codecrafters-io/languages

Powers multi-language support for CodeCrafters challenges

This repository was previously used to power multiple language support for CodeCrafters challenges.

IMPORTANT: The content in this repository has since been migrated to challenge-specific repositories like this:

• codecrafters-io/build-your-own-redis
• codecrafters-io/build-your-own-docker
• codecrafters-io/build-your-own-git
• codecrafters-io/build-your-own-sqlite
• codecrafters-io/build-your-own-grep

New PRs must be sent to the above repositories. We're still updating docs around contributing support.

Table of Contents

• Objective
• Components
  • Dockerfile
  • Starter Repo
• Constraints
  • Fast build times
  • Easy to start
• Contributing

Objective

The language one uses for a CodeCrafters challenge is an integral part of the challenge experience. A few questions to think about:

• Is it easy to setup locally?
• Does the standard library have all required functions to complete the challenge?
• Are there any tricky areas where people are likely to get stuck?

We'll tackle these problems through a combination of:

• Sample code to get started
• Troubleshooting advice in the README
• Helpful language-specific hints in stages wherever applicable

Components

For a language to be supported in a specific challenge, we need the following things in place:

• A Dockerfile, which'll be used to build the container where code is evaluated.
• A starter repo, like this one.

Dockerfile

You'll need one Dockerfile per language version supported. These'll be placed under the dockerfiles/<course> folder.

The Dockerfile needs to setup the language + all required dependencies, and make the tester executable available at /bin/tester.

Wherever possible, utilize Docker's build cache.

Starter Repo

The starter repo needs to contains the following files:

• codecrafters.yml
• README.md
• An executable script / entry point, based on the challenge. your_docker.sh for Docker, your_git.sh for Git etc.
• An app folder, that contains boilerplate code that the user will build upon. This code must also include a section that can be commented out to pass the first stage.

Any language-specific code must adhere to common conventions or style guides for that language.

Since starter repos for different languages are likely to have a lot of similar code, we use templates to create these. The raw files are under starter_templates, the compiled versions are under compiled_starters.

Constraints

Fast build times

Slow build times drastically affect the codecrafters challenge experience. Building an image for a language and executing the starter should be snappy - ideally under 1 second.

To achieve this, we use Docker's build caching.

Easy to start

The experience of downloading a repository, running it locally, receiving results via a git push etc. can be pretty daunting to a new user who isn't used to how CodeCrafters works.

We make this easier by adding a concise step-by-step README, and also including all code needed to pass the first stage.

Contributing

Thank you for considering contributing to this project!

Here's a detailed guide on Adding support for a new language. If you need help, feel free to ask in the Discord server.