Re: [RFC PATCH v1 0/8] qapi: add generator for Golang interface

[Markus Armbruster]

Andrea Bolognani <abologna@redhat.com> writes:

> On Wed, May 18, 2022 at 02:30:11PM +0200, Markus Armbruster wrote:
>> Victor Toso <victortoso@redhat.com> writes:
>> > IMHO, at this moment, qapi-go is targeting communicating with
>> > QEMU and handling multiple QEMU versions seems reasonable to me.
>>
>> It's targeting communicating in *QMP*.  QMP is designed to support
>> communicating with a range of QEMU versions.  Full compatibility is
>> promised for a narrow range.  Outside that range, graceful degradation.
>>
>> *If* you want to widen the full compatibility range, do it in *QMP*.  Or
>> do it on top of QEMU, e.g. in libvirt.
>>
>> > Perhaps libvirt can use qapi-go in the future or other generated
>> > interface. That would be cool.
>>
>> "Would be cool" and a dollar buys you a cup of bad coffee.
>>
>> Is it a good use of our limited resources?
>>
>> How much will it delay delivery of Go bindings compared to less
>> ambitious version?
>
> Yeah, this thread has basically branched to cover three topics:
>
>   1. what an MVP Go interface for QMP should look like;
>   2. how to make sure said interface uses pretty names;
>   3. how to make it work across multiple QEMU versions.
>
> All of these are important in the long run, but as far as I'm
> concerned only 1. is an actual blocker to making progress.
>
> If we get to the point where we can generate a reasonably complete
> and well-typed Go interface that can be used to communicate with a
> single version of QEMU, we should just plaster EXPERIMENTAL all over
> it and get it merged.
>
> Basically get the MVP done and then iterate over it in-tree rather
> than trying to get everything perfect from the start.
>
> Sounds reasonable?

Yes, with an undogmatic interpretation of "minimally viable".  Doing
more should be okay when it doesn't complicate things outside the
Go-generating backend.

Exploring how to generate Go bindings that make good use of static
typing will be interesting enough.  Aiming for wide compatibility in
addition risks delay and/or failure.  Exploding heads, too.