wsgi: add ws_topology application

- Topology change is notified
  - JSON-RPC/WebSocket

Signed-off-by: Satoshi Kobayashi <satoshi-k@stratosphere.co.jp>
Reviewed-by: YAMADA Hideki <yamada.hideki@po.ntts.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

ryu/app/ws_topology.py

@@ -0,0 +1,105 @@
+# Copyright (C) 2014 Stratosphere 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.
+
+"""
+Usage example
+
+1. Run this application:
+$ ryu-manager --verbose --observe-links ryu.app.ws_topology
+
+2. Connect to this application by WebSocket (use your favorite client):
+$ wscat -c ws://localhost:8080/v1.0/topology/ws
+
+3. Join switches (use your favorite method):
+$ sudo mn --controller=remote --topo linear,2
+
+4. Topology change is notified:
+< {"params": [{"ports": [{"hw_addr": "56:c7:08:12:bb:36", "name": "s1-eth1", "port_no": "00000001", "dpid": "0000000000000001"}, {"hw_addr": "de:b9:49:24:74:3f", "name": "s1-eth2", "port_no": "00000002", "dpid": "0000000000000001"}], "dpid": "0000000000000001"}], "jsonrpc": "2.0", "method": "event_switch_enter", "id": 1}
+> {"id": 1, "jsonrpc": "2.0", "result": ""}
+
+< {"params": [{"ports": [{"hw_addr": "56:c7:08:12:bb:36", "name": "s1-eth1", "port_no": "00000001", "dpid": "0000000000000001"}, {"hw_addr": "de:b9:49:24:74:3f", "name": "s1-eth2", "port_no": "00000002", "dpid": "0000000000000001"}], "dpid": "0000000000000001"}], "jsonrpc": "2.0", "method": "event_switch_leave", "id": 2}
+> {"id": 2, "jsonrpc": "2.0", "result": ""}
+...
+"""
+
+from tinyrpc.exc import InvalidReplyError
+
+from ryu.app.wsgi import (
+    ControllerBase,
+    WSGIApplication,
+    websocket,
+    WebSocketRPCClient
+)
+from ryu.base import app_manager
+from ryu.topology import event, switches
+from ryu.controller.handler import set_ev_cls
+
+
+class WebSocketTopology(app_manager.RyuApp):
+    _CONTEXTS = {
+        'wsgi': WSGIApplication,
+        'switches': switches.Switches,
+    }
+
+    def __init__(self, *args, **kwargs):
+        super(WebSocketTopology, self).__init__(*args, **kwargs)
+
+        self.rpc_clients = []
+
+        wsgi = kwargs['wsgi']
+        wsgi.register(TopologyController, {'app': self})
+
+    @set_ev_cls(event.EventSwitchEnter)
+    def _event_switch_enter_handler(self, ev):
+        msg = ev.switch.to_dict()
+        self._rpc_broadcall('event_switch_enter', msg)
+
+    @set_ev_cls(event.EventSwitchLeave)
+    def _event_switch_leave_handler(self, ev):
+        msg = ev.switch.to_dict()
+        self._rpc_broadcall('event_switch_leave', msg)
+
+    @set_ev_cls(event.EventLinkAdd)
+    def _event_link_add_handler(self, ev):
+        msg = ev.link.to_dict()
+        self._rpc_broadcall('event_link_add', msg)
+
+    @set_ev_cls(event.EventLinkDelete)
+    def _event_link_delete_handler(self, ev):
+        msg = ev.link.to_dict()
+        self._rpc_broadcall('event_link_delete', msg)
+
+    def _rpc_broadcall(self, func_name, msg):
+        for rpc_client in self.rpc_clients:
+            # NOTE: Although broadcasting is desired,
+            #       RPCClient#get_proxy(one_way=False) does not work well
+            rpc_server = rpc_client.get_proxy()
+            try:
+                getattr(rpc_server, func_name)(msg)
+            except InvalidReplyError as e:
+                self.logger.error(e)
+
+
+class TopologyController(ControllerBase):
+
+    def __init__(self, req, link, data, **config):
+        super(TopologyController, self).__init__(req, link, data, **config)
+        self.app = data['app']
+
+    @websocket('topology', '/v1.0/topology/ws')
+    def _websocket_handler(self, ws):
+        rpc_client = WebSocketRPCClient(ws)
+        self.app.rpc_clients.append(rpc_client)
+        rpc_client.serve_forever()

ryu/app/wsgi.py

@@ -27,7 +27,8 @@ from tinyrpc.server import RPCServer
 from tinyrpc.dispatch import RPCDispatcher
 from tinyrpc.dispatch import public as rpc_public
 from tinyrpc.protocols.jsonrpc import JSONRPCProtocol
-from tinyrpc.transports import ServerTransport
+from tinyrpc.transports import ServerTransport, ClientTransport
+from tinyrpc.client import RPCClient
 
 CONF = cfg.CONF
 CONF.register_cli_opts([
@@ -159,6 +160,37 @@ class WebSocketRPCServer(RPCServer):
         hub.spawn(func, *args, **kwargs)
 
 
+class WebSocketClientTransport(ClientTransport):
+
+    def __init__(self, ws, queue):
+        self.ws = ws
+        self.queue = queue
+
+    def send_message(self, message, expect_reply=True):
+        self.ws.send(unicode(message))
+
+        if expect_reply:
+            return self.queue.get()
+
+
+class WebSocketRPCClient(RPCClient):
+
+    def __init__(self, ws):
+        self.ws = ws
+        self.queue = hub.Queue()
+        super(WebSocketRPCClient, self).__init__(
+            JSONRPCProtocol(),
+            WebSocketClientTransport(ws, self.queue),
+        )
+
+    def serve_forever(self):
+        while True:
+            msg = self.ws.wait()
+            if msg is None:
+                break
+            self.queue.put(msg)
+
+
 class wsgify_hack(webob.dec.wsgify):
     def __call__(self, environ, start_response):
         self.kwargs['start_response'] = start_response