If we don't see machine that supports a build step for
'max_unsupported_time' seconds, the step is aborted. The default is 0,
which is appropriate for Hydra installations that don't provision
missing machines dynamically.
(cherry picked from commit f5cdbfe21d)
Building on macOS with the latest nixpkgs master and NixOS/nixpkgs#77147
fails. It seems some `std::experimental` (optional) for instance are
not available as `experimental`, but are in `std`. Also `toJSON` is
missing for `atomic< unsigned long long >`.
In a NixOS container, cmdBuildDerivation doesn't work because we're
not privileged. But we also don't need it because the store already
has the derivation.
Also, don't copy from/to the store since this gives errors about
missing signatures.
It now receives notifications about started/finished builds/steps via
PostgreSQL. This gets rid of the (substantial) overhead of starting
hydra-notify for every event. It also allows other programs (even on
other machines) to listen to Hydra notifications.
The hydra-queue-runner opens a connection to the builder. If the
builder is 'localhost' it starts `nix-store`, otherwise it starts
'ssh'.
Currently, if the hydra-queue-runner can not start `nix-store` (not in
the PATH for instance), the error message is:
cannot connect to ‘localhost’: error: cannot start ssh: No such file
or directory
This is not useful since ssh is actually not started:/
With this patch the error message is now:
cannot connect to ‘localhost’: error: cannot start nix-store: No such file
or directory
This cannot be done in the hydra-evaluator systemd unit, since then
every other Nix process (e.g. hydra-evaluator and nix-prefetch-*) will
also allocate the specified heap size, probably leading to OOM.
Thus, we no longer hold the send lock while substituting missing paths
on the build machine. This is a good thing in particular for macOS
builders which have a tendency to hang forever in curl downloads.
Previously, when hydra-queue-runner was restarted, any pending "build
finished" notifications were lost. Now hydra-queue-runner marks
finished but unnotified builds in the database and uses that to run
pending notifications at startup.
The queue runner can now run up to ‘max-concurrent-notifications’ in
parallel (default is 2). This is useful when some hydra-notify
invocations can take a long time to complete (e.g. because they need
to compress a giant build log) and we don't want this to block all
other notifications.
As @dtzWill discovered, with the concurrent hydra-evaluator, there can
be multiple active transactions adding builds to the database. As a
result, builds can become visible in a non-monotonically increasing
order, breaking the queue monitor's assumption that build IDs only go
up.
The fix is to have hydra-eval-jobset provide the lowest build ID it
just added in the builds_added notification, and have the queue
monitor check from there.
Fixes#496.
