[ENH] Add global config interface

docs/source/api_reference.rst

@@ -28,6 +28,27 @@ Base Classes
     BaseObject
     BaseEstimator
 
+.. _global_config:
+
+Configure ``skbase``
+====================
+
+.. automodule:: skbase.config
+    :no-members:
+    :no-inherited-members:
+
+.. currentmodule:: skbase.config
+
+.. autosummary::
+    :toctree: api_reference/auto_generated/
+    :template: function.rst
+
+    get_config
+    get_default_config
+    set_config
+    reset_config
+    config_context
+
 .. _obj_retrieval:
 
 Object Retrieval

docs/source/user_documentation/user_guide.rst

@@ -29,6 +29,7 @@ that ``skbase`` provides, see the :ref:`api_ref`.
    user_guide/lookup
    user_guide/validate
    user_guide/testing
+   user_guide/configuration
 
 
 .. grid:: 1 2 2 2
@@ -103,3 +104,17 @@ that ``skbase`` provides, see the :ref:`api_ref`.
             :expand:
 
             Testing
+
+    .. grid-item-card:: Configuration
+        :text-align: center
+
+        Configure ``skbase``.
+
+        +++
+
+        .. button-ref:: user_guide/configuration
+            :color: primary
+            :click-parent:
+            :expand:
+
+            Configuration

docs/source/user_documentation/user_guide/configuration.rst

@@ -0,0 +1,11 @@
+.. _user_guide_global_config:
+
+====================
+Configure ``skbase``
+====================
+
+.. note::
+
+    The user guide is under development. We have created a basic
+    structure and are looking for contributions to develop the user guide
+    further.

skbase/base/_base.py

@@ -63,6 +63,8 @@ class name: BaseEstimator
 
 from skbase._exceptions import NotFittedError
 from skbase.base._tagmanager import _FlagManager
+from skbase.config import get_config
+from skbase.config._config import _CONFIG_REGISTRY
 
 __author__: List[str] = ["mloning", "RNKuhns", "fkiraly"]
 __all__: List[str] = ["BaseEstimator", "BaseObject"]
@@ -437,16 +439,69 @@ def clone_tags(self, estimator, tag_names=None):
         return self
 
     def get_config(self):
-        """Get config flags for self.
+        """Get configuration parameters impacting the object.
+
+        The configuration is retrieved in the following order:
+
+        - ``skbase`` global configuration,
+        - downstream package configurations, and
+        - local configuration set via the object's _config class variable
+          or the object's `set_config` parameter.
 
         Returns
         -------
         config_dict : dict
-            Dictionary of config name : config value pairs. Collected from _config
-            class attribute via nested inheritance and then any overrides
-            and new tags from _onfig_dynamic object attribute.
+            Dictionary of config name : config value pairs.
         """
-        return self._get_flags(flag_attr_name="_config")
+        # Configuration is collected in a specific order from the farthest to
+        # most local. skbase global config -> downstream package (optional) -> local
+        # Start by collecting skbase's global config
+        config = get_config().copy()
+
+        # Use the object config extension interface to optionally retrieve the
+        # configuration of any downstream package that is subclassing BaseObject
+        if hasattr(self, "__skbase_get_config__") and callable(
+            self.__skbase_get_config__
+        ):
+            skbase_get_config_extension_dict = self.__skbase_get_config__()
+        else:
+            skbase_get_config_extension_dict = {}
+
+        # If the config extension dunder returned a dict, use it to update
+        # the dict of configs that have been retrieved so far
+        if isinstance(skbase_get_config_extension_dict, dict):
+            config.update(skbase_get_config_extension_dict)
+        # Otherwise warn the user that a dict wasn't returned (extension not
+        # done properly) and ignore the returned result
+        else:
+            msg = "Use of `__skbase_get_config__` to extend the interface for local "
+            msg += "overrides of the global configuration must return a dictionary.\n"
+            msg += f"But a {type(skbase_get_config_extension_dict)} was found."
+            msg += "Ignoring result returned from `__skbase_get_config__`."
+            warnings.warn(msg, UserWarning, stacklevel=2)
+
+        # Finally get the local config in case any optional instance config
+        # overrides were made)
+        local_config = self._get_flags(flag_attr_name="_config").copy()
+
+        # If the local config param name is one of the skbase global config
+        # options (as opposed to config of downstream package) then we want
+        # to make sure we don't return an invalid value. In this case, we'll
+        # fallback to the default value if an invalid value was set as the local
+        # override of the global config
+        for config_param, config_value in local_config.items():
+            if config_param in _CONFIG_REGISTRY:
+                msg = "Invalid value encountered for global configuration parameter "
+                msg += f"{config_param}. Using global parameter configuration value.\n"
+                config_value = _CONFIG_REGISTRY[
+                    config_param
+                ].get_valid_param_or_default(
+                    config_value, default_value=config[config_param]
+                )
+                local_config[config_param] = config_value
+        config.update(local_config)
+
+        return config
 
     def set_config(self, **config_dict):
         """Set config flags to given values.

skbase/config/__init__.py

@@ -0,0 +1,32 @@
+# -*- coding: utf-8 -*-
+""":mod:`skbase.config` provides tools for the global configuration of ``skbase``.
+
+For more information on configuration usage patterns see the
+:ref:`user guide <user_guide_global_config>`.
+"""
+# -*- coding: utf-8 -*-
+# copyright: skbase developers, BSD-3-Clause License (see LICENSE file)
+# Includes functionality like get_config, set_config, and config_context
+# that is similar to scikit-learn. These elements are copyrighted by the
+# scikit-learn developers, BSD-3-Clause License. For conditions see
+# https://github.com/scikit-learn/scikit-learn/blob/main/COPYING
+from typing import List
+
+from skbase.config._config import (
+    GlobalConfigParamSetting,
+    config_context,
+    get_config,
+    get_default_config,
+    reset_config,
+    set_config,
+)
+
+__author__: List[str] = ["RNKuhns"]
+__all__: List[str] = [
+    "GlobalConfigParamSetting",
+    "get_default_config",
+    "get_config",
+    "set_config",
+    "reset_config",
+    "config_context",
+]