llama.cpp/examples/json_schema_to_grammar.py
Olivier Chafik ab9a3240a9
JSON schema conversion: ️ faster repetitions, min/maxLength for strings, cap number length (#6555)
* json: rename python schema converter to make import easier

* server: skip null json_schema / grammar fields

* json: deps management for primitive rules (+ allow null values)

* json: optimize repetitions for minItems/maxItems and regexps: `a{,3}` goes from `"a"? "a"? "a"?` (explosive combos) to `(a (a (a)?)?)?`

* grammars: add troubleshooting section to readme

* json: cap length of numbers to 15 digits before/after decimal point

(avoids infinite gen, e.g. "one third" -> `0.333333333333...`)

* json: unify all repetition code (w/ or w/o sep)

* json: support string minLength/maxLength

* server+json: update server/README w/ result_format

* nits

* json: fix type error w/ python 3.8

* json: fix server/README (json_schema in /completion vs. result_format in /v1/chat/completions)

* json: simplify DOT `{"type": "string", "pattern": "^.$"}`

* json: remove recursion in opt_repetitions (avoids Python stack overflow)

* json: rm dead code

* json: rm useless assert & ggml.h import
2024-04-12 19:43:38 +01:00

617 lines
26 KiB
Python
Executable File

#!/usr/bin/env python3
import argparse
import itertools
import json
import re
import sys
from typing import Any, Dict, List, Set, Tuple, Union
def _build_repetition(item_rule, min_items, max_items, separator_rule=None, item_rule_is_literal=False):
if not separator_rule:
if min_items == 0 and max_items == 1:
return f'{item_rule}?'
elif min_items == 1 and max_items is None:
return f'{item_rule}+'
result = ''
if min_items > 0:
if item_rule_is_literal and separator_rule is None:
result = '"' + (item_rule[1:-1] * min_items) + '"'
else:
result = (f' {separator_rule} ' if separator_rule else ' ').join([item_rule] * min_items)
def opt_repetitions(up_to_n, prefix_with_sep=False):
'''
- n=4, no sep: '(a (a (a (a)?)?)?)?'
- n=4, sep=',', prefix: '("," a ("," a ("," a ("," a)?)?)?)?'
- n=4, sep=',', no prefix: '(a ("," a ("," a ("," a)?)?)?)?'
'''
content = f'{separator_rule} {item_rule}' if prefix_with_sep and separator_rule else item_rule
if up_to_n == 0:
return ''
elif up_to_n == 1:
return f'({content})?'
elif separator_rule and not prefix_with_sep:
return f'({content} {opt_repetitions(up_to_n - 1, prefix_with_sep=True)})?'
else:
return (f'({content} ' * up_to_n).rstrip() + (')?' * up_to_n)
if min_items > 0 and max_items != min_items:
result += ' '
if max_items is not None:
result += opt_repetitions(max_items - min_items, prefix_with_sep=min_items > 0)
else:
item_operator = f'({separator_rule + " " if separator_rule else ""}{item_rule})'
if min_items == 0 and separator_rule:
result = f'({item_rule} {item_operator}*)?'
else:
result += f'{item_operator}*'
return result
class BuiltinRule:
def __init__(self, content: str, deps: list = None):
self.content = content
self.deps = deps or []
_up_to_15_digits = _build_repetition('[0-9]', 0, 15)
# whitespace is constrained to a single space char to prevent model "running away" in
# whitespace. Also maybe improves generation quality?
SPACE_RULE = '" "?'
PRIMITIVE_RULES = {
'boolean' : BuiltinRule('("true" | "false") space', []),
'decimal-part' : BuiltinRule('[0-9] ' + _up_to_15_digits, []),
'integral-part': BuiltinRule('[0-9] | [1-9] ' + _up_to_15_digits, []),
'number' : BuiltinRule('("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space', ['integral-part', 'decimal-part']),
'integer' : BuiltinRule('("-"? integral-part) space', ['integral-part']),
'value' : BuiltinRule('object | array | string | number | boolean | null', ['object', 'array', 'string', 'number', 'boolean', 'null']),
'object' : BuiltinRule('"{" space ( string ":" space value ("," space string ":" space value)* )? "}" space', ['string', 'value']),
'array' : BuiltinRule('"[" space ( value ("," space value)* )? "]" space', ['value']),
'uuid' : BuiltinRule(r'"\"" ' + ' "-" '.join('[0-9a-fA-F]' * n for n in [8, 4, 4, 4, 12]) + r' "\"" space', []),
'char' : BuiltinRule(r'[^"\\] | "\\" (["\\/bfnrt] | "u" [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F])', []),
'string' : BuiltinRule(r'"\"" char* "\"" space', ['char']),
'null' : BuiltinRule('"null" space', []),
}
# TODO: support "uri", "email" string formats
STRING_FORMAT_RULES = {
'date' : BuiltinRule('[0-9] [0-9] [0-9] [0-9] "-" ( "0" [1-9] | "1" [0-2] ) "-" ( \"0\" [1-9] | [1-2] [0-9] | "3" [0-1] )', []),
'time' : BuiltinRule('([01] [0-9] | "2" [0-3]) ":" [0-5] [0-9] ":" [0-5] [0-9] ( "." [0-9] [0-9] [0-9] )? ( "Z" | ( "+" | "-" ) ( [01] [0-9] | "2" [0-3] ) ":" [0-5] [0-9] )', []),
'date-time' : BuiltinRule('date "T" time', ['date', 'time']),
'date-string' : BuiltinRule('"\\"" date "\\"" space', ['date']),
'time-string' : BuiltinRule('"\\"" time "\\"" space', ['time']),
'date-time-string': BuiltinRule('"\\"" date-time "\\"" space', ['date-time']),
}
DOTALL = '[\\U00000000-\\U0010FFFF]'
DOT = '[^\\x0A\\x0D]'
RESERVED_NAMES = set(["root", "dot", *PRIMITIVE_RULES.keys(), *STRING_FORMAT_RULES.keys()])
INVALID_RULE_CHARS_RE = re.compile(r'[^a-zA-Z0-9-]+')
GRAMMAR_LITERAL_ESCAPE_RE = re.compile(r'[\r\n"]')
GRAMMAR_RANGE_LITERAL_ESCAPE_RE = re.compile(r'[\r\n"\]\-\\]')
GRAMMAR_LITERAL_ESCAPES = {'\r': '\\r', '\n': '\\n', '"': '\\"', '-': '\\-', ']': '\\]'}
NON_LITERAL_SET = set('|.()[]{}*+?')
ESCAPED_IN_REGEXPS_BUT_NOT_IN_LITERALS = set('[]()|{}*+?')
class SchemaConverter:
def __init__(self, *, prop_order, allow_fetch, dotall, raw_pattern):
self._prop_order = prop_order
self._allow_fetch = allow_fetch
self._dotall = dotall
self._raw_pattern = raw_pattern
self._rules = {
'space': SPACE_RULE,
}
self._refs = {}
self._refs_being_resolved = set()
def _format_literal(self, literal):
escaped = GRAMMAR_LITERAL_ESCAPE_RE.sub(
lambda m: GRAMMAR_LITERAL_ESCAPES.get(m.group(0)), literal
)
return f'"{escaped}"'
def not_literal(self, literal: str, dotall: bool = True, maybe_escaped_underscores = False) -> str:
'''
not_literal('a') -> '[^a]'
not_literal('abc') -> '([^a] | "a" ([^b] | "b" ([^c])?)?)?'
'''
assert len(literal) > 0, 'Empty literal not supported'
def recurse(i: int):
c = literal[i]
if maybe_escaped_underscores and c == '_':
yield f'[^{c}\\\\]'
yield ' | '
yield f'"\\\\"? "{c}"'
else:
yield f'[^{c}]'
if i < len(literal) - 1:
yield ' | '
yield self._format_literal(c)
yield ' ('
yield from recurse(i + 1)
yield ')?'
return ''.join(('(', *recurse(0), ')'))
def _add_rule(self, name, rule):
esc_name = INVALID_RULE_CHARS_RE.sub('-', name)
if esc_name not in self._rules or self._rules[esc_name] == rule:
key = esc_name
else:
i = 0
while f'{esc_name}{i}' in self._rules and self._rules[f'{esc_name}{i}'] != rule:
i += 1
key = f'{esc_name}{i}'
self._rules[key] = rule
return key
def resolve_refs(self, schema: dict, url: str):
'''
Resolves all $ref fields in the given schema, fetching any remote schemas,
replacing $ref with absolute reference URL and populating self._refs with the
respective referenced (sub)schema dictionaries.
'''
def visit(n: dict):
if isinstance(n, list):
return [visit(x) for x in n]
elif isinstance(n, dict):
ref = n.get('$ref')
if ref is not None and ref not in self._refs:
if ref.startswith('https://'):
assert self._allow_fetch, 'Fetching remote schemas is not allowed (use --allow-fetch for force)'
import requests
frag_split = ref.split('#')
base_url = frag_split[0]
target = self._refs.get(base_url)
if target is None:
target = self.resolve_refs(requests.get(ref).json(), base_url)
self._refs[base_url] = target
if len(frag_split) == 1 or frag_split[-1] == '':
return target
elif ref.startswith('#/'):
target = schema
ref = f'{url}{ref}'
n['$ref'] = ref
else:
raise ValueError(f'Unsupported ref {ref}')
for sel in ref.split('#')[-1].split('/')[1:]:
assert target is not None and sel in target, f'Error resolving ref {ref}: {sel} not in {target}'
target = target[sel]
self._refs[ref] = target
else:
for v in n.values():
visit(v)
return n
return visit(schema)
def _generate_union_rule(self, name, alt_schemas):
return ' | '.join((
self.visit(alt_schema, f'{name}{"-" if name else "alternative-"}{i}')
for i, alt_schema in enumerate(alt_schemas)
))
def _visit_pattern(self, pattern, name):
'''
Transforms a regular expression pattern into a GBNF rule.
Input: https://json-schema.org/understanding-json-schema/reference/regular_expressions
Output: https://github.com/ggerganov/llama.cpp/blob/master/grammars/README.md
Unsupported features: negative/positive lookaheads, greedy/non-greedy modifiers.
Mostly a 1:1 translation, except for {x} / {x,} / {x,y} quantifiers for which
we define sub-rules to keep the output lean.
'''
assert pattern.startswith('^') and pattern.endswith('$'), 'Pattern must start with "^" and end with "$"'
pattern = pattern[1:-1]
sub_rule_ids = {}
i = 0
length = len(pattern)
def to_rule(s: Tuple[str, bool]) -> str:
(txt, is_literal) = s
return "\"" + txt + "\"" if is_literal else txt
def transform() -> Tuple[str, bool]:
'''
Parse a unit at index i (advancing it), and return its string representation + whether it's a literal.
'''
nonlocal i
nonlocal pattern
nonlocal sub_rule_ids
start = i
# For each component of this sequence, store its string representation and whether it's a literal.
# We only need a flat structure here to apply repetition operators to the last item, and
# to merge literals at the and (we're parsing grouped ( sequences ) recursively and don't treat '|' specially
# (GBNF's syntax is luckily very close to regular expressions!)
seq: list[Tuple[str, bool]] = []
def get_dot():
if self._dotall:
rule = DOTALL
else:
# Accept any character... except \n and \r line break chars (\x0A and \xOD)
rule = DOT
return self._add_rule(f'dot', rule)
def join_seq():
nonlocal seq
ret = []
for is_literal, g in itertools.groupby(seq, lambda x: x[1]):
if is_literal:
ret.append((''.join(x[0] for x in g), True))
else:
ret.extend(g)
if len(ret) == 1:
return ret[0]
return (' '.join(to_rule(x) for x in seq), False)
while i < length:
c = pattern[i]
if c == '.':
seq.append((get_dot(), False))
i += 1
elif c == '(':
i += 1
if i < length:
assert pattern[i] != '?', f'Unsupported pattern syntax "{pattern[i]}" at index {i} of /{pattern}/'
seq.append((f'({to_rule(transform())})', False))
elif c == ')':
i += 1
assert start > 0 and pattern[start-1] == '(', f'Unbalanced parentheses; start = {start}, i = {i}, pattern = {pattern}'
return join_seq()
elif c == '[':
square_brackets = c
i += 1
while i < length and pattern[i] != ']':
if pattern[i] == '\\':
square_brackets += pattern[i:i+2]
i += 2
else:
square_brackets += pattern[i]
i += 1
assert i < length, f'Unbalanced square brackets; start = {start}, i = {i}, pattern = {pattern}'
square_brackets += ']'
i += 1
seq.append((square_brackets, False))
elif c == '|':
seq.append(('|', False))
i += 1
elif c in ('*', '+', '?'):
seq[-1] = (to_rule(seq[-1]) + c, False)
i += 1
elif c == '{':
curly_brackets = c
i += 1
while i < length and pattern[i] != '}':
curly_brackets += pattern[i]
i += 1
assert i < length, f'Unbalanced curly brackets; start = {start}, i = {i}, pattern = {pattern}'
curly_brackets += '}'
i += 1
nums = [s.strip() for s in curly_brackets[1:-1].split(',')]
min_times = 0
max_times = None
try:
if len(nums) == 1:
min_times = int(nums[0])
max_times = min_times
else:
assert len(nums) == 2
min_times = int(nums[0]) if nums[0] else 0
max_times = int(nums[1]) if nums[1] else None
except ValueError:
raise ValueError(f'Invalid quantifier {curly_brackets} in /{pattern}/')
(sub, sub_is_literal) = seq[-1]
if not sub_is_literal:
id = sub_rule_ids.get(sub)
if id is None:
id = self._add_rule(f'{name}-{len(sub_rule_ids) + 1}', sub)
sub_rule_ids[sub] = id
sub = id
seq[-1] = (_build_repetition(f'"{sub}"' if sub_is_literal else sub, min_times, max_times, item_rule_is_literal=sub_is_literal), False)
else:
literal = ''
while i < length:
if pattern[i] == '\\' and i < length - 1:
next = pattern[i + 1]
if next in ESCAPED_IN_REGEXPS_BUT_NOT_IN_LITERALS:
i += 1
literal += pattern[i]
i += 1
else:
literal += pattern[i:i+2]
i += 2
elif pattern[i] == '"' and not self._raw_pattern:
literal += '\\"'
i += 1
elif pattern[i] not in NON_LITERAL_SET and \
(i == length - 1 or literal == '' or pattern[i+1] == '.' or pattern[i+1] not in NON_LITERAL_SET):
literal += pattern[i]
i += 1
else:
break
if literal:
seq.append((literal, True))
return join_seq()
return self._add_rule(
name,
to_rule(transform()) if self._raw_pattern \
else "\"\\\"\" " + to_rule(transform()) + " \"\\\"\" space")
def _resolve_ref(self, ref):
ref_name = ref.split('/')[-1]
if ref_name not in self._rules and ref not in self._refs_being_resolved:
self._refs_being_resolved.add(ref)
resolved = self._refs[ref]
ref_name = self.visit(resolved, ref_name)
self._refs_being_resolved.remove(ref)
return ref_name
def _generate_constant_rule(self, value):
return self._format_literal(json.dumps(value))
def visit(self, schema, name):
schema_type = schema.get('type')
schema_format = schema.get('format')
rule_name = name + '-' if name in RESERVED_NAMES else name or 'root'
if (ref := schema.get('$ref')) is not None:
return self._add_rule(rule_name, self._resolve_ref(ref))
elif 'oneOf' in schema or 'anyOf' in schema:
return self._add_rule(rule_name, self._generate_union_rule(name, schema.get('oneOf') or schema['anyOf']))
elif isinstance(schema_type, list):
return self._add_rule(rule_name, self._generate_union_rule(name, [{'type': t} for t in schema_type]))
elif 'const' in schema:
return self._add_rule(rule_name, self._generate_constant_rule(schema['const']))
elif 'enum' in schema:
rule = ' | '.join((self._generate_constant_rule(v) for v in schema['enum']))
return self._add_rule(rule_name, rule)
elif schema_type in (None, 'object') and \
('properties' in schema or \
('additionalProperties' in schema and schema['additionalProperties'] is not True)):
required = set(schema.get('required', []))
properties = list(schema.get('properties', {}).items())
return self._add_rule(rule_name, self._build_object_rule(properties, required, name, schema.get('additionalProperties')))
elif schema_type in (None, 'object') and 'allOf' in schema:
required = set()
properties = []
hybrid_name = name
def add_component(comp_schema, is_required):
if (ref := comp_schema.get('$ref')) is not None:
comp_schema = self._refs[ref]
if 'properties' in comp_schema:
for prop_name, prop_schema in comp_schema['properties'].items():
properties.append((prop_name, prop_schema))
if is_required:
required.add(prop_name)
for t in schema['allOf']:
if 'anyOf' in t:
for tt in t['anyOf']:
add_component(tt, is_required=False)
else:
add_component(t, is_required=True)
return self._add_rule(rule_name, self._build_object_rule(properties, required, hybrid_name, additional_properties=[]))
elif schema_type in (None, 'array') and ('items' in schema or 'prefixItems' in schema):
items = schema.get('items') or schema['prefixItems']
if isinstance(items, list):
return self._add_rule(
rule_name,
'"[" space ' +
' "," space '.join(
self.visit(item, f'{name}{"-" if name else ""}tuple-{i}')
for i, item in enumerate(items)) +
' "]" space')
else:
item_rule_name = self.visit(items, f'{name}{"-" if name else ""}item')
min_items = schema.get("minItems", 0)
max_items = schema.get("maxItems")
return self._add_rule(rule_name, '"[" space ' + _build_repetition(item_rule_name, min_items, max_items, separator_rule='"," space') + ' "]" space')
elif schema_type in (None, 'string') and 'pattern' in schema:
return self._visit_pattern(schema['pattern'], rule_name)
elif schema_type in (None, 'string') and re.match(r'^uuid[1-5]?$', schema_format or ''):
return self._add_primitive(
'root' if rule_name == 'root' else schema_format,
PRIMITIVE_RULES['uuid']
)
elif schema_type in (None, 'string') and f'{schema_format}-string' in STRING_FORMAT_RULES:
prim_name = f'{schema_format}-string'
return self._add_rule(rule_name, self._add_primitive(prim_name, STRING_FORMAT_RULES[prim_name]))
elif schema_type == 'string' and ('minLength' in schema or 'maxLength' in schema):
char_rule = self._add_primitive('char', PRIMITIVE_RULES['char'])
min_len = schema.get('minLength', 0)
max_len = schema.get('maxLength')
return self._add_rule(rule_name, r'"\"" ' + _build_repetition(char_rule, min_len, max_len) + r' "\"" space')
elif (schema_type == 'object') or (len(schema) == 0):
return self._add_rule(rule_name, self._add_primitive('object', PRIMITIVE_RULES['object']))
else:
assert schema_type in PRIMITIVE_RULES, f'Unrecognized schema: {schema}'
# TODO: support minimum, maximum, exclusiveMinimum, exclusiveMaximum at least for zero
return self._add_primitive('root' if rule_name == 'root' else schema_type, PRIMITIVE_RULES[schema_type])
def _add_primitive(self, name: str, rule: BuiltinRule):
n = self._add_rule(name, rule.content)
for dep in rule.deps:
dep_rule = PRIMITIVE_RULES.get(dep) or STRING_FORMAT_RULES.get(dep)
assert dep_rule, f'Rule {dep} not known'
if dep not in self._rules:
self._add_primitive(dep, dep_rule)
return n
def _build_object_rule(self, properties: List[Tuple[str, Any]], required: Set[str], name: str, additional_properties: Union[bool, Any]):
prop_order = self._prop_order
# sort by position in prop_order (if specified) then by original order
sorted_props = [kv[0] for _, kv in sorted(enumerate(properties), key=lambda ikv: (prop_order.get(ikv[1][0], len(prop_order)), ikv[0]))]
prop_kv_rule_names = {}
for prop_name, prop_schema in properties:
prop_rule_name = self.visit(prop_schema, f'{name}{"-" if name else ""}{prop_name}')
prop_kv_rule_names[prop_name] = self._add_rule(
f'{name}{"-" if name else ""}{prop_name}-kv',
fr'{self._format_literal(json.dumps(prop_name))} space ":" space {prop_rule_name}'
)
required_props = [k for k in sorted_props if k in required]
optional_props = [k for k in sorted_props if k not in required]
if additional_properties == True or isinstance(additional_properties, dict):
sub_name = f'{name}{"-" if name else ""}additional'
value_rule = self.visit({} if additional_properties == True else additional_properties, f'{sub_name}-value')
prop_kv_rule_names["*"] = self._add_rule(
f'{sub_name}-kv',
self._add_primitive('string', PRIMITIVE_RULES['string']) + f' ":" space {value_rule}'
)
optional_props.append("*")
rule = '"{" space '
rule += ' "," space '.join(prop_kv_rule_names[k] for k in required_props)
if optional_props:
rule += ' ('
if required_props:
rule += ' "," space ( '
def get_recursive_refs(ks, first_is_optional):
[k, *rest] = ks
kv_rule_name = prop_kv_rule_names[k]
if k == '*':
res = self._add_rule(
f'{name}{"-" if name else ""}additional-kvs',
f'{kv_rule_name} ( "," space ' + kv_rule_name + ' )*'
)
elif first_is_optional:
res = f'( "," space {kv_rule_name} )?'
else:
res = kv_rule_name
if len(rest) > 0:
res += ' ' + self._add_rule(
f'{name}{"-" if name else ""}{k}-rest',
get_recursive_refs(rest, first_is_optional=True)
)
return res
rule += ' | '.join(
get_recursive_refs(optional_props[i:], first_is_optional=False)
for i in range(len(optional_props))
)
if required_props:
rule += ' )'
rule += ' )?'
rule += ' "}" space'
return rule
def format_grammar(self):
return '\n'.join(
f'{name} ::= {rule}'
for name, rule in sorted(self._rules.items(), key=lambda kv: kv[0])
)
def main(args_in = None):
parser = argparse.ArgumentParser(
description='''
Generates a grammar (suitable for use in ./main) that produces JSON conforming to a
given JSON schema. Only a subset of JSON schema features are supported; more may be
added in the future.
''',
)
parser.add_argument(
'--prop-order',
default=[],
type=lambda s: s.split(','),
help='''
comma-separated property names defining the order of precedence for object properties;
properties not specified here are given lower precedence than those that are, and
are kept in their original order from the schema. Required properties are always
given precedence over optional properties.
'''
)
parser.add_argument(
'--allow-fetch',
action='store_true',
default=False,
help='Whether to allow fetching referenced schemas over HTTPS')
parser.add_argument(
'--dotall',
action='store_true',
default=False,
help='Whether to treat dot (".") as matching all chars including line breaks in regular expression patterns')
parser.add_argument(
'--raw-pattern',
action='store_true',
default=False,
help='Treats string patterns as raw patterns w/o quotes (or quote escapes)')
parser.add_argument('schema', help='file containing JSON schema ("-" for stdin)')
args = parser.parse_args(args_in)
if args.schema.startswith('https://'):
url = args.schema
import requests
schema = requests.get(url).json()
elif args.schema == '-':
url = 'stdin'
schema = json.load(sys.stdin)
else:
url = f'file://{args.schema}'
with open(args.schema) as f:
schema = json.load(f)
converter = SchemaConverter(
prop_order={name: idx for idx, name in enumerate(args.prop_order)},
allow_fetch=args.allow_fetch,
dotall=args.dotall,
raw_pattern=args.raw_pattern)
schema = converter.resolve_refs(schema, url)
converter.visit(schema, '')
print(converter.format_grammar())
if __name__ == '__main__':
main()