[Bug report] Add support for Python 3.12

[hugovk]

The second and final Python 3.12 release candidate is out! 🚀

Call to action

We strongly encourage maintainers of third-party Python projects to prepare their projects for 3.12 compatibilities during this phase, and where necessary publish Python 3.12 wheels on PyPI to be ready for the final release of 3.12.0.

See also https://dev.to/hugovk/help-test-python-312-beta-1508/

The full Python 3.12.0 release is in under a month: 2023-10-02.

Bug report

Consider this a PR a bug report, the Python 3.12 build fails:

________________ ERROR collecting tests/unit/ssladapter_test.py ________________
ImportError while importing test module '/home/runner/work/docker-py/docker-py/tests/unit/ssladapter_test.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/opt/hostedtoolcache/Python/3.12.0-rc.2/x64/lib/python3.12/importlib/__init__.py:90: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/unit/ssladapter_test.py:2: in <module>
    from ssl import match_hostname, CertificateError
E   ImportError: cannot import name 'match_hostname' from 'ssl' (/opt/hostedtoolcache/Python/3.12.0-rc.2/x64/lib/python3.12/ssl.py)

This is because ssl.match_hostname was removed in Python 3.12 after being deprecated in 3.7:

• https://docs.python.org/3.12/whatsnew/3.12.html#removed
• https://docs.python.org/3.11/library/ssl.html#ssl.match_hostname

Replacements

Here's how a couple of other projects dealt with it:

• [1.26] Vendor ssl.match_hostname to avoid Python 3.10 deprecation warning urllib3/urllib3#2448 vendored ssl.match_hostname
• Replace deprecated ssl.match_hostname method (fixes: #368) aiortc/aioquic#389 replaced ssl.match_hostname with PyCA's service-identity

Feel free to use this PR as a starting point for fixing it as you see best, or close this as needed.

Thanks!

[Jamim]

Hello @milas,

I'd like to gently remind that Python 3.12 was released on October 2, 2023.
It would be great if you find time to take a look at this PR.

Thanks!

[milas]

Thanks for getting the ball rolling here! I extended this branch with #3185 to resolve the compatibility issues.

Changes from this branch have been merged via that PR (with attribution).

[milas]

I just tagged 7.0.0b1 which adds Python 3.12 support among other changes.

It's a major version because there are some light breaking changes.

See the release for details: https://github.com/docker/docker-py/releases/tag/7.0.0b1

---

Will plan on a stable release in a week or so pending verification in moby/moby and any reported regressions here. Thanks!