Code review comment for lp:~gz/pyjuju/add_maas_constraints

So at this point on the Maas side, we raise a InvalidConstraint error if you ask for a tag that doesn't exist in the DB. (Which gets turned into a proper BAD_REQUEST error with a helpful error message.)

Is that enough for this to work nicely? (Or is the actual request so async that it still isn't in time.)

If so, you can query api/1.0/tags?op=list and Maas will give you a list of all tags in the db (it probably gives too much information, but you will get the list of tag names out of that).

I agree that we shouldn't be caching the known list of tags.