- Usage of GitHub's runners is [limited](https://docs.github.com/en/actions/learn-github-actions/usage-limits-billing-and-administration#usage-limits)
- Available for public repositories or accounts with subscription
- By default Actions run on GitHub's runners
- Linux, Windows, or MacOS
- Quickly evolving and significant improvements in recent years
---
## Components (1/2)
- [Workflow](https://docs.github.com/en/actions/using-workflows): Runs one or more jobs
- [Event](https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows): Triggers a workflow
- [Jobs](https://docs.github.com/en/actions/using-jobs): Set of steps (running on same runner)
- Steps executed consecutively and share data
- Jobs by default executed in parallel
- [Action](https://docs.github.com/en/actions/creating-actions): Application performing common, complex task (step) often used in workflows
- [Runner](https://docs.github.com/en/actions/learn-github-actions/understanding-github-actions#runners): Server that runs jobs
- [Artifacts](https://docs.github.com/en/actions/learn-github-actions/essential-features-of-github-actions#sharing-data-between-jobs): Files to be shared between jobs or to be kept after workflow finishes
- Import [Julia test package repository](https://github.com/uekerman/JuliaTestPackage) (the same code we used for testing)
- Set up workflow file
```bash
mkdir -p .github/workflows
cd .github/workflows
vi format-check.yml
```
- Let's check whether our code is formatted correctly. Edit `format-check.yml` to have following content
```yaml
name: format-check
on: [push, pull_request]
jobs:
format:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- uses: julia-actions/setup-julia@v1
with:
version: '1.9'
- name: Install JuliaFormatter and format
run: |
julia -e 'using Pkg; Pkg.add(PackageSpec(name="JuliaFormatter"))'
julia -e 'using JuliaFormatter; format(".", verbose=true)'
- name: Format check
run: |
julia -e '
out = Cmd(`git diff --name-only`) |> read |> String
if out == ""
exit(0)
else
@error "Some files have not been formatted"
write(stdout, out)
exit(1)
end'
```
-`runs-on` does **not** refer to a Docker container, but to a runner tag.
- Add, commit, push
- After the push, inspect "Action" panel on GitHub repository
- GitHub will schedule a run (yellow dot)
- Hooray. We have set up our first action.
- Failing test example:
- Edit settings on GitHub that one can only merge if all tests pass:
- Settings -> Branches -> Branch protection rule
- Choose `main` branch
- Enable "Require status checks to pass before merging". Optionally enable "Require branches to be up to date before merging"
- Choose status checks that need to pass: `test`
- Click on "Create" at bottom of page.
- Create a new branch `break-code`.
- Edit some file, violate the formatting, commit it and push it to the branch. Afterwards open a new PR and inspect the failing test. We are also not able to merge the changes as the "Merge" button should be inactive.
---
## act Demo
-`act` is for quick checks while developing workflows, not for developing the code
- Check available jobs (at root of repository)
```bash
act -l
```
- Run jobs for `push` event (default event)
```bash
act
```
- Run a specific job
```bash
act -j test
```
---
# 4. Exercise
Set up GitHub Actions for your statistics package. They should format your code and run the tests. To structure and parallelize things, you could use two separate jobs.
