Jekyll Docker

Jekyll Docker is a software image that has Jekyll and many of it dependencies ready to use for you in an encapsulated format. It includes a default set of gems, different image types with different extra packages, and wrappers to make Jekyll run more smoothly from start to finish for most Jekyll users. If you would like to know more about Docker you can visit https://docker.com, and if you would like to know more about Jekyll, you can visit https://github.com/jekyll/jekyll

Image Types

• jekyll/jekyll: Default image.
• jekyll/minimal: Very minimal image.
• jekyll/builder: Includes tools.

Standard

The standard images (jekyll/jekyll) include a default set of "dev" packages, along with Node.js, and other stuff that makes Jekyll easy. It also includes a bunch of default gems that the community wishes us to maintain on the image.

Usage

export JEKYLL_VERSION=3.5
docker run --rm \
  --volume="$PWD:/srv/jekyll" \
  -it jekyll/jekyll:$JEKYLL_VERSION \
  jekyll build

Builder

The builder image comes with extra stuff that is not included in the standard image, like lftp, openssh and other extra packages meant to be used by people who are deploying their Jekyll builds to another server with a CI.

Usage

export JEKYLL_VERSION=3.5
docker run --rm \
  --volume="$PWD:/srv/jekyll" \
  -it jekyll/builder:$JEKYLL_VERSION \
  jekyll build

Minimal

The minimal image skips all the extra gems, all the extra dev dependencies and leaves a very small image to download. This is intended for people who do not need anything extra but Jekyll.

Usage

You will need to provide a .apk file if you intend to use anything like Nokogiri or otherwise, we do not install any development headers or dependencies so C based gems will fail to install.

export JEKYLL_VERSION=3.5
docker run --rm \
  --volume="$PWD:/srv/jekyll" \
  -it jekyll/minimal:$JEKYLL_VERSION \
  jekyll build

Dependencies

Jekyll Docker will attempt to install any dependencies that you list inside of your Gemfile, matching the versions you have in your Gemfile.lock, including Jekyll if you have a version that does not match the version of the image you are using (you should be doing gem "jekyll", "~> 3.6" so that minor versions are installed if you use say image tag "3.5".

Updating

If you provide a Gemfile and would like to update your Gemfile.lock you can run

export JEKYLL_VERSION=3.5
docker run --rm \
  --volume="$PWD:/srv/jekyll" \
  -it jekyll/jekyll:$JEKYLL_VERSION \
  bundle update

Caching

You can enable caching in Jekyll Docker by using a docker --volume that points to /usr/local/bundle inside of the image. This is ideal for users who run builds on CI's and wish them to be fast.

My Gems Aren't Caching

If you do not diverge from the default set of gems we provide (read: add Gems to your Gemfile that aren't already on the image), then bundler by default will not create duplicates, and cache. It will simply rely on what is already installed in $GEM_HOME. This is the default (observed... but unconfirmed) behavior of bundle when using $GEM_HOME w/ $BUNDLE_HOME

Usage

export JEKYLL_VERSION=3.5
docker run --rm \
  --volume="$PWD:/srv/jekyll" \
  --volume="$PWD/vendor/bundle:/usr/local/bundle" \
  -it jekyll/jekyll:$JEKYLL_VERSION \
  jekyll build

Configuration

You can configure some pieces of Jekyll using environment variables, what you cannot with environment variables you can configure using the Jekyll CLI. Even with a wrapper, we pass all arguments onto Jekyll when we finally call it.

ENV Var	Default
JEKYLL_UID	1000
JEKYLL_GID	1000
JEKYLL_DEBUG,	""
VERBOSE	""
FORCE_POLLING	""

If you would like to know the CLI options for Jekyll, you can visit Jekyll's Help Site

Packages

You can install system packages by providing a file named .apk with one package per line. If you need to find out what the package names are for a given command you wish to use you can visit https://pkgs.alpinelinux.org. We provide many dependencies for most Ruby stuff by default for builder and standard images. This includes ruby-dev, xml, xslt, git and other stuff that most Ruby packages might need.

Tools

You will find directions for using our image with various tools.

Docker-Compose

version: "3"
services:
  site:
    command: jekyll serve
    image: jekyll/jekyll:latest
    volumes:
      - $PWD:/srv/jekyll
      - $PWD/vendor/bundle:/usr/local/bundle
    ports:
      - 4000:4000
      - 35729:35729
      - 3000:3000
      -   80:4000

Usage

docker-compose run site jekyll new site
docker-compose run --service-ports site jekyll s
docker-compose run site bundle update
docker-compose run site jekyll b

LiveReload

This image supports jekyll-reload, all you need do is to [http://www.rubydoc.info/gems/jekyll-reload/](configure it according to your needs).

Usage

export JEKYLL_VERSION=3.5
docker run --rm \
  --volume=$PWD:/srv/jekyll \
  -p 35729:35729 -p 4000:4000 \
  -it jekyll/builder:$JEKYLL_VERSION \
  jekyll build

Building Our Images

You can build our images or any specific tag of an image with bundle exec docker-template build or bundle exec docker-template build repo:tag, yes it's that simple to build our images; even if it looks complicated it's not.

Contributing

• Fork the current repo; bundle install
• opts.yml holds most of the versions, and gems.
• Test your image manually script/debug will help you with that.
• Ensure that your intended changes work as they're supposed to.
• Ship a pull request if you wish to have it reviewed!