A utility function to import a class from a module given syntax such as used by nose and setuptools entry points.

devstack/importer.py

@@ -0,0 +1,19 @@
+
+
+def import_entry_point(fullname):
+    """Given a name import the class and return it.
+
+    The name should be in dotted.path:ClassName syntax.
+    """
+    if ':' not in fullname:
+        raise ValueError('Invalid entry point specifier %r' % fullname)
+    module_name, ignore, classname = fullname.partition(':')
+    try:
+        module = __import__(module_name)
+        for submodule in module_name.split('.')[1:]:
+            module = getattr(module, submodule)
+        cls = getattr(module, classname)
+    except (ImportError, AttributeError) as err:
+        raise RuntimeError('Could not load entry point %s: %s' %
+                           (fullname, err))
+    return cls

tests/test_importer.py

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+
+from devstack import importer
+from devstack import distro
+
+
+def test_function():
+    f = importer.import_entry_point('devstack.importer:import_entry_point')
+    assert f == importer.import_entry_point
+
+
+def test_class():
+    c = importer.import_entry_point('devstack.distro:Distro')
+    assert c == distro.Distro