Upgrade to django 3.2

[rtibbles]

Description

• Does the minimal required to upgrade to Django 3.2
• Fixes all tests and updates code for Django 3.2 compatibility
• Upgrades all django related libraries to newest versions
• Makes necessary updates to code to handle API changes across versions

[codecov]

Codecov Report

Merging #2533 (1c9fb14) into unstable (7558536) will decrease coverage by 1.30%.
The diff coverage is 86.37%.

❗ Current head 1c9fb14 differs from pull request most recent head 0ee0285. Consider uploading reports for the commit 0ee0285 to get more accurate results

@@ Coverage Diff @@## unstable #2533 +/- ##
============================================
- Coverage 86.13% 84.82% -1.31% 
============================================
Files 305 182 -123 Lines 16455 15034 -1421 ============================================
- Hits 14173 12753 -1420 + Misses 2282 2281 -1 

Impacted Files	Coverage Δ
contentcuration/contentcuration/api.py	91.80% <ø> (-0.27%)	⬇️
...ntentcuration/contentcuration/db/models/manager.py	90.74% <ø> (-0.31%)	⬇️
...igrations/0001_squashed_0094_auto_20180910_2342.py	100.00% <ø> (ø)
...uration/contentcuration/tests/test_contentnodes.py	94.96% <ø> (+0.35%)	⬆️
contentcuration/search/viewsets/savedsearch.py	79.31% <0.00%> (ø)
...ation/contentcuration/tests/test_rest_framework.py	36.93% <26.92%> (ø)
contentcuration/contentcuration/views/settings.py	74.74% <31.25%> (ø)
contentcuration/contentcuration/decorators.py	56.60% <33.33%> (ø)
contentcuration/contentcuration/views/users.py	64.32% <41.66%> (+0.14%)	⬆️
contentcuration/contentcuration/tasks.py	63.25% <50.00%> (+1.67%)	⬆️
... and 111 more

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[jredrejo]

As this is a huge change in terms of requirements, could you take a look at #2236 to see if you can include some of the changes from there, so we'd be hitting two targets with one shot?
I think the only part that would need to be added to your code is:

-celery==4.1.1
-redis==2.10.5
+celery==4.3.0
+redis==3.2.0

with its associated dependencies.
If that'd work with python 3.x and Django 2.2 we'd have full support of 3.8 and ,likely, 3.9 too.

[rtibbles]

Can do, that seems in line with the big dependency shift!

[jredrejo]

Tested with python 3.8 and everything seems to work fine... but when clicking on a channel to open its edit modal, I get quite often this error trace:

"HEAD /api/contentnode/ce5297fa2c5247529b9bcc68eec77d97 HTTP/1.1" 200 1067
INFO:django.server:"HEAD /api/contentnode/ce5297fa2c5247529b9bcc68eec77d97 HTTP/1.1" 200 1067
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 56004)
Traceback (most recent call last):
File "/usr/lib/python3.8/socketserver.py", line 650, in process_request_thread
self.finish_request(request, client_address)
File "/usr/lib/python3.8/socketserver.py", line 360, in finish_request
self.RequestHandlerClass(request, client_address, self)
File "/usr/lib/python3.8/socketserver.py", line 720, in __init__
self.handle()
File "/datos/le/studio/venv/lib/python3.8/site-packages/django/core/servers/basehttp.py", line 171, in handle
self.handle_one_request()
File "/datos/le/studio/venv/lib/python3.8/site-packages/django/core/servers/basehttp.py", line 179, in handle_one_request
self.raw_requestline = self.rfile.readline(65537)
File "/usr/lib/python3.8/socket.py", line 669, in readinto
return self._sock.recv_into(b)
ConnectionResetError: [Errno 104] Connection reset by peer
----------------------------------------

But, from an user point of view, nothing happens, everything seems correct in the browser. Also, it's very seldom, editing the same channel a few minutes later does not raise this error.

I have checked the original url being INFO:django.server:"GET /channels/05436ac33a2d41e1ac600dfdf0e14835/ HTTP/1.1" 200 111499
and the browser network tab shows

so it seems the application self-recovers from the problem

[jredrejo]

Everything works perfectly after the requirements*txt files are regenerated (current ones have some minor problems with python 3.8, but with pip-compile requirements.in it's solved) . This is not a fault from this PR but from the https://github.com/rtibbles/studio/blob/django2.2/README.md file , it should say it before executing the pip install -r requirements.txt command.
In that case we could change this README.md to say that this works with Python 3.6-3.8