Fixed bug 962840, added a test case.

eventlet.tpool.Proxy doesn't work with old-style class in __str__()
or __repr__() calls. See bug #962840 for details.
We perform a monkey patch to replace those two instance methods.

Change-Id: Ia51bbd3e71cad7df45da5b3b27eef70f9d9e9002

nova/tests/test_libvirt.py

@@ -2509,3 +2509,21 @@ def fake_create_new_domain(xml):
 
         ref = self.libvirtconnection.finish_revert_migration(ins_ref, None)
         self.assertTrue(isinstance(ref, eventlet.event.Event))
+
+
+class LibvirtNonblockingTestCase(test.TestCase):
+    """Test libvirt_nonblocking option"""
+
+    def setUp(self):
+        super(LibvirtNonblockingTestCase, self).setUp()
+        self.flags(libvirt_nonblocking=True, libvirt_uri="test:///default")
+
+    def tearDown(self):
+        super(LibvirtNonblockingTestCase, self).tearDown()
+
+    @test.skip_if(missing_libvirt(), "Test requires libvirt")
+    def test_connection_to_primitive(self):
+        """Test bug 962840"""
+        import nova.virt.libvirt.connection
+        connection = nova.virt.libvirt.connection.get_connection('')
+        utils.to_primitive(connection._conn, convert_instances=True)

nova/virt/libvirt/connection.py

@@ -158,6 +158,24 @@
 flags.DECLARE('vncserver_proxyclient_address', 'nova.vnc')
 
 
+def patch_tpool_proxy():
+    """eventlet.tpool.Proxy doesn't work with old-style class in __str__()
+    or __repr__() calls. See bug #962840 for details.
+    We perform a monkey patch to replace those two instance methods.
+    """
+    def str_method(self):
+        return str(self._obj)
+
+    def repr_method(self):
+        return repr(self._obj)
+
+    tpool.Proxy.__str__ = str_method
+    tpool.Proxy.__repr__ = repr_method
+
+
+patch_tpool_proxy()
+
+
 def get_connection(read_only):
     # These are loaded late so that there's no need to install these
     # libraries when not using libvirt.