The state of Python (both 2 and 3) in Ubuntu 22.04 LTS
Ubuntu 22.04 LTS has just been released and is on our minds, because we have a lot of Ubuntu 18.04 machines to upgrade to 22.04 in the next year. Since both we and our users use Python, I've been looking into the state of it on 22.04 and it's time for an entry on it, with various bits of news.
On the Python 2 front, 22.04 still provides a package for it but takes some visible (to us) steps towards eventually not having Python 2 at all. First, there is no official package provided to make /usr/bin/python point to Python 2. You can install a package (python-is-python3) to make /usr/bin/python point to Python 3, or you can have nothing official. Ubuntu is not currently forcing /usr/bin/python to be anything, so you can create your own symlink by hand (or with your own package) if you want to. We probably will because it turns out we have a reasonable number of users using '/usr/bin/python' and currently they're getting Python 2.
(If we were very energetic we would try to identify all of the users with the Linux auditing system and then go nag them. But probably not.)
Ubuntu 22.04 also drops support for the Python 2 version of Apache's mod_wsgi, which is still relevant for our Django application. It's possible that 22.04 still provides enough Python 2 support that you could build it yourself, but I haven't looked into this. Theoretically there is a Python 2 version of pip available, as 'python-pip'; in practice this conflicts with the Python 3 version, which is much more important now. If you need the Python 2 version of pip, you're going to have to install it yourself somehow (I haven't checked to see if the information from my entry on this issue works on 22.04).
Python 3 on Ubuntu 22.04 is currently in great shape. Ubuntu 22.04 comes with Python 3.10.4, which is the most current version as of right now and, impressively, was only released a month ago. Someone pushed hard to get that into 22.04 (the actual binary says it was built on April 2nd). It also packages the Python 3.8 version of PyPy 7.3.9 (as well as a Python 2 version). This is also the current version as of writing this entry (a day after Ubuntu 22.04's official release). How current both PyPy and Python 3 are is a pleasant surprise; they may drift out of date in time in the usual Ubuntu LTS way, but at least they're starting out in the best state possible.
(Ubuntu 22.04 also packages Django 3.2.12, the current Django LTS release; as I write this, Django 4.0.4 is the latest non-LTS release. I happen to think that relying on Ubuntu's Django is probably a bad idea, Based on the Django project support timeline here, 3.2 will only be supported by the Django project for two more years, until April of 2024; after that, Canonical is on its own to keep up with security issues for the remaining three years of 22.04 LTS. The package appears to be in the 'main' repository that Canonical says they support, but what that means in practice I don't know.)
Helpfully, Ubuntu 22.04 has a current version of pipx, which is now my favorite tool for handling third party Python programs that either aren't packaged by Ubuntu at all or where you don't want to be stuck with the Ubuntu versions. However, pipx has some challenges when moving from Python version to Python version, for example if you're upgrading your version of Ubuntu.