Merge "Set reasonable defaults for TCP Keep-Alive"

keystoneclient/session.py

@@ -899,11 +899,36 @@ class Session(object):
 
 
 class TCPKeepAliveAdapter(requests.adapters.HTTPAdapter):
-    """The custom adapter used to set TCP Keep-Alive on all connections."""
+    """The custom adapter used to set TCP Keep-Alive on all connections.
+
+    This Adapter also preserves the default behaviour of Requests which
+    disables Nagle's Algorithm. See also:
+    http://blogs.msdn.com/b/windowsazurestorage/archive/2010/06/25/nagle-s-algorithm-is-not-friendly-towards-small-requests.aspx
+    """
     def init_poolmanager(self, *args, **kwargs):
         if requests.__version__ >= '2.4.1':
-            kwargs.setdefault('socket_options', [
+            socket_options = [
+                # Keep Nagle's algorithm off
                 (socket.IPPROTO_TCP, socket.TCP_NODELAY, 1),
+                # Turn on TCP Keep-Alive
                 (socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1),
-            ])
+                # Set the maximum number of keep-alive probes
+                (socket.IPPROTO_TCP, socket.TCP_KEEPCNT, 4),
+                # Send keep-alive probes every 15 seconds
+                (socket.IPPROTO_TCP, socket.TCP_KEEPINTVL, 15),
+            ]
+
+            # Some operating systems (e.g., OSX) do not support setting
+            # keepidle
+            if hasattr(socket, 'TCP_KEEPIDLE'):
+                socket_options += [
+                    # Wait 60 seconds before sending keep-alive probes
+                    (socket.IPPROTO_TCP, socket.TCP_KEEPIDLE, 60)
+                ]
+
+            # After waiting 60 seconds, and then sending a probe once every 15
+            # seconds 4 times, these options should ensure that a connection
+            # hands for no longer than 2 minutes before a ConnectionError is
+            # raised.
+            kwargs.setdefault('socket_options', socket_options)
         super(TCPKeepAliveAdapter, self).init_poolmanager(*args, **kwargs)