Adds separate class for Hypervisor Stats

Hypervisor stats was being called from the Hypervisors class, which means that
the statistics were being modeled as if they were a single Hypervisor. This
mostly worked, except that the stats didn't have an id field so a call to
__repr__() (implicitly called by print, or in the REPL) would throw an
AttributeError.

This patch creates a new class HypervisorStats which models a collection of
statistics about hypervisors. So you can now call:

  nc.hypervisor_stats.statistics()

The old call of

  nc.hypervisors.statistics()

is left for backward compatibility but just calls into the new method.

Change-Id: Ia31aacb95b1d517dab3ad38763d6448715bab68e
Closes-bug: 1370415

novaclient/tests/v1_1/test_hypervisors.py

@@ -168,3 +168,11 @@ class HypervisorsTest(utils.FixturedTestCase):
         self.assert_called('GET', '/os-hypervisors/statistics')
 
         self.compare_to_expected(expected, result)
+
+    def test_hypervisor_statistics_data_model(self):
+        result = self.cs.hypervisor_stats.statistics()
+        self.assert_called('GET', '/os-hypervisors/statistics')
+
+        # Test for Bug #1370415, the line below used to raise AttributeError
+        self.assertEqual("<HypervisorStats: 2 Hypervisors>",
+                         result.__repr__())

novaclient/v1_1/client.py

@@ -151,6 +151,7 @@ class Client(object):
         self.aggregates = aggregates.AggregateManager(self)
         self.hosts = hosts.HostManager(self)
         self.hypervisors = hypervisors.HypervisorManager(self)
+        self.hypervisor_stats = hypervisors.HypervisorStatsManager(self)
         self.services = services.ServiceManager(self)
         self.fixed_ips = fixed_ips.FixedIPsManager(self)
         self.floating_ips_bulk = floating_ips_bulk.FloatingIPBulkManager(self)

novaclient/v1_1/hypervisors.py

@@ -66,6 +66,25 @@ class HypervisorManager(base.ManagerWithFind):
         return self._get("/os-hypervisors/%s/uptime" % base.getid(hypervisor),
                          "hypervisor")
 
+    def statistics(self):
+        """
+        Get hypervisor statistics over all compute nodes.
+
+        Kept for backwards compatibility, new code should call
+        hypervisor_stats.statistics() instead of hypervisors.statistics()
+        """
+        return self.api.hypervisor_stats.statistics()
+
+
+class HypervisorStats(base.Resource):
+    def __repr__(self):
+        return ("<HypervisorStats: %d Hypervisor%s>" %
+                (self.count, "s" if self.count != 1 else ""))
+
+
+class HypervisorStatsManager(base.Manager):
+    resource_class = HypervisorStats
+
     def statistics(self):
         """
         Get hypervisor statistics over all compute nodes.

novaclient/v1_1/shell.py

@@ -3629,7 +3629,7 @@ def do_hypervisor_uptime(cs, args):
 
 def do_hypervisor_stats(cs, args):
     """Get hypervisor statistics over all compute nodes."""
-    stats = cs.hypervisors.statistics()
+    stats = cs.hypervisor_stats.statistics()
     utils.print_dict(stats._info.copy())