Akihiro Motoki 0684f0c22c Make L3RpcCallback a separate callback class
RPC has a version of itself. In Neutron a plugin implements
several RPC interface, so a single RPC version doesn't work.
In Mixin callback class approach, RPC versioning depends on
each plugin implementation and it makes harder to maintain
RPC version appropriately. This patch series replaces mixin
RPC callback of server side with a separate class.

This commit handles server-side callback of L3-agent RPC interface.
L3-agent server-side callback class is moved from db/ to
api/rpc/handlers because it doesn't involve any db operations
and defining all RPC interfaces in a single place sounds reasonable.

Note that moving other L3-agent related RPC interface class
to api/rpc/handlers will be done in a separate patch as this patch
focuses on reorganizing the server-side RPC callback class.

Partial-Bug: #1359416
Change-Id: Ie3f2c9b2ad907a1110e05fe94d42e41e93fbcaa7
2014-08-27 09:54:25 +09:00
..
2014-06-21 15:07:31 +08:00

This service plugin implements the L3 routing functionality (resources router
and floatingip) that in earlier releases before Havana was provided by core
plugins (openvswitch, linuxbridge, ... etc).

Core plugins can now choose not to implement L3 routing functionality and
instead delegate that to the L3 routing service plugin.

The required changes to a core plugin are in that case:
- Do not inherit 'l3_db.L3_NAT_db_mixin' (or its descendants like extraroute)
  anymore.
- Remove "router" from 'supported_extension_aliases'.
- Modify any 'self' references to members in L3_NAT_db_mixin to instead use
  'manager.NeutronManager.get_service_plugins().get(constants.L3_ROUTER_NAT)'
  For example,
     self.prevent_l3_port_deletion(...)
  becomes something like
     plugin = manager.NeutronManager.get_service_plugins().get(
         constants.L3_ROUTER_NAT)
     if plugin:
         plugin.prevent_l3_port_deletion(...)

If the core plugin has relied on the L3Agent the following must also be changed:
- Do not inherit 'l3_rpc_base.L3RpcCallbackMixin' in any '*RpcCallbacks' class.
- Do not be a consumer of the topics.L3PLUGIN topic for RPC.

To use the L3 routing service plugin, add
'neutron.services.l3_router.l3_router_plugin.L3RouterPlugin'
to 'service_plugins' in '/etc/neutron/neutron.conf'.
That is,
service_plugins = neutron.services.l3_router.l3_router_plugin.L3RouterPlugin