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[oslo][nova] Revert of oslo.messaging JSON serialization change


Sorry I'm late to the party....

At the risk of stating the obvious I wouldn't put much faith in the fact
that the Kafka and Amqp1 drivers use jsonutils.   The use of jsonutils in
these drivers is simply a cut-n-paste from the way old qpidd driver.    Why
jsonutils was used there... I dunno.

IMHO the RabbitMQ driver is the authoritative source for correct driver
implementation - the Fake driver (and the others) should use the same
serialization as the rabbitmq driver if possible.

-K

On Tue, Oct 1, 2019 at 4:30 AM Balázs Gibizer <balazs.gibizer at est.tech>
wrote:

>
>
> On Mon, Sep 30, 2019 at 5:35 PM, Balázs Gibizer
> <balazs.gibizer at est.tech> wrote:
> >
> >
> > On Mon, Sep 30, 2019 at 4:45 PM, Ben Nemec <openstack at nemebean.com>
> > wrote:
> >>  Hi,
> >>
> >>  I've just proposed https://review.opendev.org/#/c/685724/ which
> >>  reverts a change that recently went in to make the fake driver in
> >>  oslo.messaging use jsonutils for message serialization instead of
> >>  json.dumps.
> >>
> >>  As explained in the commit message on the revert, this is
> >> problematic
> >>  because the rabbit driver uses kombu's default serialization method,
> >>  which is json.dumps. By changing the fake driver to use jsonutils
> >>  we've made it more lenient than the most used real driver which
> >> opens
> >>  us up to merging broken changes in consumers of oslo.messaging.
> >>
> >>  We did have some discussion of whether we should try to override the
> >>  kombu default and tell it to use jsonutils too, as a number of other
> >>  drivers do. The concern with this was that the jsonutils handler for
> >>  things like datetime objects is not tz-aware, which means if you
> >> send
> >>  a datetime object over RPC and don't explicitly handle it you could
> >>  lose important information.
> >>
> >>  I'm open to being persuaded otherwise, but at the moment I'm leaning
> >>  toward less magic happening at the RPC layer and requiring projects
> >>  to explicitly handle types that aren't serializable by the standard
> >>  library json module. If you have a different preference, please
> >> share
> >>  it here.
> >
> > Hi,
> >
> > I might me totally wrong here and please help me understand how the
> > RabbitDriver works. What I did when I created the original patch that
> > I
> > looked at each drivers how they handle sending messages. The
> > oslo_messaging._drivers.base.BaseDriver defines the interface with a
> > send() message. The oslo_messaging._drivers.amqpdriver.AMQPDriverBase
> > implements the BaseDriver interface's send() method to call _send().
> > Then _send() calls rpc_commom.serialize_msg which then calls
> > jsonutils.dumps.
> >
> > The oslo_messaging._drivers.impl_rabbit.RabbitDriver driver inherits
> > from AMQPDriverBase and does not override send() or _send() so I think
> > the AMQPDriverBase ._send() is called that therefore jsonutils is used
> > during sending a message with RabbitDriver.
>
> I did some tracing in devstack to prove my point. See the result in
> https://review.opendev.org/#/c/685724/1//COMMIT_MSG at 11
>
> Cheers,
> gibi
>
> >
> > Cheers,
> > gibi
> >
> >
> > [1]
> >
> https://github.com/openstack/oslo.messaging/blob/7734ac1376a1a9285c8245a91cf43599358bfa9d/oslo_messaging/_drivers/amqpdriver.py#L599
> >
> >>
> >>  Thanks.
> >>
> >>  -Ben
> >>
> >
> >
>
>
>

-- 
Ken Giusti  (kgiusti at gmail.com)
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