Enable reuse of GitHub Actions workflows somehow (completed 💚)

[fregante]

Code reuse across workflows is impossible, we're copy-pasting across repositories and this isn't ok. I don't know when/if GitHub will allow workflow reuse like with GitHub Actions: actions/runner#748

Is this something that can be done in userland? For example:

# .github/workflows-template/test.yml
apply:
  name: fregante/gh-workflow-npm-test@hash124
  with: # If `gh-workflow-npm-test` has any custom/conditional features, `with` acts as parameters
    node-version: [8.x, 10.x, 12.x]
jobs:
  test:
    env:
      MY-COOL-ENV: an amazing project

or

jobs:
  test:
    name: Let's test stuff
    apply: fregante/gh-workflow-npm-test@hash124#jobs.test # It would only merge the specific jobs.test section
  build:
    needs: test
    steps:
      - run: echo My other steps

Then, on npm install or some other event, this module will:

1. look files under .github/workflows-template/*.yml
2. download the specified workflows from GitHub
3. merge the user's template with the specified workflow(s), applying any special variables it expects like node-version
4. save the merged workflow as .github/workflows/$1.yml

This is pretty simple, but I need your suggestions on when/how to ensure that .github/workflows/$1.yml is up to date:

• via postinstall only?
• git hooks?

[fregante]

To appease the all-in-one package.json gods, this could also just be a property:

{
  "name": "is-odd",
  ...,
  "dependencies": {
    "gh-workflows": "^1.2.3"
  },
  "gh-workflows": {
    "test": "sindresorhus/workflows@v1/test.yml"
  }
}

[fregante]

ghat is here (GitHub Action Templates) 🎉

I imagined it first of all configuration-free so, given a repo with a source template, you'll be able to pull it in with no further local configuration. You can just run this in your repository now:

npx ghat fregante/ghat/templates/node

It would copy the workflow(s) from the fregante/ghat repo in the templates/node folder and apply a header with instructions.

To update it in the future, you just re-run the same command and commit the changes, if you like them.

This does away with any versioning/installation needs, because workflows can't change automatically.