For the record, here is the Nix 2.19 version:
https://github.com/NixOS/nix/blob/2.19-maintenance/src/libstore/serve-protocol.cc,
which is what we would initially use.
It is a more complete version of what Hydra has today except for one
thing: it always unconditionally sets the start/stop times.
I think that is correct at the other end seems to unconditionally
measure them, but just to be extra careful, I reproduced the old
behavior of falling back on Hydra's own measurements if `startTime` is
0.
The only difference is that the fallback `stopTime` is now measured from
after the entire `BuildResult` is transferred over the wire, but I think
that should be negligible if it is measurable at all. (And remember,
this is fallback case I already suspect is dead code.)
An empty string is a sneaky way to avoid hard failures --- things that
expect strings still get strings, but it does conversely open the door
up to soft failures (spooky-action-at-a-distance ones because the string
did not have the expected invariants).
"Fail fast" with null will ultimately make the system more robust, but
force us to fix more things up front, and I don't want to change this
without also fixing those things up front, especially as this commit is
for now just part of the the preparatory PR for which this is dead code.
Brought up by @thufschmitt in
https://github.com/NixOS/hydra/pull/1316#discussion_r1415111329 . This
makes this closer to what was originally there --- which just dispatched
off the experimental feature rather than the presence/absense of the
output, too.
This is just C++ changes without any Perl / Frontend / SQL Schema
changes.
The idea is that it should be possible to redeploy Hydra with these
chnages with (a) no schema migration and also (b) no regressions. We
should be able to much more safely deploy these to a staging server and
then production `hydra.nixos.org`.
Extracted from #875
Co-Authored-By: Théophane Hufschmitt <theophane.hufschmitt@tweag.io>
Co-Authored-By: Alexander Sosedkin <monk@unboiled.info>
Co-Authored-By: Andrea Ciceri <andrea.ciceri@autistici.org>
Co-Authored-By: Charlotte 🦝 Delenk Mlotte@chir.rs>
Co-Authored-By: Sandro Jäckel <sandro.jaeckel@gmail.com>
- `nativeBuildInputs` vs `buildInputs`
- narrow down `with`s for clarity
- use `autoreconfHook` not `bootstrap` script
These sorts of changes have also been done in the Nix repo.
Since the default lengths in Crypt::Passphrase::Argon2 changed from 16
to 32 in in 0.009, some tests that expected the passphrase to be
unchanged started failing.
The previous implementation was O(N²lg(N)) due to sorting the full
runnables priority list once per runnable being scheduled. While not
confirmed, this is suspected to cause performance issues and
bottlenecking with the queue runner when the runnable list gets large
enough.
This commit changes the dispatcher to instead only sort runnables per
priority once per dispatch cycle. This has the drawback of being less
reactive to runnable priority changes: the previous code would react
immediately, while this might end up using "old" priorities until the
next dispatch cycle. However, dispatch cycles are not supposed to take
very long (seconds, not minutes/hours), so this is not expected to have
much or any practical impact.
Ideally runnables would be maintained in a sorted data structure instead
of the current approach of copying + sorting in the scheduler. This
would however be a much more invasive change to implement, and might
have to wait until we can confirm where the queue runner bottlenecks
actually lie.
