Support list commands by group name keyword

The output of current "command list" is so long, it's
very difficult for users to find out the commands
they care about.

Add "--group <group-keyword>" option to filter the commands by group
name keyword, like: --group volume, list all openstack.volume.v2
(cinder) commands

That support the scenario that users need to know the current support
commands of some OpenStack services(nova, neutron, cinder and so on) in
OSC.

Change-Id: Id673042729ad36a0cac0b81fb31a3537c24f03fc
Closes-Bug: #1666780

doc/source/command-objects/command.rst

@@ -15,3 +15,9 @@ List recognized commands by group
 .. code:: bash
 
     openstack command list
+        [--group <group-keyword>]
+
+.. option:: --group <group-keyword>
+
+    Show commands filtered by a command group, for example: identity, volume,
+    compute, image, network and other keywords

openstackclient/common/module.py

@@ -29,12 +29,26 @@ class ListCommand(command.Lister):
 
     auth_required = False
 
+    def get_parser(self, prog_name):
+        parser = super(ListCommand, self).get_parser(prog_name)
+        parser.add_argument(
+            '--group',
+            metavar='<group-keyword>',
+            help=_('Show commands filtered by a command group, for example: '
+                   'identity, volume, compute, image, network and '
+                   'other keywords'),
+        )
+        return parser
+
     def take_action(self, parsed_args):
         cm = self.app.command_manager
         groups = cm.get_command_groups()
         groups = sorted(groups)
         columns = ('Command Group', 'Commands')
 
+        if parsed_args.group:
+            groups = (group for group in groups if parsed_args.group in group)
+
         commands = []
         for group in groups:
             command_names = cm.get_command_names(group)

openstackclient/tests/functional/common/test_module.py

@@ -42,3 +42,38 @@ class ModuleTest(base.TestCase):
         cmd_output = json.loads(self.openstack('module list --all -f json'))
         for one_module in self.CLIENTS + self.LIBS:
             self.assertIn(one_module, cmd_output.keys())
+
+
+class CommandTest(base.TestCase):
+    """Functional tests for openstackclient command list."""
+    GROUPS = [
+        'openstack.volume.v2',
+        'openstack.network.v2',
+        'openstack.image.v2',
+        'openstack.identity.v3',
+        'openstack.compute.v2',
+        'openstack.common',
+        'openstack.cli',
+    ]
+
+    def test_command_list_no_option(self):
+        cmd_output = json.loads(self.openstack('command list -f json'))
+        group_names = [each.get('Command Group') for each in cmd_output]
+        for one_group in self.GROUPS:
+            self.assertIn(one_group, group_names)
+
+    def test_command_list_with_group(self):
+        input_groups = [
+            'volume',
+            'network',
+            'image',
+            'identity',
+            'compute.v2'
+        ]
+        for each_input in input_groups:
+            cmd_output = json.loads(self.openstack(
+                'command list --group %s -f json' % each_input
+            ))
+            group_names = [each.get('Command Group') for each in cmd_output]
+            for each_name in group_names:
+                self.assertIn(each_input, each_name)

openstackclient/tests/unit/common/test_module.py

@@ -88,6 +88,41 @@ class TestCommandList(utils.TestCommand):
 
         self.assertEqual(datalist, tuple(data))
 
+    def test_command_list_with_group_not_found(self):
+        arglist = [
+            '--group', 'not_exist',
+        ]
+        verifylist = [
+            ('group', 'not_exist'),
+        ]
+        parsed_args = self.check_parser(self.cmd, arglist, verifylist)
+
+        columns, data = self.cmd.take_action(parsed_args)
+
+        collist = ('Command Group', 'Commands')
+        self.assertEqual(collist, columns)
+        self.assertEqual([], data)
+
+    def test_command_list_with_group(self):
+        arglist = [
+            '--group', 'common',
+        ]
+        verifylist = [
+            ('group', 'common'),
+        ]
+        parsed_args = self.check_parser(self.cmd, arglist, verifylist)
+
+        columns, data = self.cmd.take_action(parsed_args)
+
+        collist = ('Command Group', 'Commands')
+        self.assertEqual(collist, columns)
+        datalist = ((
+            'openstack.common',
+            'limits show\nextension list'
+        ),)
+
+        self.assertEqual(datalist, tuple(data))
+
 
 @mock.patch.dict(
     'openstackclient.common.module.sys.modules',

releasenotes/notes/bug-1666780-c10010e9061689d3.yaml

@@ -0,0 +1,11 @@
+---
+features:
+  - |
+    Support list commands by group name keyword. Add ``--group`` option to
+    filter the commands by group name keyword, like: --group volume, list all
+    openstack.volume.v2 (cinder) commands.
+    That support the scenario that users need to know the current support
+    commands of some OpenStack services(nova, neutron, cinder and so on) in
+    OSC, and make it easier for users to find out the related commands that
+    they care about.
+    [Bug `1666780 <https://bugs.launchpad.net/python-openstackclient/+bug/1666780>`_]