Display error message when socket is closed

Give the user some additional information when Zaqar is down. Also,
move the websocket import to the third-party import list.

Change-Id: I8d4caf2ba08bceba1f014555ccd6ae3ca1a4a6c0
Closes-Bug: #1619712

tripleoclient/plugin.py

@@ -17,11 +17,12 @@
 
 import json
 import logging
+import socket
 import uuid
-import websocket
 
 from openstackclient.common import utils
 from swiftclient import client as swift_client
+import websocket
 
 LOG = logging.getLogger(__name__)
 
@@ -79,7 +80,13 @@ class WebsocketClient(object):
         self._websocket_client_id = str(uuid.uuid4())
 
         LOG.debug('Instantiating messaging websocket client: %s', endpoint)
-        self._ws = websocket.create_connection(endpoint)
+        try:
+            self._ws = websocket.create_connection(endpoint)
+        except socket.error:
+            LOG.error("Could not establish a connection to the Zaqar "
+                      "websocket. The command was sent but the answer "
+                      "could not be read.")
+            raise
 
         self.send('authenticate', extra_headers={'X-Auth-Token': token})
 

tripleoclient/tests/test_plugin.py

@@ -14,6 +14,7 @@
 
 import json
 import mock
+import socket
 
 from tripleoclient import plugin
 from tripleoclient.tests import base
@@ -83,3 +84,21 @@ class TestPlugin(base.TestCase):
                 "message": "Result for IDID",
                 "execution": {"id": "IDID"},
             })
+
+    @mock.patch("websocket.create_connection")
+    def test_websocket_creation_error(self, ws_create_connection):
+
+        ws_create_connection.side_effect = socket.error
+
+        clientmgr = mock.MagicMock()
+        clientmgr.get_endpoint_for_service_type.return_value = fakes.WS_URL
+        clientmgr.auth.get_token.return_value = "TOKEN"
+        clientmgr.auth_ref.project_id = "ID"
+
+        client = plugin.make_client(clientmgr)
+
+        msg = ("Could not establish a connection to the Zaqar websocket. The "
+               "command was sent but the answer could not be read.")
+        with mock.patch('tripleoclient.plugin.LOG') as mock_log:
+            self.assertRaises(socket.error, client.messaging_websocket)
+            mock_log.error.assert_called_once_with(msg)