openstack team mailing list archive

[Russell Bryant <rbryant@xxxxxxxxxx>]

On 04/24/2012 11:39 AM, Eric Windisch wrote:
>>
>> Actually, I think JSON schema for our message-bus messages might be a
>> really good idea (tm).  Violations could just be warnings until we get
>> things locked down... maybe I should propose a blueprint? (Although I
>> have enough of a blueprint backlog as it is...)
> 
> This was discussed at the summit in (I believe) the API versioning talk.
> There is a strong bias toward JSON inside RPC messages. However, this is
> actually transparent to Nova as the RPC implementations do the decoding
> and encoding. It is also hard to test and trigger such warnings as, as
> far as Nova knows, all the interfaces pass python data types, not JSON.
>  Some RPC mechanisms could transparently serialize.  As long as there is
> an abstraction layer, it should be oblivious to the serialization and we
> should not care too strongly.
> 
> There was a patch a few weeks ago that has enforced using a common RPC
> exception serializer using JSON, which I'm not sure is, or is not, a
> good thing. I haven't yet updated the ZeroMQ driver to use this, but am
> in the process of making these changes as I update for Folsom.

The change was just to the fake rpc backend to help catch more errors in
unit tests where non-primitive types are getting passed into rpc.

> All that said, I do intend that the ZeroMQ driver will use JSON when it
> lands in Folsom.   (it currently Pickles, but only because there was a
> bug in Essex at one point, breaking  JSON serialization)

There may still be some datetime related problems lurking in there, but
we need to fix them as they come up.  If it causes a problem for you,
it's likely a problem for the other drivers, as well.

-- 
Russell Bryant