🚗 ParkFlow Microservices-Based Smart Parking Management System
Built a backend-focused Parking Lot Management System using microservices architecture, emphasizing real-world workflows, fault tolerance, and role-based access control.
✨ Why ParkFlow?
Modern parking systems demand:
Scalability
High availability
Clean domain separation
Graceful failure handling
ParkFlow solves these challenges by modeling parking as a distributed microservice ecosystem.
🧩 Problem Statement
Design and implement a parking system that can:
✅ Dynamically allocate parking slots
✅ Generate and manage parking tickets
✅ Calculate parking charges at exit
✅ Handle service failures without breaking user flow
✅ Secure admin and user operations
🏗️ Architecture Overview
ParkFlow follows a microservices architecture with single-responsibility services and fault-tolerant communication.
Each service is:
Independently deployable Loosely coupled Designed around real-world parking domains
| Service | Responsibility |
|---|---|
| User Service | Vehicle entry & exit APIs |
| Parking Service | Central orchestration & ticket generation |
| Slot Service | Parking slot allocation & release |
| Pricing Service | Parking fee calculation |
| Admin Service | Admin-only privileged operations |
| Eureka Server | Service discovery |
📷 High-Level Architecture Diagram
⚙️ Tech Stack
☕ Java 17 🌱 Spring Boot 🔐 Spring Security ♻️ Resilience4j (Circuit Breaker) 🧭 Eureka Service Discovery 🌐 REST APIs 🧰 Maven 🧑💻 Git & GitHub
🧠 Key Design Decisions
✅ REST-based communication for clarity and simplicity
✅ No JWT / DB auth to avoid over-engineering
✅Circuit breakers only where user experience matters
✅Pricing calculated at exit to mimic real parking flow
✅Focus was on architecture clarity, not feature bloat.
♻️ Fault Tolerance & Resilience
To ensure smooth user experience even during failures:
Implemented Circuit Breaker pattern using Resilience4j
Added fallback responses for critical services
🔌 Slot Service Fallback
💰 Pricing Service Fallback
🔐 Security Implementation
Role-based authorization (USER / ADMIN) In-memory authentication for simplicity Separate security configurations for user and admin services
👤 User Authentication
🛡️ Admin Authorization
⚔️ Challenges & Solutions
| Challenge | Solution |
|---|---|
| Selecting a stable and industry-standard Java version for microservices development | Used Java 17 (LTS) for long-term support, better performance, and compatibility with Spring Boot |
| Inter-service communication between multiple microservices | Implemented Eureka Discovery Server for dynamic service registration and discovery |
| Calling other microservices from one service | Used Spring RestTemplate for synchronous REST-based inter-service communication |
| Avoiding hardcoded service URLs | Resolved service endpoints dynamically using Eureka service names |
| Handling service failures without cascading impact | Implemented Circuit Breaker pattern using Resilience4j |
| Providing fault tolerance during downstream failures | Added fallback mechanisms for graceful degradation |
| Securing APIs across microservices | Applied Spring Security with role-based authorization (ADMIN, USER) |
| Reducing repetitive boilerplate code | Used Project Lombok to auto-generate getters, setters, and constructors |
| API visibility and documentation | Integrated Swagger / OpenAPI for API documentation and testing |
| Ensuring scalability and loose coupling | Followed Microservices Architecture best practices |
| Manual API testing during development | Used Postman for request validation and debugging |
📘 API Documentation (Swagger) 📑
🔹 All services expose Swagger UI for easy API exploration and testing
🔹 Swagger is enabled using Springdoc OpenAPI
🔹 Each microservice provides interactive API documentation at:
👉 http://localhost:/swagger-ui.html 🌐
✨ This allows:
✅ Easy API testing without Postman 🧪
✅ Clear request/response contracts 📄
✅ Faster onboarding for developers 🚀
🧰 Lombok Usage 🛠️
🔹 Integrated Lombok to reduce boilerplate code ✂️
🔹 Simplified DTOs and models using annotations 📦
🔹 Eliminated repetitive getters, setters, constructors, and builders 🔁
🔹 Improved code readability and maintainability 📈
🔹 No impact on runtime performance ⚡
📸 Screenshots
🧠 Complete Architecture Diagram
🧭 Eureka Dashboard
📬 API Responses (Postman)
🚗 User Entry
🚪 User Exit
⭐ Special Entry through Admin
🔥 Circuit Breaker in Action
🚀 Future Enhancements
🔑 JWT-based authentication
🗄️ Database persistence (MySQL)
🚪 API Gateway
🧰 Implement Global Exception Handler
⚙️ Centralized configuration server
📊 Admin dashboard UI
1.Start Eureka Server
2.Start all microservices
3.Test APIs using Postman
👨💻 Author
Rahul Chakradhari
Java Backend Developer | Microservices | Spring Boot
📍 Location: Bengaluru , Karnataka
📞 Phone: +91 83058 25263
📧 Email: rahulchakradhari10september@gmail.com
🔗 LinkedIn: https://www.linkedin.com/in/rahulchakradhari
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