Registry¶

class lsst.pex.config.Registry(configBaseType=<class 'lsst.pex.config.config.Config'>)¶

Bases: collections.abc.Mapping

A base class for global registries, which map names to configurables.

A registry acts like a read-only dictionary with an additional register method to add targets. Targets in the registry are configurables (see Notes).

Parameters

configBaseTypelsst.pex.config.Config-type: The base class for config classes in the registry.

Notes

A configurable is a callable with call signature (config, *args) Configurables typically create an algorithm or are themselves the algorithm. Often configurables are lsst.pipe.base.Task subclasses, but this is not required.

A Registry has these requirements:

All configurables added to a particular registry have the same call signature.
All configurables in a registry typically share something important in common. For example, all configurables in psfMatchingRegistry return a PSF matching class that has a psfMatch method with a particular call signature.

Examples

This examples creates a configurable class Foo and adds it to a registry. First, creating the configurable:

>>> from lsst.pex.config import Registry, Config
>>> class FooConfig(Config):
...     val = Field(dtype=int, default=3, doc="parameter for Foo")
...
>>> class Foo:
...     ConfigClass = FooConfig
...     def __init__(self, config):
...         self.config = config
...     def addVal(self, num):
...         return self.config.val + num
...

Next, create a Registry instance called registry and register the Foo configurable under the "foo" key:

>>> registry = Registry()
>>> registry.register("foo", Foo)
>>> print(list(registry.keys()))
["foo"]

Now Foo is conveniently accessible from the registry itself.

Finally, use the registry to get the configurable class and create an instance of it:

>>> FooConfigurable = registry["foo"]
>>> foo = FooConfigurable(FooConfigurable.ConfigClass())
>>> foo.addVal(5)
8

Methods Summary

`get`(k[,d])
`items`()
`keys`()
`makeField`(doc[, default, optional, multi])	Create a `RegistryField` configuration field from this registry.
`register`(name, target[, ConfigClass])	Add a new configurable target to the registry.
`values`()

Methods Documentation

get(k[, d]) → D[k] if k in D, else d. d defaults to None.¶

items() → a set-like object providing a view on D's items¶

keys() → a set-like object providing a view on D's keys¶

makeField(doc, default=None, optional=False, multi=False)¶

Create a RegistryField configuration field from this registry.

Parameters

docstr: A description of the field.
defaultobject, optional: The default target for the field.
optionalbool, optional: When False, lsst.pex.config.Config.validate fails if the field’s value is None.
multibool, optional: A flag to allow multiple selections in the RegistryField if True.

Returns

fieldlsst.pex.config.RegistryField: RegistryField Configuration field.

register(name, target, ConfigClass=None)¶

Add a new configurable target to the registry.

Parameters

namestr: Name that the target is registered under. The target can be accessed later with dict-like patterns using name as the key.
targetobj: A configurable type, usually a subclass of lsst.pipe.base.Task.
ConfigClasslsst.pex.config.Config-type, optional: A subclass of lsst.pex.config.Config used to configure the configurable. If None then the configurable’s ConfigClass attribute is used.

Raises

RuntimeError: Raised if an item with name is already in the registry.
AttributeError: Raised if ConfigClass is None and target does not have a ConfigClass attribute.

Notes

If ConfigClass is provided then the target configurable is wrapped in a new object that forwards function calls to it. Otherwise the original target is stored.

values() → an object providing a view on D's values¶

Navigation

Registry¶