Extract helper method to get image metadata from volume

This refactoring needs for futher review(-s).
First is here - https://review.openstack.org/#/c/170243
But it will be divided to separate reviews and some refactoring
should be done first.

Change-Id: Iac713b832b4cbc62ae69bfa1c4680c6932a735c3

nova/compute/api.py

@@ -32,7 +32,6 @@ from oslo_serialization import jsonutils
 from oslo_utils import excutils
 from oslo_utils import strutils
 from oslo_utils import timeutils
-from oslo_utils import units
 from oslo_utils import uuidutils
 import six
 from six.moves import range
@@ -1003,26 +1002,7 @@ class API(base.Base):
                 if not volume.get('bootable', True):
                     raise exception.InvalidBDMVolumeNotBootable(id=volume_id)
 
-                properties = volume.get('volume_image_metadata', {})
-                image_meta = {'properties': properties}
-                # NOTE(yjiang5): restore the basic attributes
-                # NOTE(mdbooth): These values come from volume_glance_metadata
-                # in cinder. This is a simple key/value table, and all values
-                # are strings. We need to convert them to ints to avoid
-                # unexpected type errors.
-                image_meta['min_ram'] = int(properties.get('min_ram', 0))
-                image_meta['min_disk'] = int(properties.get('min_disk', 0))
-                # Volume size is no longer related to the original image size,
-                # so we take it from the volume directly. Cinder creates
-                # volumes in Gb increments, and stores size in Gb, whereas
-                # glance reports size in bytes. As we're returning glance
-                # metadata here, we need to convert it.
-                image_meta['size'] = volume.get('size', 0) * units.Gi
-                # NOTE(yjiang5): Always set the image status as 'active'
-                # and depends on followed volume_api.check_attach() to
-                # verify it. This hack should be harmless with that check.
-                image_meta['status'] = 'active'
-                return image_meta
+                return utils.get_image_metadata_from_volume(volume)
         return {}
 
     @staticmethod

nova/tests/unit/test_utils.py

@@ -33,6 +33,7 @@ from oslo_context import context as common_context
 from oslo_context import fixture as context_fixture
 from oslo_utils import encodeutils
 from oslo_utils import timeutils
+from oslo_utils import units
 import six
 
 
@@ -912,6 +913,31 @@ class GetImageFromSystemMetadataTestCase(test.NoDBTestCase):
         self.assertNotIn("foo1", image)
 
 
+class GetImageMetadataFromVolumeTestCase(test.NoDBTestCase):
+    def test_inherit_image_properties(self):
+        properties = {"fake_prop": "fake_value"}
+        volume = {"volume_image_metadata": properties}
+        image_meta = utils.get_image_metadata_from_volume(volume)
+        self.assertEqual(properties, image_meta["properties"])
+
+    def test_image_size(self):
+        volume = {"size": 10}
+        image_meta = utils.get_image_metadata_from_volume(volume)
+        self.assertEqual(10 * units.Gi, image_meta["size"])
+
+    def test_image_status(self):
+        volume = {}
+        image_meta = utils.get_image_metadata_from_volume(volume)
+        self.assertEqual("active", image_meta["status"])
+
+    def test_values_conversion(self):
+        properties = {"min_ram": "5", "min_disk": "7"}
+        volume = {"volume_image_metadata": properties}
+        image_meta = utils.get_image_metadata_from_volume(volume)
+        self.assertEqual(5, image_meta["min_ram"])
+        self.assertEqual(7, image_meta["min_disk"])
+
+
 class VersionTestCase(test.NoDBTestCase):
     def test_convert_version_to_int(self):
         self.assertEqual(utils.convert_version_to_int('6.2.0'), 6002000)

nova/utils.py

@@ -46,6 +46,7 @@ from oslo_utils import encodeutils
 from oslo_utils import excutils
 from oslo_utils import importutils
 from oslo_utils import timeutils
+from oslo_utils import units
 import six
 from six.moves import range
 
@@ -1126,6 +1127,29 @@ def get_image_from_system_metadata(system_meta):
     return image_meta
 
 
+def get_image_metadata_from_volume(volume):
+    properties = volume.get('volume_image_metadata', {})
+    image_meta = {'properties': properties}
+    # NOTE(yjiang5): restore the basic attributes
+    # NOTE(mdbooth): These values come from volume_glance_metadata
+    # in cinder. This is a simple key/value table, and all values
+    # are strings. We need to convert them to ints to avoid
+    # unexpected type errors.
+    image_meta['min_ram'] = int(properties.get('min_ram', 0))
+    image_meta['min_disk'] = int(properties.get('min_disk', 0))
+    # Volume size is no longer related to the original image size,
+    # so we take it from the volume directly. Cinder creates
+    # volumes in Gb increments, and stores size in Gb, whereas
+    # glance reports size in bytes. As we're returning glance
+    # metadata here, we need to convert it.
+    image_meta['size'] = volume.get('size', 0) * units.Gi
+    # NOTE(yjiang5): Always set the image status as 'active'
+    # and depends on followed volume_api.check_attach() to
+    # verify it. This hack should be harmless with that check.
+    image_meta['status'] = 'active'
+    return image_meta
+
+
 def get_hash_str(base_str):
     """returns string that represents hash of base_str (in hex format)."""
     return hashlib.md5(base_str).hexdigest()