Enable configuring tcp keepalive

Added a function set_tcp_keepalive in network_utils.py to set configuration of
tcp keepalive parameters. Projects can call this function and set values in
them, if needed.

Also added unittests to test this function.

Implements blueprint configure-tcp-keepalive
Change-Id: I8b978a604f29953911c2fe4bad74e28e5ba74c35

openstack/common/network_utils.py

@@ -17,8 +17,15 @@
 Network-related utilities and helper functions.
 """
 
+import socket
+
 from six.moves.urllib import parse
 
+from openstack.common.gettextutils import _LW
+from openstack.common import log as logging
+
+LOG = logging.getLogger(__name__)
+
 
 def parse_host_port(address, default_port=None):
     """Interpret a string as a host:port pair.
@@ -100,3 +107,58 @@ def urlsplit(url, scheme='', allow_fragments=True):
         path, query = path.split('?', 1)
     return ModifiedSplitResult(scheme, netloc,
                                path, query, fragment)
+
+
+def set_tcp_keepalive(sock, tcp_keepalive=True,
+                      tcp_keepidle=None,
+                      tcp_keepalive_interval=None,
+                      tcp_keepalive_count=None):
+    """Set values for tcp keepalive parameters
+
+    This function configures tcp keepalive parameters if users wish to do
+    so.
+    :param tcp_keepalive: Boolean, turn on or off tcp_keepalive. If users are
+      not sure, this should be True, and default values will be used.
+
+    :param tcp_keepidle: time to wait before starting to send keepalive probes
+
+    :param tcp_keepalive_interval: time between successive probes, once the
+      initial wait time is over
+
+    :param tcp_keepalive_count: number of probes to send before the connection
+      is killed
+    """
+
+    # NOTE(praneshp): Despite keepalive being a tcp concept, the level is
+    # still SOL_SOCKET. This is a quirk.
+    if isinstance(tcp_keepalive, bool):
+        sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, tcp_keepalive)
+    else:
+        raise TypeError("tcp_keepalive must be a boolean")
+
+    if not tcp_keepalive:
+        return
+
+    # These options aren't available in the OS X version of eventlet,
+    # Idle + Count * Interval effectively gives you the total timeout.
+    if tcp_keepidle is not None:
+        if hasattr(socket, 'TCP_KEEPIDLE'):
+            sock.setsockopt(socket.IPPROTO_TCP,
+                            socket.TCP_KEEPIDLE,
+                            tcp_keepidle)
+        else:
+            LOG.warning(_LW('tcp_keepidle not available on your system'))
+    if tcp_keepalive_interval is not None:
+        if hasattr(socket, 'TCP_KEEPINTVL'):
+            sock.setsockopt(socket.IPPROTO_TCP,
+                            socket.TCP_KEEPINTVL,
+                            tcp_keepalive_interval)
+        else:
+            LOG.warning(_LW('tcp_keepintvl not available on your system'))
+    if tcp_keepalive_count is not None:
+        if hasattr(socket, 'TCP_KEEPCNT'):
+            sock.setsockopt(socket.IPPROTO_TCP,
+                            socket.TCP_KEEPCNT,
+                            tcp_keepalive_count)
+        else:
+            LOG.warning(_LW('tcp_keepknt not available on your system'))

tests/unit/test_network_utils.py

@@ -13,6 +13,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import socket
+
+import mock
 from oslotest import base as test_base
 
 from openstack.common import network_utils
@@ -99,3 +102,18 @@ class NetworkUtilsTest(test_base.BaseTestCase):
         self.assertEqual(result.port, 1234)
         self.assertEqual(result.query, 'ab')
         self.assertEqual(result.fragment, '12')
+
+    def test_set_tcp_keepalive(self):
+        mock_sock = mock.Mock()
+        network_utils.set_tcp_keepalive(mock_sock, True, 100, 10, 5)
+        calls = [
+            mock.call.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, True),
+            mock.call.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPIDLE, 100),
+            mock.call.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPINTVL, 10),
+            mock.call.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPCNT, 5)
+        ]
+        mock_sock.assert_has_calls(calls)
+
+        mock_sock.reset_mock()
+        network_utils.set_tcp_keepalive(mock_sock, False)
+        self.assertEqual(1, len(mock_sock.mock_calls))