Default --nic to 'auto' if creating a server with >= 2.37

Compute API version >= 2.37 requires a 'networks' value in
the server create request. The novaclient CLI defaults this
to 'auto' if not specified, but the novaclient ServerManager.create
python API binding code does not, as it wants clients to be explicit.

For the purposes of the OSC CLI, we should follow suit and if the
user is requesting OS_COMPUTE_API_VERSION>=2.37 without specific
nics, we should just default to 'auto'.

Change-Id: Ib760c55e31209223338a4086ff1f4fee88dc6959
Closes-Bug: #1750395
(cherry picked from commit 1008544882fbdae16b045abca05cf3e2e8a14787)

4 files changed, 66 insertions, 7 deletions

diff --git a/openstackclient/compute/v2/server.py b/openstackclient/compute/v2/server.py
index a6a59084..a1647421 100644
--- a/openstackclient/compute/v2/server.py
+++ b/openstackclient/compute/v2/server.py
@@ -809,9 +809,14 @@ class CreateServer(command.ShowOne):
                     raise exceptions.CommandError(msg)
                 nics = nics[0]
         else:
-            # Default to empty list if nothing was specified, let nova side to
-            # decide the default behavior.
-            nics = []
+            # Compute API version >= 2.37 requires a value, so default to
+            # 'auto' to maintain legacy behavior if a nic wasn't specified.
+            if compute_client.api_version >= api_versions.APIVersion('2.37'):
+                nics = 'auto'
+            else:
+                # Default to empty list if nothing was specified, let nova
+                # side to decide the default behavior.
+                nics = []
 
         # Check security group exist and convert ID to name
         security_group_names = []
diff --git a/openstackclient/tests/functional/compute/v2/test_server.py b/openstackclient/tests/functional/compute/v2/test_server.py
index bba16f62..3cb72d9f 100644
--- a/openstackclient/tests/functional/compute/v2/test_server.py
+++ b/openstackclient/tests/functional/compute/v2/test_server.py
@@ -618,7 +618,9 @@ class ServerTests(common.ComputeTestCase):
                 server_name
             )
         except exceptions.CommandFailed as e:
-            self.assertIn('nics are required after microversion 2.36',
-                          e.stderr)
-        else:
-            self.fail('CommandFailed should be raised.')
+            # If we got here, it shouldn't be because a nics value wasn't
+            # provided to the server; it is likely due to something else in
+            # the functional tests like there being multiple available
+            # networks and the test didn't specify a specific network.
+            self.assertNotIn('nics are required after microversion 2.36',
+                             e.stderr)
diff --git a/openstackclient/tests/unit/compute/v2/fakes.py b/openstackclient/tests/unit/compute/v2/fakes.py
index 9a065be1..234bbd9b 100644
--- a/openstackclient/tests/unit/compute/v2/fakes.py
+++ b/openstackclient/tests/unit/compute/v2/fakes.py
@@ -17,6 +17,7 @@ import copy
 import uuid
 
 import mock
+from novaclient import api_versions
 
 from openstackclient.api import compute_v2
 from openstackclient.tests.unit import fakes
@@ -201,6 +202,8 @@ class FakeComputev2Client(object):
 
         self.management_url = kwargs['endpoint']
 
+        self.api_version = api_versions.APIVersion('2.1')
+
 
 class TestComputev2(utils.TestCommand):
 
diff --git a/openstackclient/tests/unit/compute/v2/test_server.py b/openstackclient/tests/unit/compute/v2/test_server.py
index b3d32681..cd0122ff 100644
--- a/openstackclient/tests/unit/compute/v2/test_server.py
+++ b/openstackclient/tests/unit/compute/v2/test_server.py
@@ -845,6 +845,55 @@ class TestServerCreate(TestServer):
         self.assertEqual(self.columns, columns)
         self.assertEqual(self.datalist(), data)
 
+    def test_server_create_with_auto_network_default_v2_37(self):
+        """Tests creating a server without specifying --nic using 2.37."""
+        arglist = [
+            '--image', 'image1',
+            '--flavor', 'flavor1',
+            self.new_server.name,
+        ]
+        verifylist = [
+            ('image', 'image1'),
+            ('flavor', 'flavor1'),
+            ('config_drive', False),
+            ('server_name', self.new_server.name),
+        ]
+        parsed_args = self.check_parser(self.cmd, arglist, verifylist)
+
+        # Since check_parser doesn't handle compute global options like
+        # --os-compute-api-version, we have to mock the construction of
+        # the novaclient client object with our own APIVersion.
+        with mock.patch.object(self.app.client_manager.compute, 'api_version',
+                               api_versions.APIVersion('2.37')):
+            columns, data = self.cmd.take_action(parsed_args)
+
+        # Set expected values
+        kwargs = dict(
+            meta=None,
+            files={},
+            reservation_id=None,
+            min_count=1,
+            max_count=1,
+            security_groups=[],
+            userdata=None,
+            key_name=None,
+            availability_zone=None,
+            block_device_mapping_v2=[],
+            nics='auto',
+            scheduler_hints={},
+            config_drive=None,
+        )
+        # ServerManager.create(name, image, flavor, **kwargs)
+        self.servers_mock.create.assert_called_with(
+            self.new_server.name,
+            self.image,
+            self.flavor,
+            **kwargs
+        )
+
+        self.assertEqual(self.columns, columns)
+        self.assertEqual(self.datalist(), data)
+
     def test_server_create_with_none_network(self):
         arglist = [
             '--image', 'image1',