From 5251f18d87f21483fca385a0baccf76dfff85e92 Mon Sep 17 00:00:00 2001
From: Mark Goddard <mark@stackhpc.com>
Date: Mon, 8 Jan 2018 14:15:10 +0000
Subject: [PATCH] Add get_traits() method to ComputeDriver

The get_traits() virt driver method can be used by virt driver
implementations to advertise the traits that are associated with the
resource provider representing a given compute node. If implemented, the
method should return an iterable of traits.

Adds a call to the ComputeDriver.get_traits() method in the resource
tracker, and submits the traits to the placement API using the scheduler
client. Not all compute drivers implement get_traits, so the resource
tracker gracefully handles NotImplementedError.

blueprint ironic-driver-traits

Change-Id: Ia088341d86aa87f72c9decb081e0a43c36939f18
---
 nova/compute/resource_tracker.py              | 13 ++++++++
 .../unit/compute/test_resource_tracker.py     | 31 +++++++++++++++++++
 nova/virt/driver.py                           | 10 ++++++
 3 files changed, 54 insertions(+)

diff --git a/nova/compute/resource_tracker.py b/nova/compute/resource_tracker.py
index b0f64048eaa0..ef2b26b44b30 100644
--- a/nova/compute/resource_tracker.py
+++ b/nova/compute/resource_tracker.py
@@ -883,6 +883,19 @@ class ResourceTracker(object):
             # this code branch
             self.scheduler_client.update_compute_node(context, compute_node)
 
+        try:
+            traits = self.driver.get_traits(nodename)
+        except NotImplementedError:
+            pass
+        else:
+            # NOTE(mgoddard): set_traits_for_provider does not refresh the
+            # provider tree in the report client, so we rely on the above call
+            # to set_inventory_for_provider or update_compute_node to ensure
+            # that the resource provider exists in the tree and has had its
+            # cached traits refreshed.
+            self.reportclient.set_traits_for_provider(
+                compute_node.uuid, traits)
+
         if self.pci_tracker:
             self.pci_tracker.save(context)
 
diff --git a/nova/tests/unit/compute/test_resource_tracker.py b/nova/tests/unit/compute/test_resource_tracker.py
index 94c9e8d493d9..9b957b3fa4ff 100644
--- a/nova/tests/unit/compute/test_resource_tracker.py
+++ b/nova/tests/unit/compute/test_resource_tracker.py
@@ -433,6 +433,7 @@ def setup_rt(hostname, virt_resources=_VIRT_DRIVER_AVAIL_RESOURCES,
     virt_resources = copy.deepcopy(virt_resources)
     vd.get_available_resource.return_value = virt_resources
     vd.get_inventory.side_effect = NotImplementedError
+    vd.get_traits.side_effect = NotImplementedError
     vd.get_host_ip_addr.return_value = _NODENAME
     vd.estimate_instance_overhead.side_effect = estimate_overhead
     vd.rebalances_nodes = False
@@ -1202,6 +1203,7 @@ class TestUpdateComputeNode(BaseTestCase):
         self.driver_mock.get_inventory.assert_called_once_with(_NODENAME)
         ucn_mock = self.sched_client_mock.update_compute_node
         ucn_mock.assert_called_once_with(mock.sentinel.ctx, new_compute)
+        self.driver_mock.get_traits.assert_called_once_with(_NODENAME)
 
     @mock.patch('nova.objects.ComputeNode.save')
     def test_existing_compute_node_updated_diff_updated_at(self, save_mock):
@@ -1250,6 +1252,7 @@ class TestUpdateComputeNode(BaseTestCase):
         self.assertFalse(norm_mock.called)
         ucn_mock = self.sched_client_mock.update_compute_node
         ucn_mock.assert_called_once_with(mock.sentinel.ctx, new_compute)
+        self.driver_mock.get_traits.assert_called_once_with(_NODENAME)
 
     @mock.patch('nova.compute.resource_tracker.'
                 '_normalize_inventory_from_cn_obj')
@@ -1288,6 +1291,34 @@ class TestUpdateComputeNode(BaseTestCase):
             mock.sentinel.inv_data,
         )
         self.assertFalse(ucn_mock.called)
+        self.driver_mock.get_traits.assert_called_once_with(_NODENAME)
+
+    def test_existing_node_get_traits_implemented(self):
+        """The get_traits() virt driver method is only implemented for some
+        virt drivers. This method returns traits information for a
+        node/provider, and if this method doesn't raise a NotImplementedError,
+        this triggers _update() to call the set_traits_for_provider() method of
+        the reporting client.
+        """
+        self._setup_rt()
+        rc = self.rt.reportclient
+        rc.set_traits_for_provider = mock.MagicMock()
+
+        # Emulate a driver that has implemented the new get_traits() virt
+        # driver method
+        self.driver_mock.get_traits.side_effect = [mock.sentinel.traits]
+
+        orig_compute = _COMPUTE_NODE_FIXTURES[0].obj_clone()
+        self.rt.compute_nodes[_NODENAME] = orig_compute
+        self.rt.old_resources[_NODENAME] = orig_compute
+        new_compute = orig_compute.obj_clone()
+
+        self.rt._update(mock.sentinel.ctx, new_compute)
+        rc.set_traits_for_provider.assert_called_once_with(
+            new_compute.uuid,
+            mock.sentinel.traits,
+        )
+        self.driver_mock.get_traits.assert_called_once_with(_NODENAME)
 
     def test_get_node_uuid(self):
         self._setup_rt()
diff --git a/nova/virt/driver.py b/nova/virt/driver.py
index df81af4f70cd..f575148e9c34 100644
--- a/nova/virt/driver.py
+++ b/nova/virt/driver.py
@@ -836,6 +836,16 @@ class ComputeDriver(object):
         """
         raise NotImplementedError()
 
+    def get_traits(self, nodename):
+        """Get the traits for a given node.
+
+        Returns an iterable of traits for the supplied node.
+
+        :param nodename: the name of the node.
+        :returns: an iterable of traits for the supplied node.
+        """
+        raise NotImplementedError()
+
     def get_available_resource(self, nodename):
         """Retrieve resource information.