Introduction to GitHub Actions: Understanding key terms and building your first GitHub Action

Paul Gilzow — Platform.sh

We all know we should be doing more automation of our software development lifecycle, but getting started can be challenging. Even if you have experience in continuous integration and continuous delivery (CI/CD) automation, learning a specific platform’s terminology and idiosyncrasies can be frustrating.

Notes:

• Presentation files: https://github.com/gilzow/github-actions-presentation
• GitHub Action
  • A continuous integration service on the ploatform
• Github action (with a little ‘a’) – also referred to custom actions, or just actions
• Workflow (file) kicked of based on an event. Runs a series of jobs
  • YAML file in .github/workflows (any name. can have multiple)
• Event (on:)
  • Specific activity (can be called workflow trigger)
  • Lots of available events
• Job (jobs.jobid)
  • Series of steps
  • Jobs run concurrent
• Runner
  • A virtual service that runs things
  • Public runners may take a moment to run
• Step
  • Single action in a job
  • Can call a script, or public actions
  • These are run sequentially
  • Run or Use property required
    • Must check out repo if you need to use it (uses: …)
• Action
  • A self contained task
  • Can be manual inputs
  • Context
    • ${{ <context>.<property> }}
    • A lot of these are not prepared (might need to escape text)
  • Custom actions type:
    • Docker
    • Javascript
    • Composite
• Shows us a great example of running visual regression testing
  • When a CMS updates, it scans the test and prod sites for visual changes