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

3 files changed, 63 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'))