Add importutils from openstack-common

As a side-effect, openstack.common.setup is getting updated

Change-Id: I9f8696ec5c82ef32872e1a974102dcd179eb70f9

glanceclient/openstack/common/importutils.py

@@ -0,0 +1,44 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2011 OpenStack LLC.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""
+Import related utilities and helper functions.
+"""
+
+import sys
+
+
+def import_class(import_str):
+    """Returns a class from a string including module and class"""
+    mod_str, _sep, class_str = import_str.rpartition('.')
+    try:
+        __import__(mod_str)
+        return getattr(sys.modules[mod_str], class_str)
+    except (ImportError, ValueError, AttributeError), exc:
+        raise ImportError('Class %s cannot be found (%s)' %
+                (class_str, str(exc)))
+
+
+def import_object(import_str, *args, **kwargs):
+    """Import a class and return an instance of it."""
+    return import_class(import_str)(*args, **kwargs)
+
+
+def import_module(import_str):
+    """Import a module."""
+    __import__(import_str)
+    return sys.modules[import_str]