Online-Judge

Port of the Online Judge in Python

Architecture

Working

Initially the user chooses a language in the code editor and starts to write the answer based on the coding question. When the user submits the answer, the answer passes to the server. In the server a task id is being created in the PostgreSQL and the job is being sent to the Redis queue. Then celery picks up the job and executes it in a sandbox environment which is developed using C. This helps to increase security and prevents malicious code injection attacks on the platform. When the job finnishes execution the result is sent to the frontend using long polling. In this way the system verifies the users code, evaluate it and generates it ranking based on scores from other peers.

Documentation to help with Celery

https://docs.celeryproject.org/en/stable/getting-started/next-steps.html#next-steps

API Documentation

https://documenter.getpostman.com/view/7834053/Szmh1vuz?version=latest

Safeexec Submodule

The sandbox environment has been submoduled to the original repo so the changes immediately reflect back here. To work with submodules:

1. git submodule init
2. git submodule update
3. cd safeexec
4. cmake .
5. make

From next time onwards, we need to check if the submodules have been updated, to do that:

git pull --recurse-submodules

Development Environment Config

This project uses PEP8 code style, please make sure to follow. Yapf is our preffered formatting tool. If you are using VSCode add the following in your settings.json

"python.formatting.provider": "yapf",
"python.formatting.yapfArgs": ["--style={based_on_style: pep8, indent_width: 4, column_limit: 120}"],
"python.linting.enabled": true

For the code execution part to function properly, you need to install redis. Steps to install redis are as follows:

1. sudo apt install redis-server
2. sudo nano /etc/redis/redis.conf
3. Inside the file find the supervised directive and change it to systemd. It should be set to no by default.

  ...
  supervised systemd
  ...

4. sudo systemctl restart redis.service
5. Add redis://localhost:6379 in the CELERY_BROKER_URL part of the .env file you have in your locally cloned repository.

To check if redis is working or not:

1. Type in redis-cli
2. Type ping
3. If it returns PONG, then your redis-broker server is running fine.

To add Language models after running SQL migrations run

python manage.py loaddata --app interface language_model.json