• 4.2.6, 4.2, 4, latest (Dockerfile)
• onbuild (onbuild/Dockerfile)

For more information about this image and its history, please see the relevant manifest file (library/rails). This image is updated via pull requests to the docker-library/official-images GitHub repo.

For detailed information about the virtual/transfer sizes and individual layers of each of the above supported tags, please see the rails/tag-details.md file in the docker-library/docs GitHub repo.

Ruby on Rails or, simply, Rails is an open source web application framework which runs on the Ruby programming language. It is a full-stack framework. This means that "out of the box", Rails can create pages and applications that gather information from a web server, talk to or query a database, and render templates. As a result, Rails features a routing system that is independent of the web server.

wikipedia.org/wiki/Ruby_on_Rails

FROM rails:onbuild

Put this file in the root of your app, next to the Gemfile.

This image includes multiple ONBUILD triggers which should cover most applications. The build will COPY . /usr/src/app, RUN bundle install, EXPOSE 3000, and set the default command to rails server.

You can then build and run the Docker image:

$ docker build -t my-rails-app .
$ docker run --name some-rails-app -d my-rails-app

You can test it by visiting http://container-ip:3000 in a browser or, if you need access outside the host, on port 8080:

$ docker run --name some-rails-app -p 8080:3000 -d my-rails-app

You can then go to http://localhost:8080 or http://host-ip:8080 in a browser.

The onbuild tag expects a Gemfile.lock in your app directory. This docker run will help you generate one. Run it in the root of your app, next to the Gemfile:

$ docker run --rm -v "$PWD":/usr/src/app -w /usr/src/app ruby:2.1 bundle install

If you want to generate the scaffolding for a new Rails project, you can do the following:

$ docker run -it --rm --user "$(id -u):$(id -g)" -v "$PWD":/usr/src/app -w /usr/src/app rails rails new --skip-bundle webapp

This will create a sub-directory named webapp inside your current directory.

The rails images come in many flavors, each designed for a specific use case.

This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of.

This image makes building derivative images easier. For most use cases, creating a Dockerfile in the base of your project directory with the line FROM rails:onbuild will be enough to create a stand-alone image for your project.

While the onbuild variant is really useful for "getting off the ground running" (zero to Dockerized in a short period of time), it's not recommended for long-term usage within a project due to the lack of control over when the ONBUILD triggers fire (see also docker/docker#5714, docker/docker#8240, docker/docker#11917).

Once you've got a handle on how your project functions within Docker, you'll probably want to adjust your Dockerfile to inherit from a non-onbuild variant and copy the commands from the onbuild variant Dockerfile (moving the ONBUILD lines to the end and removing the ONBUILD keywords) into your own file so that you have tighter control over them and more transparency for yourself and others looking at your Dockerfile as to what it does. This also makes it easier to add additional requirements as time goes on (such as installing more packages before performing the previously-ONBUILD steps).

View license information for the software contained in this image.

This image is officially supported on Docker version 1.10.3.

Support for older versions (down to 1.6) is provided on a best-effort basis.

Please see the Docker installation documentation for details on how to upgrade your Docker daemon.

Documentation for this image is stored in the rails/ directory of the docker-library/docs GitHub repo. Be sure to familiarize yourself with the repository's README.md file before attempting a pull request.

If you have any problems with or questions about this image, please contact us through a GitHub issue. If the issue is related to a CVE, please check for a cve-tracker issue on the official-images repository first.

You can also reach many of the official image maintainers via the #docker-library IRC channel on Freenode.

You are invited to contribute new features, fixes, or updates, large or small; we are always thrilled to receive pull requests, and do our best to process them as fast as we can.

Before you start to code, we recommend discussing your plans through a GitHub issue, especially for more ambitious contributions. This gives other contributors a chance to point you in the right direction, give you feedback on your design, and help you find out if someone else is working on the same thing.