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What is Ruby?
Ruby is a dynamic, reflective, object-oriented, general-purpose, open-source programming language. According to its authors, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, and Lisp. It supports multiple programming paradigms, including functional, object-oriented, and imperative. It also has a dynamic type system and automatic memory management.
%%LOGO%%
How to use this image
Create a Dockerfile in your Ruby app project
FROM %%IMAGE%%:2.5
# throw errors if Gemfile has been modified since Gemfile.lock
RUN bundle config --global frozen 1
WORKDIR /usr/src/app
COPY Gemfile Gemfile.lock ./
RUN bundle install
COPY . .
CMD ["./your-daemon-or-script.rb"]
Put this file in the root of your app, next to the Gemfile.
You can then build and run the Ruby image:
$ docker build -t my-ruby-app .
$ docker run -it --name my-running-script my-ruby-app
Generate a Gemfile.lock
The above example Dockerfile 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 %%IMAGE%%:2.5 bundle install
Run a single Ruby script
For many simple, single file projects, you may find it inconvenient to write a complete Dockerfile. In such cases, you can run a Ruby script by using the Ruby Docker image directly:
$ docker run -it --rm --name my-running-script -v "$PWD":/usr/src/myapp -w /usr/src/myapp %%IMAGE%%:2.5 ruby your-daemon-or-script.rb
Encoding
By default, Ruby inherits the locale of the environment in which it is run. For most users running Ruby on their desktop systems, that means it's likely using some variation of *.UTF-8 (en_US.UTF-8, etc). In Docker however, the default locale is C, which can have unexpected results. If your application needs to interact with UTF-8, it is recommended that you explicitly adjust the locale of your image/container via -e LANG=C.UTF-8 or ENV LANG C.UTF-8.