docs: replace sed invocation with an mdbook preprocessor for @docroot@

We're not entirely clear on why the links preprocessor has to be done
*before* rather than after, but we assume it is probably that as a
builtin preprocessor it does some processing on the raw book source,
and not just the JSON data.

Also a real use for Python pattern matching? I know I was surprised too.

Change-Id: Ibe8b59e7b5bd5f357a655d8b4c5f0b0f58a67d6b
This commit is contained in:
Qyriad 2024-04-02 17:01:53 -06:00
parent 9166babbaf
commit c355354772
3 changed files with 94 additions and 5 deletions

View file

@ -7,6 +7,15 @@ additional-js = ["redirects.js"]
edit-url-template = "https://github.com/NixOS/nix/tree/master/doc/manual/{path}" edit-url-template = "https://github.com/NixOS/nix/tree/master/doc/manual/{path}"
git-repository-url = "https://github.com/NixOS/nix" git-repository-url = "https://github.com/NixOS/nix"
# Handles replacing @docroot@ with a path to ./src relative to that markdown file.
[preprocessor.docroot]
renderers = ["html", "linkcheck"]
command = "python3 doc/manual/docroot.py"
# I would have thought that @docroot@ replacement had to be done *before*
# the link preprocessor gets its hands on this book, but nope it's actually
# the opposite.
after = ["links"]
[preprocessor.anchors] [preprocessor.anchors]
renderers = ["html"] renderers = ["html"]
command = "jq --from-file doc/manual/anchors.jq" command = "jq --from-file doc/manual/anchors.jq"

84
doc/manual/docroot.py Executable file
View file

@ -0,0 +1,84 @@
#!/usr/bin/env python3
from pathlib import Path
import json
import os, os.path
import sys
name = 'process-docroot.py'
def log(*args, **kwargs):
kwargs['file'] = sys.stderr
return print(f'{name}:', *args, **kwargs)
def replace_docroot(relative_md_path: Path, content: str, book_root: Path):
assert not relative_md_path.is_absolute(), f'{relative_md_path=} from mdbook should be relative'
md_path_abs = book_root / relative_md_path
docroot_abs = md_path_abs.parent
assert docroot_abs.is_dir(), f'supposed docroot {docroot_abs} is not a directory (cwd={os.getcwd()})'
# The paths mdbook gives us are relative to the directory with book.toml.
# @docroot@ wants to be replaced with the path relative to `src/`.
docroot_rel = os.path.relpath(book_root / 'src', start=docroot_abs)
return content.replace('@docroot@', docroot_rel)
def recursive_replace(data, book_root):
match data:
case {'sections': sections}:
return data | dict(
sections = [recursive_replace(section, book_root) for section in sections],
)
case {'Chapter': chapter}:
# Path to the .md file for this chapter, relative to book_root.
path_to_chapter = Path('src') / chapter['path']
chapter_content = chapter['content']
return data | dict(
Chapter = chapter | dict(
content = replace_docroot(path_to_chapter, chapter_content, book_root),
sub_items = [recursive_replace(sub_item, book_root) for sub_item in chapter['sub_items']],
),
)
case rest:
assert False, f'should have been called on a dict, not {type(rest)=}\n\t{rest=}'
def main():
if len(sys.argv) > 1 and sys.argv[1] == 'supports':
log('confirming to mdbook that we support their stuff')
return 0
# mdbook communicates with us over stdin and stdout.
# It splorks us a JSON array, the first element describing the context,
# the second element describing the book itself,
# and then expects us to send it the modified book JSON over stdout.
context, book = json.load(sys.stdin)
# book_root is *not* @docroot@. @docroot@ gets replaced with a relative path to `./src/`.
# book_root is the directory where book.toml, aka `src`'s parent.
book_root = Path(context['root'])
assert book_root.exists(), f'{book_root=} does not exist'
assert book_root.joinpath('book.toml').is_file(), f'{book_root / "book.toml"} is not a file'
log('replacing all occurrences of @docroot@ with a relative path')
# Find @docroot@ in all parts of our recursive book structure.
replaced_content = recursive_replace(book, book_root)
replaced_content_str = json.dumps(replaced_content)
# Give mdbook our changes.
print(replaced_content_str)
log('done!')
try:
sys.exit(main())
except AssertionError as e:
print(f'{name}: INTERNAL ERROR in mdbook preprocessor', file=sys.stderr)
print(f'this is a bug in {name}')
raise

View file

@ -159,17 +159,13 @@ doc/manual/generated/man1/nix3-manpages: $(d)/src/command-ref/new-cli
done done
@touch $@ @touch $@
$(docdir)/manual/index.html: $(MANUAL_SRCS) $(d)/book.toml $(d)/anchors.jq $(d)/custom.css $(d)/src/SUMMARY.md $(d)/src/command-ref/new-cli $(d)/src/contributing/experimental-feature-descriptions.md $(d)/src/command-ref/conf-file.md $(d)/src/language/builtins.md $(d)/src/language/builtin-constants.md $(d)/src/release-notes/rl-next.md $(docdir)/manual/index.html: $(MANUAL_SRCS) $(d)/book.toml $(d)/anchors.jq $(d)/custom.css $(d)/src/SUMMARY.md $(d)/src/command-ref/new-cli $(d)/src/contributing/experimental-feature-descriptions.md $(d)/src/command-ref/conf-file.md $(d)/src/language/builtins.md $(d)/src/language/builtin-constants.md $(d)/src/release-notes/rl-next.md $(d)/docroot.py
$(trace-gen) \ $(trace-gen) \
tmp="$$(mktemp -d)"; \ tmp="$$(mktemp -d)"; \
cp -r doc/manual "$$tmp"; \ cp -r doc/manual "$$tmp"; \
find "$$tmp" -name '*.md' | while read -r file; do \ find "$$tmp" -name '*.md' | while read -r file; do \
doc/manual/process-includes.sh $$file $$file; \ doc/manual/process-includes.sh $$file $$file; \
done; \ done; \
find "$$tmp" -name '*.md' | while read -r file; do \
docroot="$$(realpath --relative-to="$$(dirname "$$file")" $$tmp/manual/src)"; \
sed -i "s,@docroot@,$$docroot,g" "$$file"; \
done; \
set -euo pipefail; \ set -euo pipefail; \
RUST_LOG=warn mdbook build "$$tmp/manual" -d $(DESTDIR)$(docdir)/manual.tmp 2>&1 \ RUST_LOG=warn mdbook build "$$tmp/manual" -d $(DESTDIR)$(docdir)/manual.tmp 2>&1 \
| { grep -Fv "because fragment resolution isn't implemented" || :; }; \ | { grep -Fv "because fragment resolution isn't implemented" || :; }; \