Migrate a notifier patch from common:

commit c767e9beffe4b826eac869ce7e2eef2cc1499bbe
Author: Andrew Bogott <abogott@wikimedia.org>
Date: Thu Jul 19 03:34:31 2012 -0500

Add multiple-driver support to the notifier api.

Move all of the functionality previously provided by the list_notifier
into the basic notifier api. Move and restructure tests accordingly.

Remove the list_notifier file and test file.

For bug 1025820

Change-Id: Icadaafe8bc312942249272873d9a4a8f1aa49a94

5 files changed, 62 insertions, 158 deletions

diff --git a/nova/openstack/common/log.py b/nova/openstack/common/log.py
index 31238062b..e055e8148 100644
--- a/nova/openstack/common/log.py
+++ b/nova/openstack/common/log.py
@@ -247,10 +247,9 @@ class JSONFormatter(logging.Formatter):
 
 class PublishErrorsHandler(logging.Handler):
     def emit(self, record):
-        if 'list_notifier_drivers' in CONF:
-            if ('nova.openstack.common.notifier.log_notifier' in
-                CONF.list_notifier_drivers):
-                return
+        if ('nova.openstack.common.notifier.log_notifier' in
+            CONF.notification_driver):
+            return
         notifier.api.notify(None, 'error.publisher',
                             'error_notification',
                             notifier.api.ERROR,
diff --git a/nova/openstack/common/notifier/api.py b/nova/openstack/common/notifier/api.py
index ba6c2dd9f..f90a4eba8 100644
--- a/nova/openstack/common/notifier/api.py
+++ b/nova/openstack/common/notifier/api.py
@@ -28,16 +28,17 @@ from nova.openstack.common import timeutils
 LOG = logging.getLogger(__name__)
 
 notifier_opts = [
-    cfg.StrOpt('notification_driver',
-               default='nova.openstack.common.notifier.no_op_notifier',
-               help='Default driver for sending notifications'),
+    cfg.MultiStrOpt('notification_driver',
+                    default=[],
+                    deprecated_name='list_notifier_drivers',
+                    help='Driver or drivers to handle sending notifications'),
     cfg.StrOpt('default_notification_level',
                default='INFO',
                help='Default notification level for outgoing notifications'),
     cfg.StrOpt('default_publisher_id',
                default='$host',
                help='Default publisher_id for outgoing notifications'),
-    ]
+]
 
 CONF = cfg.CONF
 CONF.register_opts(notifier_opts)
@@ -122,21 +123,60 @@ def notify(context, publisher_id, event_type, priority, payload):
     """
     if priority not in log_levels:
         raise BadPriorityException(
-                 _('%s not in valid priorities') % priority)
+            _('%s not in valid priorities') % priority)
 
     # Ensure everything is JSON serializable.
     payload = jsonutils.to_primitive(payload, convert_instances=True)
 
-    driver = importutils.import_module(CONF.notification_driver)
     msg = dict(message_id=str(uuid.uuid4()),
-                   publisher_id=publisher_id,
-                   event_type=event_type,
-                   priority=priority,
-                   payload=payload,
-                   timestamp=str(timeutils.utcnow()))
-    try:
-        driver.notify(context, msg)
-    except Exception, e:
-        LOG.exception(_("Problem '%(e)s' attempting to "
-                        "send to notification system. Payload=%(payload)s") %
-                        locals())
+               publisher_id=publisher_id,
+               event_type=event_type,
+               priority=priority,
+               payload=payload,
+               timestamp=str(timeutils.utcnow()))
+
+    for driver in _get_drivers():
+        try:
+            driver.notify(context, msg)
+        except Exception, e:
+            LOG.exception(_("Problem '%(e)s' attempting to "
+              "send to notification system. Payload=%(payload)s") %
+                            locals())
+
+
+_drivers = None
+
+
+def _get_drivers():
+    """Instantiate, cache, and return drivers based on the CONF."""
+    global _drivers
+    if _drivers is None:
+        _drivers = {}
+        for notification_driver in CONF.notification_driver:
+            add_driver(notification_driver)
+
+    return _drivers.values()
+
+
+def add_driver(notification_driver):
+    """Add a notification driver at runtime."""
+    # Make sure the driver list is initialized.
+    _get_drivers()
+    if isinstance(notification_driver, basestring):
+        # Load and add
+        try:
+            driver = importutils.import_module(notification_driver)
+            _drivers[notification_driver] = driver
+        except ImportError as e:
+            LOG.exception(_("Failed to load notifier %s. "
+                            "These notifications will not be sent.") %
+                            notification_driver)
+    else:
+        # Driver is already loaded; just add the object.
+        _drivers[notification_driver] = notification_driver
+
+
+def _reset_drivers():
+    """Used by unit tests to reset the drivers."""
+    global _drivers
+    _drivers = None
diff --git a/nova/openstack/common/notifier/list_notifier.py b/nova/openstack/common/notifier/list_notifier.py
deleted file mode 100644
index f59106d9a..000000000
--- a/nova/openstack/common/notifier/list_notifier.py
+++ /dev/null
@@ -1,117 +0,0 @@
-# Copyright 2011 OpenStack LLC.
-# 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 nova.openstack.common import cfg
-from nova.openstack.common.gettextutils import _
-from nova.openstack.common import importutils
-from nova.openstack.common import log as logging
-
-
-list_notifier_drivers_opt = cfg.MultiStrOpt('list_notifier_drivers',
-        default=['nova.openstack.common.notifier.no_op_notifier'],
-        help='List of drivers to send notifications')
-
-CONF = cfg.CONF
-CONF.register_opt(list_notifier_drivers_opt)
-
-LOG = logging.getLogger(__name__)
-
-drivers = None
-
-
-class ImportFailureNotifier(object):
-    """Noisily re-raises some exception over-and-over when notify is called."""
-
-    def __init__(self, exception):
-        self.exception = exception
-
-    def notify(self, context, message):
-        raise self.exception
-
-
-def _get_drivers():
-    """Instantiates and returns drivers based on the flag values."""
-    global drivers
-    if drivers is None:
-        drivers = []
-        for notification_driver in CONF.list_notifier_drivers:
-            try:
-                drivers.append(importutils.import_module(notification_driver))
-            except ImportError as e:
-                drivers.append(ImportFailureNotifier(e))
-    return drivers
-
-
-def add_driver(notification_driver):
-    """Add a notification driver at runtime."""
-    # Make sure the driver list is initialized.
-    _get_drivers()
-    if isinstance(notification_driver, basestring):
-        # Load and add
-        try:
-            drivers.append(importutils.import_module(notification_driver))
-        except ImportError as e:
-            drivers.append(ImportFailureNotifier(e))
-    else:
-        # Driver is already loaded; just add the object.
-        drivers.append(notification_driver)
-
-
-def _object_name(obj):
-    name = []
-    if hasattr(obj, '__module__'):
-        name.append(obj.__module__)
-    if hasattr(obj, '__name__'):
-        name.append(obj.__name__)
-    else:
-        name.append(obj.__class__.__name__)
-    return '.'.join(name)
-
-
-def remove_driver(notification_driver):
-    """Remove a notification driver at runtime."""
-    # Make sure the driver list is initialized.
-    _get_drivers()
-    removed = False
-    if notification_driver in drivers:
-        # We're removing an object.  Easy.
-        drivers.remove(notification_driver)
-        removed = True
-    else:
-        # We're removing a driver by name.  Search for it.
-        for driver in drivers:
-            if _object_name(driver) == notification_driver:
-                drivers.remove(driver)
-                removed = True
-
-    if not removed:
-        raise ValueError("Cannot remove; %s is not in list" %
-                         notification_driver)
-
-
-def notify(context, message):
-    """Passes notification to multiple notifiers in a list."""
-    for driver in _get_drivers():
-        try:
-            driver.notify(context, message)
-        except Exception as e:
-            LOG.exception(_("Problem '%(e)s' attempting to send to "
-                            "notification driver %(driver)s."), locals())
-
-
-def _reset_drivers():
-    """Used by unit tests to reset the drivers."""
-    global drivers
-    drivers = None
diff --git a/nova/openstack/common/plugin/plugin.py b/nova/openstack/common/plugin/plugin.py
index 3db753d65..96be0af82 100644
--- a/nova/openstack/common/plugin/plugin.py
+++ b/nova/openstack/common/plugin/plugin.py
@@ -14,7 +14,6 @@
 #    under the License.
 
 from nova.openstack.common import log as logging
-from nova.openstack.common.notifier import list_notifier
 
 
 LOG = logging.getLogger(__name__)
diff --git a/nova/openstack/common/plugin/pluginmanager.py b/nova/openstack/common/plugin/pluginmanager.py
index 6b921656a..29656477d 100644
--- a/nova/openstack/common/plugin/pluginmanager.py
+++ b/nova/openstack/common/plugin/pluginmanager.py
@@ -19,7 +19,7 @@ import pkg_resources
 
 from nova.openstack.common import cfg
 from nova.openstack.common import log as logging
-from nova.openstack.common.notifier import list_notifier
+from nova.openstack.common.notifier import api as notifier_api
 
 
 CONF = cfg.CONF
@@ -53,17 +53,6 @@ class PluginManager(object):
         self._service_name = service_name
         self.plugins = []
 
-    def _force_use_list_notifier(self):
-        if (CONF.notification_driver !=
-            'nova.openstack.common.notifier.list_notifier'):
-            if not hasattr(CONF, "list_notifier_drivers"):
-                CONF.list_notifier_drivers = []
-            old_notifier = CONF.notification_driver
-            drvstring = 'nova.openstack.common.notifier.list_notifier'
-            CONF.notification_driver = drvstring
-            if old_notifier:
-                list_notifier.add_driver(old_notifier)
-
     def load_plugins(self):
         self.plugins = []
 
@@ -77,16 +66,10 @@ class PluginManager(object):
                 LOG.error(_("Failed to load plugin %(plug)s: %(exc)s") %
                           {'plug': entrypoint, 'exc': exc})
 
-        # See if we need to turn on the list notifier
-        for plugin in self.plugins:
-            if plugin.notifiers:
-                self._force_use_list_notifier()
-                break
-
         # Register individual notifiers.
         for plugin in self.plugins:
             for notifier in plugin.notifiers:
-                list_notifier.add_driver(notifier)
+                notifier_api.add_driver(notifier)
 
     def plugin_extension_factory(self, ext_mgr):
         for plugin in self.plugins: