nixpkgs/nixos/lib/make-options-doc/mergeJSON.py
pennae fc614c37c6 nixos/documentation: split options doc build
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.
2022-01-02 19:46:13 +01:00

71 lines
2.4 KiB
Python

import collections
import json
import sys
class Key:
def __init__(self, path):
self.path = path
def __hash__(self):
result = 0
for id in self.path:
result ^= hash(id)
return result
def __eq__(self, other):
return type(self) is type(other) and self.path == other.path
Option = collections.namedtuple('Option', ['name', 'value'])
# pivot a dict of options keyed by their display name to a dict keyed by their path
def pivot(options):
result = dict()
for (name, opt) in options.items():
result[Key(opt['loc'])] = Option(name, opt)
return result
# pivot back to indexed-by-full-name
# like the docbook build we'll just fail if multiple options with differing locs
# render to the same option name.
def unpivot(options):
result = dict()
for (key, opt) in options.items():
if opt.name in result:
raise RuntimeError(
'multiple options with colliding ids found',
opt.name,
result[opt.name]['loc'],
opt.value['loc'],
)
result[opt.name] = opt.value
return result
options = pivot(json.load(open(sys.argv[1], 'r')))
overrides = pivot(json.load(open(sys.argv[2], 'r')))
# fix up declaration paths in lazy options, since we don't eval them from a full nixpkgs dir
for (k, v) in options.items():
v.value['declarations'] = list(map(lambda s: f'nixos/modules/{s}', v.value['declarations']))
# merge both descriptions
for (k, v) in overrides.items():
cur = options.setdefault(k, v).value
for (ok, ov) in v.value.items():
if ok == 'declarations':
decls = cur[ok]
for d in ov:
if d not in decls:
decls += [d]
elif ok == "type":
# ignore types of placeholder options
if ov != "_unspecified" or cur[ok] == "_unspecified":
cur[ok] = ov
elif ov is not None or cur.get(ok, None) is None:
cur[ok] = ov
# check that every option has a description
# TODO: nixos-rebuild with flakes may hide the warning, maybe turn on -L by default for those?
for (k, v) in options.items():
if v.value.get('description', None) is None:
print(f"\x1b[1;31mwarning: option {v.name} has no description\x1b[0m", file=sys.stderr)
v.value['description'] = "This option has no description."
json.dump(unpivot(options), fp=sys.stdout)