Add counter type mappings

- Add mappings between counter type in collectd and Ceilometer.
  Previously, all counters were given "gauge" type.
  Now, the following mappings are applied:
    - gauge -> gauge
    - derive -> delta
    - absolute, counter -> cumulative
- Add unit tests

Closes-Bug: #1583301
Change-Id: I13e75fcc57ed2b44c2b9a02ee9562f70748d01c2

collectd_ceilometer/meters/base.py

@@ -16,6 +16,9 @@
 from __future__ import unicode_literals
 
 from collectd_ceilometer.settings import Config
+import logging
+
+LOGGER = logging.getLogger(__name__)
 
 
 class Meter(object):
@@ -45,3 +48,21 @@ class Meter(object):
         """Get meter unit"""
         # pylint: disable=no-self-use
         return Config.instance().unit(vl.plugin, vl.type)
+
+    def sample_type(self, vl):
+        """Translate from collectd counter type to Ceilometer type"""
+        types = {"gauge": "gauge",
+                 "derive": "delta",
+                 "absolute": "cumulative",
+                 "counter": "cumulative"}
+
+        try:
+            # get_dataset -> [('value', 'derive', 0.0, None)]
+            collectd_type = self._collectd.get_dataset(str(vl.type))[0][1]
+        except Exception:
+            LOGGER.warning(
+                "Cannot map counter type '%s': using type 'gauge'.", vl.type,
+                exc_info=1)
+            collectd_type = "gauge"
+
+        return types[collectd_type]

collectd_ceilometer/tests/test_meters_base.py

@@ -0,0 +1,97 @@
+# -*- coding: utf-8 -*-
+
+# Copyright 2010-2011 OpenStack Foundation
+# Copyright (c) 2015 Intel Corporation.
+#
+# 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.
+
+"""Plugin tests"""
+
+from __future__ import unicode_literals
+
+from collectd_ceilometer.meters.base import Meter
+from collectd_ceilometer.tests.base import TestCase
+import mock
+
+
+class Values(object):
+    """Stub class to replace collectd.Values"""
+    def __init__(self, plugin="my_plugin", type="my_type"):
+        self.plugin = plugin
+        self.type = type
+
+
+class CollectdMock(object):
+    """Model for the collectd class to be mocked"""
+    def get_dataset(self, string):
+        pass
+
+collectd_class = 'collectd_ceilometer.tests.test_meters_base.CollectdMock'
+
+
+class MetersTest(TestCase):
+    """Test the meters/base.py class"""
+
+    @mock.patch(collectd_class, spec=True)
+    def setUp(self, collectd):
+        super(MetersTest, self).setUp()
+        self._collectd = collectd
+        # need this as a parameter for sample_type()
+        self.vl = Values()
+        self.meter = Meter(self._collectd)
+
+    def test_sample_type_gauge(self):
+        # sample_type uses get_dataset()[0][1]
+        self._collectd.get_dataset.return_value = [('value', 'gauge', )]
+
+        actual = self.meter.sample_type(self.vl)
+
+        self._collectd.get_dataset.assert_called_once()
+        self.assertEqual("gauge", actual)
+
+    def test_sample_type_derive(self):
+        # sample_type uses get_dataset()[0][1]
+        self._collectd.get_dataset.return_value = [('value', 'derive', )]
+
+        actual = self.meter.sample_type(self.vl)
+
+        self._collectd.get_dataset.assert_called_once()
+        self.assertEqual("delta", actual)
+
+    def test_sample_type_absolute(self):
+        # sample_type uses get_dataset()[0][1]
+        self._collectd.get_dataset.return_value = [('value', 'absolute', )]
+
+        actual = self.meter.sample_type(self.vl)
+
+        self._collectd.get_dataset.assert_called_once()
+        self.assertEqual("cumulative", actual)
+
+    def test_sample_type_counter(self):
+        # sample_type uses get_dataset()[0][1]
+        self._collectd.get_dataset.return_value = [('value', 'counter', )]
+
+        actual = self.meter.sample_type(self.vl)
+
+        self._collectd.get_dataset.assert_called_once()
+        self.assertEqual("cumulative", actual)
+
+    @mock.patch('collectd_ceilometer.meters.base.LOGGER')
+    def test_sample_type_invalid(self, LOGGER):
+        self._collectd.get_dataset.side_effect = Exception("Boom!")
+
+        actual = self.meter.sample_type(self.vl)
+
+        self._collectd.get_dataset.assert_called_once()
+        LOGGER.warning.assert_called_once()
+        self.assertEqual("gauge", actual)

collectd_ceilometer/writer.py

@@ -29,14 +29,15 @@ LOGGER = logging.getLogger(__name__)
 
 
 class Sample(namedtuple('Sample', ['value', 'timestamp', 'meta',
-                                   'resource_id', 'unit', 'metername'])):
+                                   'resource_id', 'unit',
+                                   'metername', 'sample_type'])):
     """Sample data"""
 
     def to_payload(self):
         """Return a payload dictionary"""
         return {
             'counter_name': self.metername,
-            'counter_type': 'gauge',
+            'counter_type': self.sample_type,
             'counter_unit': self.unit,
             'counter_volume': self.value,
             'timestamp': self.timestamp,
@@ -106,16 +107,18 @@ class Writer(object):
         metername = plugin.meter_name(vl)
         unit = plugin.unit(vl)
         timestamp = time.asctime(time.gmtime(vl.time))
+        sample_type = plugin.sample_type(vl)
 
         LOGGER.debug(
-            'Writing: plugin="%s", metername="%s", unit="%s"',
-            vl.plugin, metername, unit)
+            'Writing: plugin="%s", metername="%s", unit="%s", type="%s"',
+            vl.plugin, metername, unit, sample_type)
 
         # store sample for every value
         data = [
             Sample(
                 value=value, timestamp=timestamp, meta=vl.meta,
-                resource_id=resource_id, unit=unit, metername=metername)
+                resource_id=resource_id, unit=unit,
+                metername=metername, sample_type=sample_type)
             for value in vl.values
         ]