Enhance network-list to allow --fields

Add the ability to specify --fields, using any valid vields, when
doing a network-list. This code was shamelessly borrowed from
do_list(). This will allow crafting network-list queries which
mirror the functionality of 'nova-manage network list', which this
query was intended to replace.

Change-Id: I7ec7066350cdb979a64d20d14362b12e3ec76496

novaclient/tests/v1_1/fakes.py

@@ -1708,7 +1708,7 @@ class FakeHTTPClient(base_client.HTTPClient):
     def get_os_networks(self, **kw):
         return (200, {}, {'networks': [{"label": "1", "cidr": "10.0.0.0/24",
                 'project_id': '4ffc664c198e435e9853f2538fbcd7a7',
-                'id': '1'}]})
+                'id': '1', 'vlan': '1234'}]})
 
     def delete_os_networks_1(self, **kw):
         return (202, {}, None)

novaclient/tests/v1_1/test_shell.py

@@ -1690,6 +1690,13 @@ class ShellTest(utils.TestCase):
         self.run_command('network-list')
         self.assert_called('GET', '/os-networks')
 
+    def test_network_list_fields(self):
+        output = self.run_command('network-list --fields '
+                         'vlan,project_id')
+        self.assert_called('GET', '/os-networks')
+        self.assertIn('1234', output)
+        self.assertIn('4ffc664c198e435e9853f2538fbcd7a7', output)
+
     def test_network_show(self):
         self.run_command('network-show 1')
         self.assert_called('GET', '/os-networks/1')

novaclient/v1_1/shell.py

@@ -779,10 +779,25 @@ def do_scrub(cs, args):
         cs.security_groups.delete(group)
 
 
-def do_network_list(cs, _args):
+@utils.arg('--fields',
+    default=None,
+    metavar='<fields>',
+    help='Comma-separated list of fields to display. '
+         'Use the show command to see which fields are available.')
+def do_network_list(cs, args):
     """Print a list of available networks."""
     network_list = cs.networks.list()
     columns = ['ID', 'Label', 'Cidr']
+
+    formatters = {}
+    field_titles = []
+    if args.fields:
+        for field in args.fields.split(','):
+            field_title, formatter = utils._make_field_formatter(field, {})
+            field_titles.append(field_title)
+            formatters[field_title] = formatter
+
+    columns = columns + field_titles
     utils.print_list(network_list, columns)