lsst.pex.config  21.0.0-1-ga51b5d4+bb73fc8373
Public Member Functions | Properties | List of all members
lsst.pex.config.config.Config Class Reference
Inheritance diagram for lsst.pex.config.config.Config:
lsst.pex.config.config.ConfigMeta

Public Member Functions

def __iter__ (self)
 
def keys (self)
 
def values (self)
 
def items (self)
 
def iteritems (self)
 
def itervalues (self)
 
def iterkeys (self)
 
def __contains__ (self, name)
 Return True if the specified field exists in this config. More...
 
def __new__ (cls, *args, **kw)
 
def __reduce__ (self)
 
def setDefaults (self)
 
def update (self, **kw)
 
def load (self, filename, root="config")
 
def loadFromStream (self, stream, root="config", filename=None)
 
def save (self, filename, root="config")
 
def saveToStream (self, outfile, root="config", skipImports=False)
 
def freeze (self)
 
def toDict (self)
 
def names (self)
 
def validate (self)
 
def formatHistory (self, name, **kwargs)
 
def __setattr__ (self, attr, value, at=None, label="assignment")
 
def __delattr__ (self, attr, at=None, label="deletion")
 
def __eq__ (self, other)
 
def __ne__ (self, other)
 
def __str__ (self)
 
def __repr__ (self)
 
def compare (self, other, shortcut=True, rtol=1E-8, atol=1E-8, output=None)
 
def __init_subclass__ (cls, **kwargs)
 
- Public Member Functions inherited from lsst.pex.config.config.ConfigMeta
def __init__ (cls, name, bases, dict_)
 
def __setattr__ (cls, name, value)
 

Properties

 history = property(lambda x: x._history)
 

Detailed Description

Base class for configuration (*config*) objects.

Notes
-----
A ``Config`` object will usually have several `~lsst.pex.config.Field`
instances as class attributes. These are used to define most of the base
class behavior.

``Config`` implements a mapping API that provides many `dict`-like methods,
such as `keys`, `values`, `items`, `iteritems`, `iterkeys`, and
`itervalues`. ``Config`` instances also support the ``in`` operator to
test if a field is in the config. Unlike a `dict`, ``Config`` classes are
not subscriptable. Instead, access individual fields as attributes of the
configuration instance.

Examples
--------
Config classes are subclasses of ``Config`` that have
`~lsst.pex.config.Field` instances (or instances of
`~lsst.pex.config.Field` subclasses) as class attributes:

>>> from lsst.pex.config import Config, Field, ListField
>>> class DemoConfig(Config):
...     intField = Field(doc="An integer field", dtype=int, default=42)
...     listField = ListField(doc="List of favorite beverages.", dtype=str,
...                           default=['coffee', 'green tea', 'water'])
...
>>> config = DemoConfig()

Configs support many `dict`-like APIs:

>>> config.keys()
['intField', 'listField']
>>> 'intField' in config
True

Individual fields can be accessed as attributes of the configuration:

>>> config.intField
42
>>> config.listField.append('earl grey tea')
>>> print(config.listField)
['coffee', 'green tea', 'water', 'earl grey tea']

Member Function Documentation

◆ __contains__()

def lsst.pex.config.config.Config.__contains__ (   self,
  name 
)

Return True if the specified field exists in this config.

    @param[in] name  field name to test for

◆ __init_subclass__()

def lsst.pex.config.config.Config.__init_subclass__ (   cls,
**  kwargs 
)
Run initialization for every subclass.

Specifically registers the subclass with a YAML representer
and YAML constructor (if pyyaml is available)

◆ __iter__()

def lsst.pex.config.config.Config.__iter__ (   self)
Iterate over fields.

◆ __new__()

def lsst.pex.config.config.Config.__new__ (   cls,
args,
**  kw 
)
Allocate a new `lsst.pex.config.Config` object.

In order to ensure that all Config object are always in a proper state
when handed to users or to derived `~lsst.pex.config.Config` classes,
some attributes are handled at allocation time rather than at
initialization.

This ensures that even if a derived `~lsst.pex.config.Config` class
implements ``__init__``, its author does not need to be concerned about
when or even the base ``Config.__init__`` should be called.

◆ __reduce__()

def lsst.pex.config.config.Config.__reduce__ (   self)
Reduction for pickling (function with arguments to reproduce).

We need to condense and reconstitute the `~lsst.pex.config.Config`,
since it may contain lambdas (as the ``check`` elements) that cannot
be pickled.

◆ __setattr__()

def lsst.pex.config.config.Config.__setattr__ (   self,
  attr,
  value,
  at = None,
  label = "assignment" 
)
Set an attribute (such as a field's value).

Notes
-----
Unlike normal Python objects, `~lsst.pex.config.Config` objects are
locked such that no additional attributes nor properties may be added
to them dynamically.

Although this is not the standard Python behavior, it helps to protect
users from accidentally mispelling a field name, or trying to set a
non-existent field.

◆ compare()

def lsst.pex.config.config.Config.compare (   self,
  other,
  shortcut = True,
  rtol = 1E-8,
  atol = 1E-8,
  output = None 
)
Compare this configuration to another `~lsst.pex.config.Config` for
equality.

Parameters
----------
other : `lsst.pex.config.Config`
    Other `~lsst.pex.config.Config` object to compare against this
    config.
shortcut : `bool`, optional
    If `True`, return as soon as an inequality is found. Default is
    `True`.
rtol : `float`, optional
    Relative tolerance for floating point comparisons.
atol : `float`, optional
    Absolute tolerance for floating point comparisons.
output : callable, optional
    A callable that takes a string, used (possibly repeatedly) to
    report inequalities.

Returns
-------
isEqual : `bool`
    `True` when the two `lsst.pex.config.Config` instances are equal.
    `False` if there is an inequality.

See also
--------
lsst.pex.config.compareConfigs

Notes
-----
Unselected targets of `~lsst.pex.config.RegistryField` fields and
unselected choices of `~lsst.pex.config.ConfigChoiceField` fields
are not considered by this method.

Floating point comparisons are performed by `numpy.allclose`.

◆ formatHistory()

def lsst.pex.config.config.Config.formatHistory (   self,
  name,
**  kwargs 
)
Format a configuration field's history to a human-readable format.

Parameters
----------
name : `str`
    Name of a `~lsst.pex.config.Field` in this config.
kwargs
    Keyword arguments passed to `lsst.pex.config.history.format`.

Returns
-------
history : `str`
    A string containing the formatted history.

See also
--------
lsst.pex.config.history.format

◆ freeze()

def lsst.pex.config.config.Config.freeze (   self)
Make this config, and all subconfigs, read-only.

◆ items()

def lsst.pex.config.config.Config.items (   self)
Get configurations as ``(field name, field value)`` pairs.

Returns
-------
items : `list`
    List of tuples for each configuration. Tuple items are:

    0. Field name.
    1. Field value.

See also
--------
lsst.pex.config.Config.iteritems

◆ iteritems()

def lsst.pex.config.config.Config.iteritems (   self)
Iterate over (field name, field value) pairs.

Yields
------
item : `tuple`
    Tuple items are:

    0. Field name.
    1. Field value.

See also
--------
lsst.pex.config.Config.items

◆ iterkeys()

def lsst.pex.config.config.Config.iterkeys (   self)
Iterate over field names

Yields
------
key : `str`
    A field's key (attribute name).

See also
--------
lsst.pex.config.Config.values

◆ itervalues()

def lsst.pex.config.config.Config.itervalues (   self)
Iterate over field values.

Yields
------
value : obj
    A field value.

See also
--------
lsst.pex.config.Config.values

◆ keys()

def lsst.pex.config.config.Config.keys (   self)
Get field names.

Returns
-------
names : `list`
    List of `lsst.pex.config.Field` names.

See also
--------
lsst.pex.config.Config.iterkeys

◆ load()

def lsst.pex.config.config.Config.load (   self,
  filename,
  root = "config" 
)
Modify this config in place by executing the Python code in a
configuration file.

Parameters
----------
filename : `str`
    Name of the configuration file. A configuration file is Python
    module.
root : `str`, optional
    Name of the variable in file that refers to the config being
    overridden.

    For example, the value of root is ``"config"`` and the file
    contains::

        config.myField = 5

    Then this config's field ``myField`` is set to ``5``.

    **Deprecated:** For backwards compatibility, older config files
    that use ``root="root"`` instead of ``root="config"`` will be
    loaded with a warning printed to `sys.stderr`. This feature will be
    removed at some point.

See also
--------
lsst.pex.config.Config.loadFromStream
lsst.pex.config.Config.save
lsst.pex.config.Config.saveFromStream

◆ loadFromStream()

def lsst.pex.config.config.Config.loadFromStream (   self,
  stream,
  root = "config",
  filename = None 
)
Modify this Config in place by executing the Python code in the
provided stream.

Parameters
----------
stream : file-like object, `str`, or compiled string
    Stream containing configuration override code.
root : `str`, optional
    Name of the variable in file that refers to the config being
    overridden.

    For example, the value of root is ``"config"`` and the file
    contains::

        config.myField = 5

    Then this config's field ``myField`` is set to ``5``.

    **Deprecated:** For backwards compatibility, older config files
    that use ``root="root"`` instead of ``root="config"`` will be
    loaded with a warning printed to `sys.stderr`. This feature will be
    removed at some point.
filename : `str`, optional
    Name of the configuration file, or `None` if unknown or contained
    in the stream. Used for error reporting.

See also
--------
lsst.pex.config.Config.load
lsst.pex.config.Config.save
lsst.pex.config.Config.saveFromStream

◆ names()

def lsst.pex.config.config.Config.names (   self)
Get all the field names in the config, recursively.

Returns
-------
names : `list` of `str`
    Field names.

◆ save()

def lsst.pex.config.config.Config.save (   self,
  filename,
  root = "config" 
)
Save a Python script to the named file, which, when loaded,
reproduces this config.

Parameters
----------
filename : `str`
    Desination filename of this configuration.
root : `str`, optional
    Name to use for the root config variable. The same value must be
    used when loading (see `lsst.pex.config.Config.load`).

See also
--------
lsst.pex.config.Config.saveToStream
lsst.pex.config.Config.load
lsst.pex.config.Config.loadFromStream

◆ saveToStream()

def lsst.pex.config.config.Config.saveToStream (   self,
  outfile,
  root = "config",
  skipImports = False 
)
Save a configuration file to a stream, which, when loaded,
reproduces this config.

Parameters
----------
outfile : file-like object
    Destination file object write the config into. Accepts strings not
    bytes.
root
    Name to use for the root config variable. The same value must be
    used when loading (see `lsst.pex.config.Config.load`).
skipImports : `bool`, optional
    If `True` then do not include ``import`` statements in output,
    this is to support human-oriented output from ``pipetask`` where
    additional clutter is not useful.

See also
--------
lsst.pex.config.Config.save
lsst.pex.config.Config.load
lsst.pex.config.Config.loadFromStream

◆ setDefaults()

def lsst.pex.config.config.Config.setDefaults (   self)
Subclass hook for computing defaults.

Notes
-----
Derived `~lsst.pex.config.Config` classes that must compute defaults
rather than using the `~lsst.pex.config.Field` instances's defaults
should do so here. To correctly use inherited defaults,
implementations of ``setDefaults`` must call their base class's
``setDefaults``.

◆ toDict()

def lsst.pex.config.config.Config.toDict (   self)
Make a dictionary of field names and their values.

Returns
-------
dict_ : `dict`
    Dictionary with keys that are `~lsst.pex.config.Field` names.
    Values are `~lsst.pex.config.Field` values.

See also
--------
lsst.pex.config.Field.toDict

Notes
-----
This method uses the `~lsst.pex.config.Field.toDict` method of
individual fields. Subclasses of `~lsst.pex.config.Field` may need to
implement a ``toDict`` method for *this* method to work.

◆ update()

def lsst.pex.config.config.Config.update (   self,
**  kw 
)
Update values of fields specified by the keyword arguments.

Parameters
----------
kw
    Keywords are configuration field names. Values are configuration
    field values.

Notes
-----
The ``__at`` and ``__label`` keyword arguments are special internal
keywords. They are used to strip out any internal steps from the
history tracebacks of the config. Do not modify these keywords to
subvert a `~lsst.pex.config.Config` instance's history.

Examples
--------
This is a config with three fields:

>>> from lsst.pex.config import Config, Field
>>> class DemoConfig(Config):
...     fieldA = Field(doc='Field A', dtype=int, default=42)
...     fieldB = Field(doc='Field B', dtype=bool, default=True)
...     fieldC = Field(doc='Field C', dtype=str, default='Hello world')
...
>>> config = DemoConfig()

These are the default values of each field:

>>> for name, value in config.iteritems():
...     print(f"{name}: {value}")
...
fieldA: 42
fieldB: True
fieldC: 'Hello world'

Using this method to update ``fieldA`` and ``fieldC``:

>>> config.update(fieldA=13, fieldC='Updated!')

Now the values of each field are:

>>> for name, value in config.iteritems():
...     print(f"{name}: {value}")
...
fieldA: 13
fieldB: True
fieldC: 'Updated!'

◆ validate()

def lsst.pex.config.config.Config.validate (   self)
Validate the Config, raising an exception if invalid.

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

Notes
-----
The base class implementation performs type checks on all fields by
calling their `~lsst.pex.config.Field.validate` methods.

Complex single-field validation can be defined by deriving new Field
types. For convenience, some derived `lsst.pex.config.Field`-types
(`~lsst.pex.config.ConfigField` and
`~lsst.pex.config.ConfigChoiceField`) are defined in `lsst.pex.config`
that handle recursing into subconfigs.

Inter-field relationships should only be checked in derived
`~lsst.pex.config.Config` classes after calling this method, and base
validation is complete.

◆ values()

def lsst.pex.config.config.Config.values (   self)
Get field values.

Returns
-------
values : `list`
    List of field values.

See also
--------
lsst.pex.config.Config.itervalues

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