Python dev - Build python packages for each of supported python versions.

[smoser]

I need to write some doc for this PR.

[smoser]

Things to point out that a reviewer would want to look at:

1. use of 'py3-supported-python' - this is a way to get rid of a hard coded list of build time dependencies.
2. use of py3-supported- (like 'py3-supported-installer' or 'py3-supported-pip') which allows a package to build-depend on a single package rather than 3.
3. building with other pythons outside wolfi is not great here.
4. HACK/NEEDS FIXING - this currently moves all programs that are put into /usr/bin into /usr/pybin// so that py3.10-pip and py3.11-pip (which would both install /usr/bin/pip) can be installed together.

Things that would make life easier:

• ability to loop or some other way avoid the '-supported' packages above.

• dynamnically building subpackages (so we don't have to have 3 lines like below. I'd rather have it "just work" than require the yaml file to declare that there is a package).

  - name: pypi-wheels-${{vars.pypi-package}}
    pipeline:
      - uses: py/collect-wheels
  

• not declare 'py-versions' everywhere.

[dlorenc]

I like this approach! it seems like it won't confuse our scanner/advisory feed because it's still one version of each python library just "linked" against different python versions.

[smoser]

I don't think the build failure right now is due to my changes, but rather the dependency resolver. I do not think it is a circular dependency (which did cause issues earlier)

2024-03-29T16:56:46.4906470Z 2024/03/29 16:56:46 INFO error during command execution: 
    failed to build package: unable to build guest: 
       unable to generate image: installing apk packages: 
         error getting package dependencies: 
         solving "py3-supported-gpep517" constraint: 
           resolving "py3-supported-gpep517-15-r3.apk" deps:
2024-03-29T16:56:46.4908250Z could not find package either named 
    py3.10-tomli or that provides py3.10-tomli for py3.10-gpep517

py3-tomli.yaml does build a py3.10-tomli-2.0.1-r5.apk.

It does build locally given this order:

py3-supported-python
py3-flit-core
py3-setuptools
py3-pip
py3-installer
py3-tomli
py3-gpep517
py3-flit-core
py3-wheel
py3-cython
py3-numpy
py3-pathspec
py3-pyyaml
py3-yamllint

[xnox]

This is really good.

1. This will enable us to trivially build numpy image latest-3.12 latest-3.11 latest-3.10 images, and then choose whichever one we need to be shipped to the user.

2. pybin thing is a necessary evil and that's fine to get there. However, I somehow feel we might want to auto-generate conflicting packages too. Or ask apko to move them around. Such that numpy image latest-3.12 tag has /usr/bin/numpy with the valid python.

3. To land this safely I do wonder if we need to generate default symlinks in the top level package for now.

[xnox]

py3-tomli.yaml does build a py3.10-tomli-2.0.1-r5.apk.

we may need to land it first / separately, as that's install check rather than build check. And install checks are done after each build, rather than after all builds are completed first.

[pnasrat]

Close in favor of #20318