Add Centralised Logging

[thebeanogamer]

This is very WIP.

[codecov]

Codecov Report

Merging #275 (aa64b92) into master (45ee449) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #275   +/-   ##
=======================================
  Coverage   96.88%   96.88%           
=======================================
  Files         111      112    +1     
  Lines        5131     5141   +10     
  Branches      281      281           
=======================================
+ Hits         4971     4981   +10     
  Misses        128      128           
  Partials       32       32           

Impacted Files	Coverage Δ
src/backend/settings/__init__.py	90.62% <ø> (ø)
src/backend/logging.py	100.00% <100.00%> (ø)

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[thebeanogamer]

I think the way this is supposed to work is as follows:

1. Add a logger to backend.settings.__init__.LOGGING. This is a logging destination code can send to.
2. Define a filter in backend.logging, which shows how to transform the log
3. Within the code you want to log from, do something like this

import logging

log = logging.getLogger("<logger name>")

log.info("Message goes here", extra={})

We probably want to send different logs to different handlers, for example sending plaintext logs to console and structured logs to syslog. We should also probably write a filter to enhance the log records by adding request and user details. The docs do imply that logging is blocking, so we might need to be careful what we do there.

[jchristgit]

Hi Daniel, I just got around to check this PR. It's incredible what you have implemented. Can we use https://docs.python.org/3/library/logging.handlers.html#sysloghandler instead?

[jchristgit]

We won't log user details. We need to obey to GDPR