the old method of pasting parts of options.json into a markdown document
and hoping for the best no longer works now that options.json contains
more than just docbook. given the infrastructure we have now we can
actually render options.md properly, so we may as well do that.
options processing is pretty slow right now, mostly because the
markdown-it-py parser is pure python (and with performance
pessimizations at that). options parsing *is* embarassingly parallel
though, so we can just fork out all the work to worker processes and
collect the results.
multiprocessing probably has a greater benefit on linux than on darwin
since the worker spawning method darwin uses is less efficient than
fork() on linux. this hasn't been tested on darwin, only on linux, but
if anything darwin will be faster with its preferred method.
using environment variables isn't great once multiple input or output
formats get involved (which will happen soon). now is a good time to set
a pattern for future converters.
this new package shall eventually contain the rendering code necessary
to produce the entirety of the nixos (not nixpkgs) manual, in all of its
various output formats.
this restores mergeJSON to its former glory if…merging json, and
extracts the MD rendering into a new script that will run instead of the
py+nix+xslt pipeline we previously ran to convert options.json to docbook.
this change alone gives a noticable performance boost when building
docs (18s instead of 27s to build optionsDocBook).
no changes to rendered output, except for a single example in the
rsnapshot module that uses hard tabs for indentation instead of spaces.
this probably isn't important.
docbook warnings remain with mergeJSON since the other processing steps
output single files instead of directories. since we'll only keep the
check until 23.11 this is probably also not important to fix.
also contains a few improvements to error reporting in the MD renderers.
only whitespace changes (mostly empty descriptions rendered as literal
line breaks and trailing space toPretty generates, but that were dropped
by mistune).
don't generate docbook for related packages, generate markdown instead.
this could be extended further to not even generate markdown but have
mergeJSON handle all of the rendering. markdown will work fine for now
though.
following the plan in https://github.com/NixOS/nixpkgs/pull/189318#discussion_r961764451
also adds an activation script to print the warning during activation
instead of during build, otherwise folks using the new CLI that hides
build logs by default might never see the warning.
Render un`_type`d defaults and examples as `literalExpression`s using
`lib.generators.toPretty` so that consumers don't have to reinvent Nix
pretty-printing. `renderOptionValue` is kept internal for now intentionally.
Make `toPretty` print floats as valid Nix values (without a tilde).
Get rid of the now-obsolete `substSpecial` function.
Move towards disallowing evaluation of packages in the manual by
raising a warning on `pkgs.foo.{outPath,drvPath}`; later, this should
throw an error. Instead, module authors should use `literalExpression`
and `mkPackageOption`.
Unlike the XML doc renderer, the AsciiDoc and CommonMark renderers don't
pretty-print certain complex types, like literal expressions, DocBook
literals, and derivations. These types are dumped into the documentation
as JSON.
This commit parses and unwraps these types when loading the
JSON-formatted NixOS options. The AsciiDoc and CommonMark renders have
also been combined into a single script to allow code reuse.
deprecate literalDocBook by adding a warning (that will not fire yet) to
its uses and other docbook literal strings by adding optional warning
message to mergeJSON.
with ever more options being markdown rather than docbook the conversion
time is starting to become a significant factor of doc build time.
luckily we can pre-convert all nixos option docs to MD and cache the
result of this conversion, then merge the already-converted json file
with user option docs. we leave options.json unconverted to keep it as
close to the actual nix code as possible.
this partially solves the problem of "missing description" warnings of the
options doc build being lost by nix build, at the cost of failing builds that
previously ran. an option to disable this behaviour is provided.
link to search.nixos.org instead of pulling package metadata out of pkgs. this
lets us cache docs of a few more modules and provides easier access to package
info from the HTML manual, but makes the manpage slightly less useful since
package description are no longer rendered.
most modules can be evaluated for their documentation in a very
restricted environment that doesn't include all of nixpkgs. this
evaluation can then be cached and reused for subsequent builds, merging
only documentation that has changed into the cached set. since nixos
ships with a large number of modules of which only a few are used in any
given config this can save evaluation a huge percentage of nixos
options available in any given config.
in tests of this caching, despite having to copy most of nixos/, saves
about 80% of the time needed to build the system manual, or about two
second on the machine used for testing. build time for a full system
config shrank from 9.4s to 7.4s, while turning documentation off
entirely shortened the build to 7.1s.
to do this we must replace derivations with attrsets in make-options-doc, since
xml can represent derivations differently from attrset but json cannot. this
also given asciidoc and mddoc the ability to handle derivation differently,
which they previously didn't have.
use the json file derivation we already have to also generate the asciidoc and
md options docs instead of formatting the options in nix. docbook docs are
already produced in derivations.
the new script produce the exact same output as the old in-nix generation.
we need the file itself as a dependency for the docbook build, but we don't need
it to be properly sorted at the nix level. push the sort out to a python script
instead to save eval time. on the machine used to write this `nix-instantiate
<nixos/nixos> -A system` went down from 7.1s to 5.4s and GC heap size decreased
by 50MB (or 70MB max RSS).
When using `documentation.nixos.includeAllModules = true;` with external
modules, the string context might contain dependencies to derivations
and so `toFile` refuses to evaluate;
```
error: in 'toFile': the file 'options.xml' cannot refer to derivation outputs, at
[...]/nixpkgs/nixos/lib/make-options-doc/default.nix:89:16
```
This is not an issue when using `writeText` (instead of manually
stripping the context).
Motivation is to support other repositories containing nixos
modules that would like to generate options documentation:
- nix-darwin
- private repos
- arion
- ??
