1 files changed, 73 insertions, 0 deletions
diff --git a/os_net_config/openstack/common/importutils.py b/os_net_config/openstack/common/importutils.py
new file mode 100644
index 0000000..890209b
--- /dev/null
+++ b/os_net_config/openstack/common/importutils.py
@@ -0,0 +1,73 @@
+# Copyright 2011 OpenStack Foundation.
+# 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
+import traceback
+
+
+def import_class(import_str):
+    """Returns a class from a string including module and class."""
+    mod_str, _sep, class_str = import_str.rpartition('.')
+    __import__(mod_str)
+    try:
+        return getattr(sys.modules[mod_str], class_str)
+    except AttributeError:
+        raise ImportError('Class %s cannot be found (%s)' %
+                          (class_str,
+                           traceback.format_exception(*sys.exc_info())))
+
+
+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_object_ns(name_space, import_str, *args, **kwargs):
+    """Tries to import object from default namespace.
+
+    Imports a class and return an instance of it, first by trying
+    to find the class in a default namespace, then failing back to
+    a full path if not found in the default namespace.
+    """
+    import_value = "%s.%s" % (name_space, import_str)
+    try:
+        return import_class(import_value)(*args, **kwargs)
+    except ImportError:
+        return import_class(import_str)(*args, **kwargs)
+
+
+def import_module(import_str):
+    """Import a module."""
+    __import__(import_str)
+    return sys.modules[import_str]
+
+
+def import_versioned_module(version, submodule=None):
+    module = 'os_net_config.v%s' % version
+    if submodule:
+        module = '.'.join((module, submodule))
+    return import_module(module)
+
+
+def try_import(import_str, default=None):
+    """Try to import a module and if it fails return default."""
+    try:
+        return import_module(import_str)
+    except ImportError:
+        return default