Merge "Avoid re-downloading the same image from Glance"

tox.ini

@@ -25,7 +25,9 @@ commands =
 commands =
   doc8 -e .rst doc/source/ CONTRIBUTING.rst HACKING.rst README.rst
   bash tools/flake8wrap.sh {posargs}
-  bandit -r zun -x tests -n5 -ll
+  # The following bandit tests are being skipped:
+  # B303 - Use of insecure MD2, MD4, or MD5 hash function.
+  bandit -r zun -x tests -n5 -ll --skip B303
 
 [testenv:venv]
 commands = {posargs}

zun/image/glance/driver.py

@@ -11,6 +11,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import hashlib
 import os
 import six
 
@@ -47,7 +48,10 @@ class GlanceDriver(driver.ContainerImageDriver):
             out_path = os.path.join(images_directory,
                                     image_meta.id + '.tar')
             if os.path.isfile(out_path):
-                return {'image': repo, 'path': out_path}
+                return {
+                    'image': repo,
+                    'path': out_path,
+                    'checksum': image_meta.checksum}
             else:
                 return None
 
@@ -56,6 +60,22 @@ class GlanceDriver(driver.ContainerImageDriver):
         #              once metadata is stored in db then handle tags
         image_loaded = False
         image = self._search_image_on_host(context, repo)
+        if image:
+            image_path = image['path']
+            image_checksum = image['checksum']
+            md5sum = hashlib.md5()
+            with open(image_path, 'rb') as fd:
+                while True:
+                    # read 10MB of data each time
+                    data = fd.read(10 * 1024 * 1024)
+                    if not data:
+                        break
+                    md5sum.update(data)
+            md5sum = md5sum.hexdigest()
+            if md5sum == image_checksum:
+                image_loaded = True
+                return image, image_loaded
+
         if not common_utils.should_pull_image(image_pull_policy, bool(image)):
             if image:
                 LOG.debug('Image  %s present locally' % repo)

zun/tests/unit/image/glance/test_driver.py

@@ -52,10 +52,15 @@ class TestDriver(base.BaseTestCase):
     def test_pull_image_should_pull_no_image_present_locally(
             self, mock_should_pull_image, mock_search):
         mock_should_pull_image.return_value = False
-        mock_search.return_value = {'image': 'nginx', 'path': 'xyz'}
+        mock_search.return_value = {'image': 'nginx', 'path': 'xyz',
-        self.assertEqual(({'image': 'nginx', 'path': 'xyz'}, True),
+                                    'checksum': 'xxx'}
+        mock_open_file = mock.mock_open()
+        with mock.patch('zun.image.glance.driver.open', mock_open_file):
+            self.assertEqual(({'image': 'nginx', 'path': 'xyz',
+                               'checksum': 'xxx'}, True),
                              self.driver.pull_image(None, 'nonexisting',
                                                     'tag', 'never'))
+        mock_open_file.assert_any_call('xyz', 'rb')
 
     @mock.patch('zun.image.glance.utils.create_glanceclient')
     @mock.patch.object(driver.GlanceDriver,
@@ -64,10 +69,14 @@ class TestDriver(base.BaseTestCase):
     def test_pull_image_failure(self, mock_should_pull_image,
                                 mock_search, mock_glance):
         mock_should_pull_image.return_value = True
-        mock_search.return_value = {'image': 'nginx', 'path': 'xyz'}
+        mock_search.return_value = {'image': 'nginx', 'path': 'xyz',
+                                    'checksum': 'xxx'}
+        mock_open_file = mock.mock_open()
+        with mock.patch('zun.image.glance.driver.open', mock_open_file):
             mock_glance.side_effect = Exception
             self.assertRaises(exception.ZunException, self.driver.pull_image,
                               None, 'nonexisting', 'tag', 'always')
+        mock_open_file.assert_any_call('xyz', 'rb')
 
     @mock.patch.object(driver.GlanceDriver,
                        '_search_image_on_host')
@@ -77,25 +86,26 @@ class TestDriver(base.BaseTestCase):
     def test_pull_image(self, mock_find_image, mock_glance,
                         mock_should_pull_image, mock_search):
         mock_should_pull_image.return_value = True
-        mock_search.return_value = {'image': 'nginx', 'path': 'xyz'}
+        mock_search.return_value = {'image': 'nginx', 'path': 'xyz',
+                                    'checksum': 'xxx'}
         mock_glance.images.data = mock.MagicMock(return_value='content')
         image_meta = mock.MagicMock()
         image_meta.id = '1234'
         mock_find_image.return_value = image_meta
         CONF.set_override('images_directory', self.test_dir, group='glance')
         out_path = os.path.join(self.test_dir, '1234' + '.tar')
+        mock_open_file = mock.mock_open()
+        with mock.patch('zun.image.glance.driver.open', mock_open_file):
             ret = self.driver.pull_image(None, 'image', 'latest', 'always')
+        mock_open_file.assert_any_call('xyz', 'rb')
+        mock_open_file.assert_any_call(out_path, 'wb')
         self.assertEqual(({'image': 'image', 'path': out_path}, False), ret)
-        self.assertTrue(os.path.isfile(ret[0]['path']))
 
     @mock.patch('zun.image.glance.utils.create_glanceclient')
-    @mock.patch.object(driver.GlanceDriver,
-                       '_search_image_on_host')
     @mock.patch('zun.common.utils.should_pull_image')
     def test_pull_image_not_found(self, mock_should_pull_image,
-                                  mock_search, mock_glance):
+                                  mock_glance):
         mock_should_pull_image.return_value = True
-        mock_search.return_value = {'image': 'nginx', 'path': 'xyz'}
         with mock.patch('zun.image.glance.utils.find_image') as mock_find:
             mock_find.side_effect = exception.ImageNotFound
             self.assertRaises(exception.ImageNotFound, self.driver.pull_image,