GitHub has a new way to publish a static site to Pages using GitHub Actions. This means you can now build with the Jekyll command (or something else) and use actions to publish, all using regular steps. This removes the need for Docker based actions and gives you all the freedom to configure the execution environment (versions of Ruby, extra dependencies...), it is a lot faster, easier to debug and closer to what you can run on your local machine.

You can check the documentation for more information on how to do this.

Maintaining this action was a great experience, but as there is now a better solution availabe I do encourage everyone to move over.

A GitHub Action to build and publish Jekyll sites to GitHub Pages

Out-of-the-box Jekyll with GitHub Pages allows you to leverage a limited, white-listed, set of gems. Complex sites requiring custom ones or non white-listed ones (AsciiDoc for instance) used to require a continuous integration build in order to pre-process the site.

Remember that GitHub is serving your built static site, not its sources. So when configuring GitHub Pages in your project settings, use gh-pages branch as a Source for GitHub Pages. If you are setting up username.github.io repository, you'll have to use master branch, so sources can be located in another orphaned branch in the repo (which you can safely mark as default after the first publication). In addition to that default behaviour, you can configure the branch this plugin pushes into with the target_branch-option. Keep in mind to set the source branch accordingly at the GitHub Pages Settings page.

Note that this is a rather simple (naive maybe) Docker based action. @limjh16 has created a JS based version of this action which saves the container download time and might help with non default use cases (such as but not limited to: specific package or library that is not available as a Gem).

If your repo doesn't already have one, create a new Jekyll site: jekyll new sample-site. See the Jekyll website for more information. In this repo, we have created a site within a sample_site folder within the repository because the repository's main goal is not to be a website. If it was the case, we would have created the site at the root of the repository.

As you are using this action to leverage specific Gems, well, you need to declare them! In the sample below we are using the Jekyll AsciiDoc plugin

source 'https://rubygems.org'

gem 'jekyll', '~> 3.8.5'
gem 'coderay', '~> 1.1.0'

group :jekyll_plugins do
  gem 'jekyll-asciidoc', '~> 2.1.1'
end

Edit the configuration file of your Jekyll site (_config.yml) to leverage these plugins. In our sample, we want to leverage AsciiDoc so we added the following section:

asciidoc: {}
asciidoctor:
  base_dir: :docdir
  safe: unsafe
  attributes:
    - idseparator=_
    - source-highlighter=coderay
    - icons=font

Note that we also renamed index.html to index.adoc and modified this file accordingly in order to leverage AsciiDoc.

The historical default behavior of GitHub Pages is to deploy the content of a gh-pages branch. If you want to rely on this and you don't have such a branch yet, you can create it with the following instructions

git switch --orphan gh-pages
git commit --allow-empty -m "Initial commit on orphan branch"
git push -u origin gh-pages

Use the helaili/jekyll-action@master action in your workflow file. It needs access to the out-of-the-box GITHUB_TOKEN secret. The directory where the Jekyll site lives will be detected (based on the location of _config.yml) but you can also explicitly set this directory by setting the jekyll_src parameter (sample_site for us). The SRC environment variable is also supported for backward compatibilty but it is deprecated. The action will search for Gemfile location. If your want to specify it explicitly (e.g. if you have multiple Gemfiles per project), you should update gem_src input parameter accordingly.

Use the actions/cache action in the workflow as well, to shorten build times and decrease load on GitHub's servers

name: Testing the GitHub Pages publication

on:
  push

jobs:
  jekyll:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2

    # Use GitHub Actions' cache to shorten build times and decrease load on servers
    - uses: actions/cache@v2
      with:
        path: vendor/bundle
        key: ${{ runner.os }}-gems-${{ hashFiles('**/Gemfile') }}
        restore-keys: |
          ${{ runner.os }}-gems-

    # Standard usage
    - uses:  helaili/jekyll-action@v2
      with:
        token: ${{ secrets.GITHUB_TOKEN }}

    # Specify the Jekyll source location as a parameter
    - uses: helaili/jekyll-action@v2
      with:
        token: ${{ secrets.GITHUB_TOKEN }}
        jekyll_src: 'sample_site'

    # Specify the target branch (optional)
    - uses: helaili/jekyll-action@v2
      with:
        token: ${{ secrets.GITHUB_TOKEN }}
        target_branch: 'gh-pages'

Upon successful execution, the GitHub Pages publishing will happen automatically and will be listed on the environment tab of your repository.

Just click on the View deployment button of the github-pages environment to navigate to your GitHub Pages site.

The GITHUB_TOKEN secret. This is mandatory unless build_only is set to true.

The Jekyll environment to build (default to production)

The Jekyll website source directory

Additional Jekyll build arguments (see the Jekyll doc)

The Jekyll Gemfile directory

The target branch name the sources get pushed to

The relative path where the site gets pushed to

When set to true, the Jekyll site will be built but not published

This is the directory which you want to build your site in

Commands to run prior to build and deploy. Useful for ensuring build dependencies are up to date or installing new dependencies. For example, use apk --update add imagemagick to install ImageMagick.

When set to true, previous version of the site will be restored before the Jekyll build takes place. You can then use the keep_files option in your _config.yml file to select the files you want to keep. Make sure you then keep at least the .git folder. This option will also remove the --force flag from the git commit... command.

keep_files: [.git, hello.html]

When set override the default bundler version provided. If not given will attempt to resolve bundler version from Gemfile.lock if one exists.

When set override the default author of the commits to be performed. The default is to use the GITHUB_ACTOR environment variable, which is usually the owner of the GITHUB_TOKEN secret. The value can for example be set to github-actions[bot]. The corresponding email address is automatically set to [commit_author]@users.noreply.github.com.

Say you want to create a documentation website where you both have the current version (v3.0), but also v1.0 and v2.0. You can then use a combination of keep_history and target_path along with the actions/checkout@v2action so that each version gets pushed in a separate folder without overwritting the previous one.

... 
  publish-current-version: 
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
      with:
        ref: main
    - name: Run with dest path
      uses: helaili/jekyll-build@v2
      with:
        target_branch: gh-pages
        target_path: /
        keep_history: true
        token: ${{ secrets.GITHUB_TOKEN }}

  publish-v2-version: 
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
      with:
        ref: v2.0
    - name: Run with dest path
      uses: helaili/jekyll-build@v2
      with:
        target_branch: gh-pages
        target_path: v2.0
        keep_history: true
        token: ${{ secrets.GITHUB_TOKEN }}
  
  publish-v1-version: 
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
      with:
        ref: v1.0
    - name: Run with dest path
      uses: helaili/jekyll-build@v2
      with:
        target_branch: gh-pages
        target_path: v1.0        
        keep_history: true
        token: ${{ secrets.GITHUB_TOKEN }}

This action previously used a JEKYLL_PAT environment variable instead of the token parameter. This is now deprecated.

Create a ACTIONS_STEP_DEBUG secret with value true and run the workflow again.

If you're using a Custom Domain for your GitHub Pages site, you will need to ensure that the CNAME file exists in the repository root of the main (or master) branch so that it can be copied to the deployment root when your site is deployed.

If your GitHub Pages site is run off the main (or master) branch, you can modify the Custom Domain setting in the Repository Settings to automatically generate and commit the CNAME file.

If your GitHub Pages site is run off an alternate branch, however, you will need to manually create and commit the CNAME file with your custom domain as its contents, otherwise the file will be committed to the deployment branch and overwritten the next time the action is run.

Note that you can force the inclusion of your CNAME file