OK, so I know this has been brought up before, and I realise that this breaks the MVC model in a purists view. However, I really think that things such as current_user or current_tenant should be available in an observer.
My specific case is that after actions have been done on a subset of my models (about half a dozen) I want something to be written to an audit log that includes the user that made the change and the tenant that made that change as well.
The first way to do this is to add a line to each controller method that carries out that function. To make this DRYer the actual activity is carried out in the application controller or the auditlog model and a simple one line statement is called from the controller. However this still means adding in the line, which isn't great and would be a whole lot more elegant if it were done in an observer.
However since an observer has no way of knowing what current_user is, this isn't possible. I've seen some work around using Thread, but these do not look that safe to me.
Now if anyone does have a more elegant solution, I'd love to hear it. Otherwise this is my case that we should have access to some controller methods in an observer. I'd like to get a sense of the feeling out there before putting this to the rails core dev team.