Sketch out a plugin system for saving metering data.

Change-Id: Ib91213ac78fd5e3baf7200849b4fa8554c652a99

ceilometer/collector/manager.py

@@ -26,6 +26,7 @@ from ceilometer import log
 from ceilometer import publish
 from ceilometer import rpc
 from ceilometer.collector import dispatcher
+from ceilometer import storage
 
 # FIXME(dhellmann): There must be another way to do this.
 # Import rabbit_notifier to register notification_topics flag
@@ -43,6 +44,10 @@ class CollectorManager(manager.Manager):
     def init_host(self):
         self.connection = rpc.Connection(flags.FLAGS)
 
+        storage.register_opts(cfg.CONF)
+        self.storage_engine = storage.get_engine(cfg.CONF)
+        self.storage_conn = self.storage_engine.get_connection(cfg.CONF)
+
         self.compute_handler = dispatcher.NotificationDispatcher(
             COMPUTE_COLLECTOR_NAMESPACE,
             self._publish_counter,
@@ -79,3 +84,8 @@ class CollectorManager(manager.Manager):
                  data['event_type'],
                  data['resource_id'],
                  data['counter_volume'])
+        try:
+            self.storage_conn.record_metering_data(data)
+        except Exception as err:
+            LOG.error('Failed to record metering data: %s', err)
+            LOG.exception(err)

ceilometer/storage/__init__.py

@@ -0,0 +1,63 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2012 New Dream Network, LLC (DreamHost)
+#
+# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
+#
+# 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.
+"""Storage backend management
+"""
+
+import pkg_resources
+
+from ceilometer import cfg
+from ceilometer import log
+
+LOG = log.getLogger(__name__)
+
+STORAGE_ENGINE_NAMESPACE = 'ceilometer.storage'
+
+STORAGE_OPTS = [
+    cfg.StrOpt('metering_storage_engine',
+               default='log',
+               help='The name of the storage engine to use',
+               ),
+    ]
+
+
+def register_opts(conf):
+    """Register any options for the storage system.
+    """
+    conf.register_opts(STORAGE_OPTS)
+    p = get_engine(conf)
+    p.register_opts(conf)
+
+
+def get_engine(conf):
+    """Load the configured engine and return an instance.
+    """
+    engine_name = conf.metering_storage_engine
+    for ep in pkg_resources.iter_entry_points(STORAGE_ENGINE_NAMESPACE,
+                                              engine_name):
+        try:
+            engine_class = ep.load()
+            engine = engine_class()
+        except Exception as err:
+            LOG.error('Failed to load storage engine %s: %s',
+                      engine_name, err)
+            LOG.exception(err)
+            raise
+        LOG.info('Loaded %s storage engine', engine_name)
+        return engine
+    else:
+        raise RuntimeError('No %r storage engine found' % engine_name)

ceilometer/storage/base.py

@@ -0,0 +1,64 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2012 New Dream Network, LLC (DreamHost)
+#
+# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
+#
+# 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.
+"""Base classes for storage engines
+"""
+
+import abc
+
+from ceilometer import log
+
+LOG = log.getLogger(__name__)
+
+
+class StorageEngine(object):
+    """Base class for storage engines.
+    """
+
+    __metaclass__ = abc.ABCMeta
+
+    @abc.abstractmethod
+    def register_opts(self, conf):
+        """Register any configuration options used by this engine.
+        """
+
+    @abc.abstractmethod
+    def get_connection(self, conf):
+        """Return a Connection instance based on the configuration settings.
+        """
+
+
+class Connection(object):
+    """Base class for storage system connections.
+    """
+
+    __metaclass__ = abc.ABCMeta
+
+    @abc.abstractmethod
+    def __init__(self, conf):
+        """Constructor"""
+
+    @abc.abstractmethod
+    def record_metering_data(self, data):
+        """Write the data to the backend storage system.
+
+        :param data: a dictionary such as returned by
+                     ceilometer.meter.meter_message_from_counter
+        """
+
+    # FIXME(dhellmann): We will eventually need to add query methods
+    # for the API server to use, too.

ceilometer/storage/impl_log.py

@@ -0,0 +1,57 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2012 New Dream Network, LLC (DreamHost)
+#
+# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
+#
+# 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.
+"""Simple logging storage backend.
+"""
+
+from ceilometer import log
+from ceilometer.storage import base
+
+LOG = log.getLogger(__name__)
+
+
+class LogStorage(base.StorageEngine):
+    """Log the data
+    """
+
+    def register_opts(self, conf):
+        """Register any configuration options used by this engine.
+        """
+
+    def get_connection(self, conf):
+        """Return a Connection instance based on the configuration settings.
+        """
+        return Connection(conf)
+
+
+class Connection(base.Connection):
+    """Base class for storage system connections.
+    """
+
+    def __init__(self, conf):
+        return
+
+    def record_metering_data(self, data):
+        """Write the data to the backend storage system.
+
+        :param data: a dictionary such as returned by
+                     ceilometer.meter.meter_message_from_counter
+        """
+        LOG.info('metering data %s for %s: %s',
+                 data['event_type'],
+                 data['resource_id'],
+                 data['counter_volume'])

setup.py

@@ -41,5 +41,8 @@ setuptools.setup(
             'network_floatingip'
             '= ceilometer.compute.network:FloatingIPPollster',
             ],
+        'ceilometer.storage': [
+            'log = ceilometer.storage.impl_log:LogStorage',
+            ],
         },
     )

tests/storage/test_get_engine.py

@@ -0,0 +1,40 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2012 New Dream Network, LLC (DreamHost)
+#
+# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
+#
+# 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.
+"""Tests for ceilometer/storage/
+"""
+
+import mox
+
+from ceilometer import storage
+from ceilometer.storage import impl_log
+
+
+def test_get_engine():
+    conf = mox.Mox().CreateMockAnything()
+    conf.metering_storage_engine = 'log'
+    engine = storage.get_engine(conf)
+    assert isinstance(engine, impl_log.LogStorage)
+
+
+def test_get_engine_no_such_engine():
+    conf = mox.Mox().CreateMockAnything()
+    conf.metering_storage_engine = 'no-such-engine'
+    try:
+        storage.get_engine(conf)
+    except RuntimeError as err:
+        assert 'no-such-engine' in unicode(err)

tests/storage/test_impl_log.py

@@ -0,0 +1,34 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2012 New Dream Network, LLC (DreamHost)
+#
+# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
+#
+# 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.
+"""Tests for ceilometer/storage/impl_log.py
+"""
+
+import mox
+
+from ceilometer.storage import impl_log
+
+
+def test_get_connection():
+    conf = mox.Mox().CreateMockAnything()
+    conf.metering_storage_engine = 'log'
+    log_stg = impl_log.LogStorage()
+    conn = log_stg.get_connection(conf)
+    conn.record_metering_data({'event_type': 'test',
+                               'resource_id': __name__,
+                               'counter_volume': 1,
+                               })

tests/storage/test_register_opts.py

@@ -0,0 +1,46 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2012 New Dream Network, LLC (DreamHost)
+#
+# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
+#
+# 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.
+"""Tests for ceilometer/storage/
+"""
+
+from nova import flags
+from nova import test
+
+from nova import rpc
+
+from ceilometer import cfg
+from ceilometer import storage
+from ceilometer.storage import base
+
+# (dhellmann): This is needed to get the fake_rabbit config value set
+# up for the test base class.
+cfg.CONF.register_opts(rpc.rpc_opts)
+
+
+class RegisterOpts(test.TestCase):
+
+    def faux_get_engine(self, conf):
+        return self._faux_engine
+
+    def test_register_opts(self):
+        self.stubs.Set(storage, 'get_engine', self.faux_get_engine)
+        flags.FLAGS.metering_storage_engine = 'log'
+        self._faux_engine = self.mox.CreateMock(base.StorageEngine)
+        self._faux_engine.register_opts(flags.FLAGS)
+        self.mox.ReplayAll()
+        storage.register_opts(flags.FLAGS)