New python bindings using pybind11

[maxnoe]

Here I replace the existing python bindings which are not working with python3 with new bindings using the excellent pybind11 library.

TODO (for @HealthyPear):

• [x] Add a python build system (setup.py / pyproject.toml etc for making this pip installable).
• [x] Add tests
• [x] Setup github actions?

I for now removed the histogram class, which was pure python 2 and seemed unrelated to the xcdf IO functionality, let me know what you think.

Also if you think that anything in the API is missing.

[HealthyPear]

Hi @jimbraun,

I added a CMake-based continuous integration pipeline for the C++ integration with python bindings (working on the pure-python one).

You should be able to activate it and make it a requirement for merging from settings-->branches-->Branch protection rules (for the masterbranch) --> Require status checks to pass before merging--> Status checks

[HealthyPear]

Dear @jimbraun ,

I added also a CI based entirely on Python, so you can add also that to the required status checks for merging. Unfortunately we have a problem in the macos installation (ubuntu works fine) so while the CMake-based pipeline will succeed the Python one will fail for the moment.

Next steps:

• [x] fix macos installation
• [x] add pytest(s), at least one in which we read a test file created with the C++ library
• [x] check/add missing API

[HealthyPear]

Dear @jimbraun ,

I now added a (simple) Python testing function to make sure we correctly read an XCDF file written by the C++ interface. The macOS installation issue should be fixed, but I could test it only manually.

It seems a good time to enable the CI pipelines (neither me or my colleague can, since we are not administrators): settings-->branches-->Branch protection rules (for master only is sufficient) --> Require status checks to pass before merging--> Status checks.

The CI pipelines are 2:

• CMake build with Python bindings
• Python package

There are still few things missing like, e.g.

• [x] a with statement to open a file in a context manager,
• [x] a Close() method
• [x] a method to restart the reading after the last event has been read (not sure if this is working correctly though...)
• [x] exposing also the attributes of XCDFFieldDescriptor and not only a __repr__ method might be useful
• +...?

[jimbraun]

@HealthyPear : Thanks much for adding the CI pipelines. I agree and I'll enable these next week.

[jimbraun]

I merged the CI pipelines manually into master, and checks are now required to pass before merging. Note that the Python checks currently fail in master, but merging this PR should be the next action in XCDF, so I feel this is OK for now.

[HealthyPear]

For what concerns early development of SWGO software (my use case) I don't think I need to export any more API for the time being. With successful checks, I am satisfied with this contribution unless you (@jimbraun and/or @maxnoe) spot some mistakes.

[jimbraun]

I'm satisfied with these changes and happy to merge the PR when the few remaining issues above have been resolved.

[HealthyPear]

@jimbraun I don't know why, but now it seems I need you to approve the workflows (they were running with not problem before...) - see here (I hope it's a one-time operation)

[maxnoe]

@HealthyPear I guess it's because I pushed changes and I wasn't approved yet

[jimbraun]

@HealthyPear : I've been manually approving all the workflow runs. They don't start automatically for first-time contributors.

[HealthyPear]

@jimbraun could please trigger the workflows? @maxnoe do you see something else that needs to be fixed in this PR?

[HealthyPear]

@jimbraun could you do it again? I think we are done @maxnoe?

For the moment I think this PR has what needs to read XCDF data to Python3 in a basic way, aside from Python packages like astropy.

[HealthyPear]

@maxnoe if everything is ready I think you have to change the status of the PR from Draft

[maxnoe]

From my side good!

[HealthyPear]

I am also satisfied!

[jimbraun]

Thanks @HealthyPear and @maxnoe!