Update to Trac 1.6 and Python 3.8

[bmispelon]

I think this PR is finally ready:

• our small test suite now runs (and passes) on Python 3.8 (see my first comment for an explanation why i skipped 3.7)
• I've tested locally and the site seems to still work
• The docker image builds and I was able to run it locally as well (and I haven't made any changes to volumes which would impact its deployment in production as far as i know). I used the image from djangoproject.com as a base, which is why the diff is a bit big on this one.
• I've used my fork of trac-github in the requirements while we wait for a new release (my PR is still pending: Add support for Trac 1.6 and Python3 trac-hacks/trac-github#141)
• This new version of Trac does not require any database upgrade (no need to run any special command)
• The noshadows script didn't detect new CSS that might need fixing

Shall we move into the future of Python3? 🐍 🐍 🐍

Refs #148

[bmispelon]

@felixxm I'm running into some problems here trying to update the Dockerfile and I could use your guidance.

According to my initial plan (#148) I want Python 3.7 but because that version is not supported anymore I'm struggling to find a base image I can use. Even Ubuntu 20.04 (focal) ships with Python 3.8 I think (1).

Do you think I should revise my upgrade plan (maybe hop over a Django version at the same time as the Trac upgrade)? Or do you know a base docker image I could use? Thanks!

EDIT: Another possible solution would be to use Python 3.8 with Django 1.11. Even though they're not officially compatible it seems to work (the new test suite from #171 passes and the site seems to run correctly locally). Maybe that's the best (or least bad) solution?

[felixxm]

Are these 3 packages required even without bumping to the Trac 1.6?

[bmispelon]

They're required for the "log in with github" functionality provided by trac-github.I was able to remove the lines from the requirements here because I'm using the [oauth] extra of trac-github[oauth] which install them automatically.

We could make this change to our requirements file already without updating Trac, yes, but it doesn't (shouldn't?) have any effect in practice because the dependencies are installed anyway. It only serves to reduce the size of the requirements file.

[felixxm]

Since these are mostly Docker-related changes I need a second pair of eyes 🦅 @tobiasmcnulty Can you take a look?

[tobiasmcnulty]

🎉 The image builds and runs, and the changes look reasonable to me! Thanks or getting us off 2️⃣.7️⃣

A couple questions:

• Do you anticipate any deployment changes being needed? I didn't see any, just double checking.
• If there is an issue during the deploy, we could in theory roll back to the previous docker image, yes?

[tobiasmcnulty]

For the future -- perhaps we could use a similar trick to allow upgrade to be run more easily, when it is needed? (Not now.)

[bmispelon]

I've updated the PR after Tobias's comments.

Do you anticipate any deployment changes being needed? I didn't see any, just double checking.

I tried to keep the changes to a minimum and in particular when it comes to volumes, ports, ... As far as I can tell, it should "just" be a matter of deploying the new image and everything should keep working.

If there is an issue during the deploy, we could in theory roll back to the previous docker image, yes?

I believe so, yes. The 1.4 -> 1.6 Trac update doesn't require and db upgrade, so I believe it should be easy to roll it back by deploying the previous image.

[tobiasmcnulty]

This builds and runs for me. Nice work! 🚀

Full disclosure: I don't have a functional database locally, but I got as far as I did on main and the running site looks the same to me.