Coverage for src/configuraptor/core.py: 100%

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1""" 

2Contains most of the loading logic. 

3""" 

4 

5import types 

6import typing 

7import warnings 

8from collections import ChainMap 

9from dataclasses import is_dataclass 

10from pathlib import Path 

11 

12from typeguard import TypeCheckError 

13from typeguard import check_type as _check_type 

14 

15from . import loaders 

16from .errors import ConfigErrorInvalidType, ConfigErrorMissingKey 

17from .helpers import camel_to_snake 

18 

19# T is a reusable typevar 

20T = typing.TypeVar("T") 

21# t_typelike is anything that can be type hinted 

22T_typelike: typing.TypeAlias = type | types.UnionType # | typing.Union 

23# t_data is anything that can be fed to _load_data 

24T_data = str | Path | dict[str, typing.Any] 

25# c = a config class instance, can be any (user-defined) class 

26C = typing.TypeVar("C") 

27# type c is a config class 

28Type_C = typing.Type[C] 

29 

30 

31def _data_for_nested_key(key: str, raw: dict[str, typing.Any]) -> dict[str, typing.Any]: 

32 """ 

33 If a key contains a dot, traverse the raw dict until the right key was found. 

34 

35 Example: 

36 key = some.nested.key 

37 raw = {"some": {"nested": {"key": {"with": "data"}}}} 

38 -> {"with": "data"} 

39 """ 

40 parts = key.split(".") 

41 while parts: 

42 raw = raw[parts.pop(0)] 

43 

44 return raw 

45 

46 

47def _guess_key(clsname: str) -> str: 

48 """ 

49 If no key is manually defined for `load_into`, \ 

50 the class' name is converted to snake_case to use as the default key. 

51 """ 

52 return camel_to_snake(clsname) 

53 

54 

55def _load_data(data: T_data, key: str = None, classname: str = None) -> dict[str, typing.Any]: 

56 """ 

57 Tries to load the right data from a filename/path or dict, based on a manual key or a classname. 

58 

59 E.g. class Tool will be mapped to key tool. 

60 It also deals with nested keys (tool.extra -> {"tool": {"extra": ...}} 

61 """ 

62 if isinstance(data, str): 

63 data = Path(data) 

64 if isinstance(data, Path): 

65 # todo: more than toml 

66 with data.open("rb") as f: 

67 data = loaders.toml(f) 

68 

69 if not data: 

70 return {} 

71 

72 if key is None: 

73 # try to guess key by grabbing the first one or using the class name 

74 if len(data) == 1: 

75 key = list(data.keys())[0] 

76 elif classname is not None: 

77 key = _guess_key(classname) 

78 

79 if key: 

80 return _data_for_nested_key(key, data) 

81 else: 

82 # no key found, just return all data 

83 return data 

84 

85 

86def check_type(value: typing.Any, expected_type: T_typelike) -> bool: 

87 """ 

88 Given a variable, check if it matches 'expected_type' (which can be a Union, parameterized generic etc.). 

89 

90 Based on typeguard but this returns a boolean instead of returning the value or throwing a TypeCheckError 

91 """ 

92 try: 

93 _check_type(value, expected_type) 

94 return True 

95 except TypeCheckError: 

96 return False 

97 

98 

99def ensure_types(data: dict[str, T], annotations: dict[str, type]) -> dict[str, T | None]: 

100 """ 

101 Make sure all values in 'data' are in line with the ones stored in 'annotations'. 

102 

103 If an annotated key in missing from data, it will be filled with None for convenience. 

104 """ 

105 # custom object to use instead of None, since typing.Optional can be None! 

106 # cast to T to make mypy happy 

107 notfound = typing.cast(T, object()) 

108 

109 final: dict[str, T | None] = {} 

110 for key, _type in annotations.items(): 

111 compare = data.get(key, notfound) 

112 if compare is notfound: # pragma: nocover 

113 warnings.warn( 

114 "This should not happen since " "`load_recursive` already fills `data` " "based on `annotations`" 

115 ) 

116 # skip! 

117 continue 

118 if not check_type(compare, _type): 

119 raise ConfigErrorInvalidType(key, value=compare, expected_type=_type) 

120 

121 final[key] = compare 

122 return final 

123 

124 

125def convert_config(items: dict[str, T]) -> dict[str, T]: 

126 """ 

127 Converts the config dict (from toml) or 'overwrites' dict in two ways. 

128 

129 1. removes any items where the value is None, since in that case the default should be used; 

130 2. replaces '-' and '.' in keys with '_' so it can be mapped to the Config properties. 

131 """ 

132 return {k.replace("-", "_").replace(".", "_"): v for k, v in items.items() if v is not None} 

133 

134 

135Type = typing.Type[typing.Any] 

136T_Type = typing.TypeVar("T_Type", bound=Type) 

137 

138 

139def is_builtin_type(_type: Type) -> bool: 

140 """ 

141 Returns whether _type is one of the builtin types. 

142 """ 

143 return _type.__module__ in ("__builtin__", "builtins") 

144 

145 

146# def is_builtin_class_instance(obj: typing.Any) -> bool: 

147# return is_builtin_type(obj.__class__) 

148 

149 

150def is_from_types_or_typing(_type: Type) -> bool: 

151 """ 

152 Returns whether _type is one of the stlib typing/types types. 

153 

154 e.g. types.UnionType or typing.Union 

155 """ 

156 return _type.__module__ in ("types", "typing") 

157 

158 

159def is_from_other_toml_supported_module(_type: Type) -> bool: 

160 """ 

161 Besides builtins, toml also supports 'datetime' and 'math' types, \ 

162 so this returns whether _type is a type from these stdlib modules. 

163 """ 

164 return _type.__module__ in ("datetime", "math") 

165 

166 

167def is_parameterized(_type: Type) -> bool: 

168 """ 

169 Returns whether _type is a parameterized type. 

170 

171 Examples: 

172 list[str] -> True 

173 str -> False 

174 """ 

175 return typing.get_origin(_type) is not None 

176 

177 

178def is_custom_class(_type: Type) -> bool: 

179 """ 

180 Tries to guess if _type is a builtin or a custom (user-defined) class. 

181 

182 Other logic in this module depends on knowing that. 

183 """ 

184 return ( 

185 type(_type) is type 

186 and not is_builtin_type(_type) 

187 and not is_from_other_toml_supported_module(_type) 

188 and not is_from_types_or_typing(_type) 

189 ) 

190 

191 

192def is_optional(_type: Type | None) -> bool: 

193 """ 

194 Tries to guess if _type could be optional. 

195 

196 Examples: 

197 None -> True 

198 NoneType -> True 

199 typing.Union[str, None] -> True 

200 str | None -> True 

201 list[str | None] -> False 

202 list[str] -> False 

203 """ 

204 if _type and is_parameterized(_type) and typing.get_origin(_type) in (dict, list): 

205 # e.g. list[str] 

206 # will crash issubclass to test it first here 

207 return False 

208 

209 return ( 

210 _type is None 

211 or issubclass(types.NoneType, _type) 

212 or issubclass(types.NoneType, type(_type)) # no type # Nonetype 

213 or type(None) in typing.get_args(_type) # union with Nonetype 

214 ) 

215 

216 

217def load_recursive(cls: Type, data: dict[str, T], annotations: dict[str, Type]) -> dict[str, T]: 

218 """ 

219 For all annotations (recursively gathered from parents with `all_annotations`), \ 

220 try to resolve the tree of annotations. 

221 

222 Uses `load_into_recurse`, not itself directly. 

223 

224 Example: 

225 class First: 

226 key: str 

227 

228 class Second: 

229 other: First 

230 

231 # step 1 

232 cls = Second 

233 data = {"second": {"other": {"key": "anything"}}} 

234 annotations: {"other": First} 

235 

236 # step 1.5 

237 data = {"other": {"key": "anything"} 

238 annotations: {"other": First} 

239 

240 # step 2 

241 cls = First 

242 data = {"key": "anything"} 

243 annotations: {"key": str} 

244 

245 """ 

246 updated = {} 

247 for _key, _type in annotations.items(): 

248 if _key in data: 

249 value: typing.Any = data[_key] # value can change so define it as any instead of T 

250 if is_parameterized(_type): 

251 origin = typing.get_origin(_type) 

252 arguments = typing.get_args(_type) 

253 if origin is list and arguments and is_custom_class(arguments[0]): 

254 subtype = arguments[0] 

255 value = [load_into_recurse(subtype, subvalue) for subvalue in value] 

256 

257 elif origin is dict and arguments and is_custom_class(arguments[1]): 

258 # e.g. dict[str, Point] 

259 subkeytype, subvaluetype = arguments 

260 # subkey(type) is not a custom class, so don't try to convert it: 

261 value = {subkey: load_into_recurse(subvaluetype, subvalue) for subkey, subvalue in value.items()} 

262 # elif origin is dict: 

263 # keep data the same 

264 elif origin is typing.Union and arguments: 

265 for arg in arguments: 

266 if is_custom_class(arg): 

267 value = load_into_recurse(arg, value) 

268 else: 

269 # print(_type, arg, value) 

270 ... 

271 

272 # todo: other parameterized/unions/typing.Optional 

273 

274 elif is_custom_class(_type): 

275 # type must be C (custom class) at this point 

276 value = load_into_recurse( 

277 # make mypy and pycharm happy by telling it _type is of type C... 

278 # actually just passing _type as first arg! 

279 typing.cast(Type_C[typing.Any], _type), 

280 value, 

281 ) 

282 

283 elif _key in cls.__dict__: 

284 # property has default, use that instead. 

285 value = cls.__dict__[_key] 

286 elif is_optional(_type): 

287 # type is optional and not found in __dict__ -> default is None 

288 value = None 

289 else: 

290 # todo: exception group? 

291 raise ConfigErrorMissingKey(_key, cls, _type) 

292 

293 updated[_key] = value 

294 

295 return updated 

296 

297 

298def _all_annotations(cls: Type) -> ChainMap[str, Type]: 

299 """ 

300 Returns a dictionary-like ChainMap that includes annotations for all \ 

301 attributes defined in cls or inherited from superclasses. 

302 """ 

303 return ChainMap(*(c.__annotations__ for c in getattr(cls, "__mro__", []) if "__annotations__" in c.__dict__)) 

304 

305 

306def all_annotations(cls: Type, _except: typing.Iterable[str]) -> dict[str, Type]: 

307 """ 

308 Wrapper around `_all_annotations` that filters away any keys in _except. 

309 

310 It also flattens the ChainMap to a regular dict. 

311 """ 

312 _all = _all_annotations(cls) 

313 return {k: v for k, v in _all.items() if k not in _except} 

314 

315 

316def _check_and_convert_data( 

317 cls: typing.Type[C], 

318 data: dict[str, typing.Any], 

319 _except: typing.Iterable[str], 

320) -> dict[str, typing.Any]: 

321 """ 

322 Based on class annotations, this prepares the data for `load_into_recurse`. 

323 

324 1. convert config-keys to python compatible config_keys 

325 2. loads custom class type annotations with the same logic (see also `load_recursive`) 

326 3. ensures the annotated types match the actual types after loading the config file. 

327 """ 

328 annotations = all_annotations(cls, _except=_except) 

329 

330 to_load = convert_config(data) 

331 to_load = load_recursive(cls, to_load, annotations) 

332 to_load = ensure_types(to_load, annotations) 

333 return to_load 

334 

335 

336def load_into_recurse( 

337 cls: typing.Type[C], 

338 data: dict[str, typing.Any], 

339 init: dict[str, typing.Any] = None, 

340) -> C: 

341 """ 

342 Loads an instance of `cls` filled with `data`. 

343 

344 Uses `load_recursive` to load any fillable annotated properties (see that method for an example). 

345 `init` can be used to optionally pass extra __init__ arguments. \ 

346 NOTE: This will overwrite a config key with the same name! 

347 """ 

348 if init is None: 

349 init = {} 

350 

351 # fixme: cls.__init__ can set other keys than the name is in kwargs!! 

352 

353 if is_dataclass(cls): 

354 to_load = _check_and_convert_data(cls, data, init.keys()) 

355 to_load |= init # add extra init variables (should not happen for a dataclass but whatev) 

356 

357 # ensure mypy inst is an instance of the cls type (and not a fictuous `DataclassInstance`) 

358 inst = typing.cast(C, cls(**to_load)) 

359 else: 

360 inst = cls(**init) 

361 to_load = _check_and_convert_data(cls, data, inst.__dict__.keys()) 

362 inst.__dict__.update(**to_load) 

363 

364 return inst 

365 

366 

367def load_into_existing( 

368 inst: C, 

369 cls: typing.Type[C], 

370 data: dict[str, typing.Any], 

371 init: dict[str, typing.Any] = None, 

372) -> C: 

373 """ 

374 Similar to `load_into_recurse` but uses an existing instance of a class (so after __init__) \ 

375 and thus does not support init. 

376 

377 """ 

378 if init is not None: 

379 raise ValueError("Can not init an existing instance!") 

380 

381 existing_data = inst.__dict__ 

382 

383 annotations = all_annotations(cls, _except=existing_data.keys()) 

384 to_load = convert_config(data) 

385 to_load = load_recursive(cls, to_load, annotations) 

386 to_load = ensure_types(to_load, annotations) 

387 

388 inst.__dict__.update(**to_load) 

389 

390 return inst 

391 

392 

393def load_into_class( 

394 cls: typing.Type[C], 

395 data: T_data, 

396 /, 

397 key: str = None, 

398 init: dict[str, typing.Any] = None, 

399) -> C: 

400 """ 

401 Shortcut for _load_data + load_into_recurse. 

402 """ 

403 to_load = _load_data(data, key, cls.__name__) 

404 return load_into_recurse(cls, to_load, init=init) 

405 

406 

407def load_into_instance( 

408 inst: C, 

409 data: T_data, 

410 /, 

411 key: str = None, 

412 init: dict[str, typing.Any] = None, 

413) -> C: 

414 """ 

415 Shortcut for _load_data + load_into_existing. 

416 """ 

417 cls = inst.__class__ 

418 to_load = _load_data(data, key, cls.__name__) 

419 return load_into_existing(inst, cls, to_load, init=init) 

420 

421 

422def load_into( 

423 cls: typing.Type[C] | C, 

424 data: T_data, 

425 /, 

426 key: str = None, 

427 init: dict[str, typing.Any] = None, 

428) -> C: 

429 """ 

430 Load your config into a class (instance). 

431 

432 Args: 

433 cls: either a class or an existing instance of that class. 

434 data: can be a dictionary or a path to a file to load (as pathlib.Path or str) 

435 key: optional (nested) dictionary key to load data from (e.g. 'tool.su6.specific') 

436 init: optional data to pass to your cls' __init__ method (only if cls is not an instance already) 

437 

438 """ 

439 if not isinstance(cls, type): 

440 return load_into_instance(cls, data, key=key, init=init) 

441 

442 # make mypy and pycharm happy by telling it cls is of type C and not just 'type' 

443 _cls = typing.cast(typing.Type[C], cls) 

444 return load_into_class(_cls, data, key=key, init=init)