"""Metods to add arguments based on class/method/function signatures."""
import inspect
from enum import Enum
from typing import Optional, Container, Type, Callable
from .util import _issubclass
from .actions import ActionEnum, _ActionConfigLoad, _ActionHelpClassPath
from .typing import is_optional
from .jsonschema import ActionJsonSchema
from .optionals import docstring_parser_support, import_docstring_parse, dataclasses_support, import_dataclasses
__all__ = ['SignatureArguments']
[docs]class SignatureArguments:
"""Methods to add arguments based on signatures to an ArgumentParser instance."""
[docs] def add_class_arguments(
self,
theclass: Type,
nested_key: Optional[str] = None,
as_group: bool = True,
as_positional: bool = False,
skip: Optional[Container[str]] = None,
) -> int:
"""Adds arguments from a class based on its type hints and docstrings.
Note: Keyword arguments without at least one valid type are ignored.
Args:
theclass: Class from which to add arguments.
nested_key: Key for nested namespace.
as_group: Whether arguments should be added to a new argument group.
as_positional: Whether to add required parameters as positional arguments.
skip: Names of parameters that should be skipped.
Returns:
Number of arguments added.
Raises:
ValueError: When not given a class.
ValueError: When there are required parameters without at least one valid type.
"""
if not inspect.isclass(theclass):
raise ValueError('Expected "theclass" argument to be a class object.')
def docs_func(base):
return [base.__init__.__doc__, base.__doc__]
def sign_func(base):
return base.__init__
return self._add_signature_arguments(inspect.getmro(theclass),
nested_key,
as_group,
as_positional,
skip,
docs_func,
sign_func,
skip_first=True)
[docs] def add_method_arguments(
self,
theclass: Type,
themethod: str,
nested_key: Optional[str] = None,
as_group: bool = True,
as_positional: bool = False,
skip: Optional[Container[str]] = None,
) -> int:
"""Adds arguments from a class based on its type hints and docstrings.
Note: Keyword arguments without at least one valid type are ignored.
Args:
theclass: Class which includes the method.
themethod: Name of the method for which to add arguments.
nested_key: Key for nested namespace.
as_group: Whether arguments should be added to a new argument group.
as_positional: Whether to add required parameters as positional arguments.
skip: Names of parameters that should be skipped.
Returns:
Number of arguments added.
Raises:
ValueError: When not given a class or the name of a method of the class.
ValueError: When there are required parameters without at least one valid type.
"""
if not inspect.isclass(theclass):
raise ValueError('Expected "theclass" argument to be a class object.')
if not hasattr(theclass, themethod) or not callable(getattr(theclass, themethod)):
raise ValueError('Expected "themethod" argument to be a callable member of the class.')
skip_first = not isinstance(inspect.getattr_static(theclass, themethod), staticmethod)
themethod = getattr(theclass, themethod)
return self._add_signature_arguments([themethod],
nested_key,
as_group,
as_positional,
skip,
skip_first=skip_first)
[docs] def add_function_arguments(
self,
function: Callable,
nested_key: Optional[str] = None,
as_group: bool = True,
as_positional: bool = False,
skip: Optional[Container[str]] = None,
) -> int:
"""Adds arguments from a function based on its type hints and docstrings.
Note: Keyword arguments without at least one valid type are ignored.
Args:
function: Function from which to add arguments.
nested_key: Key for nested namespace.
as_group: Whether arguments should be added to a new argument group.
as_positional: Whether to add required parameters as positional arguments.
skip: Names of parameters that should be skipped.
Returns:
Number of arguments added.
Raises:
ValueError: When not given a callable.
ValueError: When there are required parameters without at least one valid type.
"""
if not callable(function):
raise ValueError('Expected "function" argument to be a callable object.')
return self._add_signature_arguments([function],
nested_key,
as_group,
as_positional,
skip)
def _add_signature_arguments(
self,
objects,
nested_key: Optional[str],
as_group: bool,
as_positional: bool,
skip: Optional[Container[str]],
docs_func: Callable = lambda x: [x.__doc__],
sign_func: Callable = lambda x: x,
skip_first: bool = False,
) -> int:
"""Adds arguments from parameters of objects based on signatures and docstrings.
Args:
objects: Objects from which to add signatures.
nested_key: Key for nested namespace.
as_group: Whether arguments should be added to a new argument group.
as_positional: Whether to add required parameters as positional arguments.
skip: Names of parameters that should be skipped.
docs_func: Function that returns docstrings for a given object.
sign_func: Function that returns signature method for a given object.
skip_first: Whether to skip first argument, i.e., skip self of class methods.
Returns:
Number of arguments added.
Raises:
ValueError: When there are required parameters without at least one valid type.
"""
kinds = inspect._ParameterKind
def update_has_args_kwargs(base, has_args=True, has_kwargs=True):
params = list(inspect.signature(sign_func(base)).parameters.values())
has_args &= any(p._kind == kinds.VAR_POSITIONAL for p in params)
has_kwargs &= any(p._kind == kinds.VAR_KEYWORD for p in params)
return has_args, has_kwargs
## Determine propagation of arguments ##
add_types = [(True, True)]
has_args, has_kwargs = update_has_args_kwargs(objects[0])
for num in range(1, len(objects)):
if not (has_args or has_kwargs):
objects = objects[:num]
break
add_types.append((has_args, has_kwargs))
has_args, has_kwargs = update_has_args_kwargs(objects[num], has_args, has_kwargs)
## Gather docstrings ##
doc_group, doc_params = self._gather_docstrings(objects, docs_func)
## Create group if requested ##
group = self._create_group_if_requested(objects[0], nested_key, as_group, doc_group)
## Add objects arguments ##
added_args = set()
if skip is None:
skip = set()
if dataclasses_support:
dataclasses = import_dataclasses('_add_signature_arguments')
for obj, (add_args, add_kwargs) in zip(objects, add_types):
for num, param in enumerate(inspect.signature(sign_func(obj)).parameters.values()):
name = param.name
kind = param._kind # type: ignore
annotation = param.annotation
default = param.default
is_required = default == inspect._empty # type: ignore
skip_message = 'Skipping parameter "'+name+'" from "'+obj.__name__+'" because of: '
if kind in {kinds.VAR_POSITIONAL, kinds.VAR_KEYWORD} or \
(is_required and skip_first and num == 0) or \
(annotation == inspect._empty and not is_required and default is None): # type: ignore
continue
elif is_required and not add_args:
self.logger.debug(skip_message+'Positional parameter but *args not propagated.') # type: ignore
continue
elif not is_required and not add_kwargs:
self.logger.debug(skip_message+'Keyword parameter but **kwargs not propagated.') # type: ignore
continue
elif name in skip:
self.logger.debug(skip_message+'Parameter requested to be skipped.') # type: ignore
continue
if dataclasses_support and default.__class__ == dataclasses._HAS_DEFAULT_FACTORY_CLASS:
default = obj.__dataclass_fields__[name].default_factory()
if annotation == inspect._empty and not is_required: # type: ignore
annotation = type(default)
kwargs = {'help': doc_params.get(name)}
if not is_required:
kwargs['default'] = default
if default is None and not is_optional(annotation, object):
annotation = Optional[annotation]
elif not as_positional:
kwargs['required'] = True
if annotation in {str, int, float, bool} or \
_issubclass(annotation, (str, int, float)):
kwargs['type'] = annotation
elif _issubclass(annotation, Enum):
kwargs['action'] = ActionEnum(enum=annotation)
else:
try:
kwargs['action'] = ActionJsonSchema(annotation=annotation, enable_path=False)
except ValueError as ex:
self.logger.debug(skip_message+str(ex)) # type: ignore
if 'type' in kwargs or 'action' in kwargs:
dest = (nested_key+'.' if nested_key else '') + name
if dest in added_args:
self.logger.debug(skip_message+'Argument already added.') # type: ignore
else:
opt_str = dest if is_required and as_positional else '--'+dest
group.add_argument(opt_str, **kwargs)
added_args.add(dest)
elif is_required:
raise ValueError('Required parameter without a type for '+obj.__name__+' parameter '+name+'.')
return len(added_args)
[docs] def add_subclass_arguments(
self,
baseclass: Type,
nested_key: str,
as_group: bool = True,
metavar: str = '{"class_path":...[,"init_args":...]}',
help: str = 'Dictionary with "class_path" and "init_args" for any subclass of %(baseclass_name)s.',
**kwargs
):
"""Adds arguments to allow specifying any subclass of the given base class.
This adds an argument that requires a dictionary with a "class_path"
entry which must be a import dot notation expression. Optionally any
init arguments for the class can be given in the "init_args" entry.
Since subclasses can have different init arguments, the help does not
show the details of the arguments of the base class. Instead a help
argument is added that will print the details for a given class path.
Args:
baseclass: Base class to use to check subclasses.
nested_key: Key for nested namespace.
as_group: Whether arguments should be added to a new argument group.
metavar: Variable string to show in the argument's help.
help: Description of argument to show in the help.
Raises:
ValueError: When not given a class.
"""
if not inspect.isclass(baseclass):
raise ValueError('Expected "baseclass" argument to be a class object.')
def docs_func(base):
return [base.__init__.__doc__, base.__doc__]
doc_group = self._gather_docstrings([baseclass], docs_func)[0]
group = self._create_group_if_requested(baseclass, nested_key, as_group, doc_group, config_load=False)
group.add_argument('--'+nested_key+'.help', action=_ActionHelpClassPath(baseclass=baseclass))
group.add_argument(
'--' + nested_key,
type=baseclass,
enable_path=True,
metavar=metavar,
help=(help % {'baseclass_name': baseclass.__name__}),
**kwargs
)
def _gather_docstrings(self, objects, docs_func):
doc_group = None
doc_params = {}
if docstring_parser_support:
docstring_parse = import_docstring_parse('_gather_docstrings')
for base in objects:
for doc in docs_func(base):
try:
docstring = docstring_parse(doc)
except ValueError:
self.logger.debug('Failed parsing docstring for '+str(base))
else:
if docstring.short_description and not doc_group:
doc_group = docstring.short_description
for param in docstring.params:
if param.arg_name not in doc_params:
doc_params[param.arg_name] = param.description
return doc_group, doc_params
def _create_group_if_requested(self, obj, nested_key, as_group, doc_group, config_load=True):
group = self
if as_group:
if doc_group is None:
doc_group = str(obj)
name = obj.__name__ if nested_key is None else nested_key
group = self.add_argument_group(doc_group, name=name)
if config_load and nested_key is not None:
group.add_argument('--'+nested_key, action=_ActionConfigLoad)
return group