Hello, I was configuring an SSL Context Controller Service today and had the keystores and passwords passed into the container via environment variables. I thought it would be nice to be able to reference these from the parameter context. Maybe either giving Parameter Context values the VARIABLE_REGISTRY scope in the Expression Language, or a new scope for references external to nifi?
I think for refreshing the Parameter Context on those external changes, it would require an edit/re-apply just as it does now, and would have to make sure it is well documented. I'd be interested in creating a PR for this if the idea makes sense and is acceptable. Thanks, Chad
