Python 3.12 support

[josecastillolema]

Python 3.12 has dropped the imp module:

$ python --version
Python 3.12.0

$ ./kind.sh --install-cni-plugins --disable-snat-multiple-gws --multi-network-enable
...
+ kind_local_registry_port=5000
+ kind_local_registry_name=kind-registry
+ j2 /home/jose/dev/ovn-kubernetes/contrib/kind.yaml.j2 -o /home/jose/dev/ovn-kubernetes/contrib/kind-ovn.yaml
Traceback (most recent call last):
  File "/home/jose/.local/bin/j2", line 5, in <module>
    from j2cli import main
  File "/home/jose/.local/lib/python3.12/site-packages/j2cli/__init__.py", line 10, in <module>
    from j2cli.cli import main
  File "/home/jose/.local/lib/python3.12/site-packages/j2cli/cli.py", line 8, in <module>
    import imp, inspect
ModuleNotFoundError: No module named 'imp'

Code has to migrate to from imp to importlib

[josecastillolema]

python/cpython#104212

[josecastillolema]

It looks that the problem comes from the j2 pip dependency: kolypto/j2cli#80

[josecastillolema]

Looks like the solution is moving to Jinjanator

[skitt]

In Submariner we handled this by switching to python3-jinja2-cli with a small wrapper (which could be avoided by changing the invocations to pipe the values instead of setting them in the environment). That’s https://pypi.org/project/jinja2-cli/ from which j2cli was derived. Now the original is maintained, j2cli isn’t, and jinjanator was created to fix j2cli!

The advantage of python3-jinja2-cli is that it’s packaged for Fedora, which makes it easy to install; pip on current Debian, Ubuntu, and Fedora distributions requires using virtual environments.