GoLang Developer Test

Welcome to the technical assessment for the Senior GoLang Developer role. This test is designed to evaluate your proficiency in GoLang, problem-solving skills, debugging capabilities, and your ability to design scalable systems. Please ensure that you follow all instructions carefully.

You will be tested on three core aspects:

1. GoLang Application Development
2. Debugging and Code Review
3. Systems Design and Architecture

General Instructions:

• You are expected to complete all parts of the test independently.
• Please submit your answers, including the code, test cases, and documentation in a GitHub repository.
• Include a README.md file that explains how to run your code and any additional comments.
• The total time allocated for the test is 8 hours, divided between the three tasks as outlined below. You can distribute the time according to your comfort level.

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Part 1: GoLang Problem-Solving Task

Time Limit: 3-4 hours

Objective:
You will be developing a simple GoLang microservice that handles user management. Your task is to create a RESTful API that is scalable, efficient, and easy to maintain.

Requirements:

1. API Endpoints:

   • Implement the following user management operations:
     • POST /users: Create a new user.
     • GET /users/{id}: Retrieve user details by ID.
     • PUT /users/{id}: Update user details by ID.
     • DELETE /users/{id}: Delete a user by ID.
   • Assume users have a name, email, and age fields.

2. Concurrency and Goroutines:

   • The API should handle requests concurrently.
   • Use goroutines and channels to log the time each request takes from start to finish. Ensure proper synchronization using sync.WaitGroup.

3. Database Interaction:

   • Integrate either PostgreSQL or MongoDB (your choice) to persist user data.
   • The API should perform CRUD operations on the database (Create, Read, Update, Delete).

4. Testing:

   • Write unit tests for each API endpoint and database operation. Aim for high test coverage.

5. Error Handling:

   • Implement robust error handling for the API and database interactions. Return appropriate status codes and messages for different scenarios (e.g., user not found, invalid input).

Deliverables:

• A GoLang project with a well-structured directory.
• Unit tests with reasonable coverage.
• A README.md explaining how to run the application and tests.

Evaluation Criteria:

• Code readability and structure.
• Efficient use of GoLang constructs (goroutines, channels, error handling).
• Clean and well-documented code.
• Effective database interaction and schema design.
• Testing coverage and proper error handling.

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Part 2: Debugging and Problem-Solving (Code Review Task)

Time Limit: 2 hours

Objective:
In this part, we want to test your debugging skills. You will be provided with a GoLang project containing several coding flaws and inefficiencies. Your job is to identify and fix these issues.

Instructions:

1. The GoLang project is in the file: buggy_project.go

2. Identify Issues: Review the code and identify at least three major issues that could affect performance, security, or scalability. Common examples include:

   • Incorrect use of goroutines, race conditions, or deadlocks.
   • Mismanagement of database connections (e.g., failure to close connections).
   • Poor error handling or lack of logging.

3. Fix the Issues: Correct the issues you’ve identified and write a brief explanation (in your README.md file) of:

   • The problem you found.
   • Why it could cause a failure in production.
   • How you fixed it.

Deliverables:

• Updated project code with the issues resolved.
• A README.md file that explains your solutions.

Evaluation Criteria:

• Ability to identify subtle bugs and inefficiencies.
• Quality of your fixes and the justifications you provide.
• Code quality after the fixes are implemented.

Part 3: Systems Design and Architecture

Time Limit: 2 hours

Objective:
You will be required to demonstrate your understanding of scalable system design by proposing a simple microservices architecture for a hypothetical scenario.

Scenario: You have been tasked with designing the backend architecture for an online marketplace platform. This platform should allow users to browse products, make purchases, and manage their orders. Your job is to outline a microservices-based architecture that supports scalability and fault tolerance.

Requirements:

1. Services:

   • Design at least three microservices:
     • User Service (handles user accounts, authentication, etc.).
     • Product Service (manages the product catalog).
     • Order Service (handles order creation, updates, and tracking).

2. Database:

   • Propose the appropriate database(s) for each microservice. Explain whether you would use SQL or NoSQL databases for each, and justify your choice.

3. Scaling Considerations:

   • Discuss how each service can be scaled horizontally. Include suggestions for handling load balancing and service discovery.

4. CI/CD Pipeline:

   • Briefly explain how you would set up a CI/CD pipeline for these services using tools like Docker, Kubernetes, and any cloud platform (e.g., AWS, GCP, or Azure).

Deliverables:

• A detailed design document (1-2 pages) that outlines the architecture.
• An explanation of database and scaling choices.
• A brief description of the CI/CD pipeline.

Evaluation Criteria:

• Clarity and soundness of your architectural decisions.
• Understanding of microservices architecture.
• Knowledge of cloud platforms, databases, and scalability.
• Practicality of your CI/CD pipeline design.

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Additional Notes:

• The goal of this test is to assess your problem-solving ability and GoLang expertise. Please ensure that all code is your own and original.
• We strongly discourage using large language models (LLMs) like ChatGPT to generate code for this test. We will assess for this, and if detected, it may result in disqualification. Be prepared to discuss and explain all of your solutions in detail during a follow-up interview.

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We look forward to seeing your solutions and discussing them further with you. Good luck!

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