Comment 5 for bug 1911010

I think it is worth bringing this up at a wider meeting to discuss the workflows that we would want to have.
The problem with a request / response pairing and introspection of an application data bag is that we don't have a mechanism to inform the unit that the data has changed. So you'll always be running the risk that what you see as the application request is no longer accurate.
So either we start providing events so that the units can be aware the data has changed, or you use a peer relation which communicates with the exact units you want to be sharing that information with, and has the correct update semantics.

I don't think we want to make charm writing harder than we need to. But we *do* want to provide accurate semantics and make sure we don't lead people down the "its easy to do it this way, but subtly wrong and hard to debug when it goes wrong".