Remove the unused plugins framework

This framework was merged a year ago and AFAICT hasn't seen use beyond
the two initial wikimedia extensions for Nova.

The framework basically allows a way for a single plugin to register API
extensions and notification hooks. Both of these can be done by directly
using config opts like osapi_compute_extension and notification_driver
so this framework really only helps if we expected to (and wanted to)
lots of these plugins in the wild.

Nova is the only project using this and we don't have an active
maintainer listed in the MAINTAINERS file, so it seems like it's time to
remove it from the incubator.

Change-Id: I5552b5625e26f4821464807743545ec6f5117f2b

8 files changed, 0 insertions, 501 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 128cb22..0500c53 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -199,12 +199,6 @@ M: Michael Still <mikal@stillhq.com>
 S: Maintained
 F: periodic_task.py
 
-== plugins ==
-
-M:
-S: Orphan
-F: plugin/
-
 == policy ==
 
 M:
diff --git a/openstack/common/plugin/__init__.py b/openstack/common/plugin/__init__.py
deleted file mode 100644
index b706747..0000000
--- a/openstack/common/plugin/__init__.py
+++ /dev/null
@@ -1,14 +0,0 @@
-# Copyright 2012 OpenStack Foundation.
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
diff --git a/openstack/common/plugin/callbackplugin.py b/openstack/common/plugin/callbackplugin.py
deleted file mode 100644
index 2de7fb0..0000000
--- a/openstack/common/plugin/callbackplugin.py
+++ /dev/null
@@ -1,93 +0,0 @@
-# Copyright 2012 OpenStack Foundation.
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-
-from openstack.common import log as logging
-from openstack.common.plugin import plugin
-
-
-LOG = logging.getLogger(__name__)
-
-
-class _CallbackNotifier(object):
-    """Manages plugin-defined notification callbacks.
-
-    For each Plugin, a CallbackNotifier will be added to the
-    notification driver list.  Calls to notify() with appropriate
-    messages will be hooked and prompt callbacks.
-
-    A callback should look like this:
-      def callback(context, message, user_data)
-    """
-
-    def __init__(self):
-        self._callback_dict = {}
-
-    def _add_callback(self, event_type, callback, user_data):
-        callback_list = self._callback_dict.get(event_type, [])
-        callback_list.append({'function': callback,
-                              'user_data': user_data})
-        self._callback_dict[event_type] = callback_list
-
-    def _remove_callback(self, callback):
-        for callback_list in self._callback_dict.values():
-            for entry in callback_list:
-                if entry['function'] == callback:
-                    callback_list.remove(entry)
-
-    def notify(self, context, message):
-        if message.get('event_type') not in self._callback_dict:
-            return
-
-        for entry in self._callback_dict[message.get('event_type')]:
-            entry['function'](context, message, entry.get('user_data'))
-
-    def callbacks(self):
-        return self._callback_dict
-
-
-class CallbackPlugin(plugin.Plugin):
-    """Plugin with a simple callback interface.
-
-    This class is provided as a convenience for producing a simple
-    plugin that only watches a couple of events.  For example, here's
-    a subclass which prints a line the first time an instance is created.
-
-    class HookInstanceCreation(CallbackPlugin):
-
-        def __init__(self, _service_name):
-            super(HookInstanceCreation, self).__init__()
-            self._add_callback(self.magic, 'compute.instance.create.start')
-
-        def magic(self):
-            print "An instance was created!"
-            self._remove_callback(self, self.magic)
-    """
-
-    def __init__(self, service_name):
-        super(CallbackPlugin, self).__init__(service_name)
-        self._callback_notifier = _CallbackNotifier()
-        self._add_notifier(self._callback_notifier)
-
-    def _add_callback(self, callback, event_type, user_data=None):
-        """Add callback for a given event notification.
-
-        Subclasses can call this as an alternative to implementing
-        a fullblown notify notifier.
-        """
-        self._callback_notifier._add_callback(event_type, callback, user_data)
-
-    def _remove_callback(self, callback):
-        """Remove all notification callbacks to specified function."""
-        self._callback_notifier._remove_callback(callback)
diff --git a/openstack/common/plugin/plugin.py b/openstack/common/plugin/plugin.py
deleted file mode 100644
index d2be0b3..0000000
--- a/openstack/common/plugin/plugin.py
+++ /dev/null
@@ -1,86 +0,0 @@
-# Copyright 2012 OpenStack Foundation.
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-
-from openstack.common import log as logging
-
-
-LOG = logging.getLogger(__name__)
-
-
-class Plugin(object):
-    """Defines an interface for adding functionality to an OpenStack service.
-
-    A plugin interacts with a service via the following pathways:
-
-    - An optional set of notifiers, managed by calling add_notifier()
-      or by overriding _notifiers()
-
-    - A set of api extensions, managed via add_api_extension_descriptor()
-
-    - Direct calls to service functions.
-
-    - Whatever else the plugin wants to do on its own.
-
-    This is the reference implementation.
-    """
-
-    # The following functions are provided as convenience methods
-    # for subclasses.  Subclasses should call them but probably not
-    # override them.
-    def _add_api_extension_descriptor(self, descriptor):
-        """Subclass convenience method which adds an extension descriptor.
-
-           Subclass constructors should call this method when
-           extending a project's REST interface.
-
-           Note that once the api service has loaded, the
-           API extension set is more-or-less fixed, so
-           this should mainly be called by subclass constructors.
-        """
-        self._api_extension_descriptors.append(descriptor)
-
-    def _add_notifier(self, notifier):
-        """Subclass convenience method which adds a notifier.
-
-           Notifier objects should implement the function notify(message).
-           Each notifier receives a notify() call whenever an openstack
-           service broadcasts a notification.
-
-           Best to call this during construction.  Notifiers are enumerated
-           and registered by the pluginmanager at plugin load time.
-        """
-        self._notifiers.append(notifier)
-
-    # The following methods are called by OpenStack services to query
-    #  plugin features.  Subclasses should probably not override these.
-    def _notifiers(self):
-        """Returns list of notifiers for this plugin."""
-        return self._notifiers
-
-    notifiers = property(_notifiers)
-
-    def _api_extension_descriptors(self):
-        """Return a list of API extension descriptors.
-
-           Called by a project API during its load sequence.
-        """
-        return self._api_extension_descriptors
-
-    api_extension_descriptors = property(_api_extension_descriptors)
-
-    # Most plugins will override this:
-    def __init__(self, service_name):
-        self._notifiers = []
-        self._api_extension_descriptors = []
diff --git a/openstack/common/plugin/pluginmanager.py b/openstack/common/plugin/pluginmanager.py
deleted file mode 100644
index 3962447..0000000
--- a/openstack/common/plugin/pluginmanager.py
+++ /dev/null
@@ -1,78 +0,0 @@
-# Copyright 2012 OpenStack Foundation.
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-
-import pkg_resources
-
-from oslo.config import cfg
-
-from openstack.common.gettextutils import _
-from openstack.common import log as logging
-from openstack.common.notifier import api as notifier_api
-
-
-CONF = cfg.CONF
-LOG = logging.getLogger(__name__)
-
-
-class PluginManager(object):
-    """Manages plugin entrypoints and loading.
-
-    For a service to implement this plugin interface for callback purposes:
-
-      - Make use of the openstack-common notifier system
-      - Instantiate this manager in each process (passing in
-        project and service name)
-
-    For an API service to extend itself using this plugin interface,
-    it needs to query the plugin_extension_factory provided by
-    the already-instantiated PluginManager.
-    """
-
-    def __init__(self, project_name, service_name):
-        """Construct Plugin Manager; load and initialize plugins.
-
-        project_name (e.g. 'nova' or 'glance') is used
-        to construct the entry point that identifies plugins.
-
-        The service_name (e.g. 'compute') is passed on to
-        each plugin as a raw string for it to do what it will.
-        """
-        self._project_name = project_name
-        self._service_name = service_name
-        self.plugins = []
-
-    def load_plugins(self):
-        self.plugins = []
-
-        for entrypoint in pkg_resources.iter_entry_points('%s.plugin' %
-                                                          self._project_name):
-            try:
-                pluginclass = entrypoint.load()
-                plugin = pluginclass(self._service_name)
-                self.plugins.append(plugin)
-            except Exception as exc:
-                LOG.error(_("Failed to load plugin %(plug)s: %(exc)s") %
-                          {'plug': entrypoint, 'exc': exc})
-
-        # Register individual notifiers.
-        for plugin in self.plugins:
-            for notifier in plugin.notifiers:
-                notifier_api.add_driver(notifier)
-
-    def plugin_extension_factory(self, ext_mgr):
-        for plugin in self.plugins:
-            descriptors = plugin.api_extension_descriptors
-            for descriptor in descriptors:
-                ext_mgr.load_extension(descriptor)
diff --git a/tests/unit/plugin/__init__.py b/tests/unit/plugin/__init__.py
deleted file mode 100644
index b706747..0000000
--- a/tests/unit/plugin/__init__.py
+++ /dev/null
@@ -1,14 +0,0 @@
-# Copyright 2012 OpenStack Foundation.
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
diff --git a/tests/unit/plugin/test_callback_plugin.py b/tests/unit/plugin/test_callback_plugin.py
deleted file mode 100644
index 3f3fd63..0000000
--- a/tests/unit/plugin/test_callback_plugin.py
+++ /dev/null
@@ -1,92 +0,0 @@
-# Copyright 2012 OpenStack Foundation.
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-
-import pkg_resources
-
-from openstack.common.notifier import api as notifier_api
-from openstack.common.plugin import callbackplugin
-from openstack.common.plugin import pluginmanager
-from tests import utils as test_utils
-
-userdatastring = "magic user data string"
-
-
-class TestCBP(callbackplugin.CallbackPlugin):
-
-    def callback1(self, context, message, userdata):
-        self.callback1count += 1
-
-    def callback2(self, context, message, userdata):
-        self.callback2count += 1
-
-    def callback3(self, context, message, userdata):
-        self.callback3count += 1
-        self.userdata = userdata
-
-    def __init__(self, service_name):
-        super(TestCBP, self).__init__(service_name)
-        self.callback1count = 0
-        self.callback2count = 0
-        self.callback3count = 0
-
-        self._add_callback(self.callback1, 'type1', None)
-        self._add_callback(self.callback2, 'type1', None)
-        self._add_callback(self.callback3, 'type2', 'magic user data string')
-
-
-class CallbackTestCase(test_utils.BaseTestCase):
-    """Tests for the callback plugin convenience class."""
-
-    def test_callback_plugin_subclass(self):
-
-        class MockEntrypoint(pkg_resources.EntryPoint):
-            def load(self):
-                return TestCBP
-
-        def mock_iter_entry_points(_t):
-            return [MockEntrypoint("fake", "fake", ["fake"])]
-
-        self.stubs.Set(pkg_resources, 'iter_entry_points',
-                       mock_iter_entry_points)
-
-        plugmgr = pluginmanager.PluginManager("testproject", "testservice")
-        plugmgr.load_plugins()
-        self.assertEqual(len(plugmgr.plugins), 1)
-        plugin = plugmgr.plugins[0]
-        self.assertEqual(len(plugin.notifiers), 1)
-
-        notifier_api.notify('contextarg', 'publisher_id', 'type1',
-                            notifier_api.WARN, dict(a=3))
-
-        self.assertEqual(plugin.callback1count, 1)
-        self.assertEqual(plugin.callback2count, 1)
-        self.assertEqual(plugin.callback3count, 0)
-
-        notifier_api.notify('contextarg', 'publisher_id', 'type2',
-                            notifier_api.WARN, dict(a=3))
-
-        self.assertEqual(plugin.callback1count, 1)
-        self.assertEqual(plugin.callback2count, 1)
-        self.assertEqual(plugin.callback3count, 1)
-        self.assertEqual(plugin.userdata, userdatastring)
-
-        plugin._remove_callback(plugin.callback1)
-
-        notifier_api.notify('contextarg', 'publisher_id', 'type1',
-                            notifier_api.WARN, dict(a=3))
-
-        self.assertEqual(plugin.callback1count, 1)
-        self.assertEqual(plugin.callback2count, 2)
-        self.assertEqual(plugin.callback3count, 1)
diff --git a/tests/unit/test_plugin.py b/tests/unit/test_plugin.py
deleted file mode 100644
index fd653d7..0000000
--- a/tests/unit/test_plugin.py
+++ /dev/null
@@ -1,118 +0,0 @@
-# Copyright 2012 OpenStack Foundation.
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-
-import pkg_resources
-
-from openstack.common.notifier import api as notifier_api
-from openstack.common.plugin import plugin
-from openstack.common.plugin import pluginmanager
-from tests import utils
-
-
-class SimpleNotifier(object):
-    def __init__(self):
-        self.message_list = []
-
-    def notify(self, context, message):
-        self.context = context
-        self.message_list.append(message)
-
-
-class ManagerTestCase(utils.BaseTestCase):
-    def test_constructs(self):
-        manager1 = pluginmanager.PluginManager("testproject", "testservice")
-        self.assertNotEqual(manager1, False)
-
-
-class NotifyTestCase(utils.BaseTestCase):
-    """Test case for the plugin notification interface."""
-
-    def test_add_notifier(self):
-        notifier1 = SimpleNotifier()
-        notifier2 = SimpleNotifier()
-        notifier3 = SimpleNotifier()
-
-        testplugin = plugin.Plugin('service')
-        testplugin._add_notifier(notifier1)
-        testplugin._add_notifier(notifier2)
-        self.assertEqual(len(testplugin.notifiers), 2)
-
-        testplugin._add_notifier(notifier3)
-        self.assertEqual(len(testplugin.notifiers), 3)
-
-    def test_notifier_action(self):
-        def mock_iter_entry_points(_t):
-            return [MockEntrypoint("fake", "fake", ["fake"])]
-
-        self.stubs.Set(pkg_resources, 'iter_entry_points',
-                       mock_iter_entry_points)
-
-        plugmgr = pluginmanager.PluginManager("testproject", "testservice")
-        plugmgr.load_plugins()
-        self.assertEqual(len(plugmgr.plugins), 1)
-        self.assertEqual(len(plugmgr.plugins[0].notifiers), 1)
-        notifier = plugmgr.plugins[0].notifiers[0]
-
-        notifier_api.notify('contextarg', 'publisher_id', 'event_type',
-                            notifier_api.WARN, dict(a=3))
-
-        self.assertEqual(len(notifier.message_list), 1)
-
-
-class StubControllerExtension(object):
-    name = 'stubextension'
-    alias = 'stubby'
-
-
-class TestPluginClass(plugin.Plugin):
-
-    def __init__(self, service_name):
-        super(TestPluginClass, self).__init__(service_name)
-        self._add_api_extension_descriptor(StubControllerExtension)
-        notifier1 = SimpleNotifier()
-        self._add_notifier(notifier1)
-
-
-class MockEntrypoint(pkg_resources.EntryPoint):
-    def load(self):
-        return TestPluginClass
-
-
-class MockExtManager():
-    def __init__(self):
-        self.descriptors = []
-
-    def load_extension(self, descriptor):
-        self.descriptors.append(descriptor)
-
-
-class APITestCase(utils.BaseTestCase):
-    """Test case for the plugin api extension interface."""
-    def test_add_extension(self):
-        def mock_load(_s):
-            return TestPluginClass()
-
-        def mock_iter_entry_points(_t):
-            return [MockEntrypoint("fake", "fake", ["fake"])]
-
-        self.stubs.Set(pkg_resources, 'iter_entry_points',
-                       mock_iter_entry_points)
-
-        mgr = MockExtManager()
-        plugmgr = pluginmanager.PluginManager("testproject", "testservice")
-        plugmgr.load_plugins()
-        plugmgr.plugin_extension_factory(mgr)
-
-        self.assertTrue(StubControllerExtension in mgr.descriptors)