Improve way of addon detection

copulas/__init__.py

@@ -8,14 +8,14 @@
 
 import contextlib
 import importlib
+import sys
+import warnings
 from copy import deepcopy
+from operator import attrgetter
 
 import numpy as np
 import pandas as pd
-
-from copulas._addons import _find_addons
-
-_find_addons(group='copulas_modules', parent_globals=globals())
+from pkg_resources import iter_entry_points
 
 EPSILON = np.finfo(np.float32).eps
 
@@ -262,3 +262,71 @@ def decorated(self, X, *args, **kwargs):
         return function(self, X, *args, **kwargs)
 
     return decorated
+
+
+def _get_addon_target(addon_path_name):
+    """Find the target object for the add-on.
+
+    Args:
+        addon_path_name (str):
+            The add-on's name. The add-on's name should be the full path of valid Python
+            identifiers (i.e. importable.module:object.attr).
+
+    Returns:
+        tuple:
+            * object:
+                The base module or object the add-on should be added to.
+            * str:
+                The name the add-on should be added to under the module or object.
+    """
+    module_path, _, object_path = addon_path_name.partition(':')
+    module_path = module_path.split('.')
+
+    if module_path[0] != __name__:
+        msg = f"expected base module to be '{__name__}', found '{module_path[0]}'"
+        raise AttributeError(msg)
+
+    target_base = sys.modules[__name__]
+    for submodule in module_path[1:-1]:
+        target_base = getattr(target_base, submodule)
+
+    addon_name = module_path[-1]
+    if object_path:
+        if len(module_path) > 1 and not hasattr(target_base, module_path[-1]):
+            msg = f"cannot add '{object_path}' to unknown submodule '{'.'.join(module_path)}'"
+            raise AttributeError(msg)
+
+        if len(module_path) > 1:
+            target_base = getattr(target_base, module_path[-1])
+
+        split_object = object_path.split('.')
+        addon_name = split_object[-1]
+
+        if len(split_object) > 1:
+            target_base = attrgetter('.'.join(split_object[:-1]))(target_base)
+
+    return target_base, addon_name
+
+
+def _find_addons():
+    """Find and load all copulas add-ons."""
+    group = 'copulas_modules'
+    for entry_point in iter_entry_points(group=group):
+        try:
+            addon = entry_point.load()
+        except Exception:  # pylint: disable=broad-exception-caught
+            msg = f'Failed to load "{entry_point.name}" from "{entry_point.module_name}".'
+            warnings.warn(msg)
+            continue
+
+        try:
+            addon_target, addon_name = _get_addon_target(entry_point.name)
+        except AttributeError as error:
+            msg = f"Failed to set '{entry_point.name}': {error}."
+            warnings.warn(msg)
+            continue
+
+        setattr(addon_target, addon_name, addon)
+
+
+_find_addons()

tests/unit/test___init__.py

@@ -1,3 +1,4 @@
+import sys
 from unittest import TestCase
 from unittest.mock import MagicMock, call, patch
 
@@ -6,8 +7,10 @@
 import pytest
 from numpy.testing import assert_array_equal
 
+import copulas
 from copulas import (
-    check_valid_values, get_instance, random_state, scalarize, validate_random_state, vectorize)
+    _find_addons, check_valid_values, get_instance, random_state, scalarize, validate_random_state,
+    vectorize)
 from copulas.multivariate import GaussianMultivariate
 
 
@@ -421,3 +424,152 @@ def test_get_instance_with_kwargs(self):
         assert not instance.fitted
         assert isinstance(instance, GaussianMultivariate)
         assert instance.distribution == 'copulas.univariate.truncnorm.TruncNorm'
+
+
+@pytest.fixture()
+def mock_copulas():
+    copulas_module = sys.modules['copulas']
+    copulas_mock = MagicMock()
+    sys.modules['copulas'] = copulas_mock
+    yield copulas_mock
+    sys.modules['copulas'] = copulas_module
+
+
+@patch.object(copulas, 'iter_entry_points')
+def test__find_addons_module(entry_points_mock, mock_copulas):
+    """Test loading an add-on."""
+    # Setup
+    entry_point = MagicMock()
+    entry_point.name = 'copulas.submodule.entry_name'
+    entry_point.load.return_value = 'entry_point'
+    entry_points_mock.return_value = [entry_point]
+
+    # Run
+    _find_addons()
+
+    # Assert
+    entry_points_mock.assert_called_once_with(group='copulas_modules')
+    assert mock_copulas.submodule.entry_name == 'entry_point'
+
+
+@patch.object(copulas, 'iter_entry_points')
+def test__find_addons_object(entry_points_mock, mock_copulas):
+    """Test loading an add-on."""
+    # Setup
+    entry_point = MagicMock()
+    entry_point.name = 'copulas.submodule:entry_object.entry_method'
+    entry_point.load.return_value = 'new_method'
+    entry_points_mock.return_value = [entry_point]
+
+    # Run
+    _find_addons()
+
+    # Assert
+    entry_points_mock.assert_called_once_with(group='copulas_modules')
+    assert mock_copulas.submodule.entry_object.entry_method == 'new_method'
+
+
+@patch('warnings.warn')
+@patch('copulas.iter_entry_points')
+def test__find_addons_bad_addon(entry_points_mock, warning_mock):
+    """Test failing to load an add-on generates a warning."""
+    # Setup
+    def entry_point_error():
+        raise ValueError()
+
+    bad_entry_point = MagicMock()
+    bad_entry_point.name = 'bad_entry_point'
+    bad_entry_point.module_name = 'bad_module'
+    bad_entry_point.load.side_effect = entry_point_error
+    entry_points_mock.return_value = [bad_entry_point]
+    msg = 'Failed to load "bad_entry_point" from "bad_module".'
+
+    # Run
+    _find_addons()
+
+    # Assert
+    entry_points_mock.assert_called_once_with(group='copulas_modules')
+    warning_mock.assert_called_once_with(msg)
+
+
+@patch('warnings.warn')
+@patch('copulas.iter_entry_points')
+def test__find_addons_wrong_base(entry_points_mock, warning_mock):
+    """Test incorrect add-on name generates a warning."""
+    # Setup
+    bad_entry_point = MagicMock()
+    bad_entry_point.name = 'bad_base.bad_entry_point'
+    entry_points_mock.return_value = [bad_entry_point]
+    msg = (
+        "Failed to set 'bad_base.bad_entry_point': expected base module to be 'copulas', found "
+        "'bad_base'."
+    )
+
+    # Run
+    _find_addons()
+
+    # Assert
+    entry_points_mock.assert_called_once_with(group='copulas_modules')
+    warning_mock.assert_called_once_with(msg)
+
+
+@patch('warnings.warn')
+@patch('copulas.iter_entry_points')
+def test__find_addons_missing_submodule(entry_points_mock, warning_mock):
+    """Test incorrect add-on name generates a warning."""
+    # Setup
+    bad_entry_point = MagicMock()
+    bad_entry_point.name = 'copulas.missing_submodule.new_submodule'
+    entry_points_mock.return_value = [bad_entry_point]
+    msg = (
+        "Failed to set 'copulas.missing_submodule.new_submodule': module 'copulas' has no "
+        "attribute 'missing_submodule'."
+    )
+
+    # Run
+    _find_addons()
+
+    # Assert
+    entry_points_mock.assert_called_once_with(group='copulas_modules')
+    warning_mock.assert_called_once_with(msg)
+
+
+@patch('warnings.warn')
+@patch('copulas.iter_entry_points')
+def test__find_addons_module_and_object(entry_points_mock, warning_mock):
+    """Test incorrect add-on name generates a warning."""
+    # Setup
+    bad_entry_point = MagicMock()
+    bad_entry_point.name = 'copulas.missing_submodule:new_object'
+    entry_points_mock.return_value = [bad_entry_point]
+    msg = (
+        "Failed to set 'copulas.missing_submodule:new_object': cannot add 'new_object' to unknown "
+        "submodule 'copulas.missing_submodule'."
+    )
+
+    # Run
+    _find_addons()
+
+    # Assert
+    entry_points_mock.assert_called_once_with(group='copulas_modules')
+    warning_mock.assert_called_once_with(msg)
+
+
+@patch('warnings.warn')
+@patch.object(copulas, 'iter_entry_points')
+def test__find_addons_missing_object(entry_points_mock, warning_mock, mock_copulas):
+    """Test incorrect add-on name generates a warning."""
+    # Setup
+    bad_entry_point = MagicMock()
+    bad_entry_point.name = 'copulas.submodule:missing_object.new_method'
+    entry_points_mock.return_value = [bad_entry_point]
+    msg = ("Failed to set 'copulas.submodule:missing_object.new_method': missing_object.")
+
+    del mock_copulas.submodule.missing_object
+
+    # Run
+    _find_addons()
+
+    # Assert
+    entry_points_mock.assert_called_once_with(group='copulas_modules')
+    warning_mock.assert_called_once_with(msg)