I'd like to share feedback on GitHub Actions. Tried it out, and the learning curve was too much. I want to use stuff I already know -- e.g., write a Dockerfile, and then GH could run it on PR builds. The "workflow" concept didn't land for me, and I hope you consider a more generalized, open-source approach to running arbitrary scripts in response to PRs being opened, merges to master, etc.
They opened sourced the runner[0] if you're interested in learning how it works. Understanding the internals of it may or may not help the syntax and concepts of Actions land though.
My guess is that it is unlikely to see your request for a more generalized script or Dockerfile runner realized because that (Dockerfiles) was the original implementation of Actions during the beta; they pivoted away from that to the current form.
Counterpoint: I've never used Docker at all (I'm a Mac/iOS dev), and was able to get GitHub actions set up and doing what I needed it to in ~30 minutes. Its general similarity to other CI/CD solutions, TravisCI being the one I'm most familiar with, helped a lot.
Coming from Travis CI and GitLab CI, GitHub Actions was very intuitive and I had it running in the very first take.
The concept of actions is new, but it is brilliant compared to traditional approach of doing everything inside the CI jobs, or bring your own docker images.
The YAML configuration is something I have to learn that provides no value-add outside of GitHub. If it was at least based on Docker, you could re-use existing technical knowledge or teach people something that's valuable in other contexts.
