GitHub Actions as CI/CD

WarningCaution

This section is being revised. Thank you for your patience.

In this lab we’re going to cover using GitHub Actions (or just Actions) for deploying your R or Python code (i.e., models, APIs, apps, etc).

To help explain/demonstrate GitHub Actions, I’ll cover a few examples I use often.

Quarto/GitHub Pages

This book is published using GitHub Pages, which is a free hosting service provided by GitHub. Quarto provides an easy Terminal command for publishing using GitHub Pages:

quarto publish gh-pages 

If I wanted to accomplish the same thing using GitHub Actions, I could create a workflow file in the .github/workflows directory of my repository. The workflow file would look something like this:

# .github/workflows/publish.yml

name: Publish Quarto Site to GitHub Pages

on:
  push:
    branches: [main]

jobs:
  build-deploy:
    runs-on: ubuntu-latest
    permissions:
      contents: write

    steps:
      - name: Check out repository
        uses: actions/checkout@v4

      - name: Set up Quarto
        uses: quarto-dev/quarto-actions/setup@v2

      - name: Render and Publish to GitHub Pages
        uses: quarto-dev/quarto-actions/publish@v2
        with:
          target: gh-pages
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

What it does:

• This triggers on every push to main, mirroring the behavior of running quarto publish gh-pages locally.
• The contents: write permission is required so the action can push the rendered output to the gh-pages branch.
  
• The GITHUB_TOKEN is automatically provided by GitHub Actions — no manual secret setup required.

We would also have to make sure our repository’s Pages settings (Settings → Pages) is configured to deploy from the gh-pages branch.

Running Tests

You can also use GitHub Actions to run tests on your code. For example, if you have an R package, you can set up a workflow to run R CMD check on every push or pull request. Here’s an example workflow file for that:

The original _labs/lab5/publish-r-py.yml file is below for reference:

on:
  workflow_dispatch:
  push:
    branches: main

name: Quarto Publish

jobs:
  build-deploy:
    runs-on: ubuntu-latest
    permissions:
      contents: write
    steps:
      - name: Check out repository
        uses: actions/checkout@v2

      - name: Set up Quarto
        uses: quarto-dev/quarto-actions/setup@v2

      - name: Install R
        uses: r-lib/actions/setup-r@v2
        with:
          r-version: '4.2.0'
          use-public-rspm: true

      - name: Setup renv and install packages
        uses: r-lib/actions/setup-renv@v2
        with:
          cache-version: 1
        env:
          RENV_CONFIG_REPOS_OVERRIDE: https://packagemanager.rstudio.com/all/latest

      - name: Install Python and Dependencies
        uses: actions/setup-python@v4
        with:
          python-version: '3.10'
          cache: 'pip'
      - run: pip install jupyter
      - run: pip install -r requirements.txt

      - name: Render and Publish
        uses: quarto-dev/quarto-actions/publish@v2
        with:
          target: gh-pages
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}