We differentiate between modules and baseModules in the
VM builder for NixOS tests. This way, nesting.children, eventhough
it doesn't inherit from parent, still has enough config to
actually complete the test. Otherwise, the qemu modules
would not be loaded, for example, and a nesting.children
statement would not evaluate.
Before this change `man 5 configuration.nix` would only show options of modules in
the `baseModules` set, which consists only of the list of modules in
`nixos/modules/module-list.nix`
With this change applied and `documentation.nixos.includeAllModules` option enabled
all modules included in `configuration.nix` file will be used instead.
This makes configurations with custom modules self-documenting. It also means
that importing non-`baseModules` modules like `gce.nix` or `azure.nix`
will make their documentation available in `man 5 configuration.nix`.
`documentation.nixos.includeAllModules` is currently set to `false` by
default as enabling it usually uncovers bugs and prevents evaluation.
It should be set to `true` in a release or two.
This was originally implemented in #47177, edited for more configurability,
documented and rebased onto master by @oxij.
Fixes#5185856e12aae54 ends up passing config to pkgs. Unfortunately this might be null and pkgs/top-level/default.nix assumes it is an attrset. To fix this, we just make the default for config = {}. Thanks to @kristoff3r for tracking this down.
/cc @domenkozar
See #49441 for an earlier attempt, which was subsequently reverted. I am
assuming that doubling the time will be sufficient if the machine is
overloaded since so many of the tests already pass at 5 minutes, while
still not holding back failures for needlessly long.
cleanSource does not appear to work correctly in this case. The path
does not get coerced to a string, resulting in a dangling symlink
produced in channel.nix. Not sure why, but this
seems to fix it.
Fixes#51025.
/cc @elvishjericco
Since 113a6b9325 the test driver
explicitly ensures if the node names won't break the resulting Perl
script at runtime. This slightly improves the correctness of the error
message.
These names are referenced by Perl variables inside the testing
frameworks which don't allow chars like `-` as character inside. An exemplary
expression may look like this:
```
{
x11-vm = {
services.xserver.enable = true;
};
}
```
This expression evaluates, e.g. when running `nixos-build-vms`, but when
trying to run `./result/bin/nixos-run-vms`, an error like this occurs:
```
starting VDE switch for network 1
running the VM test script
error: Can't modify subtraction (-) in scalar assignment at (eval 17) line 1, at EOF
Bareword "test" not allowed while "strict subs" in use at (eval 17) line 1.
Can't modify subtraction (-) in scalar assignment at (eval 17) line 1, at EOF
Bareword "test" not allowed while "strict subs" in use at (eval 17) line 1.
vde_switch: EOF on stdin, cleaning up and exiting
cleaning up
```
This can be very confusing for beginners, this change breaks evaluation
if such names are used for machines.
This is to try and squeeze more lost space from the image, so that hydra
starts building it again.
The fsck previous to the resize2fs is required so resize2fs works.
The one afterwards is a sanity check.
Using `-M` from resize2fs will not give much saved space due to a known
(in the manual) issue.
```
[samueldr@aarch64:~/nixpkgs]$ ls -lh result-*/*/*.img
-r--r--r-- 1 root root 2.2G Jan 1 1970 result-original/sd-image/nixos-sd-image-18.09.git.a7fd431-aarch64-linux.img
-r--r--r-- 1 root root 2.1G Jan 1 1970 result-M/sd-image/nixos-sd-image-18.09.git.a7fd431-aarch64-linux.img
-r--r--r-- 1 root root 1.9G Jan 1 1970 result-slimmed/sd-image/nixos-sd-image-18.09.git.a7fd431-aarch64-linux.img
```
```
[samueldr@aarch64:~/nixpkgs]$ nix path-info -S ./result-original
/nix/store/c8k9n78gylx293rjh762fr05a069kxp2-nixos-sd-image-18.09.git.a7fd431-aarch64-linux.img 3844125000
[samueldr@aarch64:~/nixpkgs]$ nix path-info -S ./result-slimmed
/nix/store/962238skj5mnzhrsmjy23dyzmxk77sp4-nixos-sd-image-18.09.git.a7fd431-aarch64-linux.img 3447473208
```
Rationale
---------
Currently, tests are hard to discover. For instance, someone updating
`dovecot` might not notice that the interaction of `dovecot` with
`opensmtpd` is handled in the `opensmtpd.nix` test.
And even for someone updating `opensmtpd`, it requires manual work to go
check in `nixos/tests` whether there is actually a test, especially
given not so many packages in `nixpkgs` have tests and this is thus most
of the time useless.
Finally, for the reviewer, it is much easier to check that the “Tested
via one or more NixOS test(s)” has been checked if the file modified
already includes the list of relevant tests.
Implementation
--------------
Currently, this commit only adds the metadata in the package. Each
element of the `meta.tests` attribute is a derivation that, when it
builds successfully, means the test has passed (ie. following the same
convention as NixOS tests).
Future Work
-----------
In the future, the tools could be made aware of this `meta.tests`
attribute, and for instance a `--with-tests` could be added to
`nix-build` so that it also builds all the tests. Or a `--without-tests`
to build without all the tests. @Profpatsch described in his NixCon talk
such systems.
Another thing that would help in the future would be the possibility to
reasonably easily have cross-derivation nix tests without the whole
NixOS VM stack. @7c6f434c already proposed such a system.
This RFC currently handles none of these concerns. Only the addition of
`meta.tests` as metadata to be used by maintainers to remember to run
relevant tests.
Referencing modulesPath in NixOS configurations can cause evaluation
errors in restricted mode. If used as `${modulesPath}` (as in all
use-sites in nixpkgs) the modules subtree is copied into its own store
path. Access to this path will be forbidden in restricted mode.
Converting to a string solves this issue.
`${builtins.toString modulesPath}` will point to a subdirectory of the
nixpkgs tree out of which evalModules is called.
This change converts modulesPath to a string by default so that the
call-site doesn't have to anymore.
