How do I enable GitHub-hosted runners for a GitHub Action? - github

Question

I created a workflow for my Python repo as follows:
name: Python package
on: [push, pull_request]
jobs:
build:
runs-on: [ubuntu-latest, macos-latest]
strategy:
fail-fast: false
matrix:
python-version: ["3.7", "3.8", "3.9", "3.10"]
steps:
- uses: actions/checkout#v3
- name: Set up Python ${{ matrix.python-version }}
uses: actions/setup-python#v3
with:
python-version: ${{ matrix.python-version }}
- name: Install dependencies
run: |
python -m pip install --upgrade pip
python -m pip install flake8 pytest semver
if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
- name: Lint with flake8
run: |
# stop the build if there are Python syntax errors or undefined names
flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
# exit-zero treats all errors as warnings.
flake8 . --count --exit-zero --max-complexity=10 --ignore=E501 --statistics
- name: Test with pytest
run: |
pytest
Unfortunately, the action never runs and times out with the error:
This request was automatically failed because there were no enabled runners online to process the request for more than 1 days.
Did I do something silly in the configuration file?
I'm currently on a free GitHub account. Are GitHub-hosted runners available on free accounts? If so how do I enable one of those?

Answer 1

Turns out
runs-on: [ubuntu-latest, macos-latest]
doesn't run the action on each platforms. Instead it tries to find a runner that satisfies both conditions, i.e. running on ubuntu-latest and macos-latest which is, of course, never found.
The way to so what I originally intended is to, instead, do a two-dimensional matrix for os and python-version.