bitnami-containers/bitnami/ruby/README.md

What is Ruby?

Ruby is a dynamic, open source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write.

ruby-lang.org

TLDR

docker run -it --name ruby bitnami/ruby:latest

Docker Compose

ruby:
  image: bitnami/ruby:latest
  command: ruby script.rb
  volumes:
    - .:/app

Get this image

The recommended way to get the Bitnami Ruby Docker Image is to pull the prebuilt image from the Docker Hub Registry.

docker pull bitnami/ruby:latest

To use a specific version, you can pull a versioned tag. You can view the list of available versions in the Docker Hub Registry.

docker pull bitnami/ruby:[TAG]

If you wish, you can also build the image yourself.

docker build -t bitnami/ruby:latest https://github.com/bitnami/bitnami-docker-ruby.git

Entering the REPL

By default, running this image will drop you into the Ruby REPL (irb), where you can interactively test and try things out in Ruby.

docker run -it --name ruby bitnami/ruby:latest

Further Reading:

• Ruby IRB Documentation

Running your Ruby script

The default work directory for the Ruby image is /app. You can mount a folder from your host here that includes your Ruby script, and run it normally using the ruby command.

docker run -it --name ruby -v /path/to/app:/app bitnami/ruby:latest \
  ruby script.rb

Running a Ruby app with gems

If your Ruby app has a Gemfile defining your app's dependencies and start script, you can install the dependencies before running your app.

docker run -it --name ruby -v /path/to/app:/app bitnami/ruby:latest \
  sh -c "bundle install && ruby script.rb"

or using Docker Compose:

ruby:
  image: bitnami/ruby:latest
  command: "sh -c 'bundle install && ruby script.rb'"
  volumes:
    - .:/app

Further Reading:

• rubygems.org
• bundler.io

Accessing a Ruby app running a web server

This image exposes port 3000 in the container, so you should ensure that your web server is binding to port 3000, as well as listening on 0.0.0.0 to accept remote connections from your host.

Below is an example of a Sinatra app listening to remote connections on port 3000:

require 'sinatra'

set :bind, '0.0.0.0'
set :port, 3000

get '/hi' do
  "Hello World!"
end

To access your web server from your host machine you can ask Docker to map a random port on your host to port 3000 inside the container.

docker run -it --name ruby -P bitnami/ruby:latest

Run docker port to determine the random port Docker assigned.

$ docker port ruby
3000/tcp -> 0.0.0.0:32769

You can also manually specify the port you want forwarded from your host to the container.

docker run -it --name ruby -p 8080:3000 bitnami/ruby:latest

Access your web server in the browser by navigating to http://localhost:8080.

Linking

If you want to connect to your Ruby web server inside another container, you can use the linking system provided by Docker.

Serving your Ruby app through an nginx frontend

We may want to make our Ruby web server only accessible via an nginx web server. Doing so will allow us to setup more complex configuration, serve static assets using nginx, load balance to different Ruby instances, etc.

Step 1: Create a virtual host

Let's create an nginx virtual host to reverse proxy to our Ruby container.

server {
    listen 0.0.0.0:80;
    server_name yourapp.com;

    location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header HOST $http_host;
        proxy_set_header X-NginX-Proxy true;

        # proxy_pass http://[your_ruby_container_link_alias]:3000;
        proxy_pass http://yourapp:3000;
        proxy_redirect off;
    }
}

Notice we've substituted the link alias name yourapp, we will use the same name when creating the link.

Copy the virtual host above, saving the file somewhere on your host. We will mount it as a volume in our nginx container.

Step 2: Run the Ruby image with a specific name

Docker's linking system uses container ids or names to reference containers. We can explicitly specify a name for our Ruby server to make it easier to connect to other containers.

docker run -it --name ruby -v /path/to/app:/app bitnami/ruby:latest ruby script.rb

or using Docker Compose:

ruby:
  image: bitnami/ruby:latest
  command: ruby script.rb
  volumes:
    - .:/app

Step 3: Run the nginx image and link it to the Ruby server

Now that we have our Ruby server running, we can create another container that links to it by giving Docker the --link option. This option takes the id or name of the container we want to link it to as well as a hostname to use inside the container, separated by a colon. For example, to have our Ruby server accessible in another container with yourapp as it's hostname we would pass --link ruby:yourapp to the Docker run command.

docker run -it -v /path/to/vhost.conf:/bitnami/nginx/conf/vhosts/yourapp.conf \
  --link ruby:yourapp \
  bitnami/nginx:latest

or using Docker Compose:

nginx:
  image: bitnami/nginx:latest
  links:
    - ruby:yourapp
  volumes:
    - /path/to/vhost.conf:/bitnami/nginx/conf/vhosts/yourapp.conf

We started the nginx server, mounting the virtual host we created in Step 1, and created a link to the Ruby server with the alias yourapp.

Maintenance

Upgrade this image

Bitnami provides up-to-date versions of Ruby, including security patches, soon after they are made upstream. We recommend that you follow these steps to upgrade your container.

Step 1: Get the updated image

docker pull bitnami/ruby:latest

or if you're using Docker Compose, update the value of the image property to bitnami/ruby:latest.

Step 2: Remove the currently running container

docker rm -v ruby

or using Docker Compose:

docker-compose rm -v ruby

Step 3: Run the new image

Re-create your container from the new image.

docker run --name ruby bitnami/ruby:latest

or using Docker Compose:

docker-compose start ruby

Testing

This image is tested for expected runtime behavior, using the Bats testing framework. You can run the tests on your machine using the bats command.

bats test.sh

Notable Changes

2.3.1-r0 (2016-05-11)

• Commands are now executed as the root user. Use the --user argument to switch to another user or change to the required user using sudo to launch applications. Alternatively, as of Docker 1.10 User Namespaces are supported by the docker daemon. Refer to the daemon user namespace options for more details.

2.2.3-0-r02 (2015-09-30)

• /app directory no longer exported as a volume. This caused problems when building on top of the image, since changes in the volume were not persisted between RUN commands. To keep the previous behavior (so that you can mount the volume in another container), create the container with the -v /app option.

2.2.3-0-r01 (2015-08-26)

• Permissions fixed so bitnami user can install gems without needing sudo.

Contributing

We'd love for you to contribute to this Docker image. You can request new features by creating an issue, or submit a pull request with your contribution.

Issues

If you encountered a problem running this container, you can file an issue. For us to provide better support, be sure to include the following information in your issue:

• Host OS and version
• Docker version (docker version)
• Output of docker info
• Version of this container (echo $BITNAMI_IMAGE_VERSION inside the container)
• The command you used to run the container, and any relevant output you saw (masking any sensitive information)

License

Copyright (c) 2015-2016 Bitnami

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.