pyrox.dev
1# Meta Attributes {#sec-meta-attributes}
2
3Like Nix packages, NixOS modules can declare meta-attributes to provide
4extra information. Module meta attributes are defined in the `meta.nix`
5special module.
6
7`meta` is a top level attribute like `options` and `config`. Available
8meta-attributes are `maintainers`, `doc`, and `buildDocsInSandbox`.
9
10Each of the meta-attributes must be defined at most once per module
11file.
12
13```nix
14{ config, lib, pkgs, ... }:
15{
16 options = {
17 ...
18 };
19
20 config = {
21 ...
22 };
23
24 meta = {
25 maintainers = with lib.maintainers; [ ericsagnes ];
26 doc = ./default.xml;
27 buildDocsInSandbox = true;
28 };
29}
30```
31
32- `maintainers` contains a list of the module maintainers.
33
34- `doc` points to a valid DocBook file containing the module
35 documentation. Its contents is automatically added to
36 [](#ch-configuration). Changes to a module documentation have to
37 be checked to not break building the NixOS manual:
38
39 ```ShellSession
40 $ nix-build nixos/release.nix -A manual.x86_64-linux
41 ```
42
43- `buildDocsInSandbox` indicates whether the option documentation for the
44 module can be built in a derivation sandbox. This option is currently only
45 honored for modules shipped by nixpkgs. User modules and modules taken from
46 `NIXOS_EXTRA_MODULE_PATH` are always built outside of the sandbox, as has
47 been the case in previous releases.
48
49 Building NixOS option documentation in a sandbox allows caching of the built
50 documentation, which greatly decreases the amount of time needed to evaluate
51 a system configuration that has NixOS documentation enabled. The sandbox also
52 restricts which attributes may be referenced by documentation attributes
53 (such as option descriptions) to the `options` and `lib` module arguments and
54 the `pkgs.formats` attribute of the `pkgs` argument, `config` and the rest of
55 `pkgs` are disallowed and will cause doc build failures when used. This
56 restriction is necessary because we cannot reproduce the full nixpkgs
57 instantiation with configuration and overlays from a system configuration
58 inside the sandbox. The `options` argument only includes options of modules
59 that are also built inside the sandbox, referencing an option of a module
60 that isn't built in the sandbox is also forbidden.
61
62 The default is `true` and should usually not be changed; set it to `false`
63 only if the module requires access to `pkgs` in its documentation (e.g.
64 because it loads information from a linked package to build an option type)
65 or if its documentation depends on other modules that also aren't sandboxed
66 (e.g. by using types defined in the other module).