CFE-4450: Allow passing environment variables to package managers

[amousset]

Allow passing options to the package managers modules through env:NAME=VERSION options.

Taking the easiest path. If it is considered acceptable I'll add a test case and documentation.

[nickanderson]

Do you have some explicit examples of the use case for each of the package managers as well?

[amousset]

For APT, for example controling needrestart's behavior.

But the main use case is for non-standard packages that allow customizing the configuration through env vars used in the postinst script. GitLab is one of them (https://docs.gitlab.com/omnibus/installation/index.html#set-up-the-initial-account):

sudo GITLAB_ROOT_EMAIL="<gitlab_admin@example.com>" GITLAB_ROOT_PASSWORD="<strongpassword>" EXTERNAL_URL="http://gitlab.example.com" apt install gitlab-ee

[nickanderson]

From my side I think it makes sense, I will invite @olehermanse @craigcomstock to bike shed a bit.

[craigcomstock]

Seems fine to me. Seeing this change here kind of begs to have a common python script to share such repeated code.

Also, it's a shame to not have the same for non-python modules if they even need it. For example, apk for alpine, but I have never needed to use env vars so probably fine. We can leave the complex usage to the complex systems: apt, yum and zypper. ;)

Definitely was looking for documentation and examples (a test case is usually a great example) before I read your description. So with those two pieces this looks good to me!

Thanks for the contribution!

[amousset]

I created some basic documentation in cfengine/documentation#3374. I also took a look at the tests but it seems there are no tests covering the options attribute, and that there is no testing mechanism for "real module/fake package manager" that would be convenient here (there is "fake module/no PM" and "real module/real PM"). I'll try to take a closer look.