Provide a handy CLI function and/or method on Func objects, to list all session names for a given Func, for easier Github Actions integration

[smarie]

Let's consider the following prototypical noxfile.py :

import nox

@nox.session(python=["3.7", "3.8"])
def tests(session):
    print("Interesting stuff going on here")

@nox.session(python=["3.7", "3.8"])
@nox.parametrize("a", [-1, 1])
@nox.parametrize("b", [False, True])
def tests_with_params(session, a, b):
    print("Interesting stuff going on here")

@nox.session(python="3.7")
def other(session):
    print("another session")

When integrating such a nox-based project into github actions, the basic way to do it is to list the sessions:

# (in .github/workflows/base.yml)
jobs:
  run_all_tests:
    strategy:
      fail-fast: false
      matrix:
        # Here we manually list two nox sessions
        nox_session: ["tests-3.7", "tests-3.8"]
    name: Run nox session ${{ matrix.nox_session }}
    runs-on: ubuntu-latest
    steps:
      # (other steps before this: checkout code, install python and nox...)
      - run: nox -s "${{ matrix.nox_session }}"

It would be handy to not have to redefine the list of test sessions in the github actions build matrix.

I found a way to solve this issue, and have the GHA build workflow dynamically create a build matrix from nox sessions : see this post.

However it would be even better to not have to create a dedicated session for this. In other words if

> nox --list <base_session_name>

was a valid CLI command, the example demonstrated in the above stackoverflow post would be simplified greatly.

As a companion, I think that providing a method on the Func object to list all generated session names could also be handy.

Note that all of this may need to evolve slightly when #404 is merged

[FollowTheProcess]

I may me missing something but could you not just do something similar to nox's own ci.yml i.e:

# noxfile.py
@nox.session(python=ALL_SUPPORTED_VERSIONS_HERE)
def test(session: nox.Session) -> None:
   """
   Runs all the tests for all python versions.
   """
   <some_good_stuff>
   ...

# CI.yml
name: CI

on: [push, pull_request]

jobs:
  test:
    name: Test
    runs-on: ${{ matrix.os }}

    strategy:
      matrix:
        os: [ubuntu-latest]
        python-version: ["3.8", "3.9", "3.10.0-rc.2"]

    steps:
      - name: Checkout Code
        uses: actions/checkout@v2

      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v2
        with:
          python-version: ${{ matrix.python-version }}

      - name: Install Dependencies
        run: |
          python3 -m pip install --upgrade pip setuptools wheel
          python3 -m pip install nox

      - name: Run Tests and Coverage
        run: nox --non-interactive --session "test-${{ matrix.python-version }}"

Here we've not had to specify explicit nox session, albeit we have had to specify supported python versions in both places, but there's an open issue suggesting parsing of python_requires to set this, which would be great! #384

[smarie]

@FollowTheProcess : sure we can do as you suggest, but it only works for a single session, non-parametrized, and you have to put all versions in the yaml.

My point is more general-purpose: consider a random project with a random number of sessions, possibly with various python versions and/or parameters. Plus, consider that only some sessions are relevant for gh actions.

See for example this project: https://github.com/smarie/python-pytest-cases/actions

[FollowTheProcess]

@FollowTheProcess : sure we can do as you suggest, but it only works for a single session, non-parametrized, and you have to put all versions in the yaml.

My point is more general-purpose: consider a random project with a random number of sessions, possibly with various python versions and/or parameters. Plus, consider that only some sessions are relevant for gh actions.

See for example this project: https://github.com/smarie/python-pytest-cases/actions

Ahh yeah I get it now! I was imagining a simpler case. I'm on board with this idea 👍🏻

[Wirg]

I might have implemented something that could be easily added to nox and solve this issue before running into it.
It use a "hack" on the base nox's workflow and directly takes the sessions from the manifest.
What do you think about it ? @FollowTheProcess
See : https://github.com/Wirg/stqdm/blob/main/commands/list_nox_manifest.py#L83-L136'

Usage :

$ python commands/list_nox_manifest.py --sessions tests
> ["tests(python='3.7', streamlit_version='~=0.66', tqdm_version='~=4.50')", "tests(python='3.8', streamlit_version='~=0.66', tqdm_version='~=4.50')"]
$ python commands/list_nox_manifest.py --return-base-sessions
> ["isort", "lint", "coverage", "tests", "black"]
$ python commands/list_nox_manifest.py --list-python-versions
> ["3.10", "3.7", "3.8", "3.9"]

EDIT : seems related to #658

[FollowTheProcess]

It looks like this use case would now be addressed by #658 (PR #665)?

[henryiii]

Should be addressed by json output, I think!