Modernize pyspedas packaging tools

[jameswilburlewis]

Using setup.py files to build releases, as we currently do with pyspedas, is deprecated, and probably won't pass muster with upcoming PyHC tiering requirements or PyOpenSci reviews.

We should explore moving to something more modern, like pyproject.toml or some of the other packaging tools that are in use.

Some options are listed here: https://packaging.python.org/en/latest/guides/tool-recommendations/

[Beforerr]

For comparison of python packaging tools https://www.pyopensci.org/python-package-guide/package-structure-code/python-package-build-tools.html

I have some experience of using pdm and would love to contribute if we decide to switching to that.

[jameswilburlewis]

I looked at the pyopensci page you linked, and pdm does seem like a pretty solid choice

[jameswilburlewis]

In addition to switching to a different set of build tools, there is probably room for improvement in our release management workflow.

Right now we build new releases from the head of the main branch, editing release name strings in the various config and metadata files. We probably should make separate release branches to have more control over what changes go in what releases, and take the release string from a git tag on the release branch. It seems pdm has some good built-in support for this.

See also:

#1037 : Minting a DOI and including it in the release metadata should be part of our release workflow

#1031 : We should test each release candidate build "as built", not just from a git clone as our current Github actions do. So: build the package, release to test-pypi, then install and test in a fresh environment. Then, if the tests are all passing, we can finally push it to production pypi.

[jameswilburlewis]

We have an initial pyproject.toml file now (thanks @Beforerr!) that's set up for the PDM build backend. There are still a few issues to sort out before putting it into production. (And I think we'll need to switch it temporarily to the setuptools backend, so pip install continues to work as desired? We need to check that before putting out any new releases that include this pyproject.toml.)

[Beforerr]

With pdm we could just use pdm install

[jameswilburlewis]

Latest pyproject.toml replaces MANIFEST.in and setup.py. Next step will be to start using PDM as the build tool.