Disables TCP_KEEPCNT when using Windows Subsystem for Linux

The Windows Subsystem for Linux is not a complete implementation
of the Linux APIs, and setting TCP_KEEPCNT is currently
unimplmenented. Attempting to use this option will cause HTTP
connections to fail. This change checks if we are running under
WSL, and disables changing TCP_KEEPCNT parameters if so.

Change-Id: Ic8b41dea2a75660d9adbce88a00a0fe703a4d120
Closes-Bug: #1614688

keystoneauth1/_utils.py

@@ -73,3 +73,11 @@ def before_utcnow(**timedelta_kwargs):
     now = datetime.datetime.utcnow()
     delta = datetime.timedelta(**timedelta_kwargs)
     return now - delta
+
+
+# Detect if running on the Windows Subsystem for Linux
+try:
+    with open('/proc/version', 'r') as f:
+        is_windows_linux_subsystem = 'microsoft' in f.read().lower()
+except IOError:
+    is_windows_linux_subsystem = False

keystoneauth1/session.py

@@ -893,7 +893,9 @@ class TCPKeepAliveAdapter(requests.adapters.HTTPAdapter):
                     (socket.IPPROTO_TCP, socket.TCP_KEEPIDLE, 60)
                 ]
 
-            if hasattr(socket, 'TCP_KEEPCNT'):
+            # Windows subsystem for Linux does not support this feature
+            if (hasattr(socket, 'TCP_KEEPCNT') and
+                    not utils.is_windows_linux_subsystem):
                 socket_options += [
                     # Set the maximum number of keep-alive probes
                     (socket.IPPROTO_TCP, socket.TCP_KEEPCNT, 4),

keystoneauth1/tests/unit/test_session.py

@@ -1060,6 +1060,7 @@ class TCPKeepAliveAdapterTest(utils.TestCase):
 
     def test_init_poolmanager_with_tcp_keepcnt(self):
         self.patch(client_session, 'REQUESTS_VERSION', (2, 4, 1))
+        self.patch(client_session.utils, 'is_windows_linux_subsystem', False)
         socket = self.patch_socket_with_options(
             ['IPPROTO_TCP', 'TCP_NODELAY', 'SOL_SOCKET', 'SO_KEEPALIVE',
              'TCP_KEEPCNT'])
@@ -1075,6 +1076,23 @@ class TCPKeepAliveAdapterTest(utils.TestCase):
                 (socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1),
                 (socket.IPPROTO_TCP, socket.TCP_KEEPCNT, 4)])
 
+    def test_init_poolmanager_with_tcp_keepcnt_on_windows(self):
+        self.patch(client_session, 'REQUESTS_VERSION', (2, 4, 1))
+        self.patch(client_session.utils, 'is_windows_linux_subsystem', True)
+        socket = self.patch_socket_with_options(
+            ['IPPROTO_TCP', 'TCP_NODELAY', 'SOL_SOCKET', 'SO_KEEPALIVE',
+             'TCP_KEEPCNT'])
+        given_adapter = client_session.TCPKeepAliveAdapter()
+
+        # when pool manager is initialized
+        given_adapter.init_poolmanager(1, 2, 3)
+
+        # then socket_options are given
+        self.init_poolmanager.assert_called_once_with(
+            1, 2, 3, socket_options=[
+                (socket.IPPROTO_TCP, socket.TCP_NODELAY, 1),
+                (socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)])
+
     def test_init_poolmanager_with_tcp_keepintvl(self):
         self.patch(client_session, 'REQUESTS_VERSION', (2, 4, 1))
         socket = self.patch_socket_with_options(

releasenotes/notes/bug-1614688-c4a1bd54f4ba5644.yaml

@@ -0,0 +1,9 @@
+---
+prelude: >
+    HTTP connections work under Windows Subsystem for Linux
+fixes:
+  - >
+    [`bug 1614688 <https://bugs.launchpad.net/keystoneauth/+bug/1614688>`_]
+    HTTP connections were failing under Windows subsystem for Linux because
+    TCP_KEEPCNT was being set and that environment does not support such
+    override yet.