pex.config.configField.ConfigField Class Reference

Inheritance diagram for pex.config.configField.ConfigField:

Public Member Functions
def	__init__ (self, doc, dtype, default=None, check=None, deprecated=None)
def	__get__ (self, instance, owner=None)
def	__set__ (self, instance, value, at=None, label="assignment")
def	rename (self, instance)
def	save (self, outfile, instance)
def	freeze (self, instance)
def	toDict (self, instance)
def	validate (self, instance)
def	__get__ (self, instance, owner=None, at=None, label="default")
def	__delete__ (self, instance, at=None, label='deletion')

Public Attributes
	dtype
	doc
	deprecated
	default
	check
	optional
	source

Static Public Attributes
	supportedTypes = set((str, bool, float, int, complex))

Detailed Description

A configuration field (`~lsst.pex.config.Field` subclass) that takes a
`~lsst.pex.config.Config`-type as a value.

Parameters
----------
doc : `str`
    A description of the configuration field.
dtype : `lsst.pex.config.Config`-type
    The type of the field, which must be a subclass of
    `lsst.pex.config.Config`.
default : `lsst.pex.config.Config`, optional
    If default is `None`, the field will default to a default-constructed
    instance of ``dtype``. Additionally, to allow for fewer deep-copies,
    assigning an instance of ``ConfigField`` to ``dtype`` itself, is
    considered equivalent to assigning a default-constructed sub-config.
    This means that the argument default can be ``dtype``, as well as an
    instance of ``dtype``.
check : callable, optional
    A callback function that validates the field's value, returning `True`
    if the value is valid, and `False` otherwise.
deprecated : None or `str`, optional
    A description of why this Field is deprecated, including removal date.
    If not None, the string is appended to the docstring for this Field.

See also
--------
ChoiceField
ConfigChoiceField
ConfigDictField
ConfigurableField
DictField
Field
ListField
RangeField
RegistryField

Notes
-----
The behavior of this type of field is much like that of the base `Field`
type.

Assigning to ``ConfigField`` will update all of the fields in the
configuration.

Definition at line 35 of file configField.py.

Constructor & Destructor Documentation

__init__()

def pex.config.configField.ConfigField.__init__	(		self,
			doc,
			dtype,
			default = None,
			check = None,
			deprecated = None
	)

Definition at line 81 of file configField.py.

    def __init__(self, doc, dtype, default=None, check=None, deprecated=None):
        if not issubclass(dtype, Config):
            raise ValueError("dtype=%s is not a subclass of Config" %
                             _typeStr(dtype))
        if default is None:
            default = dtype
        source = getStackFrame()
        self._setup(doc=doc, dtype=dtype, default=default, check=check,
                    optional=False, source=source, deprecated=deprecated)
 

Member Function Documentation

__delete__()

def pex.config.config.Field.__delete__ (   self,   instance,   at = None,   label = 'deletion'  )

inherited

Delete an attribute from a `lsst.pex.config.Config` instance.

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains this field.
at : `list` of `lsst.pex.config.callStack.StackFrame`
    The call stack (created by
    `lsst.pex.config.callStack.getCallStack`).
label : `str`, optional
    Event label for the history.

Notes
-----
This is invoked by the owning `~lsst.pex.config.Config` object and
should not be called directly.

Definition at line 573 of file config.py.

    def __delete__(self, instance, at=None, label='deletion'):
        """Delete an attribute from a `lsst.pex.config.Config` instance.
 
        Parameters
        ----------
        instance : `lsst.pex.config.Config`
            The config instance that contains this field.
        at : `list` of `lsst.pex.config.callStack.StackFrame`
            The call stack (created by
            `lsst.pex.config.callStack.getCallStack`).
        label : `str`, optional
            Event label for the history.
 
        Notes
        -----
        This is invoked by the owning `~lsst.pex.config.Config` object and
        should not be called directly.
        """
        if at is None:
            at = getCallStack()
        self.__set__(instance, None, at=at, label=label)
 

__get__() [1/2]

def pex.config.configField.ConfigField.__get__	(		self,
			instance,
			owner = None
	)

Definition at line 91 of file configField.py.

    def __get__(self, instance, owner=None):
        if instance is None or not isinstance(instance, Config):
            return self
        else:
            value = instance._storage.get(self.name, None)
            if value is None:
                at = getCallStack()
                at.insert(0, self.source)
                self.__set__(instance, self.default, at=at, label="default")
            return value
 

__get__() [2/2]

def pex.config.config.Field.__get__ (   self,   instance,   owner = None,   at = None,   label = "default"  )

inherited

Define how attribute access should occur on the Config instance
This is invoked by the owning config object and should not be called
directly

When the field attribute is accessed on a Config class object, it
returns the field object itself in order to allow inspection of
Config classes.

When the field attribute is access on a config instance, the actual
value described by the field (and held by the Config instance) is
returned.

Reimplemented in pex.config.configurableField.ConfigurableField.

Definition at line 498 of file config.py.

    def __get__(self, instance, owner=None, at=None, label="default"):
        """Define how attribute access should occur on the Config instance
        This is invoked by the owning config object and should not be called
        directly
 
        When the field attribute is accessed on a Config class object, it
        returns the field object itself in order to allow inspection of
        Config classes.
 
        When the field attribute is access on a config instance, the actual
        value described by the field (and held by the Config instance) is
        returned.
        """
        if instance is None or not isinstance(instance, Config):
            return self
        else:
            return instance._storage[self.name]
 

__set__()

def pex.config.configField.ConfigField.__set__	(		self,
			instance,
			value,
			at = None,
			label = "assignment"
	)

Set an attribute on the config instance.

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains this field.
value : obj
    Value to set on this field.
at : `list` of `lsst.pex.config.callStack.StackFrame`
    The call stack (created by
    `lsst.pex.config.callStack.getCallStack`).
label : `str`, optional
    Event label for the history.

Notes
-----
This method is invoked by the owning `lsst.pex.config.Config` object
and should not be called directly.

Derived `~lsst.pex.config.Field` classes may need to override the
behavior. When overriding ``__set__``, `~lsst.pex.config.Field` authors
should follow the following rules:

- Do not allow modification of frozen configs.
- Validate the new value **before** modifying the field. Except if the
  new value is `None`. `None` is special and no attempt should be made
  to validate it until `lsst.pex.config.Config.validate` is called.
- Do not modify the `~lsst.pex.config.Config` instance to contain
  invalid values.
- If the field is modified, update the history of the
  `lsst.pex.config.field.Field` to reflect the changes.

In order to decrease the need to implement this method in derived
`~lsst.pex.config.Field` types, value validation is performed in the
`lsst.pex.config.Field._validateValue`. If only the validation step
differs in the derived `~lsst.pex.config.Field`, it is simpler to
implement `lsst.pex.config.Field._validateValue` than to reimplement
``__set__``. More complicated behavior, however, may require
reimplementation.

Reimplemented from pex.config.config.Field.

Definition at line 102 of file configField.py.

    def __set__(self, instance, value, at=None, label="assignment"):
        if instance._frozen:
            raise FieldValidationError(self, instance,
                                       "Cannot modify a frozen Config")
        name = _joinNamePath(prefix=instance._name, name=self.name)
 
        if value != self.dtype and type(value) != self.dtype:
            msg = "Value %s is of incorrect type %s. Expected %s" % \
                (value, _typeStr(value), _typeStr(self.dtype))
            raise FieldValidationError(self, instance, msg)
 
        if at is None:
            at = getCallStack()
 
        oldValue = instance._storage.get(self.name, None)
        if oldValue is None:
            if value == self.dtype:
                instance._storage[self.name] = self.dtype(__name=name, __at=at, __label=label)
            else:
                instance._storage[self.name] = self.dtype(__name=name, __at=at,
                                                          __label=label, **value._storage)
        else:
            if value == self.dtype:
                value = value()
            oldValue.update(__at=at, __label=label, **value._storage)
        history = instance._history.setdefault(self.name, [])
        history.append(("config value set", at, label))
 

freeze()

def pex.config.configField.ConfigField.freeze	(		self,
			instance
	)

Make this field read-only.

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains this field.

Notes
-----
Freezing is only relevant for fields that hold subconfigs. Fields which
hold subconfigs should freeze each subconfig.

**Subclasses should implement this method.**

Reimplemented from pex.config.config.Field.

Definition at line 181 of file configField.py.

    def freeze(self, instance):
        """Make this field read-only.
 
        Parameters
        ----------
        instance : `lsst.pex.config.Config`
            The config instance that contains this field.
 
        Notes
        -----
        Freezing is only relevant for fields that hold subconfigs. Fields which
        hold subconfigs should freeze each subconfig.
 
        **Subclasses should implement this method.**
        """
        value = self.__get__(instance)
        value.freeze()
 

rename()

def pex.config.configField.ConfigField.rename	(		self,
			instance
	)

Rename the field in a `~lsst.pex.config.Config` (for internal use
only).

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains this field.

Notes
-----
This method is invoked by the `lsst.pex.config.Config` object that
contains this field and should not be called directly.

Renaming is only relevant for `~lsst.pex.config.Field` instances that
hold subconfigs. `~lsst.pex.config.Fields` that hold subconfigs should
rename each subconfig with the full field name as generated by
`lsst.pex.config.config._joinNamePath`.

Reimplemented from pex.config.config.Field.

Definition at line 130 of file configField.py.

    def rename(self, instance):
        """Rename the field in a `~lsst.pex.config.Config` (for internal use
        only).
 
        Parameters
        ----------
        instance : `lsst.pex.config.Config`
            The config instance that contains this field.
 
        Notes
        -----
        This method is invoked by the `lsst.pex.config.Config` object that
        contains this field and should not be called directly.
 
        Renaming is only relevant for `~lsst.pex.config.Field` instances that
        hold subconfigs. `~lsst.pex.config.Fields` that hold subconfigs should
        rename each subconfig with the full field name as generated by
        `lsst.pex.config.config._joinNamePath`.
        """
        value = self.__get__(instance)
        value._rename(_joinNamePath(instance._name, self.name))
 

save()

def pex.config.configField.ConfigField.save	(		self,
			outfile,
			instance
	)

Save this field to a file (for internal use only).

Parameters
----------
outfile : file-like object
    A writeable field handle.
instance : `Config`
    The `Config` instance that contains this field.

Notes
-----
This method is invoked by the `~lsst.pex.config.Config` object that
contains this field and should not be called directly.

The output consists of the documentation string
(`lsst.pex.config.Field.doc`) formatted as a Python comment. The second
line is formatted as an assignment: ``{fullname}={value}``.

This output can be executed with Python.

Reimplemented from pex.config.config.Field.

Definition at line 157 of file configField.py.

    def save(self, outfile, instance):
        """Save this field to a file (for internal use only).
 
        Parameters
        ----------
        outfile : file-like object
            A writeable field handle.
        instance : `Config`
            The `Config` instance that contains this field.
 
        Notes
        -----
        This method is invoked by the `~lsst.pex.config.Config` object that
        contains this field and should not be called directly.
 
        The output consists of the documentation string
        (`lsst.pex.config.Field.doc`) formatted as a Python comment. The second
        line is formatted as an assignment: ``{fullname}={value}``.
 
        This output can be executed with Python.
        """
        value = self.__get__(instance)
        value._save(outfile)
 

toDict()

def pex.config.configField.ConfigField.toDict	(		self,
			instance
	)

Convert the field value so that it can be set as the value of an
item in a `dict` (for internal use only).

Parameters
----------
instance : `Config`
    The `Config` that contains this field.

Returns
-------
value : object
    The field's value. See *Notes*.

Notes
-----
This method invoked by the owning `~lsst.pex.config.Config` object and
should not be called directly.

Simple values are passed through. Complex data structures must be
manipulated. For example, a `~lsst.pex.config.Field` holding a
subconfig should, instead of the subconfig object, return a `dict`
where the keys are the field names in the subconfig, and the values are
the field values in the subconfig.

Reimplemented from pex.config.config.Field.

Definition at line 199 of file configField.py.

    def toDict(self, instance):
        """Convert the field value so that it can be set as the value of an
        item in a `dict` (for internal use only).
 
        Parameters
        ----------
        instance : `Config`
            The `Config` that contains this field.
 
        Returns
        -------
        value : object
            The field's value. See *Notes*.
 
        Notes
        -----
        This method invoked by the owning `~lsst.pex.config.Config` object and
        should not be called directly.
 
        Simple values are passed through. Complex data structures must be
        manipulated. For example, a `~lsst.pex.config.Field` holding a
        subconfig should, instead of the subconfig object, return a `dict`
        where the keys are the field names in the subconfig, and the values are
        the field values in the subconfig.
        """
        value = self.__get__(instance)
        return value.toDict()
 

validate()

def pex.config.configField.ConfigField.validate	(		self,
			instance
	)

Validate the field (for internal use only).

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains this field.

Raises
------
lsst.pex.config.FieldValidationError
    Raised if verification fails.

Notes
-----
This method provides basic validation:

- Ensures that the value is not `None` if the field is not optional.
- Ensures type correctness.
- Ensures that the user-provided ``check`` function is valid.

Most `~lsst.pex.config.Field` subclasses should call
`lsst.pex.config.field.Field.validate` if they re-implement
`~lsst.pex.config.field.Field.validate`.

Reimplemented from pex.config.config.Field.

Definition at line 227 of file configField.py.

    def validate(self, instance):
        """Validate the field (for internal use only).
 
        Parameters
        ----------
        instance : `lsst.pex.config.Config`
            The config instance that contains this field.
 
        Raises
        ------
        lsst.pex.config.FieldValidationError
            Raised if verification fails.
 
        Notes
        -----
        This method provides basic validation:
 
        - Ensures that the value is not `None` if the field is not optional.
        - Ensures type correctness.
        - Ensures that the user-provided ``check`` function is valid.
 
        Most `~lsst.pex.config.Field` subclasses should call
        `lsst.pex.config.field.Field.validate` if they re-implement
        `~lsst.pex.config.field.Field.validate`.
        """
        value = self.__get__(instance)
        value.validate()
 
        if self.check is not None and not self.check(value):
            msg = "%s is not a valid value" % str(value)
            raise FieldValidationError(self, instance, msg)
 

Member Data Documentation

check

pex.config.config.Field.check

inherited

Definition at line 311 of file config.py.

default

pex.config.config.Field.default

inherited

Definition at line 307 of file config.py.

deprecated

pex.config.config.Field.deprecated

inherited

Definition at line 298 of file config.py.

doc

pex.config.config.Field.doc

inherited

Definition at line 294 of file config.py.

dtype

pex.config.config.Field.dtype

inherited

Definition at line 287 of file config.py.

optional

pex.config.config.Field.optional

inherited

Definition at line 315 of file config.py.

source

pex.config.config.Field.source

inherited

Definition at line 322 of file config.py.

supportedTypes

pex.config.config.Field.supportedTypes = set((str, bool, float, int, complex))

staticinherited

Definition at line 272 of file config.py.

---

The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/cb4e2dc/Linux64/pex_config/20.0.0+34a42eae2c/python/lsst/pex/config/configField.py