Coverage for src/configuraptor/core.py: 100%
150 statements
« prev ^ index » next coverage.py v7.2.7, created at 2023-06-14 15:57 +0200
« prev ^ index » next coverage.py v7.2.7, created at 2023-06-14 15:57 +0200
1"""
2Contains most of the loading logic.
3"""
5import types
6import typing
7import warnings
8from collections import ChainMap
9import dataclasses as dc
10from pathlib import Path
12from typeguard import TypeCheckError
13from typeguard import check_type as _check_type
15from . import loaders
16from .errors import ConfigErrorInvalidType, ConfigErrorMissingKey
17from .helpers import camel_to_snake
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]
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.
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)]
44 return raw
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)
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.
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 with data.open("rb") as f:
66 loader = loaders.get(data.suffix)
67 data = loader(f)
69 if not data:
70 return {}
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)
79 if key:
80 return _data_for_nested_key(key, data)
81 else:
82 # no key found, just return all data
83 return data
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.).
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
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'.
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())
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)
121 final[key] = compare
122 return final
125def convert_config(items: dict[str, T]) -> dict[str, T]:
126 """
127 Converts the config dict (from toml) or 'overwrites' dict in two ways.
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}
135Type = typing.Type[typing.Any]
136T_Type = typing.TypeVar("T_Type", bound=Type)
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")
146# def is_builtin_class_instance(obj: typing.Any) -> bool:
147# return is_builtin_type(obj.__class__)
150def is_from_types_or_typing(_type: Type) -> bool:
151 """
152 Returns whether _type is one of the stlib typing/types types.
154 e.g. types.UnionType or typing.Union
155 """
156 return _type.__module__ in ("types", "typing")
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")
167def is_parameterized(_type: Type) -> bool:
168 """
169 Returns whether _type is a parameterized type.
171 Examples:
172 list[str] -> True
173 str -> False
174 """
175 return typing.get_origin(_type) is not None
178def is_custom_class(_type: Type) -> bool:
179 """
180 Tries to guess if _type is a builtin or a custom (user-defined) class.
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 )
192def is_optional(_type: Type | None) -> bool:
193 """
194 Tries to guess if _type could be optional.
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
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 )
217def dataclass_field(cls: Type, key: str) -> typing.Optional[dc.Field]:
218 """
219 Get Field info for a dataclass cls.
220 """
221 fields = getattr(cls, "__dataclass_fields__", {})
222 return fields.get(key)
225def load_recursive(cls: Type, data: dict[str, T], annotations: dict[str, Type]) -> dict[str, T]:
226 """
227 For all annotations (recursively gathered from parents with `all_annotations`), \
228 try to resolve the tree of annotations.
230 Uses `load_into_recurse`, not itself directly.
232 Example:
233 class First:
234 key: str
236 class Second:
237 other: First
239 # step 1
240 cls = Second
241 data = {"second": {"other": {"key": "anything"}}}
242 annotations: {"other": First}
244 # step 1.5
245 data = {"other": {"key": "anything"}
246 annotations: {"other": First}
248 # step 2
249 cls = First
250 data = {"key": "anything"}
251 annotations: {"key": str}
253 """
255 updated = {}
256 for _key, _type in annotations.items():
258 if _key in data:
259 value: typing.Any = data[_key] # value can change so define it as any instead of T
260 if is_parameterized(_type):
261 origin = typing.get_origin(_type)
262 arguments = typing.get_args(_type)
263 if origin is list and arguments and is_custom_class(arguments[0]):
264 subtype = arguments[0]
265 value = [load_into_recurse(subtype, subvalue) for subvalue in value]
267 elif origin is dict and arguments and is_custom_class(arguments[1]):
268 # e.g. dict[str, Point]
269 subkeytype, subvaluetype = arguments
270 # subkey(type) is not a custom class, so don't try to convert it:
271 value = {subkey: load_into_recurse(subvaluetype, subvalue) for subkey, subvalue in value.items()}
272 # elif origin is dict:
273 # keep data the same
274 elif origin is typing.Union and arguments:
275 for arg in arguments:
276 if is_custom_class(arg):
277 value = load_into_recurse(arg, value)
278 else:
279 # print(_type, arg, value)
280 ...
282 # todo: other parameterized/unions/typing.Optional
284 elif is_custom_class(_type):
285 # type must be C (custom class) at this point
286 value = load_into_recurse(
287 # make mypy and pycharm happy by telling it _type is of type C...
288 # actually just passing _type as first arg!
289 typing.cast(Type_C[typing.Any], _type),
290 value,
291 )
293 elif _key in cls.__dict__:
294 # property has default, use that instead.
295 value = cls.__dict__[_key]
296 elif is_optional(_type):
297 # type is optional and not found in __dict__ -> default is None
298 value = None
299 elif (
300 dc.is_dataclass(cls)
301 and (field := dataclass_field(cls, _key))
302 and field.default_factory is not dc.MISSING
303 ):
304 # could have a default factory
305 # todo: do something with field.default?
306 value = field.default_factory()
307 else:
308 # todo: exception group?
309 raise ConfigErrorMissingKey(_key, cls, _type)
311 updated[_key] = value
313 return updated
316def _all_annotations(cls: Type) -> ChainMap[str, Type]:
317 """
318 Returns a dictionary-like ChainMap that includes annotations for all \
319 attributes defined in cls or inherited from superclasses.
320 """
321 return ChainMap(*(c.__annotations__ for c in getattr(cls, "__mro__", []) if "__annotations__" in c.__dict__))
324def all_annotations(cls: Type, _except: typing.Iterable[str]) -> dict[str, Type]:
325 """
326 Wrapper around `_all_annotations` that filters away any keys in _except.
328 It also flattens the ChainMap to a regular dict.
329 """
330 _all = _all_annotations(cls)
331 return {k: v for k, v in _all.items() if k not in _except}
334def _check_and_convert_data(
335 cls: typing.Type[C],
336 data: dict[str, typing.Any],
337 _except: typing.Iterable[str],
338) -> dict[str, typing.Any]:
339 """
340 Based on class annotations, this prepares the data for `load_into_recurse`.
342 1. convert config-keys to python compatible config_keys
343 2. loads custom class type annotations with the same logic (see also `load_recursive`)
344 3. ensures the annotated types match the actual types after loading the config file.
345 """
346 annotations = all_annotations(cls, _except=_except)
348 to_load = convert_config(data)
349 to_load = load_recursive(cls, to_load, annotations)
350 to_load = ensure_types(to_load, annotations)
351 return to_load
354def load_into_recurse(
355 cls: typing.Type[C],
356 data: dict[str, typing.Any],
357 init: dict[str, typing.Any] = None,
358) -> C:
359 """
360 Loads an instance of `cls` filled with `data`.
362 Uses `load_recursive` to load any fillable annotated properties (see that method for an example).
363 `init` can be used to optionally pass extra __init__ arguments. \
364 NOTE: This will overwrite a config key with the same name!
365 """
366 if init is None:
367 init = {}
369 # fixme: cls.__init__ can set other keys than the name is in kwargs!!
371 if dc.is_dataclass(cls):
372 to_load = _check_and_convert_data(cls, data, init.keys())
373 to_load |= init # add extra init variables (should not happen for a dataclass but whatev)
375 # ensure mypy inst is an instance of the cls type (and not a fictuous `DataclassInstance`)
376 inst = typing.cast(C, cls(**to_load))
377 else:
378 inst = cls(**init)
379 to_load = _check_and_convert_data(cls, data, inst.__dict__.keys())
380 inst.__dict__.update(**to_load)
382 return inst
385def load_into_existing(
386 inst: C,
387 cls: typing.Type[C],
388 data: dict[str, typing.Any],
389 init: dict[str, typing.Any] = None,
390) -> C:
391 """
392 Similar to `load_into_recurse` but uses an existing instance of a class (so after __init__) \
393 and thus does not support init.
395 """
396 if init is not None:
397 raise ValueError("Can not init an existing instance!")
399 existing_data = inst.__dict__
401 annotations = all_annotations(cls, _except=existing_data.keys())
402 to_load = convert_config(data)
403 to_load = load_recursive(cls, to_load, annotations)
404 to_load = ensure_types(to_load, annotations)
406 inst.__dict__.update(**to_load)
408 return inst
411def load_into_class(
412 cls: typing.Type[C],
413 data: T_data,
414 /,
415 key: str = None,
416 init: dict[str, typing.Any] = None,
417) -> C:
418 """
419 Shortcut for _load_data + load_into_recurse.
420 """
421 to_load = _load_data(data, key, cls.__name__)
422 return load_into_recurse(cls, to_load, init=init)
425def load_into_instance(
426 inst: C,
427 data: T_data,
428 /,
429 key: str = None,
430 init: dict[str, typing.Any] = None,
431) -> C:
432 """
433 Shortcut for _load_data + load_into_existing.
434 """
435 cls = inst.__class__
436 to_load = _load_data(data, key, cls.__name__)
437 return load_into_existing(inst, cls, to_load, init=init)
440def load_into(
441 cls: typing.Type[C] | C,
442 data: T_data,
443 /,
444 key: str = None,
445 init: dict[str, typing.Any] = None,
446) -> C:
447 """
448 Load your config into a class (instance).
450 Args:
451 cls: either a class or an existing instance of that class.
452 data: can be a dictionary or a path to a file to load (as pathlib.Path or str)
453 key: optional (nested) dictionary key to load data from (e.g. 'tool.su6.specific')
454 init: optional data to pass to your cls' __init__ method (only if cls is not an instance already)
456 """
457 if not isinstance(cls, type):
458 return load_into_instance(cls, data, key=key, init=init)
460 # make mypy and pycharm happy by telling it cls is of type C and not just 'type'
461 _cls = typing.cast(typing.Type[C], cls)
462 return load_into_class(_cls, data, key=key, init=init)