Part of the Lith Labs series

Goal

The goal is to be able to open a pull request and have Github automatically run quality checks and run tests.

Github Actions

Before adding any Github workflows, I need the ability to run the application in the background (otherwise it’ll block next steps in its job). I introduced a dup Make target that runs the app in daemon mode, as well as a down target to tear down the containers:

dup:
	docker compose up --build -d

down:
	docker compose down

I then started off with this simple workflow with two jobs: a lint and test that runs when a PR is opened to master.

# .github/workflows/quality-checks.yaml
name: Quality Checks
on:
  pull_request:
    branches: [ "master" ]
jobs:
  lint:
    name: Run Linters
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: echo "🚀Starting app"
      - run: make dup
      - run: echo "🔎Running linters"
      - run: make lint
  test:
    name: Run Test Suite
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: echo "🚀Starting app"
      - run: make dup
      - run: echo "🧪Running tests"
      - run: make test

Once merged to master, I updated the repository settings to prevent merging of pull requests when there’s a failing status check.

Linting and Formatting

I identified a gap in my current Makefile — the lint target actually writes the changes and doesn’t report back with a status code to signify that a change is made. This makes it unsuitable as a status check.

I had to introduce a new format target for development usage. I then updated lint to do a check, which is exactly what linting should do.

format:
	docker compose exec app black .

lint:
	docker compose exec app black --check .
	docker compose exec app flake8 .

Conclusion

Pull requests that fail the specified status checks can no longer be merged to master. See this PR for example.

The source is available at the feature/002-pr-checks branch