Support lookup of value using "group.key"

Let us check if the opt_name has a '.', if it does then split it
into a group/key and try lookup using that combination. Since
LazyPluggable uses "CONF[self.__pivot]" if we just add this
capability to cfg, we get "LazyPluggable doesn't support
option groups" for free.

Fixes LP #1093043

Change-Id: I9cedcf22014038e9fe4ed5e66ca5427aa99b5091

openstack/common/cfg.py

@@ -1567,7 +1567,11 @@ def _get_opt_info(self, opt_name, group=None):
             opts = group._opts
 
         if not opt_name in opts:
-            raise NoSuchOptError(opt_name, group)
+            if group is None and '.' in opt_name:
+                group, opt_name = opt_name.split('.')
+                return self._get_opt_info(opt_name, group)
+            else:
+                raise NoSuchOptError(opt_name, group)
 
         return opts[opt_name]
 

tests/unit/test_cfg.py

@@ -1120,6 +1120,12 @@ def test_group_override(self):
         self.conf.clear_override('foo', group='blaa')
         self.assertEquals(self.conf.blaa.foo, None)
 
+    def test_group_get_group_option(self):
+        self.conf.register_group(OptGroup('blaa'))
+        self.conf.register_opt(StrOpt('foo', default='foo2'), group='blaa')
+        self.conf([])
+        self.assertEquals(self.conf['blaa.foo'], 'foo2')
+
     def test_cli_bool_default(self):
         self.conf.register_cli_opt(BoolOpt('foo'))
         self.conf.set_default('foo', True)