* Fix issue #614: restart queue/evaluator on sufficient disk space available.
* Only try to stop the service if it is currently running.
* Use named variables and added restarting message.
As of https://github.com/NixOS/hydra/pull/737 (removal of sqlite
dependency), the only supported database is Postgresql.
This change removes all references to hydra-postgresql.sql file. This
file is generated using a cpp on hydra.sql, but doesn't differ from
hydra.sql at all.
PathInput plugin keeps a cache of path evaluations. This cache is simple, and
path is not checked more than once every N seconds, where N=30. The caching is
there to avoid expensive calls to `nix-store --add`.
This change makes the validity period configurable. The main use case is
`api-test.pl` which was implemented wrong for a while, as the invocation of
`hydra-eval-jobset` would return the previous evaluation, claiming there are no
changes. The test has been fixed to check better for a new evaluation.
`build_finished` Postgres event will never be fired for the dependent builds.
For example, on our Hydra, the following query always returns increasing
numbers, even though all notifications have been delivered:
```
hydra=> select count(1) from builds where notificationpendingsince is not null;
count
-------
4583
(1 row)
```
Thus, we have to iterate over all dependent builds and mark their
`notificationpendingsince` as `null`, otherwise they will pile up until
the next restart of hydra-notify, when they will get delivered.
When deploying Hydra different than hydra.nixos.org one may encounter a problem
as building any job that uses IFD fails with:
May 22 19:41:07 hydra hydra-evaluator[6960]: error: "attempted to realize '/nix/store/1jm02mfiv58rpy8zrx95cpqxzsp64ssh-source.drv' during evaluation but 'allow-import-from-derivation' is false"
May 22 19:41:07 hydra hydra-evaluator[6960]: error: "attempted to realize '/nix/store/av3jr8ix4qcadq2wm3y3hplvxwzlhl4y-source.drv' during evaluation but 'allow-import-from-derivation' is false"
May 22 19:41:07 hydra hydra-evaluator[6960]: error: "attempted to realize
'/nix/store/2jm02mfiv58rpy8zrx95cpqxzsp64ssh-source.drv' during evaluation but
'allow-import-from-derivation' is false"
The recent change enforced passing `--no-allow-import-from-derivation`
to `hydra-eval-job` unconditionally. This change makes it configurable and
defaults to **NOT PASSING IT** -- most of the deployments allow IFDs.
The configuration option is called `allow_import_from_derivation` and
defaults to `true`. It is interpreted as a boolean, with only true option being
`true`.
Taken from `Perl::Critic`:
A common idiom in perl for dealing with possible errors is to use `eval`
followed by a check of `$@`/`$EVAL_ERROR`:
eval {
...
};
if ($EVAL_ERROR) {
...
}
There's a problem with this: the value of `$EVAL_ERROR` (`$@`) can change
between the end of the `eval` and the `if` statement. The issue are object
destructors:
package Foo;
...
sub DESTROY {
...
eval { ... };
...
}
package main;
eval {
my $foo = Foo->new();
...
};
if ($EVAL_ERROR) {
...
}
Assuming there are no other references to `$foo` created, when the
`eval` block in `main` is exited, `Foo::DESTROY()` will be invoked,
regardless of whether the `eval` finished normally or not. If the `eval`
in `main` fails, but the `eval` in `Foo::DESTROY()` succeeds, then
`$EVAL_ERROR` will be empty by the time that the `if` is executed.
Additional issues arise if you depend upon the exact contents of
`$EVAL_ERROR` and both `eval`s fail, because the messages from both will
be concatenated.
Even if there isn't an `eval` directly in the `DESTROY()` method code,
it may invoke code that does use `eval` or otherwise affects
`$EVAL_ERROR`.
The solution is to ensure that, upon normal exit, an `eval` returns a
true value and to test that value:
# Constructors are no problem.
my $object = eval { Class->new() };
# To cover the possiblity that an operation may correctly return a
# false value, end the block with "1":
if ( eval { something(); 1 } ) {
...
}
eval {
...
1;
}
or do {
# Error handling here
};
Unfortunately, you can't use the `defined` function to test the result;
`eval` returns an empty string on failure.
Various modules have been written to take some of the pain out of
properly localizing and checking `$@`/`$EVAL_ERROR`. For example:
use Try::Tiny;
try {
...
} catch {
# Error handling here;
# The exception is in $_/$ARG, not $@/$EVAL_ERROR.
}; # Note semicolon.
"But we don't use DESTROY() anywhere in our code!" you say. That may be
the case, but do any of the third-party modules you use have them? What
about any you may use in the future or updated versions of the ones you
already use?
Jörg Thalheim
Maximilian Bosch