Use TCP Keep-Alive on the socket level

There is not a way to pass the socket options to the HTTPAdapter upon
creation so we have to sub-class it and override the init_poolmanager
method.  This also requires at least python-requests 2.4.0 but that
has 2 severe bugs that were fixed in 2.4.1. If we try to fix this
without a hard lower limit, we will not be able to properly set these
options on the socket at creation time.

Change-Id: I06e0d2c67d3197607e5f23f623c8fca69e1b23d7
Closes-bug: 1323862

novaclient/client.py

@@ -28,6 +28,7 @@ import hashlib
 import logging
 import os
 import re
+import socket
 import time
 
 from keystoneclient import adapter
@@ -48,6 +49,17 @@ from novaclient import service_catalog
 from novaclient import utils
 
 
+class TCPKeepAliveAdapter(adapters.HTTPAdapter):
+    """The custom adapter used to set TCP Keep-Alive on all connections."""
+    def init_poolmanager(self, *args, **kwargs):
+        if requests.__version__ >= '2.4.1':
+            kwargs.setdefault('socket_options', [
+                (socket.IPROTO_TCP, socket.TCP_NODELAY, 1),
+                (socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1),
+            ])
+        super(TCPKeepAliveAdapter, self).init_poolmanager(*args, **kwargs)
+
+
 class _ClientConnectionPool(object):
 
     def __init__(self):
@@ -58,7 +70,7 @@ class _ClientConnectionPool(object):
         Store and reuse HTTP adapters per Service URL.
         """
         if url not in self._adapters:
-            self._adapters[url] = adapters.HTTPAdapter()
+            self._adapters[url] = TCPKeepAliveAdapter()
 
         return self._adapters[url]
 

novaclient/tests/test_client.py

@@ -31,7 +31,7 @@ import novaclient.v3.client
 
 class ClientConnectionPoolTest(utils.TestCase):
 
-    @mock.patch("novaclient.client.adapters.HTTPAdapter")
+    @mock.patch("novaclient.client.TCPKeepAliveAdapter")
     def test_get(self, mock_http_adapter):
         mock_http_adapter.side_effect = lambda: mock.Mock()
         pool = novaclient.client._ClientConnectionPool()