As suggested in #131205.
Now it's possible to pretty-print a value with `lib.generators` like
this:
with lib.generators;
toPretty { }
(withRecursion { depthLimit = 10; } /* arbitrarily complex value */)
Also, this can be used for any other pretty-printer now if needed.
The message I originally implemented here was to catch a mixup of
`config' and `options' in a `types.submodule'[1]. However it looks
rather weird for a wrongly declared top-level option.
So I decided to throw
error: The option `foo' does not exist. Definition values:
- In `<unknown-file>':
{
bar = {
_type = "option";
type = {
_type = "option-type";
...
It seems as you're trying to declare an option by placing it into `config' rather than `options'!
for an expression like
with import ./lib;
evalModules {
modules = [
{
foo.bar = mkOption {
type = types.str;
};
}
];
}
[1] fa30c9abed
When having a bogus declaration such as
{ lib, ... }:
{
foo.bar = mkOption {
type = types.str;
};
}
the evaluation will terminate with a not-so helpful
error: stack overflow (possible infinite recursion)
To make sure a useful error is still provided, I added a `depthLimit` of
`10` which should be perfectly sufficient to `toPretty` when it's used
in an error-case for `showDefs`.
When having e.g. recursive attr-set, it cannot be printed which is
solved by Nix itself like this:
$ nix-instantiate --eval -E 'let a.b = 1; a.c = a; in builtins.trace a 1'
trace: { b = 1; c = <CYCLE>; }
1
However, `generators.toPretty` tries to evaluate something until it's
done which can result in a spurious `stack-overflow`-error:
$ nix-instantiate --eval -E 'with import <nixpkgs/lib>; generators.toPretty { } (mkOption { type = types.str; })'
error: stack overflow (possible infinite recursion)
Those attr-sets are in fact rather common, one example is shown above, a
`types.<type>`-declaration is such an example. By adding an optional
`depthLimit`-argument, `toPretty` will stop evaluating as soon as the
limit is reached:
$ nix-instantiate --eval -E 'with import ./Projects/nixpkgs-update-int/lib; generators.toPretty { depthLimit = 2; } (mkOption { type = types.str; })' |xargs -0 echo -e
"{
_type = \"option\";
type = {
_type = \"option-type\";
check = <function>;
deprecationMessage = null;
description = \"string\";
emptyValue = { };
functor = {
binOp = <unevaluated>;
name = <unevaluated>;
payload = <unevaluated>;
type = <unevaluated>;
wrapped = <unevaluated>;
};
getSubModules = null;
getSubOptions = <function>;
merge = <function>;
name = \"str\";
nestedTypes = { };
substSubModules = <function>;
typeMerge = <function>;
};
}"
Optionally, it's also possible to let `toPretty` throw an error if the
limit is exceeded.
Having a disks object with a dictionary of all the disks and their
properties makes it easier to process multi-disk images.
Note the rename of `label` to `system_label` is because `$label`i
is something of a special token to jq.
Introduce an AWS EC2 AMI which supports aarch64 and x86_64 with a ZFS
root.
This uses `make-zfs-image` which implies two EBS volumes are needed
inside EC2, one for boot, one for root. It should not matter which
is identified `xvda` and which is `xvdb`, though I have always
uploaded `boot` as `xvda`.
This is a private interface for internal NixOS use. It is similar
to `make-disk-image` except it is much more opinionated about what
kind of disk image it'll make.
Specifically, it will always create *two* disks:
1. a `boot` disk formatted with FAT in a hybrid GPT mode.
2. a `root` disk which is completely owned by a single zpool.
The partitioning and FAT decisions should make the resulting images
bootable under EFI or BIOS, with systemd-boot or grub.
The root disk's zpools options are highly customizable, including
fully customizable datasets and their options.
Because the boot disk and partition are highly opinionated, it is
expected that the `boot` disk will be mounted at `/boot`. It is
always labeled ESP even on BIOS boot systems.
In order for the datasets to be mounted properly, the `datasets`
passed in to `make-zfs-image` are turned in to NixOS configuration
stored at /etc/nixos/configuration.nix inside the VM.
NOTE: The function accepts a system configuration in the `config`
argument. The *caller* must manually configure the system
in `config` to have each specified `dataset` be represented
by a corresponding `fileSystems` entry.
One way to test the resulting images is with qemu:
```sh
boot=$(find ./result/ -name '*.boot.*');
root=$(find ./result/ -name '*.root.*');
echo '`Ctrl-a h` to get help on the monitor';
echo '`Ctrl-a x` to exit';
qemu-kvm \
-nographic \
-cpu max \
-m 16G \
-drive file=$boot,snapshot=on,index=0,media=disk \
-drive file=$root,snapshot=on,index=1,media=disk \
-boot c \
-net user \
-net nic \
-msg timestamp=on
```
The way `(lib.formats.yaml {}).generate` generates YAML is compliant
because on YAML 1.2 spec JSON is a subset of YAML but it bugs people's
minds and can lead to problems with software that is not compatible with
YAML 1.2.
This commit also changes the test of the generation function. Data
validation/typing remains the same.
See #133802.
Signed-off-by: lucasew <lucas59356@gmail.com>
