Sample: Composite action to install Python and Poetry on GitHub Actions workflows

action.yml

name: 'Install Python and Poetry'
description: 'Add Poetry, dependency manager for Python'

inputs:
  python-version:
    description: 'Python version'
    required: true
  poetry-version:
    description: 'Poetry version'
    required: true

runs:
  using: 'composite'
  steps:
    - name: Set up Python ${{ inputs.python-version }}
      uses: actions/setup-python@v4
      with:
        python-version: ${{ inputs.python-version }}
      id: setup_python
    - name: Install Poetry ${{ inputs.poetry-version }}
      run: |
        curl -sSL ${{ env.POETRY_URL }} | \
          python - --version ${{ inputs.poetry-version }}
        echo "$HOME/.local/bin" >> $GITHUB_PATH
      shell: bash
      env:
        POETRY_URL: https://install.python-poetry.org
    - name: Cache Poetry cache
      uses: actions/cache@v3
      with:
        path: ~/.cache/pypoetry
        key: poetry-cache-${{ runner.os }}-${{ steps.setup_python.outputs.python-version }}-${{ inputs.poetry-version }}
    - name: Cache Packages
      uses: actions/cache@v3
      with:
        path: ~/.local
        key: poetry-local-${{ runner.os }}-${{ steps.setup_python.outputs.python-version }}-${{ hashFiles('**/poetry.lock') }}-${{ hashFiles('.github/workflows/*.yml') }}

Usage

1. Put the file in <project_root>/.github/actions/setup-python-poetry/action.yml
2. Use the action in a workflow:

jobs:
  my_job_name:
    name: ...
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v3      
      - uses: ./.github/actions/setup-python-poetry
        with:
          python-version: "3.11"
          poetry-version: "1.4.2"

This might not work in the future due to GitHub Actions changes.

Alternatively, there is a Github Action that does this
https://github.com/packetcoders/action-setup-cache-python-poetry