Add ConfigFilter wrapper class

Implements blueprint cfg-filter-view

At the moment, if a module requires a configuration option from another
module, we do:

  CONF.import_opt('source.module', 'option_name')

but, in fact, all options from the imported module are available for
use.

The new ConfigFilter class makes it possible to enforce which options
are available within a module e.g. with

  CONF = cfgfilter.ConfigFilter(cfg.CONF)
  CONF.import_opt('foo', 'source.module')
  CONF.register_opt(StrOpt('bar'))

then the foo and bar options would be the only options available via
this CONF object while still being available via the global cfg.CONF
object.

Change-Id: Ie3aa2cd090a626da8afd27ecb78853cbf279bc8b

4 files changed, 182 insertions, 0 deletions

diff --git a/tests/testmods/baar_baa_opt.py b/tests/testmods/baar_baa_opt.py
new file mode 100644
index 0000000..bd0cef1
--- /dev/null
+++ b/tests/testmods/baar_baa_opt.py
@@ -0,0 +1,21 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2012 Red Hat, Inc.
+#
+#    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.
+
+from oslo.config import cfg
+
+CONF = cfg.CONF
+
+CONF.register_opt(cfg.StrOpt('baa'), group='baar')
diff --git a/tests/testmods/fbar_foo_opt.py b/tests/testmods/fbar_foo_opt.py
new file mode 100644
index 0000000..fb206c5
--- /dev/null
+++ b/tests/testmods/fbar_foo_opt.py
@@ -0,0 +1,21 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2013 Red Hat, Inc.
+#
+#    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.
+
+from oslo.config import cfg
+
+CONF = cfg.CONF
+
+CONF.register_opt(cfg.StrOpt('foo'), group='bbar')
diff --git a/tests/testmods/fblaa_opt.py b/tests/testmods/fblaa_opt.py
new file mode 100644
index 0000000..0c886af
--- /dev/null
+++ b/tests/testmods/fblaa_opt.py
@@ -0,0 +1,21 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2013 Red Hat, Inc.
+#
+#    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.
+
+from oslo.config import cfg
+
+CONF = cfg.CONF
+
+CONF.register_opt(cfg.StrOpt('fblaa'))
diff --git a/tests/unit/test_cfgfilter.py b/tests/unit/test_cfgfilter.py
new file mode 100644
index 0000000..e78acc8
--- /dev/null
+++ b/tests/unit/test_cfgfilter.py
@@ -0,0 +1,119 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2013 Red Hat, Inc.
+#
+#    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.
+
+from oslo.config.cfg import *
+
+from openstack.common.cfgfilter import *
+from tests import utils
+
+
+class ConfigFilterTestCase(utils.BaseTestCase):
+
+    def setUp(self):
+        super(ConfigFilterTestCase, self).setUp()
+        self.conf = ConfigOpts()
+        self.fconf = ConfigFilter(self.conf)
+
+    def test_register_opt_default(self):
+        self.fconf.register_opt(StrOpt('foo', default='bar'))
+
+        self.assertEquals(self.fconf.foo, 'bar')
+        self.assertEquals(self.fconf['foo'], 'bar')
+        self.assertTrue('foo' in self.fconf)
+        self.assertEquals(list(self.fconf), ['foo'])
+        self.assertEquals(len(self.fconf), 1)
+
+    def test_register_opt_none_default(self):
+        self.fconf.register_opt(StrOpt('foo'))
+
+        self.assertTrue(self.fconf.foo is None)
+        self.assertTrue(self.fconf['foo'] is None)
+        self.assertTrue('foo' in self.fconf)
+        self.assertEquals(list(self.fconf), ['foo'])
+        self.assertEquals(len(self.fconf), 1)
+
+    def test_register_grouped_opt_default(self):
+        self.fconf.register_opt(StrOpt('foo', default='bar'), group='blaa')
+
+        self.assertEquals(self.fconf.blaa.foo, 'bar')
+        self.assertEquals(self.fconf['blaa']['foo'], 'bar')
+        self.assertTrue('blaa' in self.fconf)
+        self.assertTrue('foo' in self.fconf.blaa)
+        self.assertEquals(list(self.fconf), ['blaa'])
+        self.assertEquals(list(self.fconf.blaa), ['foo'])
+        self.assertEquals(len(self.fconf), 1)
+        self.assertEquals(len(self.fconf.blaa), 1)
+
+    def test_register_grouped_opt_none_default(self):
+        self.fconf.register_opt(StrOpt('foo'), group='blaa')
+
+        self.assertTrue(self.fconf.blaa.foo is None)
+        self.assertTrue(self.fconf['blaa']['foo'] is None)
+        self.assertTrue('blaa' in self.fconf)
+        self.assertTrue('foo' in self.fconf.blaa)
+        self.assertEquals(list(self.fconf), ['blaa'])
+        self.assertEquals(list(self.fconf.blaa), ['foo'])
+        self.assertEquals(len(self.fconf), 1)
+        self.assertEquals(len(self.fconf.blaa), 1)
+
+    def test_register_group(self):
+        group = OptGroup('blaa')
+        self.fconf.register_group(group)
+        self.fconf.register_opt(StrOpt('foo'), group=group)
+
+        self.assertTrue(self.fconf.blaa.foo is None)
+        self.assertTrue(self.fconf['blaa']['foo'] is None)
+        self.assertTrue('blaa' in self.fconf)
+        self.assertTrue('foo' in self.fconf.blaa)
+        self.assertEquals(list(self.fconf), ['blaa'])
+        self.assertEquals(list(self.fconf.blaa), ['foo'])
+        self.assertEquals(len(self.fconf), 1)
+        self.assertEquals(len(self.fconf.blaa), 1)
+
+    def test_unknown_opt(self):
+        self.assertFalse('foo' in self.fconf)
+        self.assertEquals(len(self.fconf), 0)
+        self.assertRaises(NoSuchOptError, getattr, self.fconf, 'foo')
+
+    def test_blocked_opt(self):
+        self.conf.register_opt(StrOpt('foo'))
+
+        self.assertTrue('foo' in self.conf)
+        self.assertEquals(len(self.conf), 1)
+        self.assertTrue(self.conf.foo is None)
+        self.assertFalse('foo' in self.fconf)
+        self.assertEquals(len(self.fconf), 0)
+        self.assertRaises(NoSuchOptError, getattr, self.fconf, 'foo')
+
+    def test_import_opt(self):
+        self.fconf = ConfigFilter(CONF)
+        self.assertFalse(hasattr(self.fconf, 'blaa'))
+        self.fconf.import_opt('blaa', 'tests.testmods.blaa_opt')
+        self.assertTrue(hasattr(self.fconf, 'blaa'))
+
+    def test_import_opt_in_group(self):
+        self.fconf = ConfigFilter(CONF)
+        self.assertFalse(hasattr(self.fconf, 'bar'))
+        self.fconf.import_opt('foo', 'tests.testmods.bar_foo_opt', group='bar')
+        self.assertTrue(hasattr(self.fconf, 'bar'))
+        self.assertTrue(hasattr(self.fconf.bar, 'foo'))
+
+    def test_import_group(self):
+        self.fconf = ConfigFilter(CONF)
+        self.assertFalse(hasattr(self.fconf, 'baar'))
+        self.fconf.import_group('baar', 'tests.testmods.baar_baa_opt')
+        self.assertTrue(hasattr(self.fconf, 'baar'))
+        self.assertTrue(hasattr(self.fconf.baar, 'baa'))