rehome common topics into neutron-lib

The neutron.common.topics module is used by a number of consumers [1].
This patch rehomes the module into neutron-lib.

[1] http://codesearch.openstack.org/?q=from%20neutron.common%20import%20topics

Change-Id: Ie88b84949cbd55a4e7ad06341aab77b286cdc485

neutron_lib/agent/topics.py

@@ -0,0 +1,65 @@
+# Copyright (c) 2012 OpenStack Foundation.
+#
+# 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 neutron_lib.api.definitions import network
+from neutron_lib.api.definitions import port
+from neutron_lib.api.definitions import subnet
+
+
+NETWORK = network.RESOURCE_NAME
+SUBNET = subnet.RESOURCE_NAME
+PORT = port.RESOURCE_NAME
+SECURITY_GROUP = 'security_group'
+L2POPULATION = 'l2population'
+DVR = 'dvr'
+RESOURCES = 'resources'
+
+CREATE = 'create'
+DELETE = 'delete'
+UPDATE = 'update'
+
+AGENT = 'q-agent-notifier'
+PLUGIN = 'q-plugin'
+SERVER_RESOURCE_VERSIONS = 'q-server-resource-versions'
+L3PLUGIN = 'q-l3-plugin'
+REPORTS = 'q-reports-plugin'
+DHCP = 'q-dhcp-notifer'
+METERING_PLUGIN = 'q-metering-plugin'
+
+L3_AGENT = 'l3_agent'
+DHCP_AGENT = 'dhcp_agent'
+METERING_AGENT = 'metering_agent'
+
+RESOURCE_TOPIC_PATTERN = "neutron-vo-%(resource_type)s-%(version)s"
+
+
+def get_topic_name(prefix, table, operation, host=None):
+    """Create a topic name.
+
+    The topic name needs to be synced between the agent and the
+    plugin. The plugin will send a fanout message to all of the
+    listening agents so that the agents in turn can perform their
+    updates accordingly.
+
+    :param prefix: Common prefix for the plugin/agent message queues.
+    :param table: The table in question (NETWORK, SUBNET, PORT).
+    :param operation: The operation that invokes notification (CREATE,
+                      DELETE, UPDATE)
+    :param host: Add host to the topic
+    :returns: The topic name.
+    """
+    if host:
+        return '%s-%s-%s.%s' % (prefix, table, operation, host)
+    return '%s-%s-%s' % (prefix, table, operation)

releasenotes/notes/rehome-topics-ca451e72c8c9603a.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - The public constants and ``get_topic_name`` function from
+    ``neutron.common.topics`` are now available in
+    ``neutron_lib.agent.topics``.