Allow command hooks to make changes

This changes the signature of two private methods, but also expects
the new-ish Command.before() and Command.after() methods to now return
values.  We ensure that the previous behavior does not change if
nothing is returned explicitly.

Change-Id: I1cc0958dbce0c2516891df64f60d4bfd84c2e1a0
This commit is contained in:
Dean Troyer 2017-09-14 12:39:48 -05:00
parent 9ce5e930e5
commit 42b169123d
4 changed files with 225 additions and 7 deletions

View File

@ -133,9 +133,9 @@ class Command(object):
Return the value returned by :meth:`take_action` or 0.
"""
self._run_before_hooks(parsed_args)
parsed_args = self._run_before_hooks(parsed_args)
return_code = self.take_action(parsed_args) or 0
self._run_after_hooks(parsed_args, return_code)
return_code = self._run_after_hooks(parsed_args, return_code)
return return_code
def _run_before_hooks(self, parsed_args):
@ -149,7 +149,12 @@ class Command(object):
hook processing behavior.
"""
for hook in self._hooks:
hook.obj.before(parsed_args)
ret = hook.obj.before(parsed_args)
# If the return is None do not change parsed_args, otherwise
# set up to pass it to the next hook
if ret is not None:
parsed_args = ret
return parsed_args
def _run_after_hooks(self, parsed_args, return_code):
"""Calls after() method of the hooks.
@ -162,7 +167,12 @@ class Command(object):
hook processing behavior.
"""
for hook in self._hooks:
hook.obj.after(parsed_args, return_code)
ret = hook.obj.after(parsed_args, return_code)
# If the return is None do not change return_code, otherwise
# set up to pass it to the next hook
if ret is not None:
return_code = ret
return return_code
class _SmartHelpFormatter(_argparse.HelpFormatter):

View File

@ -110,10 +110,11 @@ class DisplayCommandBase(command.Command):
return columns_to_include, selector
def run(self, parsed_args):
self._run_before_hooks(parsed_args)
parsed_args = self._run_before_hooks(parsed_args)
self.formatter = self._formatter_plugins[parsed_args.formatter].obj
column_names, data = self.take_action(parsed_args)
self._run_after_hooks(parsed_args, (column_names, data))
column_names, data = self._run_after_hooks(parsed_args,
(column_names, data))
self.produce_output(parsed_args, column_names, data)
return 0

View File

@ -51,6 +51,7 @@ class CommandHook(object):
:param parsed_args: The arguments to the command.
:paramtype parsed_args: argparse.Namespace
"""
return parsed_args
@abc.abstractmethod
def after(self, parsed_args, return_code):
@ -63,3 +64,4 @@ class CommandHook(object):
:param return_code: The value returned from take_action().
:paramtype return_code: int
"""
return return_code

View File

@ -97,6 +97,75 @@ class TestHook(hooks.CommandHook):
self._after_called = True
class TestChangeHook(hooks.CommandHook):
_before_called = False
_after_called = False
def get_parser(self, parser):
parser.add_argument('--added-by-hook')
return parser
def get_epilog(self):
return 'hook epilog'
def before(self, parsed_args):
self._before_called = True
parsed_args.added_by_hook = 'othervalue'
parsed_args.added_by_before = True
return parsed_args
def after(self, parsed_args, return_code):
self._after_called = True
return 24
class TestDisplayChangeHook(hooks.CommandHook):
_before_called = False
_after_called = False
def get_parser(self, parser):
parser.add_argument('--added-by-hook')
return parser
def get_epilog(self):
return 'hook epilog'
def before(self, parsed_args):
self._before_called = True
parsed_args.added_by_hook = 'othervalue'
parsed_args.added_by_before = True
return parsed_args
def after(self, parsed_args, return_code):
self._after_called = True
return (('Name',), ('othervalue',))
class TestListerChangeHook(hooks.CommandHook):
_before_called = False
_after_called = False
def get_parser(self, parser):
parser.add_argument('--added-by-hook')
return parser
def get_epilog(self):
return 'hook epilog'
def before(self, parsed_args):
self._before_called = True
parsed_args.added_by_hook = 'othervalue'
parsed_args.added_by_before = True
return parsed_args
def after(self, parsed_args, return_code):
self._after_called = True
return (('Name',), [('othervalue',)])
class TestCommandLoadHooks(base.TestBase):
def test_no_app_or_name(self):
@ -147,8 +216,54 @@ class TestHooks(base.TestBase):
def test_after(self):
self.assertFalse(self.hook._after_called)
self.cmd.run(None)
result = self.cmd.run(None)
self.assertTrue(self.hook._after_called)
self.assertEqual(result, 42)
class TestChangeHooks(base.TestBase):
def setUp(self):
super(TestChangeHooks, self).setUp()
self.app = make_app()
self.cmd = TestCommand(self.app, None, cmd_name='test')
self.hook = TestChangeHook(self.cmd)
self.mgr = extension.ExtensionManager.make_test_instance(
[extension.Extension(
'parser-hook',
None,
None,
self.hook)],
)
# Replace the auto-loaded hooks with our explicitly created
# manager.
self.cmd._hooks = self.mgr
def test_get_parser(self):
parser = self.cmd.get_parser('test')
results = parser.parse_args(['--added-by-hook', 'value'])
self.assertEqual(results.added_by_hook, 'value')
def test_get_epilog(self):
results = self.cmd.get_epilog()
self.assertIn('hook epilog', results)
def test_before(self):
self.assertFalse(self.hook._before_called)
parser = self.cmd.get_parser('test')
results = parser.parse_args(['--added-by-hook', 'value'])
self.cmd.run(results)
self.assertTrue(self.hook._before_called)
self.assertEqual(results.added_by_hook, 'othervalue')
self.assertTrue(results.added_by_before)
def test_after(self):
self.assertFalse(self.hook._after_called)
parser = self.cmd.get_parser('test')
results = parser.parse_args(['--added-by-hook', 'value'])
result = self.cmd.run(results)
self.assertTrue(self.hook._after_called)
self.assertEqual(result, 24)
class TestShowOneHooks(base.TestBase):
@ -193,6 +308,51 @@ class TestShowOneHooks(base.TestBase):
self.assertTrue(self.hook._after_called)
class TestShowOneChangeHooks(base.TestBase):
def setUp(self):
super(TestShowOneChangeHooks, self).setUp()
self.app = make_app()
self.cmd = TestShowCommand(self.app, None, cmd_name='test')
self.hook = TestDisplayChangeHook(self.cmd)
self.mgr = extension.ExtensionManager.make_test_instance(
[extension.Extension(
'parser-hook',
None,
None,
self.hook)],
)
# Replace the auto-loaded hooks with our explicitly created
# manager.
self.cmd._hooks = self.mgr
def test_get_parser(self):
parser = self.cmd.get_parser('test')
results = parser.parse_args(['--added-by-hook', 'value'])
self.assertEqual(results.added_by_hook, 'value')
def test_get_epilog(self):
results = self.cmd.get_epilog()
self.assertIn('hook epilog', results)
def test_before(self):
self.assertFalse(self.hook._before_called)
parser = self.cmd.get_parser('test')
results = parser.parse_args(['--added-by-hook', 'value'])
self.cmd.run(results)
self.assertTrue(self.hook._before_called)
self.assertEqual(results.added_by_hook, 'othervalue')
self.assertTrue(results.added_by_before)
def test_after(self):
self.assertFalse(self.hook._after_called)
parser = self.cmd.get_parser('test')
results = parser.parse_args(['--added-by-hook', 'value'])
result = self.cmd.run(results)
self.assertTrue(self.hook._after_called)
self.assertEqual(result, 0)
class TestListerHooks(base.TestBase):
def setUp(self):
@ -233,3 +393,48 @@ class TestListerHooks(base.TestBase):
results = parser.parse_args(['--added-by-hook', 'value'])
self.cmd.run(results)
self.assertTrue(self.hook._after_called)
class TestListerChangeHooks(base.TestBase):
def setUp(self):
super(TestListerChangeHooks, self).setUp()
self.app = make_app()
self.cmd = TestListerCommand(self.app, None, cmd_name='test')
self.hook = TestListerChangeHook(self.cmd)
self.mgr = extension.ExtensionManager.make_test_instance(
[extension.Extension(
'parser-hook',
None,
None,
self.hook)],
)
# Replace the auto-loaded hooks with our explicitly created
# manager.
self.cmd._hooks = self.mgr
def test_get_parser(self):
parser = self.cmd.get_parser('test')
results = parser.parse_args(['--added-by-hook', 'value'])
self.assertEqual(results.added_by_hook, 'value')
def test_get_epilog(self):
results = self.cmd.get_epilog()
self.assertIn('hook epilog', results)
def test_before(self):
self.assertFalse(self.hook._before_called)
parser = self.cmd.get_parser('test')
results = parser.parse_args(['--added-by-hook', 'value'])
self.cmd.run(results)
self.assertTrue(self.hook._before_called)
self.assertEqual(results.added_by_hook, 'othervalue')
self.assertTrue(results.added_by_before)
def test_after(self):
self.assertFalse(self.hook._after_called)
parser = self.cmd.get_parser('test')
results = parser.parse_args(['--added-by-hook', 'value'])
result = self.cmd.run(results)
self.assertTrue(self.hook._after_called)
self.assertEqual(result, 0)