1 files changed, 116 insertions, 0 deletions
diff --git a/nova/openstack/common/notifier/list_notifier.py b/nova/openstack/common/notifier/list_notifier.py
new file mode 100644
index 000000000..7c2ec6e6d
--- /dev/null
+++ b/nova/openstack/common/notifier/list_notifier.py
@@ -0,0 +1,116 @@
+# 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 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