Add functionality for counting events

Similar to the existing streams functionality, this patch adds
the ability to get just a count of filtered events rather than
the full list of events.

There are corresponding changes in quince, quincy, and klugman.

Change-Id: Ic14845db48170a8481c764f5f2468f137758bd19

setup.cfg

@@ -1,7 +1,7 @@
 [metadata]
 description-file = README.md
 name = winchester
-version = 0.4
+version = 0.5
 author = Monsyne Dragon
 author_email = mdragon@rackspace.com
 summary = An OpenStack notification event processing library.

tests/test_db.py

@@ -486,6 +486,10 @@ class TestDB(unittest.TestCase):
         for event in events:
             self.assertTrue(event['message_id'] in self.events)
 
+    def test_find_event_count(self):
+        count = self.db.find_events(count=True)
+        self.assertEqual([{'count': 4}], count)
+
     def test_find_events_date_filter(self):
         _from = datetime.datetime(2014,8,1,10)
         _to = datetime.datetime(2014,8,1,16)

winchester/db/interface.py

@@ -130,7 +130,7 @@ class DBInterface(object):
     @sessioned
     def find_events(self, from_datetime=None, to_datetime=None,
                     event_name=None, traits=None, mark=None, limit=None,
-                    session=None):
+                    session=None, count=False):
 
         order_desc = True
 
@@ -161,6 +161,10 @@ class DBInterface(object):
                         models.Trait.name == name,
                         models.Trait.value == val)))
 
+        if count:
+            q = q.count()
+            return [{"count": q}]
+
         if order_desc:
             q = q.order_by(models.Event.id.desc())
             mark_fmt = '%x'