add ryu.cfg

also, make CONF accessible via RyuApp.CONF.
add a comment to explain the intention.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

2 files changed, 37 insertions, 0 deletions

diff --git a/ryu/base/app_manager.py b/ryu/base/app_manager.py
index 31e99985..669e58bb 100644
--- a/ryu/base/app_manager.py
+++ b/ryu/base/app_manager.py
@@ -19,6 +19,7 @@ import itertools
 import logging
 import sys
 
+from ryu import cfg
 from ryu import utils
 from ryu.controller.handler import register_instance, get_dependent_services
 from ryu.controller.controller import Datapath
@@ -120,6 +121,7 @@ class RyuApp(object):
             self.logger = logging.getLogger(self.__class__.LOGGER_NAME)
         else:
             self.logger = logging.getLogger(self.name)
+        self.CONF = cfg.CONF
 
         # prevent accidental creation of instances of this class outside RyuApp
         class _EventThreadStop(event.EventBase):
diff --git a/ryu/cfg.py b/ryu/cfg.py
new file mode 100644
index 00000000..871533cb
--- /dev/null
+++ b/ryu/cfg.py
@@ -0,0 +1,35 @@
+# Copyright (C) 2014 Nippon Telegraph and Telephone Corporation.
+# Copyright (C) 2014 YAMAMOTO Takashi <yamamoto at valinux co jp>
+#
+# 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 oslo.config.cfg
+
+# there are 3 ways to access the configuration.
+#
+#    a. ryu.cfg.CONF  (used to register cli options)
+#    b. RyuApp.CONF  (preferred way for ryu applications)
+#    c. oslo.config.cfg.CONF
+#
+# Currently all of above shares a single ConfigOpts instance.
+# We will unshare c. (and stop using it) as soon as ofagent neutron agent
+# is updated.
+# We want to avoid using c. for our options as a python program which embeds
+# ryu applications (eg. neutron agent) might want to its own set of cli
+# options into it, which can conflict with ours.  (Currently there seems
+# no conflict for the neutron agent.  But who knows?)
+# At some point later we might want to unshare a. and b. as well, in order
+# to allow app-specific options.
+
+CONF = oslo.config.cfg.CONF