Day_02: a meta-Julia GitHub actions journey

Today the goal was to build Julia notebooks in an automatic deployment with GitHub actions. I have used this workflow for all of my Python notebooks, but I hadn’t added the extra Julia requirement. I wasn’t sure at first how to use Julia’s excellent Pkg tools from bash.

Starting with what works

My action to deploy the Jupyter Book I took directly from the Jupyter Book project.

Here was my existing build-docs.yml

name: deploy-book

# Only run this when the master branch changes
on:
  push:
    branches:
    - master

# This job installs dependencies, build the book, and pushes it to `gh-pages`
jobs:
  deploy-book:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2

    # Install dependencies
    - name: Set up Python 3.9
      uses: actions/setup-python@v1
      with:
        python-version: 3.9

    - name: Install dependencies
      run: |
        pip install -r requirements.txt
    # Build the book
    - name: Build the book
      run: |
        jupyter-book build .
    # Push the book's HTML to github-pages
    - name: GitHub Pages action
      uses: peaceiris/actions-gh-pages@v3.5.9
      with:
        github_token: ${{ secrets.GITHUB_TOKEN }}
        publish_dir: ./_build/html

This action executes automatically as I merge into the master branch and deploys in my personal github-pages site. Its a great way to share content.

Adding Julia + IJulia to the workflow

Yaml files can be finicky, so when I copy-pasted another github action from the excellent QuantEcon with Julia I had some troubleshooting in whitespaces vs tabs. The main lines I needed were:

    - name: Set up Julia
      uses: julia-actions/setup-julia@v1
      with: 
        version: 1.7.2
    - name: Install IJulia and setup project
      shell: bash
      run: |
        julia -e 'using Pkg; Pkg.add("IJulia");'
        julia --project=Julia-learning --threads auto -e 'using Pkg; Pkg.instantiate();'

Where I would use julia-actions to get access to Julia. Then, install IJulia using the julia -e 'using Pkg; Pkg.add("IJulia")'. Nice!

The result was that I had the new Day_01 post added to the sections in the Learning Julia table of contents.

Including plots

The page existed, but yesterday I was working on plotting with the Plots package. I received this error in the notebook:

ArgumentError: Package Plots not found in current path:
- Run `import Pkg; Pkg.add("Plots")` to install the Plots package.


Stacktrace:
 [1] require(into::Module, mod::Symbol)
   @ Base ./loading.jl:967
 [2] eval
   @ ./boot.jl:373 [inlined]
 [3] include_string(mapexpr::typeof(REPL.softscope), mod::Module, code::String, filename::String)
   @ Base ./loading.jl:1196

So, I updated the Julia build with Plots:

    - name: Install IJulia and setup project
      shell: bash
      run: |
        julia -e 'using Pkg; Pkg.add("IJulia");'
        julia -e 'using Pkg; Pkg.add("Plots");' # <---------  the magic word!
        julia --project=Julia-learning --threads auto -e 'using Pkg; Pkg.instantiate();'

Once I had Plots added, the figures and even animations showed up without widgets or any other magic! Mostly because the animations are cleverly built as gifs.

Wrapping up

Today I didn’t get any real Julia development work, but I was able to build scripts to

• install Julia packages via julia -e 'using Pkg; ...'

• build Jupyter Books using the Julia kernel

• display Julia figures and animations on my website