portage: drop usage of gentoolkit, add knobs for --with-bdeps, --backtrack

[ajakk]

SUMMARY

This solves the issue brought up in #3870. The Portage Ansible module depends on an external shell command, when it could simply use the Portage module on every system that uses Portage.

Additionally, this adds support for handling the --with-bdeps and --backtrack emerge command line options.

ISSUE TYPE

• Feature Pull Request

COMPONENT NAME

Portage

ADDITIONAL INFORMATION

Similar to the other PR, this fixes the following kind of issue when running on a system that doesn't have the requisite external shell command:

host | FAILED! => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python3.9"
    },
    "changed": false,
    "msg": "Failed to find required executable \"equery\" in paths: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/bin"
}

[ansibullbot]

cc @Tatsh @wltjr
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[ajakk]

Not sure how to handle the failing tests. Running ansible with a different Python than the system python on Gentoo is nonsensical - /usr/bin/python shouldn't ever be a Python implementation that the Portage module isn't installed for.

[github-actions]

Docs Build 📝

Thank you for contribution!✨

This PR has been merged and your docs changes will be incorporated when they are next published.

[felixfontein]

Check out https://docs.ansible.com/ansible-core/devel/dev_guide/testing/sanity/import.html, it shows how to properly import Python modules that are not part of the standard library.

[felixfontein]

Thanks for your contribution! Please add a changelog fragment.

Since it is possible that the module is run with another Python interpreter (could also simply be inside a venv), you need to use respawning to make sure that the module can fall back to the correct Python interpreter that has access to the required Python module. See https://github.com/ansible/ansible/blob/devel/lib/ansible/modules/yum.py#L1693 and https://github.com/ansible/ansible/blob/devel/lib/ansible/modules/dnf.py#L579 for how to do this (they both use https://github.com/ansible/ansible/blob/devel/lib/ansible/module_utils/common/respawn.py, which is available since ansible-core 2.11, which since community.general 5.0.0 is the minimum supported version of ansible-core).

[felixfontein]

These imports need to be guarded, see https://docs.ansible.com/ansible/devel/dev_guide/testing/sanity/import.html for details.

[ajakk]

I think I've addressed this and the respawn issue, and I've tested at runtime but I haven't tried terribly hard to break it.

Forgot to do the changelog before pushing just now, looking into that now.

[ajakk]

To fix the PORTAGE_IMPORT_ERROR used-before-assignment issue, what's best? Should I assign it to None before the portage import try/catch?