Glance should use openstack.common.importutils

Implements blueprint use-common-importutils

Change-Id: If92fcf85c6bbcd330fd3675401d03b12a5fc055c

glance/common/exception.py

@@ -92,11 +92,6 @@ class StorageWriteDenied(GlanceException):
     message = _("Permission to write image storage media denied.")
 
 
-class ImportFailure(GlanceException):
-    message = _("Failed to import requested object/class: '%(import_str)s'. "
-                "Reason: %(reason)s")
-
-
 class AuthBadRequest(GlanceException):
     message = _("Connect error/bad request to Auth service at URL %(url)s.")
 

glance/common/utils.py

@@ -149,27 +149,6 @@ def bool_from_string(subject):
     return False
 
 
-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), e:
-        raise exception.ImportFailure(import_str=import_str,
-                                      reason=e)
-
-
-def import_object(import_str):
-    """Returns an object including a module or module and class"""
-    try:
-        __import__(import_str)
-        return sys.modules[import_str]
-    except ImportError:
-        cls = import_class(import_str)
-        return cls()
-
-
 def generate_uuid():
     return str(uuid.uuid4())
 

glance/common/wsgi.py

@@ -43,6 +43,7 @@ import webob.exc
 from glance.common import exception
 from glance.common import utils
 from glance.openstack.common import cfg
+from glance.openstack.common import importutils
 
 
 bind_opts = [
@@ -564,7 +565,7 @@ class BasePasteFactory(object):
         we strip() the value before using it.
         """
         class_name = local_conf[self.KEY].replace(':', '.').strip()
-        return utils.import_class(class_name)
+        return importutils.import_class(class_name)
 
 
 class AppFactory(BasePasteFactory):

glance/image_cache/__init__.py

@@ -24,6 +24,7 @@ import logging
 from glance.common import exception
 from glance.common import utils
 from glance.openstack.common import cfg
+from glance.openstack.common import importutils
 
 logger = logging.getLogger(__name__)
 DEFAULT_MAX_CACHE_SIZE = 10 * 1024 * 1024 * 1024  # 10 GB
@@ -52,17 +53,17 @@ class ImageCache(object):
         driver_name = self.conf.image_cache_driver
         driver_module = (__name__ + '.drivers.' + driver_name + '.Driver')
         try:
-            self.driver_class = utils.import_class(driver_module)
+            self.driver_class = importutils.import_class(driver_module)
             logger.info(_("Image cache loaded driver '%s'.") %
                         driver_name)
-        except exception.ImportFailure, import_err:
+        except ImportError, import_err:
             logger.warn(_("Image cache driver "
                           "'%(driver_name)s' failed to load. "
                           "Got error: '%(import_err)s.") % locals())
 
             driver_module = __name__ + '.drivers.sqlite.Driver'
             logger.info(_("Defaulting to SQLite driver."))
-            self.driver_class = utils.import_class(driver_module)
+            self.driver_class = importutils.import_class(driver_module)
         self.configure_driver()
 
     def configure_driver(self):
@@ -80,7 +81,7 @@ class ImageCache(object):
                           "Got error: '%(config_err)s") % locals())
             logger.info(_("Defaulting to SQLite driver."))
             default_module = __name__ + '.drivers.sqlite.Driver'
-            self.driver_class = utils.import_class(default_module)
+            self.driver_class = importutils.import_class(default_module)
             self.driver = self.driver_class(self.conf)
             self.driver.configure()
 

glance/notifier/__init__.py

@@ -21,8 +21,8 @@ import socket
 import uuid
 
 from glance.common import exception
-from glance.common import utils
 from glance.openstack.common import cfg
+from glance.openstack.common import importutils
 
 
 _STRATEGIES = {
@@ -45,7 +45,8 @@ class Notifier(object):
         conf.register_opts(self.opts)
         strategy = conf.notifier_strategy
         try:
-            self.strategy = utils.import_class(_STRATEGIES[strategy])(conf)
+            strategy_cls = _STRATEGIES[strategy]
+            self.strategy = importutils.import_class(strategy_cls)(conf)
         except (KeyError, ImportError):
             raise exception.InvalidNotifierStrategy(strategy=strategy)
 

glance/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]

glance/store/__init__.py

@@ -23,6 +23,7 @@ import time
 from glance.common import exception
 from glance.common import utils
 from glance.openstack.common import cfg
+from glance.openstack.common import importutils
 from glance import registry
 from glance.store import location
 
@@ -129,7 +130,7 @@ def _get_store_class(store_entry):
     store_cls = None
     try:
         logger.debug("Attempting to import store %s", store_entry)
-        store_cls = utils.import_class(store_entry)
+        store_cls = importutils.import_class(store_entry)
     except exception.NotFound:
         raise BackendException('Unable to load store. '
                                'Could not find a class named %s.'

glance/store/base.py

@@ -20,7 +20,7 @@
 import logging
 
 from glance.common import exception
-from glance.common import utils
+from glance.openstack.common import importutils
 
 logger = logging.getLogger('glance.store.base')
 
@@ -68,7 +68,7 @@ class Store(object):
         if not self.store_location_class:
             class_name = "%s.StoreLocation" % (self.__module__)
             logger.debug("Late loading location class %s", class_name)
-            self.store_location_class = utils.import_class(class_name)
+            self.store_location_class = importutils.import_class(class_name)
         return self.store_location_class
 
     def configure_add(self):

glance/tests/unit/test_misc.py

@@ -23,6 +23,7 @@ import re
 from glance.common import crypt
 from glance.common import exception
 from glance.common import utils
+from glance.openstack.common import importutils
 from glance.tests import utils as test_utils
 
 
@@ -45,36 +46,6 @@ class UtilsTestCase(test_utils.BaseTestCase):
             self.assertFalse(utils.bool_from_string(value),
                              "Got True for value: %r" % value)
 
-    def test_import_class_or_object(self):
-        # Test that import_class raises a descriptive error when the
-        # class to import could not be found.
-        self.assertRaises(exception.ImportFailure, utils.import_class,
-                          'nomodule')
-
-        self.assertRaises(exception.ImportFailure, utils.import_class,
-                          'mymodule.nonexistingclass')
-
-        self.assertRaises(exception.ImportFailure, utils.import_class,
-                          'sys.nonexistingclass')
-
-        self.assertRaises(exception.ImportFailure, utils.import_object,
-                          'os.path.NONEXISTINGOBJECT')
-
-        store_class = utils.import_class('glance.store.s3.Store')
-
-        self.assertTrue(store_class.__name__ == 'Store')
-
-        # Try importing an object by supplying a class and
-        # verify the object's class name is the same as that supplied
-        ex_obj = utils.import_object('glance.common.exception.GlanceException')
-
-        self.assertTrue(ex_obj.__class__.__name__ == 'GlanceException')
-
-        # Try importing a module itself
-        module_obj = utils.import_object('glance.registry')
-
-        self.assertEqual('glance.registry', module_obj.__package__)
-
     def test_isotime(self):
         dt1 = datetime.datetime(2001, 11, 10, 1, 2, 3)
         self.assertEqual('2001-11-10T01:02:03Z', utils.isotime(dt1))

glance/tests/unit/test_notifier.py

@@ -28,9 +28,9 @@ except ImportError:
 import stubout
 
 from glance.common import exception
-from glance.common import utils as common_utils
 from glance import notifier
 import glance.notifier.notify_kombu
+from glance.openstack.common import importutils
 from glance.tests import utils
 
 
@@ -105,8 +105,8 @@ class TestRabbitNotifier(utils.BaseTestCase):
             rabbit_self.connection = 'fake_connection'
             return None
 
-        self.notify_kombu = common_utils.import_object(
+        self.notify_kombu = importutils.import_module("glance.notifier."
-                                        "glance.notifier.notify_kombu")
+                                                      "notify_kombu")
         self.notify_kombu.RabbitStrategy._send_message = self._send_message
         self.notify_kombu.RabbitStrategy._connect = _fake_connect
         self.called = False
@@ -302,8 +302,8 @@ class TestQpidNotifier(utils.BaseTestCase):
         qpid.messaging.Sender = lambda *_x, **_y: self.mock_sender
         qpid.messaging.Receiver = lambda *_x, **_y: self.mock_receiver
 
-        self.notify_qpid = common_utils.import_object(
+        self.notify_qpid = importutils.import_module("glance.notifier."
-                                        "glance.notifier.notify_qpid")
+                                                     "notify_qpid")
 
     def tearDown(self):
         super(TestQpidNotifier, self).tearDown()

openstack-common.conf

@@ -1,7 +1,7 @@
 [DEFAULT]
 
 # The list of modules to copy from openstack-common
-modules=iniparser,cfg,setup
+modules=cfg,importutils,iniparser,setup
 
 # The base module to hold the copy of openstack.common
 base=glance