Fix role validation in release PUT handler

Plugins' roles can be assigned to some nodes, so we can't
assume that release roles is be a superset of node roles
everywhere.

So check that there are no nodes in all clusters, which
have roles assigned, that we are trying top delete.

Change-Id: Ia10f7b0662866da0872863bba7f97c8ad361fcf4
Closes-Bug: #1625592

nailgun/nailgun/api/v1/validators/release.py

@@ -94,27 +94,29 @@ class ReleaseValidator(BasicValidator):
             )
 
         if 'roles_metadata' in d:
-            new_roles = set(d['roles_metadata'])
-            clusters = [cluster.id for cluster in instance.clusters]
+            deleted_roles = (set(instance.roles_metadata) -
+                             set(d['roles_metadata']))
+            clusters_ids = (cluster.id for cluster in instance.clusters)
 
-            new_roles_array = sa.cast(
-                psql.array(new_roles),
+            deleted_roles_array = sa.cast(
+                psql.array(deleted_roles),
                 psql.ARRAY(sa.String(consts.ROLE_NAME_MAX_SIZE)))
 
             node = db().query(models.Node).filter(
-                models.Node.cluster_id.in_(clusters)
-            ).filter(sa.not_(sa.and_(
-                models.Node.roles.contained_by(new_roles_array),
-                models.Node.pending_roles.contained_by(new_roles_array)
-            ))).first()
+                models.Node.cluster_id.in_(clusters_ids)
+            ).filter(sa.or_(
+                models.Node.roles.overlap(deleted_roles_array),
+                models.Node.pending_roles.overlap(deleted_roles_array)
+            )).first()
 
             if node:
                 used_role = set(node.roles + node.pending_roles)
-                used_role -= new_roles
+                used_role = used_role.intersection(deleted_roles)
 
                 raise errors.CannotDelete(
-                    "Cannot delete roles already assigned "
-                    "to nodes: {0}".format(','.join(used_role))
+                    "The following roles: {0} cannot be deleted "
+                    "since they are already assigned "
+                    "to nodes.".format(','.join(used_role))
                 )
 
         return d

nailgun/nailgun/test/integration/test_roles.py

@@ -146,5 +146,6 @@ class TestRoles(BaseIntegrationTest):
         self.assertEqual(resp.status_code, 400)
         self.assertEqual(
             resp.json_body["message"],
-            "Cannot delete roles already assigned to nodes: controller"
+            "The following roles: controller cannot be deleted "
+            "since they are already assigned to nodes."
         )

nailgun/nailgun/test/unit/test_release_validator.py

@@ -16,6 +16,7 @@ from oslo_serialization import jsonutils
 from nailgun.api.v1.validators.release import ReleaseValidator
 from nailgun import errors
 from nailgun.test.base import BaseTestCase
+from nailgun.utils import reverse
 
 
 class TestReleaseValidator(BaseTestCase):
@@ -62,3 +63,40 @@ class TestReleaseValidator(BaseTestCase):
 
     def test_default_are_good(self):
         self.validator.validate(self.get_release(self.release))
+
+    def test_release_delete_role(self):
+        cluster = self.env.create(
+            nodes_kwargs=[{
+                "roles": ['test_plugin_role_1'],
+                "pending_roles": ['cinder', 'test_plugin_role_2'],
+            }])
+
+        resp = self.app.get(
+            reverse('ReleaseHandler',
+                    kwargs={'obj_id': cluster.release.id}),
+            headers=self.default_headers
+        )
+
+        data = dict(resp.json_body)
+        resp = self.app.put(
+            reverse('ReleaseHandler',
+                    kwargs={'obj_id': cluster.release.id}),
+            params=jsonutils.dumps(data),
+            headers=self.default_headers,
+            expect_errors=False
+        )
+
+        data['roles_metadata'].pop('cinder')
+        resp = self.app.put(
+            reverse('ReleaseHandler',
+                    kwargs={'obj_id': cluster.release.id}),
+            params=jsonutils.dumps(data),
+            headers=self.default_headers,
+            expect_errors=True
+        )
+
+        self.assertEqual(resp.status_code, 400)
+        self.assertIn(
+            "The following roles: cinder cannot be deleted",
+            resp.json_body["message"],
+        )