Re: [PoC] Federated Authn/z with OAUTHBEARER

On Tue, Apr 15, 2025 at 2:38 PM Jelte Fennema-Nio <postgres(at)jeltef(dot)nl> wrote:
> libpq_append_conn_error(conn, "no custom OAuth flows are available,
> and libpq-oauth could not be loaded library could not be loaded. Try
> installing the libpq-oauth package from the same source that you
> installed libpq from");

Thanks! I think that's a little too prescriptive for packagers,
personally, but I agree that the current message isn't correct
anymore. I've gone with "no custom OAuth flows are available, and the
builtin flow is not installed". (I suppose packagers could patch in a
platform-specific message if they really wanted?)

--

Other changes in v7:

- The option name remains --with-libcurl.
- Daniel and I have tweaked the documentation, and a draft commit message is up
- Removed the ENABLE_NLS-mismatch assertion in oauth-utils.c; we don't
need to care anymore
- Added an initialization mutex

I was feeling paranoid about injecting dependency pointers
concurrently to their use in another thread. They're _supposed_ to be
constant... but I have no doubt that someone somewhere knows of a
platform/compiler/linker combo where that blows up anyway.
Initialization is now run once, under pthread_mutex protection.

- Fixed module load on macOS

The green CI was masking a bug with its use of DYLD_LIBRARY_PATH: we
don't make use of RPATH on macOS, so after installing libpq, it lost
the ability to find libpq-oauth. (A stale installation due to SIP
weirdness was masking this on my local machine; sorry for not catching
it before.)

I have swapped to using an absolute path on Mac only, because unlike
LD_LIBRARY_PATH on *nix, DYLD_LIBRARY_PATH can still override absolute
paths in dlopen()! Whee. I could use a sanity check from a native Mac
developer, but I believe this mirrors the expected behavior for a
"typical" runtime dependency: libraries point directly to the things
they depend on.

With those, I have no more TODOs and I believe this is ready for a
final review round.

Thanks,
--Jacob