Make Server.networks use a predictable sort order

This changes the Server.networks property method to return
an OrderedDict where the keys (network labels) are sorted
which will allow for a predictable sort order on the resulting
networks attached to a Server resource.

This affects the output of "nova list" and "nova show" commands
so a simple release note is added to mention the change.

Change-Id: I2e9b3c6a256509c045966035da24d58628f1b33b

novaclient/tests/unit/v2/test_servers.py

@@ -453,6 +453,12 @@ class ServersTest(utils.FixturedTestCase):
         self.assert_request_id(server, fakes.FAKE_REQUEST_ID_LIST)
         self.assert_called('GET', '/servers/1234')
         self.assertEqual('sample-server', server.name)
+        # The networks should be sorted.
+        networks = server.networks
+        self.assertEqual(2, len(networks))
+        labels = list(networks)  # returns the dict keys
+        self.assertEqual('private', labels[0])
+        self.assertEqual('public', labels[1])
 
         self.assertRaises(exceptions.NoUniqueMatch, self.cs.servers.find,
                           flavor={"id": 1, "name": "256 MiB Server"})

novaclient/v2/servers.py

@@ -20,6 +20,7 @@ Server interface.
 """
 
 import base64
+import collections
 
 from oslo_utils import encodeutils
 import six
@@ -399,10 +400,16 @@ class Server(base.Resource):
     def networks(self):
         """
         Generate a simplified list of addresses
+
+        :returns: An OrderedDict, keyed by network name, and sorted by network
+            name in ascending order.
         """
-        networks = {}
+        networks = collections.OrderedDict()
         try:
-            for network_label, address_list in self.addresses.items():
+            # Sort the keys by network name in natural (ascending) order.
+            network_labels = sorted(self.addresses.keys())
+            for network_label in network_labels:
+                address_list = self.addresses[network_label]
                 networks[network_label] = [a['addr'] for a in address_list]
             return networks
         except AttributeError:

releasenotes/notes/server-networks-sorted-1d3a7f1c1f88e846.yaml

@@ -0,0 +1,7 @@
+---
+other:
+  - |
+    The ``novaclient.v2.servers.Server.networks`` property method now returns
+    an OrderedDict where the keys are sorted in natural (ascending) order.
+    This means the ``nova show`` and ``nova list`` output will have predictable
+    sort order on the networks attached to a server.