Add a timestamp to LB stats object.

Timestamp will be used to identify when the stats are recorded.

Change-Id: I1d73f360055447b0e8cde91aadd622250881ab00

libra/common/lbstats.py

@@ -12,6 +12,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import datetime
+
 
 class LBStatistics(object):
     """ Load balancer statistics class. """
@@ -20,6 +22,7 @@ class LBStatistics(object):
         self.stats = {}
         self.bytes_out = 0
         self.bytes_in = 0
+        self.utc_timestamp = datetime.datetime.utcnow()
 
     @property
     def bytes_out(self):
@@ -40,3 +43,14 @@ class LBStatistics(object):
         if not isinstance(value, int):
             raise TypeError("Must be an integer: '%s'" % value)
         self.stats['bytes_in'] = value
+
+    @property
+    def utc_timestamp(self):
+        """ UTC timestamp for when these statistics are generated. """
+        return self._utc_ts
+
+    @utc_timestamp.setter
+    def utc_timestamp(self, value):
+        if not isinstance(value, datetime.datetime):
+            raise TypeError("Must be a datetime.datetime: '%s'" % value)
+        self._utc_ts = value

tests/test_lbstats.py

@@ -1,3 +1,4 @@
+import datetime
 import unittest
 from libra.common.lbstats import LBStatistics
 
@@ -10,8 +11,14 @@ class TestLBStatistics(unittest.TestCase):
         pass
 
     def testInitValues(self):
+        now = datetime.datetime.utcnow()
         self.assertEquals(self.stats.bytes_out, 0)
         self.assertEquals(self.stats.bytes_in, 0)
+        ts = self.stats.utc_timestamp
+        self.assertEquals(ts.year, now.year)
+        self.assertEquals(ts.month, now.month)
+        self.assertEquals(ts.day, now.day)
+        self.assertEquals(ts.hour, now.hour)
 
     def testSetBytesIn(self):
         self.stats.bytes_in = 99
@@ -24,3 +31,10 @@ class TestLBStatistics(unittest.TestCase):
         self.assertEquals(self.stats.bytes_out, 100)
         with self.assertRaises(TypeError):
             self.stats.bytes_out = "NaN"
+
+    def testSetUTCTimestamp(self):
+        ts = datetime.datetime.utcnow()
+        self.stats.utc_timestamp = ts
+        self.assertEquals(self.stats.utc_timestamp, ts)
+        with self.assertRaises(TypeError):
+            self.stats.utc_timestamp = "2012-01-01 12:00:00"