"""Action to support type hints."""
import copy
import inspect
import os
import re
import sys
import warnings
from argparse import Action
from collections import abc, defaultdict
from contextlib import contextmanager
from contextvars import ContextVar
from copy import deepcopy
from enum import Enum
from functools import partial
from types import FunctionType
from typing import (
Any,
Callable,
Dict,
Iterable,
List,
Mapping,
MutableMapping,
MutableSequence,
MutableSet,
Sequence,
Set,
Tuple,
Type,
TypeVar,
Union,
)
from .actions import _find_action, _find_parent_action, _is_action_value_list
from .loaders_dumpers import get_loader_exceptions, load_value
from .namespace import is_empty_namespace, Namespace
from .typing import is_final_class, registered_types
from .optionals import (
argcomplete_warn_redraw_prompt,
files_completer,
typing_extensions_import,
)
from .util import (
change_to_path_dir,
get_import_path,
import_object,
object_path_serializer,
ParserError,
Path,
NoneType,
indent_text,
_issubclass,
_parse_value_or_config,
warning,
lenient_check,
)
__all__ = ['lazy_instance']
Literal = False if sys.version_info[:2] == (3, 6) else typing_extensions_import('Literal')
root_types = {
str,
int,
float,
bool,
Any,
Literal,
Type, type,
Union,
List, list, Iterable, Sequence, MutableSequence, abc.Iterable, abc.Sequence, abc.MutableSequence,
Tuple, tuple,
Set, set, frozenset, MutableSet, abc.MutableSet,
Dict, dict, Mapping, MutableMapping, abc.Mapping, abc.MutableMapping,
Callable, abc.Callable,
}
leaf_types = {
str,
int,
float,
bool,
NoneType,
}
leaf_or_root_types = leaf_types.union(root_types)
tuple_set_origin_types = {Tuple, tuple, Set, set, frozenset, MutableSet, abc.Set, abc.MutableSet}
sequence_origin_types = {List, list, Iterable, Sequence, MutableSequence, abc.Iterable, abc.Sequence,
abc.MutableSequence}
mapping_origin_types = {Dict, dict, Mapping, MutableMapping, abc.Mapping, abc.MutableMapping}
callable_origin_types = {Callable, abc.Callable}
subclass_arg_parser: ContextVar = ContextVar('subclass_arg_parser')
sub_defaults: ContextVar = ContextVar('sub_defaults', default=False)
class ActionTypeHint(Action):
"""Action to parse a type hint."""
def __init__(
self,
typehint: Type = None,
enable_path: bool = False,
**kwargs
):
"""Initializer for ActionTypeHint instance.
Args:
typehint: The type hint to use for parsing.
enable_path: Whether to try to load parsed value from path.
Raises:
ValueError: If a parameter is invalid.
"""
if typehint is not None:
if not self.is_supported_typehint(typehint, full=True):
raise ValueError(f'Unsupported type hint {typehint}.')
self._typehint = typehint
self._enable_path = False if is_optional(typehint, Path) else enable_path
elif '_typehint' not in kwargs:
raise ValueError('Expected typehint keyword argument.')
else:
self._typehint = kwargs.pop('_typehint')
self._enable_path = kwargs.pop('_enable_path')
if 'metavar' not in kwargs:
kwargs['metavar'] = typehint_metavar(self._typehint)
super().__init__(**kwargs)
self.normalize_default()
def normalize_default(self):
default = self.default
if isinstance(default, LazyInitBaseClass):
self.default = default.lazy_get_init_data()
elif is_enum_type(self._typehint) and isinstance(default, Enum):
self.default = default.name
elif is_callable_type(self._typehint) and callable(default) and not inspect.isclass(default):
self.default = get_import_path(default)
@staticmethod
def is_supported_typehint(typehint, full=False):
"""Whether the given type hint is supported."""
supported = \
typehint in root_types or \
get_typehint_origin(typehint) in root_types or \
typehint in registered_types or \
_issubclass(typehint, Enum) or \
ActionTypeHint.is_subclass_typehint(typehint)
if full and supported:
typehint_origin = get_typehint_origin(typehint) or typehint
if typehint not in root_types and typehint_origin in root_types and typehint_origin != Literal:
for typehint in getattr(typehint, '__args__', []):
if not (
typehint == Ellipsis or
(typehint_origin == type and isinstance(typehint, TypeVar)) or
typehint in leaf_types or
ActionTypeHint.is_supported_typehint(typehint, full=True)
):
return False
return supported
@staticmethod
def is_subclass_typehint(typehint, all_subtypes=True):
typehint = typehint_from_action(typehint)
if typehint is None:
return False
typehint_origin = get_typehint_origin(typehint)
if typehint_origin == Union:
subtypes = [a for a in typehint.__args__ if a != NoneType]
test = all if all_subtypes else any
return test(ActionTypeHint.is_subclass_typehint(s) for s in subtypes)
return inspect.isclass(typehint) and \
typehint not in leaf_or_root_types and \
typehint not in registered_types and \
typehint_origin is None and \
not _issubclass(typehint, (Path, Enum))
@staticmethod
def is_mapping_typehint(typehint):
typehint_origin = get_typehint_origin(typehint) or typehint
if typehint in mapping_origin_types or typehint_origin in mapping_origin_types or is_optional(typehint, tuple(mapping_origin_types)):
return True
return False
def is_init_arg_mapping_typehint(self, key, cfg):
result = False
class_path = cfg.get(f'{self.dest}.class_path')
if isinstance(class_path, str) and key.startswith(f'{self.dest}.init_args.') and self.is_subclass_typehint(self):
sub_add_kwargs = dict(self.sub_add_kwargs)
sub_add_kwargs.pop('linked_targets', None)
parser = ActionTypeHint.get_class_parser(class_path, sub_add_kwargs=sub_add_kwargs)
key = re.sub(f'^{self.dest}.init_args.', '', key)
typehint = getattr(_find_action(parser, key), '_typehint', None)
result = self.is_mapping_typehint(typehint)
return result
@staticmethod
def parse_subclass_arg(arg_string):
parser = subclass_arg_parser.get()
action = None
if arg_string.startswith('--'):
arg_base, explicit_arg = (arg_string, None)
if '=' in arg_string:
arg_base, explicit_arg = arg_string.split('=', 1)
if '.' in arg_base and arg_base not in parser._option_string_actions:
action = _find_parent_action(parser, arg_base[2:])
if ActionTypeHint.is_subclass_typehint(action, all_subtypes=False):
return action, arg_base, explicit_arg
elif parser._subcommands_action and arg_string in parser._subcommands_action._name_parser_map:
subparser = parser._subcommands_action._name_parser_map[arg_string]
subclass_arg_parser.set(subparser)
@staticmethod
@contextmanager
def subclass_arg_context(parser):
subclass_arg_parser.set(parser)
yield
@staticmethod
@contextmanager
def sub_defaults_context():
t = sub_defaults.set(True)
try:
yield
finally:
sub_defaults.reset(t)
@staticmethod
def add_sub_defaults(parser, cfg):
with ActionTypeHint.sub_defaults_context():
parser._apply_actions(cfg)
def serialize(self, value, dump_kwargs=None):
sub_add_kwargs = getattr(self, 'sub_add_kwargs', {})
with dump_kwargs_context(dump_kwargs):
if _is_action_value_list(self):
return [adapt_typehints(v, self._typehint, serialize=True, sub_add_kwargs=sub_add_kwargs) for v in value]
return adapt_typehints(value, self._typehint, serialize=True, sub_add_kwargs=sub_add_kwargs)
def __call__(self, *args, **kwargs):
"""Parses an argument validating against the corresponding type hint.
Raises:
TypeError: If the argument is not valid.
"""
if len(args) == 0:
kwargs['_typehint'] = self._typehint
kwargs['_enable_path'] = self._enable_path
if 'nargs' in kwargs and kwargs['nargs'] == 0:
raise ValueError('ActionTypeHint does not allow nargs=0.')
return ActionTypeHint(**kwargs)
if self.nargs == '?' and args[2] is None:
val = None
else:
parser, cfg, val, opt_str = args
if isinstance(opt_str, str) and opt_str.startswith(f'--{self.dest}.'):
sub_opt = opt_str[len(f'--{self.dest}.'):]
if sub_opt != 'class_path':
cfg_dest = deepcopy(cfg.get(self.dest, Namespace()))
if self.dest not in cfg:
try:
default = parser.get_default(self.dest)
cfg_dest['class_path'] = default['class_path']
except (KeyError, TypeError):
pass
if 'class_path' not in cfg_dest:
raise ParserError(f'Found {opt_str} but not yet known to which class_path this corresponds.')
if not sub_opt.startswith('init_args.'):
sub_opt = 'init_args.' + sub_opt
if len(sub_opt.split('.', 2)) == 3:
val = NestedArg(key=sub_opt[len('init_args.'):], val=val)
sub_opt = 'init_args'
cfg_dest[sub_opt] = val
val = cfg_dest
val = self._check_type(val, cfg=cfg)
args[1].update(val, self.dest)
def _check_type(self, value, cfg=None):
islist = _is_action_value_list(self)
if not islist:
value = [value]
for num, val in enumerate(value):
try:
orig_val = val
try:
val, config_path = _parse_value_or_config(val, enable_path=self._enable_path)
except get_loader_exceptions():
config_path = None
path_meta = val.pop('__path__', None) if isinstance(val, dict) else None
sub_add_kwargs = getattr(self, 'sub_add_kwargs', {})
prev_val = cfg.get(self.dest) if cfg else None
try:
with change_to_path_dir(config_path):
val = adapt_typehints(val, self._typehint, prev_val=prev_val, sub_add_kwargs=sub_add_kwargs)
except ValueError as ex:
val_is_int_float_or_none = isinstance(val, (int, float)) or val is None
if lenient_check.get():
value[num] = orig_val if val_is_int_float_or_none else val
continue
if val_is_int_float_or_none and config_path is None:
val = adapt_typehints(orig_val, self._typehint, prev_val=prev_val, sub_add_kwargs=sub_add_kwargs)
else:
if self._enable_path and config_path is None and isinstance(orig_val, str):
msg = f'\n- Expected a config path but "{orig_val}" either not accessible or invalid.\n- '
raise type(ex)(msg+str(ex)) from ex
raise ex
if path_meta is not None:
val['__path__'] = path_meta
if isinstance(val, (Namespace, dict)) and config_path is not None:
val['__path__'] = config_path
value[num] = val
except (TypeError, ValueError) as ex:
elem = '' if not islist else f' element {num+1}'
raise TypeError(f'Parser key "{self.dest}"{elem}: {ex}') from ex
return value if islist else value[0]
def instantiate_classes(self, value):
islist = _is_action_value_list(self)
if not islist:
value = [value]
sub_add_kwargs = getattr(self, 'sub_add_kwargs', {})
for num, val in enumerate(value):
value[num] = adapt_typehints(val, self._typehint, instantiate_classes=True, sub_add_kwargs=sub_add_kwargs)
return value if islist else value[0]
@staticmethod
def get_class_parser(val_class, sub_add_kwargs=None):
from .core import ArgumentParser
if isinstance(val_class, str):
val_class = import_object(val_class)
parser = ArgumentParser(error_handler=None)
parser.add_class_arguments(val_class, **(sub_add_kwargs or {}))
return parser
def extra_help(self):
extra = ''
if self.is_subclass_typehint(self, all_subtypes=False):
class_paths = get_all_subclass_paths(self._typehint)
if class_paths:
extra = ', known class paths: '+', '.join(class_paths)
return extra
def completer(self, prefix, **kwargs):
"""Used by argcomplete, validates value and shows expected type."""
if self._typehint == bool:
return ['true', 'false']
elif is_optional(self._typehint, bool):
return ['true', 'false', 'null']
elif _issubclass(self._typehint, Enum):
enum = self._typehint
return list(enum.__members__.keys())
elif is_optional(self._typehint, Enum):
enum = self._typehint.__args__[0]
return list(enum.__members__.keys())+['null']
elif is_optional(self._typehint, Path):
return ['null'] + sorted(files_completer(prefix, **kwargs))
elif chr(int(os.environ['COMP_TYPE'])) == '?':
try:
if prefix.strip() == '':
raise ValueError()
self._check_type(prefix)
msg = 'value already valid, '
except (TypeError, ValueError) + get_loader_exceptions():
msg = 'value not yet valid, '
msg += 'expected type '+type_to_str(self._typehint)
return argcomplete_warn_redraw_prompt(prefix, msg)
def adapt_typehints(val, typehint, serialize=False, instantiate_classes=False, prev_val=None, sub_add_kwargs=None):
adapt_kwargs = {
'serialize': serialize,
'instantiate_classes': instantiate_classes,
'prev_val': prev_val,
'sub_add_kwargs': sub_add_kwargs or {},
}
subtypehints = getattr(typehint, '__args__', None)
typehint_origin = get_typehint_origin(typehint) or typehint
# Any
if typehint == Any:
type_val = type(val)
if type_val in registered_types or _issubclass(type_val, Enum):
val = adapt_typehints(val, type_val, **adapt_kwargs)
elif isinstance(val, str):
try:
val, _ = _parse_value_or_config(val, enable_path=False)
except get_loader_exceptions():
pass
# Literal
elif typehint_origin == Literal:
if val not in subtypehints:
raise ValueError(f'Expected a {typehint} but got "{val}"')
# Basic types
elif typehint in leaf_types:
if not isinstance(val, typehint):
if typehint is float and isinstance(val, int):
val = float(val)
else:
raise ValueError(f'Expected a {typehint} but got "{val}"')
# Registered types
elif typehint in registered_types:
registered_type = registered_types[typehint]
if serialize:
if registered_type.is_value_of_type(val):
val = registered_type.serializer(val)
else:
registered_type.deserializer(val)
elif not serialize and not registered_type.is_value_of_type(val):
val = registered_type.deserializer(val)
# Enum
elif _issubclass(typehint, Enum):
if serialize:
if isinstance(val, typehint):
val = val.name
else:
if val not in typehint.__members__:
raise ValueError(f'Value "{val}" is not a valid member name for the enum "{typehint}"')
elif not serialize and not isinstance(val, typehint):
val = typehint[val]
# Type
elif typehint in {Type, type} or typehint_origin in {Type, type}:
if serialize:
val = object_path_serializer(val)
elif not serialize and not isinstance(val, type):
path = val
val = import_object(val)
if (typehint in {Type, type} and not isinstance(val, type)) or \
(typehint not in {Type, type} and not _issubclass(val, subtypehints[0])):
raise ValueError(f'Value "{path}" is not a {typehint}.')
# Union
elif typehint_origin == Union:
vals = []
for subtypehint in subtypehints:
try:
vals.append(adapt_typehints(val, subtypehint, **adapt_kwargs))
break
except Exception as ex:
vals.append(ex)
if all(isinstance(v, Exception) for v in vals):
e = indent_text('\n- '.join(str(v) for v in ['']+vals))
raise ValueError(f'Value "{val}" does not validate against any of the types in {typehint}:{e}')
val = [v for v in vals if not isinstance(v, Exception)][0]
# Tuple or Set
elif typehint_origin in tuple_set_origin_types:
if not isinstance(val, (list, tuple, set)):
raise ValueError(f'Expected a {typehint_origin} but got "{val}"')
val = list(val)
if subtypehints is not None:
is_tuple = typehint_origin in {Tuple, tuple}
is_ellipsis = is_ellipsis_tuple(typehint)
if is_tuple and not is_ellipsis and len(val) != len(subtypehints):
raise ValueError(f'Expected a tuple with {len(subtypehints)} elements but got "{val}"')
for n, v in enumerate(val):
subtypehint = subtypehints[0 if is_ellipsis else n]
val[n] = adapt_typehints(v, subtypehint, **adapt_kwargs)
if is_tuple and len(val) == 0:
raise ValueError('Expected a non-empty tuple')
if not serialize:
val = tuple(val) if typehint_origin in {Tuple, tuple} else set(val)
# List, Iterable or Sequence
elif typehint_origin in sequence_origin_types:
if not isinstance(val, list):
raise ValueError(f'Expected a List but got "{val}"')
if subtypehints is not None:
for n, v in enumerate(val):
val[n] = adapt_typehints(v, subtypehints[0], **adapt_kwargs)
# Dict, Mapping
elif typehint_origin in mapping_origin_types:
if not isinstance(val, dict):
raise ValueError(f'Expected a Dict but got "{val}"')
if subtypehints is not None:
if subtypehints[0] == int:
cast = str if serialize else int
val = {cast(k): v for k, v in val.items()}
for k, v in val.items():
if "linked_targets" in adapt_kwargs["sub_add_kwargs"]:
kwargs = copy.deepcopy(adapt_kwargs)
sub_add_kwargs = kwargs["sub_add_kwargs"]
sub_add_kwargs["linked_targets"] = {t[len(k + "."):] for t in sub_add_kwargs["linked_targets"]
if t.startswith(k + ".")}
sub_add_kwargs["linked_targets"] = {t[len("init_args."):] if t.startswith("init_args.") else t
for t in sub_add_kwargs["linked_targets"]}
else:
kwargs = adapt_kwargs
val[k] = adapt_typehints(v, subtypehints[1], **kwargs)
# Callable
elif typehint_origin in callable_origin_types or typehint in callable_origin_types:
if serialize:
if is_class_object(val):
class_path = val['class_path']
init_args = val.get('init_args', Namespace())
val['init_args'] = adapt_class_type(class_path, init_args, True, False, sub_add_kwargs)
else:
val = object_path_serializer(val)
else:
try:
if isinstance(val, str):
val_obj = import_object(val)
if inspect.isclass(val_obj):
val = {'class_path': val}
elif callable(val_obj):
val = val_obj
else:
raise ImportError(f'Unexpected import object {val_obj}')
if isinstance(val, (dict, Namespace)):
if not is_class_object(val):
raise ImportError(f'Dict must include a class_path and optionally init_args, but got {val}')
val = Namespace(val)
val_class = import_object(val.class_path)
if not (inspect.isclass(val_class) and callable_instances(val_class)):
raise ImportError(f'"{val.class_path}" is not a callable class.')
val['class_path'] = get_import_path(val_class)
init_args = val.get('init_args', Namespace())
adapted = adapt_class_type(val_class, init_args, False, instantiate_classes, sub_add_kwargs)
if instantiate_classes and sub_add_kwargs.get('instantiate', True):
val = adapted
elif adapted is not None and not is_empty_namespace(adapted):
val['init_args'] = adapted
except (ImportError, AttributeError, ParserError) as ex:
raise ValueError(f'Type {typehint} expects a function or a callable class: {ex}')
# Subclass
elif not hasattr(typehint, '__origin__') and inspect.isclass(typehint):
if isinstance(val, typehint):
if serialize:
val = serialize_class_instance(val)
return val
if serialize and isinstance(val, str):
return val
if not (isinstance(val, str) or is_class_object(val)):
raise ValueError(f'Type {typehint} expects an str or a Dict/Namespace with a class_path entry but got "{val}"')
try:
if isinstance(val, str):
val = Namespace(class_path=val)
elif isinstance(val, dict):
val = Namespace(val)
val_class = import_object(resolve_class_path_by_name(typehint, val['class_path']))
if not _issubclass(val_class, typehint):
raise ValueError(f'"{val["class_path"]}" is not a subclass of {typehint}')
val['class_path'] = class_path = get_import_path(val_class)
if isinstance(prev_val, Namespace) and 'class_path' in prev_val and 'init_args' not in val:
prev_class_path = prev_val['class_path']
prev_init_args = prev_val.get('init_args')
if prev_class_path != class_path and not (prev_init_args is None or is_empty_namespace(prev_init_args)):
warnings.warn(
f'Changing class_path to {class_path} implies discarding init_args {prev_init_args.as_dict()} '
f'defined for class_path {prev_class_path}.'
)
init_args = val.get('init_args', Namespace())
adapted = adapt_class_type(val_class, init_args, serialize, instantiate_classes, sub_add_kwargs, prev_val=prev_val)
if instantiate_classes and sub_add_kwargs.get('instantiate', True):
val = adapted
elif adapted is not None and not is_empty_namespace(adapted):
val['init_args'] = adapted
except (ImportError, AttributeError, AssertionError, ParserError) as ex:
class_path = val if isinstance(val, str) else val['class_path']
e = indent_text(f'\n- {ex}')
raise ValueError(f'Problem with given class_path "{class_path}":{e}') from ex
return val
def is_class_object(val):
is_class = isinstance(val, (dict, Namespace)) and 'class_path' in val
if is_class:
keys = getattr(val, '__dict__', val).keys()
is_class = len(set(keys)-{'class_path', 'init_args', '__path__'}) == 0
return is_class
class NestedArg:
def __init__(self, key, val):
self.key = key
self.val = val
def get_all_subclass_paths(cls: Type) -> List[str]:
subclass_list = []
def is_local(cl):
return '.<locals>.' in getattr(cl, '__qualname__', '.<locals>.')
def is_private(class_path):
return '._' in class_path
def add_subclasses(cl):
class_path = get_import_path(cl)
if is_local(cl) or issubclass(cl, LazyInitBaseClass):
return
if not (inspect.isabstract(cl) or is_private(class_path)):
subclass_list.append(class_path)
for subclass in cl.__subclasses__() if hasattr(cl, '__subclasses__') else []:
add_subclasses(subclass)
if get_typehint_origin(cls) == Union:
for arg in cls.__args__:
if ActionTypeHint.is_subclass_typehint(arg):
add_subclasses(arg)
else:
add_subclasses(cls)
return subclass_list
def resolve_class_path_by_name(cls: Type, name: str) -> str:
class_path = name
if '.' not in class_path:
subclass_dict = defaultdict(list)
for subclass in get_all_subclass_paths(cls):
subclass_name = subclass.rsplit('.', 1)[1]
subclass_dict[subclass_name].append(subclass)
if name in subclass_dict:
name_subclasses = subclass_dict[name]
if len(name_subclasses) > 1:
raise ValueError(
f'Multiple subclasses with name {name}. Give the full class path to '
f'avoid ambiguity: {", ".join(name_subclasses)}.'
)
class_path = name_subclasses[0]
return class_path
dump_kwargs: ContextVar = ContextVar('dump_kwargs', default={})
@contextmanager
def dump_kwargs_context(kwargs):
dump_kwargs.set(kwargs if kwargs else {})
yield
def adapt_class_type(val_class, init_args, serialize, instantiate_classes, sub_add_kwargs, prev_val=None):
if isinstance(init_args, dict):
init_args = Namespace(init_args)
parser = ActionTypeHint.get_class_parser(val_class, sub_add_kwargs)
# No need to re-create the linked arg but just "inform" the corresponding parser actions that it exists upstream.
for target in sub_add_kwargs.get('linked_targets', []):
split_index = target.find(".")
if split_index != -1:
split = ".init_args." if target[split_index:].startswith(".init_args.") else "."
parent_key, key = target.split(split, maxsplit=1)
action = next(a for a in parser._actions if a.dest == parent_key)
sub_add_kwargs = getattr(action, 'sub_add_kwargs')
sub_add_kwargs.setdefault('linked_targets', set())
sub_add_kwargs['linked_targets'].add(key)
break
if instantiate_classes:
init_args = parser.instantiate_classes(init_args)
if not sub_add_kwargs.get('instantiate', True):
return init_args
return val_class(**init_args)
if serialize:
init_args = None if is_empty_namespace(init_args) else load_value(parser.dump(init_args, **dump_kwargs.get()))
elif isinstance(init_args, NestedArg):
prev_val = prev_val.init_args.clone()
init_args = parser.parse_args([f'--{init_args.key}={init_args.val}'], namespace=prev_val, defaults=sub_defaults.get())
else:
init_args = parser.parse_object(init_args, defaults=sub_defaults.get())
return init_args
def get_typehint_origin(typehint):
if not hasattr(typehint, '__origin__') and get_import_path(typehint.__class__) == 'types.UnionType':
return Union
return getattr(typehint, '__origin__', None)
def is_ellipsis_tuple(typehint):
return typehint.__origin__ in {Tuple, tuple} and len(typehint.__args__) > 1 and typehint.__args__[1] == Ellipsis
def is_optional(annotation, ref_type):
"""Checks whether a type annotation is an optional for one type class."""
return get_typehint_origin(annotation) == Union and \
len(annotation.__args__) == 2 and \
any(NoneType == a for a in annotation.__args__) and \
any(_issubclass(a, ref_type) for a in annotation.__args__)
def is_enum_type(annotation):
return _issubclass(annotation, Enum) or \
(get_typehint_origin(annotation) == Union and
any(_issubclass(a, Enum) for a in annotation.__args__))
def is_callable_type(annotation):
def is_callable(a):
return (get_typehint_origin(a) or a) in callable_origin_types or a in callable_origin_types
return is_callable(annotation) or \
(get_typehint_origin(annotation) == Union and
any(is_callable(a) for a in annotation.__args__))
def typehint_from_action(action_or_typehint):
if isinstance(action_or_typehint, Action):
action_or_typehint = getattr(action_or_typehint, '_typehint', None)
return action_or_typehint
def type_to_str(obj):
if _issubclass(obj, (bool, int, float, str, Enum)):
return obj.__name__
elif obj is not None:
return re.sub(r'[a-z_.]+\.', '', str(obj)).replace('NoneType', 'null')
def typehint_metavar(typehint):
"""Generates a metavar for some types."""
metavar = None
if typehint == bool:
metavar = '{true,false}'
elif is_optional(typehint, bool):
metavar = '{true,false,null}'
elif _issubclass(typehint, Enum):
enum = typehint
metavar = '{'+','.join(list(enum.__members__.keys()))+'}'
elif is_optional(typehint, Enum):
enum = typehint.__args__[0]
metavar = '{'+','.join(list(enum.__members__.keys())+['null'])+'}'
return metavar
def serialize_class_instance(val):
type_val = type(val)
val = str(val)
warning(f"""
Not possible to serialize an instance of {type_val}. It will be
represented as the string {val}. If this was set as a default, consider
using lazy_instance.
""")
return val
def callable_instances(cls: Type):
# https://stackoverflow.com/a/71568161/2732151
return isinstance(getattr(cls, '__call__', None), FunctionType)
def check_lazy_kwargs(class_type: Type, lazy_kwargs: dict):
if lazy_kwargs:
from .core import ArgumentParser
parser = ArgumentParser(error_handler=None)
parser.add_class_arguments(class_type)
try:
parser.parse_object(lazy_kwargs)
except ParserError as ex:
raise ValueError(str(ex)) from ex
class LazyInitBaseClass:
def __init__(self, class_type: Type, lazy_kwargs: dict):
check_lazy_kwargs(class_type, lazy_kwargs)
self._lazy_class_type = class_type
self._lazy_class_path = get_import_path(class_type)
self._lazy_kwargs = lazy_kwargs
self._lazy_methods = {}
seen_methods: Dict = {}
for name, _ in inspect.getmembers(class_type, predicate=inspect.isfunction):
method = getattr(self, name)
if not inspect.ismethod(method) or \
name in {'__init__', '_lazy_init', '_lazy_init_then_call_method', 'lazy_get_init_data'}:
continue
assert name not in self.__dict__
self._lazy_methods[name] = method
if method in seen_methods:
self.__dict__[name] = seen_methods[method]
else:
self.__dict__[name] = partial(self._lazy_init_then_call_method, name)
seen_methods[method] = self.__dict__[name]
def _lazy_init(self):
for name in self._lazy_methods.keys():
del self.__dict__[name]
super().__init__(**self._lazy_kwargs)
def _lazy_init_then_call_method(self, method_name, *args, **kwargs):
self._lazy_init()
return getattr(self, method_name)(*args, **kwargs)
def lazy_get_init_data(self):
init_args = Namespace(self._lazy_kwargs)
if is_final_class(self._lazy_class_type):
return init_args
init = Namespace(class_path=self._lazy_class_path)
if len(self._lazy_kwargs) > 0:
init['init_args'] = init_args
return init
ClassType = TypeVar('ClassType')
[docs]def lazy_instance(class_type: Type[ClassType], **kwargs) -> ClassType:
"""Instantiates a lazy instance of the given type.
By lazy it is meant that the __init__ is delayed unit the first time that a
method of the instance is called. It also provides a `lazy_get_init_data` method
useful for serializing.
Args:
class_type: The class to instantiate.
**kwargs: Any keyword arguments to use for instantiation.
"""
lazy_init_class = type(
'LazyInstance_'+class_type.__name__,
(LazyInitBaseClass, class_type),
{'__doc__': f'Class for lazy instances of {class_type}'},
)
return lazy_init_class(class_type, kwargs)