Coverage for src/typedconfig/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 return ( 

205 _type is None 

206 or issubclass(types.NoneType, _type) 

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

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

209 ) 

210 

211 

212def load_recursive(cls: Type, data: dict[str, T], annotations: dict[str, Type]) -> dict[str, T]: 

213 """ 

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

215 try to resolve the tree of annotations. 

216 

217 Uses `load_into_recurse`, not itself directly. 

218 

219 Example: 

220 class First: 

221 key: str 

222 

223 class Second: 

224 other: First 

225 

226 # step 1 

227 cls = Second 

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

229 annotations: {"other": First} 

230 

231 # step 1.5 

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

233 annotations: {"other": First} 

234 

235 # step 2 

236 cls = First 

237 data = {"key": "anything"} 

238 annotations: {"key": str} 

239 

240 """ 

241 updated = {} 

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

243 if _key in data: 

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

245 if is_parameterized(_type): 

246 origin = typing.get_origin(_type) 

247 arguments = typing.get_args(_type) 

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

249 subtype = arguments[0] 

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

251 

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

253 # e.g. dict[str, Point] 

254 subkeytype, subvaluetype = arguments 

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

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

257 # elif origin is dict: 

258 # keep data the same 

259 elif origin is typing.Union and arguments: 

260 for arg in arguments: 

261 if is_custom_class(arg): 

262 value = load_into_recurse(arg, value) 

263 else: 

264 # print(_type, arg, value) 

265 ... 

266 

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

268 

269 elif is_custom_class(_type): 

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

271 value = load_into_recurse( 

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

273 # actually just passing _type as first arg! 

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

275 value, 

276 ) 

277 

278 elif _key in cls.__dict__: 

279 # property has default, use that instead. 

280 value = cls.__dict__[_key] 

281 elif is_optional(_type): 

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

283 value = None 

284 else: 

285 # todo: exception group? 

286 raise ConfigErrorMissingKey(_key, cls, _type) 

287 

288 updated[_key] = value 

289 

290 return updated 

291 

292 

293def _all_annotations(cls: Type) -> ChainMap[str, Type]: 

294 """ 

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

296 attributes defined in cls or inherited from superclasses. 

297 """ 

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

299 

300 

301def all_annotations(cls: Type, _except: typing.Iterable[str]) -> dict[str, Type]: 

302 """ 

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

304 

305 It also flattens the ChainMap to a regular dict. 

306 """ 

307 _all = _all_annotations(cls) 

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

309 

310 

311def _check_and_convert_data( 

312 cls: typing.Type[C], 

313 data: dict[str, typing.Any], 

314 _except: typing.Iterable[str], 

315) -> dict[str, typing.Any]: 

316 """ 

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

318 

319 1. convert config-keys to python compatible config_keys 

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

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

322 """ 

323 annotations = all_annotations(cls, _except=_except) 

324 

325 to_load = convert_config(data) 

326 to_load = load_recursive(cls, to_load, annotations) 

327 to_load = ensure_types(to_load, annotations) 

328 return to_load 

329 

330 

331def load_into_recurse( 

332 cls: typing.Type[C], 

333 data: dict[str, typing.Any], 

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

335) -> C: 

336 """ 

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

338 

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

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

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

342 """ 

343 if init is None: 

344 init = {} 

345 

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

347 

348 if is_dataclass(cls): 

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

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

351 

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

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

354 else: 

355 inst = cls(**init) 

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

357 inst.__dict__.update(**to_load) 

358 

359 return inst 

360 

361 

362def load_into_existing( 

363 inst: C, 

364 cls: typing.Type[C], 

365 data: dict[str, typing.Any], 

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

367) -> C: 

368 """ 

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

370 and thus does not support init. 

371 

372 """ 

373 if init is not None: 

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

375 

376 existing_data = inst.__dict__ 

377 

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

379 to_load = convert_config(data) 

380 to_load = load_recursive(cls, to_load, annotations) 

381 to_load = ensure_types(to_load, annotations) 

382 

383 inst.__dict__.update(**to_load) 

384 

385 return inst 

386 

387 

388def load_into_class( 

389 cls: typing.Type[C], 

390 data: T_data, 

391 /, 

392 key: str = None, 

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

394) -> C: 

395 """ 

396 Shortcut for _load_data + load_into_recurse. 

397 """ 

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

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

400 

401 

402def load_into_instance( 

403 inst: C, 

404 data: T_data, 

405 /, 

406 key: str = None, 

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

408) -> C: 

409 """ 

410 Shortcut for _load_data + load_into_existing. 

411 """ 

412 cls = inst.__class__ 

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

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

415 

416 

417def load_into( 

418 cls: typing.Type[C] | C, 

419 data: T_data, 

420 /, 

421 key: str = None, 

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

423) -> C: 

424 """ 

425 Load your config into a class (instance). 

426 

427 Args: 

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

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

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

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

432 

433 """ 

434 if not isinstance(cls, type): 

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

436 

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

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

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