[APIv2] Update registry images tagging

The endpoint of image tag should be changed to follow guidelines
on tag[*]. Main ideas are:
1. To add, remove, or change tags, a PUT request should be sent to
   the root tags URL, the server responds with a 200 status code.
2. To delete the entire tag list associated with a resource, a
   DELETE request must be sent to the root tags URL.
3. the resource identified by URL must expose its tags with root
   URL like: http://example.com:8386/servers/1234567890/tags.
4. There also add a get tags method and a dozen of unit test

*: http://specs.openstack.org/openstack/api-wg/guidelines/tags.html

Partial-Implements: bp v2-api-experimental-impl
Change-Id: Ia70322538f966ad032ae804c99f6f07463461e7d

etc/sahara/policy.json

@@ -32,6 +32,7 @@
     "data-processing:images:register": "",
     "data-processing:images:unregister": "",
     "data-processing:images:add_tags": "",
+    "data-processing:images:set_tags": "",
     "data-processing:images:remove_tags": "",
 
     "data-processing:job-executions:get_all": "",

sahara/api/v2/images.py

@@ -54,17 +54,25 @@ def images_unset(image_id):
     return u.render()
 
 
-@rest.post('/images/<image_id>/tag')
-@acl.enforce("data-processing:images:add_tags")
+@rest.get('/images/<image_id>/tags')
+@acl.enforce("data-processing:images:get_tags")
+@v.check_exists(api.get_image, id='image_id')
+def image_tags_get(image_id):
+    return u.render(api.get_image_tags(image_id))
+
+
+@rest.put('/images/<image_id>/tags', status_code=200)
+@acl.enforce("data-processing:images:set_tags")
 @v.check_exists(api.get_image, id='image_id')
 @v.validate(v_images.image_tags_schema, v_images.check_tags)
-def image_tags_add(image_id, data):
-    return u.render(api.add_image_tags(image_id, **data).wrapped_dict)
+def image_tags_update(image_id, data):
+    return u.render(api.set_image_tags(image_id, **data).wrapped_dict)
 
 
-@rest.post('/images/<image_id>/untag')
+@rest.delete('/images/<image_id>/tags')
 @acl.enforce("data-processing:images:remove_tags")
 @v.check_exists(api.get_image, id='image_id')
 @v.validate(v_images.image_tags_schema)
-def image_tags_delete(image_id, data):
-    return u.render(api.remove_image_tags(image_id, **data).wrapped_dict)
+def image_tags_delete(image_id):
+    api.remove_image_tags(image_id)
+    return u.render()

sahara/service/api/v2/images.py

@@ -56,13 +56,32 @@ def unregister_image(image_id):
     return b.execute_with_retries(manager.get, image_id)
 
 
-def add_image_tags(image_id, tags):
+def get_image_tags(image_id):
+    return b.execute_with_retries(
+        sahara_images.image_manager().get, image_id).tags
+
+
+def set_image_tags(image_id, tags):
     manager = sahara_images.image_manager()
-    b.execute_with_retries(manager.tag, image_id, tags)
+    image_obj = b.execute_with_retries(manager.get, image_id)
+    org_tags = frozenset(image_obj.tags)
+    new_tags = frozenset(tags)
+
+    to_add = list(new_tags - org_tags)
+    to_remove = list(org_tags - new_tags)
+
+    if to_add:
+        b.execute_with_retries(manager.tag, image_id, to_add)
+
+    if to_remove:
+        b.execute_with_retries(manager.untag, image_id, to_remove)
+
     return b.execute_with_retries(manager.get, image_id)
 
 
-def remove_image_tags(image_id, tags):
+def remove_image_tags(image_id):
     manager = sahara_images.image_manager()
+    image_obj = b.execute_with_retries(manager.get, image_id)
+    tags = image_obj.tags
     b.execute_with_retries(manager.untag, image_id, tags)
     return b.execute_with_retries(manager.get, image_id)

sahara/tests/unit/service/api/v2/test_images.py

@@ -0,0 +1,68 @@
+# Copyright (c) 2017 EasyStack Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import mock
+
+from sahara.service.api.v2 import images
+from sahara.tests.unit import base
+
+
+class TestImageApi(base.SaharaTestCase):
+    def SetUp(self):
+        super(TestImageApi, self).SetUp()
+
+    @mock.patch('sahara.utils.openstack.images.SaharaImageManager')
+    def test_get_image_tags(self, mock_manager):
+        image = mock.Mock()
+        manager = mock.Mock()
+        manager.get.return_value = mock.Mock(tags=['foo', 'bar', 'baz'])
+        mock_manager.return_value = manager
+        self.assertEqual(['foo', 'bar', 'baz'], images.get_image_tags(image))
+
+    @mock.patch('sahara.utils.openstack.images.SaharaImageManager')
+    def test_set_image_tags(self, mock_manager):
+        def _tag(image, to_add):
+            return tags.append('qux')
+
+        def _untag(image, to_remove):
+            return tags.remove('bar')
+
+        expected_tags = ['foo', 'baz', 'qux']
+        tags = ['foo', 'bar', 'baz']
+        image = mock.Mock()
+        manager = mock.Mock()
+        manager.get.return_value = mock.Mock(tags=tags)
+        manager.tag.side_effect = _tag
+        manager.untag.side_effect = _untag
+        mock_manager.return_value = manager
+
+        self.assertEqual(expected_tags,
+                         images.set_image_tags(image, expected_tags).tags)
+
+    @mock.patch('sahara.utils.openstack.images.SaharaImageManager')
+    def test_remove_image_tags(self, mock_manager):
+        def _untag(image, to_remove):
+            for i in range(len(to_remove)):
+                actual_tags.pop()
+            return actual_tags
+
+        actual_tags = ['foo', 'bar', 'baz']
+        image = mock.Mock()
+        manager = mock.Mock()
+        manager.get.return_value = mock.Mock(tags=actual_tags)
+        manager.untag.side_effect = _untag
+        mock_manager.return_value = manager
+
+        self.assertEqual([], images.remove_image_tags(image).tags)