Improve image.v2.tag

While looking into create_by_id usage, I came across image.v2.tag as
something that needed to be adjusted. It was a bit cumbersome to use and
is doesn't benefit from a lot of the usual resource things since it
it just needs to join a string to the base_path and doesn't send or
receive anything else.

    t = tag.Tag({"image": image_resource_or_id})
    t.create(conn.session, "new tag")
    t.delete(conn.session, "old tag")

Building a proxy will be trivial for this. Viewing tags isn't offered by
this resource, but you can see them via image.Image.tags

Change-Id: I2bd549c55a8c21ac292752509122896a6fd51fe8

openstack/image/v2/tag.py

@@ -11,25 +11,45 @@
 # under the License.
 
 from openstack.image import image_service
+from openstack.image.v2 import image
 from openstack import resource
+from openstack import utils
 
 
 class Tag(resource.Resource):
-    id_attribute = 'tag'
-    resources_key = 'tags'
-    base_path = '/images/%(image_id)s/tags'
+    id_attribute = "image"
+    base_path = "/images/%(image)s/tags"
     service = image_service.ImageService()
 
     # capabilities
     allow_create = True
     allow_delete = True
 
-    # Properties
-    image_id = resource.prop('image_id')
+    #: The image to manipulate
+    image = resource.prop("image", type=image.Image)
 
-    def create(self, session):
-        """Create a remote resource from this instance."""
-        # Service expects a naked PUT. Omit properties.
-        self.create_by_id(session, None, self.id, path_args=self)
-        self._reset_dirty()
-        return self
+    def create(self, session, tag):
+        """Set a tag on the image
+
+        :param session: The session to use for making this request.
+        :type session: :class:`~openstack.session.Session`
+        :param string tag: A tag to set on the image
+
+        :return: ``None``
+        """
+        url = utils.urljoin(self.base_path %
+                            {"image": self.image.id}, tag)
+        session.put(url, service=self.service, accept=None)
+
+    def delete(self, session, tag):
+        """Delete a tag on the image
+
+        :param session: The session to use for making this request.
+        :type session: :class:`~openstack.session.Session`
+        :param string tag: The tag to delete on the image
+
+        :return: ``None``
+        """
+        url = utils.urljoin(self.base_path %
+                            {"image": self.image.id}, tag)
+        session.delete(url, service=self.service, accept=None)

openstack/tests/unit/image/v2/test_tag.py

@@ -13,23 +13,27 @@
 import mock
 import testtools
 
+from openstack.image.v2 import image
 from openstack.image.v2 import tag
 
-IDENTIFIER = 'IDENTIFIER'
-EXAMPLE = {
-    'image_id': 'IMAGE_ID',
-    'tag': IDENTIFIER,
-}
-
 
 class TestTag(testtools.TestCase):
+
+    def setUp(self):
+        super(TestTag, self).setUp()
+
+        self.session = mock.Mock()
+        self.session.put = mock.Mock()
+        self.session.delete = mock.Mock()
+
+        self.img = image.Image({"id": "123"})
+
     def test_basic(self):
         sot = tag.Tag()
         self.assertIsNone(sot.resource_key)
-        self.assertEqual('tags', sot.resources_key)
-        self.assertEqual('/images/%(image_id)s/tags', sot.base_path)
+        self.assertEqual('/images/%(image)s/tags', sot.base_path)
         self.assertEqual('image', sot.service.service_type)
-        self.assertEqual('tag', sot.id_attribute)
+        self.assertEqual('image', sot.id_attribute)
         self.assertTrue(sot.allow_create)
         self.assertFalse(sot.allow_retrieve)
         self.assertFalse(sot.allow_update)
@@ -37,14 +41,23 @@ class TestTag(testtools.TestCase):
         self.assertFalse(sot.allow_list)
 
     def test_make_it(self):
-        sot = tag.Tag(EXAMPLE)
-        self.assertEqual(IDENTIFIER, sot.id)
-        self.assertEqual(EXAMPLE['image_id'], sot.image_id)
+        sot = tag.Tag({"image": self.img})
+        self.assertEqual(self.img, sot.image)
+
+    def _test_action(self, sot_method, session_method):
+        test_tag = "testing"
+
+        sot = tag.Tag({"image": self.img})
+        rv = getattr(sot, sot_method)(self.session, test_tag)
+
+        url = 'images/%(image)s/tags/%(tag)s' % {
+            "image": self.img.get_id(self.img), "tag": test_tag}
+        self.assertIsNone(rv)
+        session_method.assert_called_with(url, service=sot.service,
+                                          accept=None)
 
     def test_create(self):
-        sess = mock.Mock()
-        resp = mock.Mock()
-        sess.put = mock.Mock(return_value=resp)
-        url = 'images/{image_id}/tags/{tag}'.format(**EXAMPLE)
-        tag.Tag(EXAMPLE).create(sess)
-        sess.put.assert_called_with(url, service=tag.Tag.service, json=None)
+        self._test_action("create", self.session.put)
+
+    def test_delete(self):
+        self._test_action("delete", self.session.delete)