This repository contains dev container images and features that can be used to create a convenient and consistent development environment for working on Rails applications.

A dev container is a running Docker container that provides a fully-featured development environment which can be used to run an application, to separate tools, libraries, or runtimes needed for working with a codebase, and to aid in continuous integration and testing. Dev container features are self-contained units of installation and configuration that can be installed on top of a container image to provide additional functionality in a container. Dev container images are prebuilt docker images based on dev container features. For more information on the dev container specification see https://containers.dev/.

As of Rails 7.2, all newly generated Rails applications will come with a dev container that utilizes the images and features in this repository to create a development environment for that app.

You can add a dev container to an existing application by creating devcontainer.json in the .devcontainer/ directory at the top level of the repository. A minimal dev container setup, for an application using SQLite and Active Storage would look like this:

{
  "image": "ghcr.io/rails/devcontainer/images/ruby:3.3.0",
  "features": {
    "ghcr.io/rails/devcontainer/features/activestorage": {}
  }
}

This dev container uses the Ruby image, which includes an installation of Ruby (in this case version 3.3.0) and a Ruby version manager (mise by default, but configurable to use rbenv), as well as other common utilities such as Git. It also uses the Active Storage feature, which installs dependencies needed for Active Storage.

The dev container can be initialized by VSCode or by using the dev container CLI.

Detailed information about the images and features provided by this repository can be found in their individual readme files.

This repository is open for contributions. See the contributions guide for details.

You can create your own features, and images based on them.

The best place to start is the feature starter repository which is maintained by the devcontainers org.

The repository is released under the MIT License.