lsst.pex.config.config Namespace Reference

Classes
class	_PexConfigGenericAlias
class	Config
class	ConfigMeta
class	Field
class	FieldValidationError
class	RecordingImporter
class	UnexpectedProxyUsageError

Functions
	_joinNamePath (prefix=None, name=None, index=None)
	_autocast (x, dtype)
	_typeStr (x)
	_yaml_config_representer (dumper, data)
	_yaml_config_constructor (loader, node)
	_classFromPython (config_py)
	unreduceConfig (cls_, stream)

Variables
	yaml = None
tuple	YamlLoaders = (yaml.Loader, yaml.FullLoader, yaml.SafeLoader, yaml.UnsafeLoader)
	doImport = None
	FieldTypeVar = TypeVar("FieldTypeVar")
	_yaml_config_constructor
	Loader

Function Documentation

_autocast()

lsst.pex.config.config._autocast ( x, dtype )

protected

Cast a value to a type, if appropriate.

Parameters
----------
x : object
    A value.
dtype : type
    Data type, such as `float`, `int`, or `str`.

Returns
-------
values : object
    If appropriate, the returned value is ``x`` cast to the given type
    ``dtype``. If the cast cannot be performed the original value of
    ``x`` is returned.

Notes
-----
Will convert numpy scalar types to the standard Python equivalents.

Definition at line 122 of file config.py.

def _autocast(x, dtype):
    """Cast a value to a type, if appropriate.
 
    Parameters
    ----------
    x : object
        A value.
    dtype : type
        Data type, such as `float`, `int`, or `str`.
 
    Returns
    -------
    values : object
        If appropriate, the returned value is ``x`` cast to the given type
        ``dtype``. If the cast cannot be performed the original value of
        ``x`` is returned.
 
    Notes
    -----
    Will convert numpy scalar types to the standard Python equivalents.
    """
    if dtype is float and isinstance(x, numbers.Real):
        return float(x)
    if dtype is int and isinstance(x, numbers.Integral):
        return int(x)
    return x
 
 

_classFromPython()

lsst.pex.config.config._classFromPython ( config_py )

protected

Return the Config subclass required by this Config serialization.

Parameters
----------
config_py : `str`
    A serialized form of the Config as created by
    `Config.saveToStream`.

Returns
-------
cls : `type`
    The `Config` subclass associated with this config.

Definition at line 1694 of file config.py.

def _classFromPython(config_py):
    """Return the Config subclass required by this Config serialization.
 
    Parameters
    ----------
    config_py : `str`
        A serialized form of the Config as created by
        `Config.saveToStream`.
 
    Returns
    -------
    cls : `type`
        The `Config` subclass associated with this config.
    """
    # standard serialization has the form:
    #     import config.class
    #     assert type(config) is config.class.Config, ...
    # Older files use "type(config)==" instead.
    # We want to parse these two lines so we can get the class itself
 
    # Do a single regex to avoid large string copies when splitting a
    # large config into separate lines.
    # The assert regex cannot be greedy because the assert error string
    # can include both "," and " is ".
    matches = re.search(r"^import ([\w.]+)\nassert type\‍(\S+\‍)(?:\s*==\s*| is )(.*?),", config_py)
 
    if not matches:
        first_line, second_line, _ = config_py.split("\n", 2)
        raise ValueError(
            f"First two lines did not match expected form. Got:\n - {first_line}\n - {second_line}"
        )
 
    module_name = matches.group(1)
    module = importlib.import_module(module_name)
 
    # Second line
    full_name = matches.group(2)
 
    # Remove the module name from the full name
    if not full_name.startswith(module_name):
        raise ValueError(f"Module name ({module_name}) inconsistent with full name ({full_name})")
 
    # if module name is a.b.c and full name is a.b.c.d.E then
    # we need to remove a.b.c. and iterate over the remainder
    # The +1 is for the extra dot after a.b.c
    remainder = full_name[len(module_name) + 1 :]
    components = remainder.split(".")
    pytype = module
    for component in components:
        pytype = getattr(pytype, component)
    return pytype
 
 

_joinNamePath()

lsst.pex.config.config._joinNamePath ( prefix = None, name = None, index = None )

protected

Generate nested configuration names.

Definition at line 107 of file config.py.

def _joinNamePath(prefix=None, name=None, index=None):
    """Generate nested configuration names."""
    if not prefix and not name:
        raise ValueError("Invalid name: cannot be None")
    elif not name:
        name = prefix
    elif prefix and name:
        name = prefix + "." + name
 
    if index is not None:
        return f"{name}[{index!r}]"
    else:
        return name
 
 

_typeStr()

lsst.pex.config.config._typeStr ( x )

protected

Generate a fully-qualified type name.

Returns
-------
`str`
    Fully-qualified type name.

Notes
-----
This function is used primarily for writing config files to be executed
later upon with the 'load' function.

Definition at line 150 of file config.py.

def _typeStr(x):
    """Generate a fully-qualified type name.
 
    Returns
    -------
    `str`
        Fully-qualified type name.
 
    Notes
    -----
    This function is used primarily for writing config files to be executed
    later upon with the 'load' function.
    """
    if hasattr(x, "__module__") and hasattr(x, "__name__"):
        xtype = x
    else:
        xtype = type(x)
    if xtype.__module__ == "builtins":
        return xtype.__name__
    else:
        return f"{xtype.__module__}.{xtype.__name__}"
 
 

_yaml_config_constructor()

lsst.pex.config.config._yaml_config_constructor ( loader, node )

protected

Construct a config from YAML.

Definition at line 195 of file config.py.

    def _yaml_config_constructor(loader, node):
        """Construct a config from YAML."""
        config_py = loader.construct_scalar(node)
        return Config._fromPython(config_py)
 

_yaml_config_representer()

lsst.pex.config.config._yaml_config_representer ( dumper, data )

protected

Represent a Config object in a form suitable for YAML.

Stores the serialized stream as a scalar block string.

Definition at line 175 of file config.py.

    def _yaml_config_representer(dumper, data):
        """Represent a Config object in a form suitable for YAML.
 
        Stores the serialized stream as a scalar block string.
        """
        stream = io.StringIO()
        data.saveToStream(stream)
        config_py = stream.getvalue()
 
        # Strip multiple newlines from the end of the config
        # This simplifies the YAML to use | and not |+
        config_py = config_py.rstrip() + "\n"
 
        # Trailing spaces force pyyaml to use non-block form.
        # Remove the trailing spaces so it has no choice
        config_py = re.sub(r"\s+$", "\n", config_py, flags=re.MULTILINE)
 
        # Store the Python as a simple scalar
        return dumper.represent_scalar("lsst.pex.config.Config", config_py, style="|")
 

unreduceConfig()

lsst.pex.config.config.unreduceConfig	(		cls_,
			stream )

Create a `~lsst.pex.config.Config` from a stream.

Parameters
----------
cls_ : `lsst.pex.config.Config`-type
    A `lsst.pex.config.Config` type (not an instance) that is instantiated
    with configurations in the ``stream``.
stream : file-like object, `str`, or `~types.CodeType`
    Stream containing configuration override code.

Returns
-------
config : `lsst.pex.config.Config`
    Config instance.

See Also
--------
lsst.pex.config.Config.loadFromStream

Definition at line 1747 of file config.py.

def unreduceConfig(cls_, stream):
    """Create a `~lsst.pex.config.Config` from a stream.
 
    Parameters
    ----------
    cls_ : `lsst.pex.config.Config`-type
        A `lsst.pex.config.Config` type (not an instance) that is instantiated
        with configurations in the ``stream``.
    stream : file-like object, `str`, or `~types.CodeType`
        Stream containing configuration override code.
 
    Returns
    -------
    config : `lsst.pex.config.Config`
        Config instance.
 
    See Also
    --------
    lsst.pex.config.Config.loadFromStream
    """
    config = cls_()
    config.loadFromStream(stream)
    return config

Variable Documentation

_yaml_config_constructor

lsst.pex.config.config._yaml_config_constructor

protected

Definition at line 203 of file config.py.

doImport

lsst.pex.config.config.doImport = None

Definition at line 75 of file config.py.

FieldTypeVar

lsst.pex.config.config.FieldTypeVar = TypeVar("FieldTypeVar")

Definition at line 98 of file config.py.

Loader

lsst.pex.config.config.Loader

Definition at line 203 of file config.py.

yaml

lsst.pex.config.config.yaml = None

Definition at line 58 of file config.py.

YamlLoaders

tuple lsst.pex.config.config.YamlLoaders = (yaml.Loader, yaml.FullLoader, yaml.SafeLoader, yaml.UnsafeLoader)

Definition at line 64 of file config.py.