JobApp-Microservices is a self-learning project that demonstrates a microservices architecture using Spring Boot. It covers inter-service communication, event-driven patterns, service discovery, API gateway routing, containerization, resilience features, and distributed tracing with Zipkin.

• CRUD operations for jobs, companies, and reviews.
• Inter-service communication using OpenFeign for synchronous calls and RabbitMQ for asynchronous events.
• Event-driven updates:
  • When a review is created/updated/deleted, the company's average rating and review count are automatically updated.
  • When a company is deleted, all its reviews are removed via RabbitMQ events.
• API Gateway routes requests to appropriate microservices.
• Resilience patterns: Circuit breaker, rate limiting, and retry mechanisms.
• Distributed Tracing: Zipkin integration for monitoring inter-service calls.
• Profiles: dev, prod, docker, kubernetes.
• Containerization & Orchestration: Docker and Kubernetes.
• Service Discovery & Config Management: Spring Cloud Config Server and Service Registry.

• Backend: Spring Boot, Spring Cloud
• Messaging: RabbitMQ
• Databases: H2 (dev), PostgreSQL (prod/docker/k8s)
• Containerization & Orchestration: Docker, Kubernetes
• Patterns & Tools: API Gateway, Service Registry, OpenFeign, Circuit Breaker, Rate Limiting, Retry, Zipkin

• Synchronous Communication: OpenFeign is used to fetch related data between services.
• Asynchronous Communication: RabbitMQ handles event-driven updates like review changes and company deletions.
• Distributed Tracing: Zipkin tracks inter-service calls.

Example Flows:

1. Fetch Company: Retrieves associated jobs and reviews via OpenFeign.
2. Fetch Job: Retrieves its parent company.
3. Review Updates: Triggers RabbitMQ events to update company’s aggregated ratings.
4. Company Deletion: Triggers RabbitMQ event to delete all associated reviews.

• Java 17+
• Maven
• Docker & Docker Compose (for containerized deployment)
• Kubernetes (for orchestration)
• PostgreSQL (for prod/docker/kubernetes profiles)
• RabbitMQ
• Zipkin (for distributed tracing)

Each microservice must be started separately in the correct order:

# Clone repository
git clone https://github.com/RishavHimmatramka/JobApp-Microservices.git
cd JobApp-Microservices

# Service Registry
cd service_registry
mvn spring-boot:run -Dspring-boot.run.profiles=dev

# Config Server
cd ../config_server
mvn spring-boot:run -Dspring-boot.run.profiles=dev

# Company Microservice
cd ../companyms
mvn spring-boot:run -Dspring-boot.run.profiles=dev

# Job Microservice
cd ../jobms
mvn spring-boot:run -Dspring-boot.run.profiles=dev

# Review Microservice
cd ../reviewms
mvn spring-boot:run -Dspring-boot.run.profiles=dev

# API Gateway
cd ../api_gateway
mvn spring-boot:run -Dspring-boot.run.profiles=dev

# Build and start all services
docker-compose -f docker-compose.yaml up --build

The Kubernetes manifests are located in k8s/. Apply them in the following order:

# PostgreSQL
kubectl apply -f k8s/postgres

# RabbitMQ
kubectl apply -f k8s/rabbitmq

# Zipkin for distributed tracing
kubectl apply -f k8s/zipkin

# Bootstrap microservices (companyms, jobms, reviewms)
kubectl apply -f k8s/bootstrap/jobms
kubectl apply -f k8s/bootstrap/companyms
kubectl apply -f k8s/bootstrap/reviewms