Re: [PoC] Federated Authn/z with OAUTHBEARER

On Tue, Oct 29, 2024 at 3:52 AM Daniel Gustafsson <daniel(at)yesql(dot)se> wrote:
> Currently we don't support any conditional compilation which only affects
> backend or frontend, all --without-XXX flags turn it off for both.

I don't think that's strictly true; see --with-pam which affects only
server-side code, since the hard part is in the server. Similarly,
--with-oauth currently affects only client-side code.

But in any case, that confusion is why I'm proposing a change to the
option name. I chose --with-oauth way before the architecture
solidified, and it doesn't reflect reality anymore. OAuth support on
the server side doesn't require Curl, and likely never will. So if you
want to support that on a Windows server, it's going to be strange if
we also force you to build the client with a libcurl dependency that
we won't even make use of on that platform.

> 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.

I agree, but if the server asks for OAUTHBEARER, that's the end of it.
Either the client supports OAuth and initiates a token flow, or it
doesn't and the connection fails. That's very different from the
client-initiated transport negotiation.

On the other hand, if we're concerned about the link-time overhead
(time and/or RAM) of the new dependency, I think that's going to need
something different from a build-time switch. My guess is that
maintainers are only going to want to ship one libpq.

Thanks,
--Jacob