🧮 Distributed Calculator with Vector Clocks & Rollback

Built with .NET Core & gRPC

🎯 Objective

This project simulates a distributed calculator system using gRPC services in .NET Core. It demonstrates key distributed systems concepts such as vector clocks, rollback, eventual consistency, and CAP theorem trade-offs.

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📦 Project Structure

DistributedCalculator/
├── CalculatorClient/       # gRPC client with vector clock logic
├── GrpcServer1/
├── GrpcServer2/
├── GrpcServer3/     
├── Shared/                 # Shared VectorClock class and models
└── README.md               # This file

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🚀 Features

• ✅ gRPC-based calculator with Square, Cube, and SlowMultiply operations
• ✅ Vector Clock tracking for causality
• ✅ Rollback mechanism on simulated errors
• ✅ CAP theorem simulation: prioritizes Availability + Partition Tolerance
• ✅ Eventual consistency with delayed clock sync
• ✅ Leader election (simulated)
• ✅ Two-phase commit for multi-server operations

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🛠️ Technologies Used

• .NET Core 8
• gRPC
• C#
• GitHub Actions (optional CI/CD)

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🧪 How It Works

1. Client sends a number and operation to selected server
2. Server merges vector clock, simulates delay, and may fail randomly
3. On failure → rollback and return isSuccess = false
4. Client retries with previous clock
5. Vector clocks evolve and log causal relationships

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📖 CAP Theorem in Practice

• Consistency: relaxed (vector clocks allow divergence)
• Availability: prioritized (client always gets a response)
• Partition Tolerance: supported (servers operate independently)

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🧠 Learning Goals

• Understand vector clocks vs Lamport clocks
• Implement rollback and compensation logic
• Simulate distributed failures and recovery
• Explore consistency models and trade-off

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🧑‍💻 Author

Chamod –