j CircuitBreaker + Retry
• On open circuit: fallback returns a cached/degraded response instead of propagating failure

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Tech Stack

Concern	Technology
Framework	Spring Boot 3.4+, Java 21
Security	Spring Security 6.x, OAuth2 Resource Server, JWT
Messaging	Kafka via Spring Cloud Stream
Resilience	Resilience4j (Circuit Breaker, Retry)
Observability	OpenTelemetry + Micrometer
Containerization	Distroless multi-stage Docker builds
Orchestration	Kubernetes (Deployment, Service, Ingress, ConfigMap)

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Quick Start

make build          # Build all services (skip tests)
make install        # Build all services and run tests
make clean          # Wipe all build artifacts
make test           # Run tests only
make docker-build   # Build Docker images for all services locally
make docker-push    # Push images to GHCR
make run            # Start all services with Docker Compose
make stop           # Stop all running containers
make logs           # Tail logs from all containers

CI/CD

Two GitHub Actions workflows run automatically:

Workflow	Trigger	What it does
CI	PR or push to main	mvn clean install — build + test all services, upload test reports
CD	Push to main	Maven package → build Docker image per service → push to GHCR

Images are published to ghcr.io/<owner>/coursehunter/<service> tagged with the short commit SHA and latest.

No secrets need to be configured — the CD workflow uses the built-in GITHUB_TOKEN for GHCR access.

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Module Layout

campusconnect/
├── gateway-service/
├── identity-service/
├── student-service/
├── course-service/
├── payment-service/
├── notification-service/
├── gradebook-service/
├── audit-service/
├── common-library/
└── kubernetes/

See project.md for the full end-to-end flow, code blueprints, and infrastructure details.