[openstack-dev] [api] Minor changes to API

Chris Friesen chris.friesen at windriver.com
Mon Apr 20 19:57:26 UTC 2015

On 04/20/2015 01:19 PM, Douglas Mendizabal wrote:
> Hi openstack-dev@
> I was wondering if the API Working Group had an opinion on how to deal with
> minor changes to the api?  For example, what if you wanted to add a new
> attribute to a JSON response?  I would think that a minor change like that could
> be done without having to create a new versioned endpoint.  So a newer release
> would just add the new attribute without having to create a new /v1.1/ endpoint.

> 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?

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?  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.


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