CodeBench

A code judge that doesn't just check your output — it checks if you understand your solution. Submit Python code, run it in an isolated Docker container, get evaluated against multiple test cases. On accepted, Gemini generates follow-up questions specific to your code and evaluates your answers.

How It Works

1. User submits Python code via the React frontend
2. Rails saves the submission and enqueues a Sidekiq job — returns 202 immediately
3. Sidekiq worker runs the code inside an isolated Docker container with strict resource limits
4. Output is compared against all test cases — partial results tracked (e.g. 3/4 passed)
5. Frontend polls until status is terminal
6. On accepted: Gemini generates 3 short follow-up questions specific to the user's code
7. User has 3 minutes to answer — Gemini evaluates leniently and explains each result

Submission Statuses

• accepted: All test cases passed
• wrong_answer: Output mismatch on at least one test case
• runtime_error: Non-zero exit code
• compile_error: Python SyntaxError detected
• time_limit_exceeded: Execution exceeded 10 seconds

Stack

• API: Ruby on Rails 7.2 (API mode)
• Background jobs: Sidekiq + Redis
• Database: PostgreSQL
• Execution sandbox: Docker (python:3.11-alpine)
• AI follow-up: Google Gemini 2.5 Flash
• Frontend: React + Vite

Run Locally

Prerequisites: Ruby 3.2.2, Rails 7.2, PostgreSQL, Redis, Docker

git clone https://github.com/Alokxk/CodeBench.git
cd CodeBench
bundle install
rails db:create db:migrate db:seed
docker pull python:3.11-alpine

Create .env in the project root:

GEMINI_API_KEY=your_key_here
SIDEKIQ_WEB_PASSWORD=any_password_you_want
SIDEKIQ_WEB_SECRET=run `ruby -e "require 'securerandom'; puts SecureRandom.hex(32)"` and paste output here

Get a free Gemini API key at aistudio.google.com.

# Terminal 1
rails server

# Terminal 2
bundle exec sidekiq -C config/sidekiq.yml

# Terminal 3
cd frontend && npm install && npm run dev

Open http://localhost:5173

NOTE

See ARCHITECTURE.md for engineering decisions.