Simple Arithmetic Calculator gRPC Server

This challenge asks you to implement a basic gRPC server in Go that provides arithmetic operations. Building gRPC servers is a fundamental skill for microservices and distributed systems, allowing for efficient and strongly-typed communication between services. This exercise will solidify your understanding of gRPC concepts, protocol buffers, and Go's concurrency features.

Problem Description

You need to create a gRPC server that exposes a service for performing addition, subtraction, multiplication, and division. The service will receive two integer inputs and return the result of the selected operation. The server should handle potential errors, such as division by zero.

What needs to be achieved:

1. Define a protocol buffer (.proto) file that specifies the gRPC service and its methods. This file should define the ArithmeticService with four methods: Add, Subtract, Multiply, and Divide. Each method takes two integer inputs (num1 and num2) and returns an integer result.
2. Generate Go code from the protocol buffer definition using the protoc compiler.
3. Implement the ArithmeticService server logic in Go. This involves creating a server implementation that handles the requests for each arithmetic operation.
4. Start the gRPC server and listen for incoming connections on a specified port (e.g., 50051).
5. Implement error handling, specifically for division by zero. If num2 is zero in the Divide method, return an error message indicating "Division by zero is not allowed."

Key Requirements:

• The server must correctly perform the specified arithmetic operations.
• The server must handle division by zero gracefully and return an appropriate error.
• The server must be functional and able to receive and process gRPC requests.
• The code should be well-structured, readable, and follow Go best practices.

Expected Behavior:

When a client sends a request to the server for a specific arithmetic operation with valid inputs, the server should return the correct result. If the client sends a request for division by zero, the server should return an error message.

Edge Cases to Consider:

• Division by zero.
• Large integer inputs that might cause overflow (though this is not a primary focus, consider it for robustness).
• Invalid input types (though the .proto file defines integer inputs, consider how the server would handle unexpected input types if it were extended).

Examples

Example 1:

Input: Add(num1=5, num2=3)
Output: 8
Explanation: The server receives a request to add 5 and 3, and returns the sum, which is 8.

Example 2:

Input: Divide(num1=10, num2=0)
Output: Error: "Division by zero is not allowed."
Explanation: The server receives a request to divide 10 by 0.  Since division by zero is not allowed, the server returns an error message.

Example 3:

Input: Multiply(num1=-2, num2=4)
Output: -8
Explanation: The server receives a request to multiply -2 and 4, and returns the product, which is -8.

Constraints

• The server must listen on port 50051 (or a configurable port).
• The server must be implemented in Go.
• The protocol buffer definition must be clear and concise.
• The server should be able to handle a reasonable number of concurrent requests (e.g., 10-20). Focus on correctness first, performance optimization can be considered later.
• The error message for division by zero must be a clear and informative string.

Notes

• You'll need to install the gRPC and protocol buffers tools for Go.
• Use the protoc compiler to generate the Go code from your .proto file.
• Consider using Go's built-in net/http/httpgrpc package for creating the gRPC server.
• Remember to handle errors appropriately throughout your code.
• Start with a minimal implementation and gradually add functionality.
• Think about how you would test your gRPC server (though writing tests is not explicitly required for this challenge, it's good practice).