From babf11d6dd310ab5e752655a9b59efd7bb611197 Mon Sep 17 00:00:00 2001
From: Andrey Kurilin <andr.kurilin@gmail.com>
Date: Tue, 8 Nov 2016 17:23:08 +0200
Subject: [PATCH] [Services] redesign metaclass to support subclasses

Previous implementation restricts to create Mixin classes and it leds to
duplicate a bunch of code.

Restricted code:

   class SomeService(Service):
       def some_func(self):
           self._impl.some_func()

       def another_func(self):
           self._impl.another_func()

   class SomeMixin(object):
       def some_func(self): <- this method is common for several versions
           # do something

   class SomeV1(SomeService, SomeMixin):
       def another_func(self):
           # do something

   class SomeV2(SomeService, SomeMixin):
       def another_func(self):
           # do something

   class SomeV3(SomeService):
       def some_func(self):
           # do something

       def another_func(self):
           # do something

Instead of requiring all methods to be overridden and hardcode several
exceptions, it would be nice to provide more simplier way(similar to abstract
classes) to do it - simple decorator to mark which methods should be
implemented in subclasses

Change-Id: Ib5e9dcecfc1497ceb746d96f0917abd6e2cc7c82
---
 rally/plugins/openstack/service.py            |  1 +
 .../openstack/services/identity/identity.py   | 19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/rally/plugins/openstack/service.py b/rally/plugins/openstack/service.py
index dd2ab5a9..6c7bcd26 100644
--- a/rally/plugins/openstack/service.py
+++ b/rally/plugins/openstack/service.py
@@ -18,6 +18,7 @@ from rally.task import service as base_service
 service = base_service.service
 compat_layer = base_service.compat_layer
 Service = base_service.Service
+should_be_overridden = base_service.should_be_overridden
 
 
 class UnifiedOpenStackService(base_service.UnifiedService):
diff --git a/rally/plugins/openstack/services/identity/identity.py b/rally/plugins/openstack/services/identity/identity.py
index 99c3a2ab..820fe62e 100644
--- a/rally/plugins/openstack/services/identity/identity.py
+++ b/rally/plugins/openstack/services/identity/identity.py
@@ -30,6 +30,7 @@ class Identity(service.UnifiedOpenStackService):
         cloud_version = clients.keystone().version.split(".")[0][1:]
         return cloud_version == cls._meta_get("impl")._meta_get("version")
 
+    @service.should_be_overridden
     def create_project(self, project_name=None, domain_name="Default"):
         """Creates new project/tenant and return project object.
 
@@ -41,16 +42,20 @@ class Identity(service.UnifiedOpenStackService):
         return self._impl.create_project(project_name,
                                          domain_name=domain_name)
 
+    @service.should_be_overridden
     def delete_project(self, project_id):
         """Deletes project."""
         return self._impl.delete_project(project_id)
 
+    @service.should_be_overridden
     def list_projects(self):
         """List all projects."""
         return self._impl.list_projects()
 
-    def create_user(self, username, password, email=None, project_id=None,
-                    domain_name="Default", default_role="member"):
+    @service.should_be_overridden
+    def create_user(self, username=None, password=None, email=None,
+                    project_id=None, domain_name="Default",
+                    default_role="member"):
         """Create user.
 
         :param username: name of user
@@ -71,22 +76,27 @@ class Identity(service.UnifiedOpenStackService):
                                       domain_name=domain_name,
                                       default_role=default_role)
 
+    @service.should_be_overridden
     def delete_user(self, user_id):
         """Deletes user by its id."""
         self._impl.delete_user(user_id)
 
+    @service.should_be_overridden
     def list_users(self):
         """List all users."""
         return self._impl.list_users()
 
+    @service.should_be_overridden
     def delete_service(self, service_id):
         """Deletes service."""
         self._impl.delete_service(service_id)
 
+    @service.should_be_overridden
     def list_services(self):
         """List all services."""
         return self._impl.list_services()
 
+    @service.should_be_overridden
     def create_role(self, name=None, domain_name="Default"):
         """Create role with specific name
 
@@ -97,20 +107,24 @@ class Identity(service.UnifiedOpenStackService):
         """
         return self._impl.create_role(name=name, domain_name=domain_name)
 
+    @service.should_be_overridden
     def add_role(self, role_id, user_id, project_id):
         """Add role to user."""
         return self._impl.add_role(role_id=role_id, user_id=user_id,
                                    project_id=project_id)
 
+    @service.should_be_overridden
     def delete_role(self, role_id):
         """Deletes role."""
         self._impl.delete_role(role_id)
 
+    @service.should_be_overridden
     def revoke_role(self, role_id, user_id, project_id):
         """Revokes a role from a user."""
         return self._impl.revoke_role(role_id=role_id, user_id=user_id,
                                       project_id=project_id)
 
+    @service.should_be_overridden
     def list_roles(self, user_id=None, project_id=None, domain_name=None):
         """List all roles.
 
@@ -124,6 +138,7 @@ class Identity(service.UnifiedOpenStackService):
         return self._impl.list_roles(user_id=user_id, project_id=project_id,
                                      domain_name=domain_name)
 
+    @service.should_be_overridden
     def get_role(self, role_id):
         """Get role."""
         return self._impl.get_role(role_id)