Open Stack

On Mon, 2015-04-20 at 13:57 -0600, Chris Friesen wrote:
> > However, minor changes like that could still possibly break clients that are not
> > expecting them.  For example, a client that uses the json response as arguments
> > to a method via **kwargs would start seeing TypeErrors for unexpected arguments.
> 
> Isn't this what microversions were intended to solve?

Yes.

> I'm relatively recent with OpenStack, so I don't have the history.  Did anyone 
> ever consider explicitly allowing new attributes to be added to responses?  

The problem is advertising that this information is available.  That's
why, in the past, nova required a new extension even if all you were
doing was adding an attribute, and that's why we want a new microversion
nowadays.

> That 
> would put the onus on clients to explicitly grab the attributes that they're 
> looking for, but that doesn't seem too crazy and it would simplify adding new 
> attributes on the server side.  You'd still need versioning to handle deleting 
> attributes or changing their meaning, of course.

-- 
Kevin L. Mitchell <kevin.mitchell at rackspace.com>
Rackspace