stebje / example-github-action

Probot & GitHub Action example

Probot & GitHub Action example

This repository is an example of how to create a GitHub Action using Probot

If you build a GitHub Action using Probot, we recommend you watch this repository as we will keep updating it implementing best practises and new APIs.

Usage

You can use the action from this example repository:

name: Say Hello World
on:
  issues:
    types:
      - opened

jobs:
  sayHelloWorld:
    runs-on: ubuntu-latest
    steps:
      - uses: probot/exmaple-github-action@v1
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

See the action in ... action #1

Alternatively, you can pass the token with with:

- uses: probot/exmaple-github-action@v1
  with:
    token: ${{ secrets.GITHUB_TOKEN }}
    # or
    # GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Configuration

GitHub App authentication via APP_ID/PRIVATE_KEY is not supported. Only token authentication is supported by setting GITHUB_TOKEN.

Note that the LOG_LEVEL environment variable is ignored. Debug logs are not logged by default in GitHub Actions, but can be enabled by creating a ACTIONS_STEP_DEBUG repository secret and setting it to 1.

How it works

The Probot application function is defined in app.js.

The Action will run the index.js file which verifies the required environment variables are set, loads the Probot application function and then receives the event from the file system.

Important: GitHub Actions do not automatically install npm dependencies. Because you need to use @probot/github-action and probably other external dependencies, you need to bundle your app into a single file and reference that file as entry run.mains in your action.yml file. You can use ncc for that.

This repository is continuously publishing new versions to the special v1 branch using semantic-release. See package.json. Relevant bits are

1. "build": "ncc build index.js -o dist" script - bundle the app into dist/index.js
2. "release" - configure publishing from the "main" branch, and configure the git plugin to add a commit after publishing

The other relevant bit is .github/workflows/release.yml, which is run on each push to the default branch (main). It installs all dependencies, runs the build script, runs semantic-release which creates the GitHub release based on semantic commit message conventions (fix: ..., feat: ...) and commits the dist/index.js file. Then it pushes the changes to the v1 branch, so that users will always get the latest version when referencing probot/exmaple-github-action@v1. If there should ever be a breaking change, we would change the publish branch to v2, etc.

License

ISC