Re: [PoC] Federated Authn/z with OAUTHBEARER

> On 28 Oct 2024, at 17:09, Jacob Champion <jacob(dot)champion(at)enterprisedb(dot)com> wrote:
> On Mon, Oct 28, 2024 at 6:24 AM Daniel Gustafsson <daniel(at)yesql(dot)se> wrote:

>> Looking more at the patchset I think we need to apply conditional compilation
>> of the backend for oauth like how we do with other opt-in schemes in configure
>> and meson. The attached .txt has a diff for making --with-oauth a requirement
>> for compiling support into backend libpq.
>
> Do we get the flexibility we need with that approach? With other
> opt-in schemes, the backend and the frontend both need some sort of
> third-party dependency, but that's not true for OAuth. I could see
> some people wanting to support an offline token validator on the
> server side but not wanting to build the HTTP dependency into their
> clients.

Currently we don't support any conditional compilation which only affects
backend or frontend, all --without-XXX flags turn it off for both. Maybe this
is something which should change but I'm not sure that property should be
altered as part of a patch rather than discussed on its own merit.

> I was considering going in the opposite direction: With the client
> hooks, a user could plug in their own implementation without ever
> having to touch the built-in flow, and I'm wondering if --with-oauth
> should really just be --with-builtin-oauth or similar. Then if the
> server sends OAUTHBEARER, the client only complains if it doesn't have
> a flow available to use, rather than checking USE_OAUTH. This kind of
> ties into the other big open question of "what do we do about users
> that don't want the additional overhead of something they're not
> using?"

We already know that GSS cause measurable performance impact on connections
even when compiled but not in use [0], so I think we should be careful about
piling on more.

--
Daniel Gustafsson

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