Consistent handling of HTTP/S proxy environment variables

[davidwegs]

Consistent handling of HTTP/S proxy environment variables

Description

This PR provides consistent handling of the http_proxy, https_proxy, and no_proxy environment variables in line with the behavior of the Requests python library. Previously no_proxy wasn't being respected (#2077).

This is done by removing explicit handling of the http_proxy and https_proxy env variables in favor of downstream handling through the Requests library. Explicitly provided proxy settings through the proxy_url argument to the connection class and through the set_http_proxy method are still supported and still take precedence over the environment variables.

Status

done, ready for review

Checklist (tick everything that applies)

• Code linting (required, can be done after the PR checks)
• Documentation
• Tests
• ICLA (required for bigger changes)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 93.93939% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.36%. Comparing base (de03f1d) to head (34e8ab8).

Files with missing lines	Patch %	Lines
libcloud/test/test_connection.py	93.75%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            trunk    #2079   +/-   ##
=======================================
  Coverage   83.36%   83.36%           
=======================================
  Files         353      353           
  Lines       81886    81906   +20     
  Branches     9004     9007    +3     
=======================================
+ Hits        68258    68278   +20     
  Misses      10799    10799           
  Partials     2829     2829           

Files with missing lines	Coverage Δ
libcloud/http.py	92.09% <100.00%> (-0.22%)	⬇️
libcloud/test/test_connection.py	97.64% <93.75%> (+0.14%)	⬆️

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[tisonkun]

black-check: commands[1]> black --config pyproject.toml --check libcloud/
would reformat /home/runner/work/libcloud/libcloud/libcloud/test/test_connection.py

Oh no! 💥 💔 💥
1 file would be reformatted, 366 files would be left unchanged.
black-check: exit 1 (15.10 seconds) /home/runner/work/libcloud/libcloud> black --config pyproject.toml --check libcloud/ pid=3129
black-check: FAIL ✖ in 27.07 seconds

@davidwegs I'd approve this PR once the format issue get resolved :D

[davidwegs]

Thanks @tisonkun! Format issue should be resolved now

[tisonkun]

Thanks for your contribution @davidwegs! LGTM.

cc @micafer if you have time to give a review as well

I'm going to merge this patch in days.

[micafer]

LGTM

[tisonkun]

With one more approval I'd merge it now :D