Ability to use Environment Flag with Branch Environments #85
Description
From my testing and reading of https://github.com/github/octocatalog-diff/blob/master/doc/advanced-environments.md#preserving-the-environments it looks like it is not possible to use an environment other than 'production' when running octocatalog-diff.
The Puppet setup we have uses each branch as its own environment, and we currently manage 4 "production" like branches:
- production
- perftest
- international
- development
Our hiera hierarchy and a lot of code is dependant on the environment puppet variable so it is difficult to test our non-production branches.
So the ideal octocatalog-diff testing scenario would be to compare branch feature/my_improvement in environment 'perftest' against 'origin/production' in the 'perftest' environment. Optionally 'origin/perftest' in the perftest environment would also work.
This doesn't fit with the current requirement of preserve-environments having an environments folder in the repo, going by the example here: https://github.com/github/octocatalog-diff/blob/master/doc/advanced-environments.md#examples
The ability to specify an environment independent of the preserve-environments structure would be the best solution for my use case. I can see this is currently disabled here:
I was going to look into the implementation of this for my use case but I wanted to raise a card to make sure there wasn't a strong reason not to implement something like this, or if it should be a separate set of command line options.
If I've totally misunderstood --preserve-environments I'd love to know how to achieve this use case.