Implement custom constraint for nova server

Many resources have 'InstanceId' property related
with nova server, add nova server custom constraint
to validate the existent of the server.

Change-Id: I4ee5a392488f26b2de708412d58f9c206d6f2c43
Implements: blueprint nova-custom-constraints

heat/common/exception.py

@@ -231,6 +231,10 @@ class ImageNotFound(HeatException):
     msg_fmt = _("The Image (%(image_name)s) could not be found.")
 
 
+class ServerNotFound(HeatException):
+    msg_fmt = _("The server (%(server)s) could not be found.")
+
+
 class PhysicalResourceNameAmbiguity(HeatException):
     msg_fmt = _(
         "Multiple physical resources were found with name (%(name)s).")

heat/engine/clients/os/nova.py

@@ -32,6 +32,7 @@ from heat.common import exception
 from heat.common.i18n import _
 from heat.common.i18n import _LW
 from heat.engine.clients import client_plugin
+from heat.engine import constraints
 from heat.engine import scheduler
 
 LOG = logging.getLogger(__name__)
@@ -410,8 +411,24 @@ echo -e '%s\tALL=(ALL)\tNOPASSWD: ALL' >> /etc/sudoers
                 if len(server.networks[n]) > 0:
                     return server.networks[n][0]
 
+    def get_server(self, server):
+        try:
+            return self.client().servers.get(server)
+        except exceptions.NotFound as ex:
+            LOG.warn(_LW('Server (%(server)s) not found: %(ex)s'),
+                     {'server': server, 'ex': ex})
+            raise exception.ServerNotFound(server=server)
+
     def absolute_limits(self):
         """Return the absolute limits as a dictionary."""
         limits = self.client().limits.get()
         return dict([(limit.name, limit.value)
                     for limit in list(limits.absolute)])
+
+
+class ServerConstraint(constraints.BaseCustomConstraint):
+
+    expected_exceptions = (exception.ServerNotFound,)
+
+    def validate_with_client(self, client, server):
+        client.client_plugin('nova').get_server(server)

heat/tests/test_nova_client.py

@@ -96,6 +96,19 @@ class NovaClientPluginTests(NovaClientPluginTestCase):
                           self.nova_plugin.get_keypair, 'notakey')
         self.m.VerifyAll()
 
+    def test_get_server(self):
+        """Tests the get_server function."""
+        my_server = self.m.CreateMockAnything()
+        self.nova_client.servers = self.m.CreateMockAnything()
+        self.nova_client.servers.get('my_server').AndReturn(my_server)
+        self.nova_client.servers.get('idontexist').AndRaise(
+            nova_exceptions.NotFound(404))
+        self.m.ReplayAll()
+        self.assertEqual(my_server, self.nova_plugin.get_server('my_server'))
+        self.assertRaises(exception.ServerNotFound,
+                          self.nova_plugin.get_server, 'idontexist')
+        self.m.VerifyAll()
+
     def test_get_status(self):
         server = self.m.CreateMockAnything()
         server.status = 'ACTIVE'
@@ -256,3 +269,23 @@ class NovaUtilsMetadataTests(NovaClientPluginTestCase):
         }
 
         self.assertEqual(expected, self.nova_plugin.meta_serialize(original))
+
+
+class ServerConstraintTest(NovaClientPluginTestCase):
+
+    def setUp(self):
+        super(ServerConstraintTest, self).setUp()
+        self.ctx = utils.dummy_context()
+        self.mock_get_server = mock.Mock()
+        self.ctx.clients.client_plugin(
+            'nova').get_server = self.mock_get_server
+        self.constraint = nova.ServerConstraint()
+
+    def test_validation(self):
+        self.mock_get_server.return_value = mock.MagicMock()
+        self.assertTrue(self.constraint.validate("foo", self.ctx))
+
+    def test_validation_error(self):
+        self.mock_get_server.side_effect = exception.ServerNotFound(
+            server='bar')
+        self.assertFalse(self.constraint.validate("bar", self.ctx))

setup.cfg

@@ -57,6 +57,7 @@ heat.constraints =
     glance.image = heat.engine.clients.os.glance:ImageConstraint
     iso_8601 = heat.engine.resources.iso_8601:ISO8601Constraint
     nova.keypair = heat.engine.resources.nova_keypair:KeypairConstraint
+    nova.server = heat.engine.clients.os.nova:ServerConstraint
 
 heat.stack_lifecycle_plugins =