nixpkgs/nixos/lib/make-options-doc/default.nix
Johannes Kirschbauer 9a21db7be8
doc: write improved documentation for nixosOptionsDoc (#295279)
* doc: write improved documentation for nixosOptionsDoc

* Apply suggestions from @infinisil

Co-authored-by: Silvan Mosberger <github@infinisil.com>

* doc: minor fixup

---------

Co-authored-by: Silvan Mosberger <github@infinisil.com>
2024-03-21 16:07:18 +01:00

250 lines
8.5 KiB
Nix

/**
Generates documentation for [nix modules](https://nix.dev/tutorials/module-system/module-system.html).
It uses the declared `options` to generate documentation in various formats.
# Outputs
This function returns an attribute set with the following entries.
## optionsCommonMark
Documentation in CommonMark text format.
## optionsJSON
All options in a JSON format suitable for further automated processing.
`example.json`
```json
{
...
"fileSystems.<name>.options": {
"declarations": ["nixos/modules/tasks/filesystems.nix"],
"default": {
"_type": "literalExpression",
"text": "[\n \"defaults\"\n]"
},
"description": "Options used to mount the file system.",
"example": {
"_type": "literalExpression",
"text": "[\n \"data=journal\"\n]"
},
"loc": ["fileSystems", "<name>", "options"],
"readOnly": false,
"type": "non-empty (list of string (with check: non-empty))"
"relatedPackages": "- [`pkgs.tmux`](\n https://search.nixos.org/packages?show=tmux&sort=relevance&query=tmux\n )\n",
},
...
}
```
## optionsDocBook
deprecated since 23.11 and will be removed in 24.05.
## optionsAsciiDoc
Documentation rendered as AsciiDoc. This is useful for e.g. man pages.
> Note: NixOS itself uses this ouput to to build the configuration.nix man page"
## optionsNix
All options as a Nix attribute set value, with the same schema as `optionsJSON`.
# Example
## Example: NixOS configuration
```nix
let
# Evaluate a NixOS configuration
eval = import (pkgs.path + "/nixos/lib/eval-config.nix") {
# Overriden explicitly here, this would include all modules from NixOS otherwise.
# See: docs of eval-config.nix for more details
baseModules = [];
modules = [
./module.nix
];
};
in
pkgs.nixosOptionsDoc {
inherit (eval) options;
}
```
## Example: non-NixOS modules
`nixosOptionsDoc` can also be used to build documentation for non-NixOS modules.
```nix
let
eval = lib.evalModules {
modules = [
./module.nix
];
};
in
pkgs.nixosOptionsDoc {
inherit (eval) options;
}
```
*/
{ pkgs
, lib
, options
, transformOptions ? lib.id # function for additional transformations of the options
, documentType ? "appendix" # TODO deprecate "appendix" in favor of "none"
# and/or rename function to moduleOptionDoc for clean slate
# If you include more than one option list into a document, you need to
# provide different ids.
, variablelistId ? "configuration-variable-list"
# String to prefix to the option XML/HTML id attributes.
, optionIdPrefix ? "opt-"
, revision ? "" # Specify revision for the options
# a set of options the docs we are generating will be merged into, as if by recursiveUpdate.
# used to split the options doc build into a static part (nixos/modules) and a dynamic part
# (non-nixos modules imported via configuration.nix, other module sources).
, baseOptionsJSON ? null
# instead of printing warnings for eg options with missing descriptions (which may be lost
# by nix build unless -L is given), emit errors instead and fail the build
, warningsAreErrors ? true
# allow docbook option docs if `true`. only markdown documentation is allowed when set to
# `false`, and a different renderer may be used with different bugs and performance
# characteristics but (hopefully) indistinguishable output.
# deprecated since 23.11.
# TODO remove in a while.
, allowDocBook ? false
# whether lib.mdDoc is required for descriptions to be read as markdown.
# deprecated since 23.11.
# TODO remove in a while.
, markdownByDefault ? true
}:
assert markdownByDefault && ! allowDocBook;
let
rawOpts = lib.optionAttrSetToDocList options;
transformedOpts = map transformOptions rawOpts;
filteredOpts = lib.filter (opt: opt.visible && !opt.internal) transformedOpts;
optionsList = lib.flip map filteredOpts
(opt: opt
// lib.optionalAttrs (opt ? relatedPackages && opt.relatedPackages != []) { relatedPackages = genRelatedPackages opt.relatedPackages opt.name; }
);
# Generate DocBook documentation for a list of packages. This is
# what `relatedPackages` option of `mkOption` from
# ../../../lib/options.nix influences.
#
# Each element of `relatedPackages` can be either
# - a string: that will be interpreted as an attribute name from `pkgs` and turned into a link
# to search.nixos.org,
# - a list: that will be interpreted as an attribute path from `pkgs` and turned into a link
# to search.nixos.org,
# - an attrset: that can specify `name`, `path`, `comment`
# (either of `name`, `path` is required, the rest are optional).
#
# NOTE: No checks against `pkgs` are made to ensure that the referenced package actually exists.
# Such checks are not compatible with option docs caching.
genRelatedPackages = packages: optName:
let
unpack = p: if lib.isString p then { name = p; }
else if lib.isList p then { path = p; }
else p;
describe = args:
let
title = args.title or null;
name = args.name or (lib.concatStringsSep "." args.path);
in ''
- [${lib.optionalString (title != null) "${title} aka "}`pkgs.${name}`](
https://search.nixos.org/packages?show=${name}&sort=relevance&query=${name}
)${
lib.optionalString (args ? comment) "\n\n ${args.comment}"
}
'';
in lib.concatMapStrings (p: describe (unpack p)) packages;
optionsNix = builtins.listToAttrs (map (o: { name = o.name; value = removeAttrs o ["name" "visible" "internal"]; }) optionsList);
in rec {
inherit optionsNix;
optionsAsciiDoc = pkgs.runCommand "options.adoc" {
nativeBuildInputs = [ pkgs.nixos-render-docs ];
} ''
nixos-render-docs -j $NIX_BUILD_CORES options asciidoc \
--manpage-urls ${pkgs.path + "/doc/manpage-urls.json"} \
--revision ${lib.escapeShellArg revision} \
${optionsJSON}/share/doc/nixos/options.json \
$out
'';
optionsCommonMark = pkgs.runCommand "options.md" {
nativeBuildInputs = [ pkgs.nixos-render-docs ];
} ''
nixos-render-docs -j $NIX_BUILD_CORES options commonmark \
--manpage-urls ${pkgs.path + "/doc/manpage-urls.json"} \
--revision ${lib.escapeShellArg revision} \
${optionsJSON}/share/doc/nixos/options.json \
$out
'';
optionsJSON = pkgs.runCommand "options.json"
{ meta.description = "List of NixOS options in JSON format";
nativeBuildInputs = [
pkgs.brotli
pkgs.python3
];
options = builtins.toFile "options.json"
(builtins.unsafeDiscardStringContext (builtins.toJSON optionsNix));
# merge with an empty set if baseOptionsJSON is null to run markdown
# processing on the input options
baseJSON =
if baseOptionsJSON == null
then builtins.toFile "base.json" "{}"
else baseOptionsJSON;
}
''
# Export list of options in different format.
dst=$out/share/doc/nixos
mkdir -p $dst
TOUCH_IF_DB=$dst/.used-docbook \
python ${./mergeJSON.py} \
${lib.optionalString warningsAreErrors "--warnings-are-errors"} \
$baseJSON $options \
> $dst/options.json
if grep /nixpkgs/nixos/modules $dst/options.json; then
echo "The manual appears to depend on the location of Nixpkgs, which is bad"
echo "since this prevents sharing via the NixOS channel. This is typically"
echo "caused by an option default that refers to a relative path (see above"
echo "for hints about the offending path)."
exit 1
fi
brotli -9 < $dst/options.json > $dst/options.json.br
mkdir -p $out/nix-support
echo "file json $dst/options.json" >> $out/nix-support/hydra-build-products
echo "file json-br $dst/options.json.br" >> $out/nix-support/hydra-build-products
'';
optionsDocBook = lib.warn "optionsDocBook is deprecated since 23.11 and will be removed in 24.05"
(pkgs.runCommand "options-docbook.xml" {
nativeBuildInputs = [
pkgs.nixos-render-docs
];
} ''
nixos-render-docs -j $NIX_BUILD_CORES options docbook \
--manpage-urls ${pkgs.path + "/doc/manpage-urls.json"} \
--revision ${lib.escapeShellArg revision} \
--document-type ${lib.escapeShellArg documentType} \
--varlist-id ${lib.escapeShellArg variablelistId} \
--id-prefix ${lib.escapeShellArg optionIdPrefix} \
${optionsJSON}/share/doc/nixos/options.json \
"$out"
'');
}