Ensure combination alarms can be evaluated

Fixes bug 1237589

Previously the retrieval of state for the constituent alarms always
failed for combination alarms, due to an incorrect attribute of
ceilometerclient being used. As a result combination alarms could
never be successfully evaluated.

Now the correct pluralized attribute is used.

Change-Id: Id58a5d185854367e5a08011048774ab5aed93d4e
(cherry picked from commit f44e292)

ceilometer/alarm/evaluator/combination.py

@@ -31,7 +31,7 @@ class CombinationEvaluator(evaluator.Evaluator):
 
     def _get_alarm_state(self, alarm_id):
         try:
-            alarm = self._client.alarm.get(alarm_id)
+            alarm = self._client.alarms.get(alarm_id)
         except Exception:
             LOG.exception(_('alarm retrieval failed'))
             return None

tests/alarm/evaluator/test_combination.py

@@ -103,7 +103,7 @@ def test_retry_transient_api_failure(self):
         with mock.patch('ceilometerclient.client.get_client',
                         return_value=self.api_client):
             broken = exc.CommunicationError(message='broken')
-            self.api_client.alarm.get.side_effect = [
+            self.api_client.alarms.get.side_effect = [
                 broken,
                 broken,
                 broken,
@@ -123,7 +123,7 @@ def test_simple_insufficient(self):
         with mock.patch('ceilometerclient.client.get_client',
                         return_value=self.api_client):
             broken = exc.CommunicationError(message='broken')
-            self.api_client.alarm.get.side_effect = broken
+            self.api_client.alarms.get.side_effect = broken
             self._evaluate_all_alarms()
             self._assert_all_alarms('insufficient data')
             expected = [mock.call(alarm.alarm_id, state='insufficient data')
@@ -141,7 +141,7 @@ def test_to_ok_with_all_ok(self):
         self._set_all_alarms('insufficient data')
         with mock.patch('ceilometerclient.client.get_client',
                         return_value=self.api_client):
-            self.api_client.alarm.get.side_effect = [
+            self.api_client.alarms.get.side_effect = [
                 self._get_alarm('ok'),
                 self._get_alarm('ok'),
                 self._get_alarm('ok'),
@@ -161,7 +161,7 @@ def test_to_ok_with_one_alarm(self):
         self._set_all_alarms('alarm')
         with mock.patch('ceilometerclient.client.get_client',
                         return_value=self.api_client):
-            self.api_client.alarm.get.side_effect = [
+            self.api_client.alarms.get.side_effect = [
                 self._get_alarm('ok'),
                 self._get_alarm('ok'),
                 self._get_alarm('alarm'),
@@ -181,7 +181,7 @@ def test_to_alarm_with_all_alarm(self):
         self._set_all_alarms('ok')
         with mock.patch('ceilometerclient.client.get_client',
                         return_value=self.api_client):
-            self.api_client.alarm.get.side_effect = [
+            self.api_client.alarms.get.side_effect = [
                 self._get_alarm('alarm'),
                 self._get_alarm('alarm'),
                 self._get_alarm('alarm'),
@@ -201,7 +201,7 @@ def test_to_alarm_with_one_ok(self):
         self._set_all_alarms('ok')
         with mock.patch('ceilometerclient.client.get_client',
                         return_value=self.api_client):
-            self.api_client.alarm.get.side_effect = [
+            self.api_client.alarms.get.side_effect = [
                 self._get_alarm('ok'),
                 self._get_alarm('alarm'),
                 self._get_alarm('alarm'),
@@ -222,7 +222,7 @@ def test_to_unknown(self):
         with mock.patch('ceilometerclient.client.get_client',
                         return_value=self.api_client):
             broken = exc.CommunicationError(message='broken')
-            self.api_client.alarm.get.side_effect = [
+            self.api_client.alarms.get.side_effect = [
                 broken,
                 self._get_alarm('ok'),
                 self._get_alarm('insufficient data'),
@@ -249,7 +249,7 @@ def test_no_state_change(self):
         self._set_all_alarms('ok')
         with mock.patch('ceilometerclient.client.get_client',
                         return_value=self.api_client):
-            self.api_client.alarm.get.side_effect = [
+            self.api_client.alarms.get.side_effect = [
                 self._get_alarm('ok'),
                 self._get_alarm('ok'),
                 self._get_alarm('ok'),
@@ -266,7 +266,7 @@ def test_no_state_change_and_repeat_actions(self):
         self._set_all_alarms('ok')
         with mock.patch('ceilometerclient.client.get_client',
                         return_value=self.api_client):
-            self.api_client.alarm.get.side_effect = [
+            self.api_client.alarms.get.side_effect = [
                 self._get_alarm('ok'),
                 self._get_alarm('ok'),
                 self._get_alarm('ok'),