Document `--base-config` and `env-file` + add new project local defaults

[ssbarnea]

Current base configuration is fully undocumented. The page that is most likely to describe it contain nothing https://molecule.readthedocs.io/en/latest/configuration.html and neither other page of the documentation.

We not only need to document this but also make molecule load its base configuration automatically by discovering it from the code repository.

For local development is ok to keep configuration in a ~/.config but any colaborative project would expect to have a git hosted base config file that would be found and used when molecule is run.

[decentral1se]

Asked for in https://github.com/ansible/molecule/issues/1423#issuecomment-474963763 as well :+1:

[tace]

Good there is already ticket for this! +1 for the documentation. Trying to try/error how it works.

Please document also --env-file option.

[decentral1se]

Right, we have auto-loading already:

• https://github.com/ansible/molecule/blob/master/molecule/config.py#L312
• https://github.com/ansible/molecule/blob/master/molecule/config.py#L514

I'd like to suggest then to close this off that we provide new default paths:

• ${MOLECULE_PROJECT_DIRECTORY}/.molecule/molecule.yml # base-config
• ${MOLECULE_PROJECT_DIRECTORY}/.molecule/env.yml # env-file

We document this and keep loading from the existing defaults to not break anyones use case.

Thoughts?

[WithoutAnAce]

Is there a default env.yml path already, or is this a proposed change?

[dzintars]

Yeah, molecule --base-config .config/molecule/config.yml converge -s dev -- --limit workstations --tags nushell --list-tasks is a little bit verbose. I would like to drop base-config and scenario flags when iterating on some constant setup. But definitely "nice-to-have" thing.

[dzintars]

Similar issue https://github.com/ansible-community/molecule/issues/1664