Deploy Jekyll 4.x.x via GitHub Actions

• Create a brand new Jekyll site:

jekyll new deploy-jekyll-github-action

• We need to take care of few things in the _config.yml to deploy the site in GitHub pages. Change the url and baseurl. In my case:

baseurl: "/deploy-jekyll-github-action"
url: "https://pranabdas.github.io"

• Let's commit and push the code to github:

git init
git branch -m main
git remote add origin https://github.com/pranabdas/deploy-jekyll-github-action.git
git add --all
git commit -m "first commit"
git push -u origin main

• For the first time we will deploy the website via built-in github pages service. Create a new branch and name it to gh-pages.

• This will trigger, github-pages to deploy to https://pranabdas.github.io/deploy-jekyll-github-action. You can head over and check it out.

• Now let's add our GitHub Actions to deploy automatically, every time we push out code to main branch.

• Create our workflow file:

mkdir -p .github/workflows
vi .github/workflows/deploy-gh-pages.yml

• Add following content to our workflow:

name: Deploy gh-pages

on:
  push:
    branches:
      - main

jobs:
  deploy:
    runs-on: ubuntu-20.04
    concurrency:
      group: ${{ github.workflow }}-${{ github.ref }}

    steps:
      - uses: actions/checkout@v3

      - name: Prepare Ruby and Jekyll
        uses: ruby/setup-ruby@v1
        with:
          ruby-version: '2.7'

      - name: Install ruby dependencies
        run: bundle install

      - name: Build website
        run: bundle exec jekyll build

      - name: Deploy on gh-pages
        uses: peaceiris/actions-gh-pages@v3
        if: ${{ github.ref == 'refs/heads/main' }}
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          publish_dir: ./_site
          user_name: 'github-actions[bot]'
          user_email: 'github-actions[bot]@users.noreply.github.com'

• Commit and push changes to github.

• Note that if GitHub Pages is not already activated, the push from the workflow to gh-pages branch, won't automatically activate GitHub pages. All you have to do: go to your repository Settings → Pages, and select your source branch and path once the workflow pushed commit to the gh-pages brach. This is one time settings you need to follow if your GitHub Pages is not set up. Once GitHub Pages is active, it will deploy subsequent pushes from the workflow automatically.

• Finally, we will make some changes to our website, and see it automatically reflects in the automatic deploy. We will add some math equation to our about page.

• In order to parse math equation, we will use katex math engine. Add following to your _config.yml:

markdown: kramdown
kramdown:
  math_engine: katex

• Also we need to add a new gem for this. Add kramdown-math-katex to the list of gems in Gemfile:

group :jekyll_plugins do
  gem "jekyll-feed", "~> 0.12"
  gem "kramdown-math-katex"
end

• Run bundle install to update Gemfile.lock
• Open about.markdown and include katex stylesheet just below front matter:

---
layout: page
title: About
permalink: /about/
---

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.15.3/dist/katex.min.css" integrity="sha384-KiWOvVjnN8qwAZbuQyWDIbfCLFhLXNETzBQjA/92pIowpC0d2O3nppDGQVgwd2nB" crossorigin="anonymous">


This is the base Jekyll theme. You can find out more info about customizing your Jekyll theme, as well as basic Jekyll usage documentation at [jekyllrb.com](https://jekyllrb.com/)

• Now add some test math equation, in the bottom of about page:

[jekyll-organization]: https://github.com/jekyll

$$
I = \int_0^1 f(x) dx
$$

• That's all. Commit and push changes again, and we should see our equation rendered perfectly here.