Speed up Python Github Actions

If you want to speed up your CI builds you can use this setup on your GitHub actions. Doing this from the previous method cut my build times from 2 minutes to 1 minute.

Using UV + Python

Using uv as part of your project already should give you great performance benefits so why not include it as part of your CI builds? It allows for faster package resolution, dependency resolution and can cache your dependencies to your uv.lock file so that you don't need to worry about hammering pypi every build.

As per usual here is the tweak.

Migrating Your Requirements

Firstly, if you aren't using uv and are still using requirements.txt files you can do the following.

1. Init a pyproject.toml

uv init

2. Add the current requirements to the project

uv add -r requirements.txt

# If you have separate dev requirements
uv add  --dev -r dev-requirements.txt

This should generate a uv.lock file which we will need for the next section. This also means you can now just install local dependencies with uv sync and install pacakges without dev dependencies with uv sync --no-dev.

Updating Github Actions

You likely have something to this effect in your .github/workflows/test.yml

jobs:
  tests:
    runs-on: ubuntu-latest
    steps:
      - name: Set up Python
        uses: actions/setup-python@v5
        with:
          python-version: '3.12'

      - name: Install Requirements
        run: |
          python -m venv venv
          source venv/bin/activate
          pip install -r requirements.txt
          pip install -r requirements.dev.txt

      - name: Run The Tests
        run: |
          source venv/bin/activate
          pytest

Simply update to this instead and enjoy shedding off 30 seconds to a minute off your build times!

jobs:
  tests:
    runs-on: ubuntu-latest
    steps:
      - name: Install uv
        uses: astral-sh/setup-uv@v3
        with:
          enable-cache: true
          cache-dependency-glob: "uv.lock"

      - name: Set up Python
        uses: actions/setup-python@v5
        with:
          python-version: '3.12'

      - name: Install Requirements
        run: |
          uv sync --frozen

      - name: Run The Tests
        run: |
          source .venv/bin/activate
          pytest