Support create a volume from image snapshot

The instance boot from volume, snapshot the instance will create
a image in glance. The image size is 0, it just a link to the
volume snapshot. When the user create volume from the snapshot
image, in the current version, it will create a blank volume. so
the user is troubled. This patch fix it.

The scheme: when the user create volume from snapshot image, the
api create interface will parse out the snapshot image corresponds
to the volume snapshot id. Then create a volume from the volume
snapshot. So, the user can use this way to restore the instance's
bootable volume.

Change-Id: Ic44dfae8bb187a5aa9c2c1f50f7b5dc0ef0f28f8
Closes-Bug: #1560867

cinder/api/microversions.py

@@ -129,6 +129,8 @@ NEW_ATTACH_COMPLETION = '3.44'
 
 SUPPORT_COUNT_INFO = '3.45'
 
+SUPPORT_NOVA_IMAGE = '3.46'
+
 
 def get_mv_header(version):
     """Gets a formatted HTTP microversion header.

cinder/api/openstack/api_version_request.py

@@ -109,6 +109,7 @@ REST_API_VERSION_HISTORY = """
     * 3.44 - Add attachment-complete.
     * 3.45 - Add ``count`` field to volume, backup and snapshot list and
              detail APIs.
+    * 3.46 - Support create volume by Nova specific image (0 size image).
 """
 
 # The minimum and maximum versions of the API supported
@@ -116,7 +117,7 @@ REST_API_VERSION_HISTORY = """
 # minimum version of the API supported.
 # Explicitly using /v2 endpoints will still work
 _MIN_API_VERSION = "3.0"
-_MAX_API_VERSION = "3.45"
+_MAX_API_VERSION = "3.46"
 _LEGACY_API_VERSION2 = "2.0"
 UPDATED = "2017-09-19T20:18:14Z"
 

cinder/api/openstack/rest_api_version_history.rst

@@ -377,3 +377,7 @@ user documentation.
 3.45
 ----
   Add ``count`` field to volume, backup and snapshot list and detail APIs.
+
+3.46
+----
+  Support create volume by Nova specific image (0 size image).

cinder/api/v3/volumes.py

@@ -28,6 +28,7 @@ from cinder.api.v3.views import volumes as volume_views_v3
 from cinder import exception
 from cinder import group as group_api
 from cinder.i18n import _
+from cinder.image import glance
 from cinder import objects
 from cinder.policies import volumes as policy
 from cinder import utils
@@ -193,6 +194,31 @@ class VolumeController(volumes_v2.VolumeController):
         except exception.VolumeSizeExceedsAvailableQuota as e:
             raise exc.HTTPForbidden(explanation=six.text_type(e))
 
+    def _get_image_snapshot(self, context, image_uuid):
+        image_snapshot = None
+        if image_uuid:
+            image_service = glance.get_default_image_service()
+            image_meta = image_service.show(context, image_uuid)
+            if image_meta is not None:
+                bdms = image_meta.get('properties', {}).get(
+                    'block_device_mapping', [])
+                if bdms:
+                    boot_bdm = [bdm for bdm in bdms if (
+                        bdm.get('source_type') == 'snapshot' and
+                        bdm.get('boot_index') == 0)]
+                    if boot_bdm:
+                        try:
+                            image_snapshot = self.volume_api.get_snapshot(
+                                context, boot_bdm[0].get('snapshot_id'))
+                            return image_snapshot
+                        except exception.NotFound:
+                            explanation = _(
+                                'Nova specific image is found, but boot '
+                                'volume snapshot id:%s not found.'
+                            ) % boot_bdm[0].get('snapshot_id')
+                            raise exc.HTTPNotFound(explanation=explanation)
+            return image_snapshot
+
     @wsgi.response(http_client.ACCEPTED)
     def create(self, req, body):
         """Creates a new volume.
@@ -297,6 +323,17 @@ class VolumeController(volumes_v2.VolumeController):
             # Not found exception will be handled at the wsgi level
             kwargs['group'] = self.group_api.get(context, group_id)
 
+        if self.ext_mgr.is_loaded('os-image-create'):
+            image_ref = volume.get('imageRef')
+            if image_ref is not None:
+                image_uuid = self._image_uuid_from_ref(image_ref, context)
+                image_snapshot = self._get_image_snapshot(context, image_uuid)
+                if (req_version.matches(mv.get_api_version(
+                        mv.SUPPORT_NOVA_IMAGE)) and image_snapshot):
+                    kwargs['snapshot'] = image_snapshot
+                else:
+                    kwargs['image_id'] = image_uuid
+
         size = volume.get('size', None)
         if size is None and kwargs['snapshot'] is not None:
             size = kwargs['snapshot']['volume_size']
@@ -305,12 +342,6 @@ class VolumeController(volumes_v2.VolumeController):
 
         LOG.info("Create volume of %s GB", size)
 
-        if self.ext_mgr.is_loaded('os-image-create'):
-            image_ref = volume.get('imageRef')
-            if image_ref is not None:
-                image_uuid = self._image_uuid_from_ref(image_ref, context)
-                kwargs['image_id'] = image_uuid
-
         kwargs['availability_zone'] = volume.get('availability_zone', None)
         kwargs['scheduler_hints'] = volume.get('scheduler_hints', None)
         multiattach = volume.get('multiattach', False)

cinder/tests/unit/api/v3/test_volumes.py

@@ -34,6 +34,7 @@ from cinder.tests.unit.api import fakes
 from cinder.tests.unit.api.v2 import fakes as v2_fakes
 from cinder.tests.unit.api.v2 import test_volumes as v2_test_volumes
 from cinder.tests.unit import fake_constants as fake
+from cinder.tests.unit.image import fake as fake_image
 from cinder.tests.unit import utils as test_utils
 from cinder import utils
 from cinder.volume import api as volume_api
@@ -48,6 +49,7 @@ class VolumeApiTest(test.TestCase):
         super(VolumeApiTest, self).setUp()
         self.ext_mgr = extensions.ExtensionManager()
         self.ext_mgr.extensions = {}
+        fake_image.mock_image_service(self)
         self.controller = volumes.VolumeController(self.ext_mgr)
 
         self.flags(host='fake')
@@ -259,6 +261,40 @@ class VolumeApiTest(test.TestCase):
         req.api_version_request = mv.get_api_version(version)
         return req
 
+    @mock.patch.object(db.sqlalchemy.api, '_volume_type_get_full',
+                       autospec=True)
+    @mock.patch.object(volume_api.API, 'get_snapshot', autospec=True)
+    @mock.patch.object(volume_api.API, 'create', autospec=True)
+    @mock.patch(
+        'cinder.api.openstack.wsgi.Controller.validate_name_and_description')
+    def test_volume_create_with_snapshot_image(self, mock_validate, create,
+                                               get_snapshot, volume_type_get):
+        create.side_effect = v2_fakes.fake_volume_api_create
+        get_snapshot.side_effect = v2_fakes.fake_snapshot_get
+        volume_type_get.side_effect = v2_fakes.fake_volume_type_get
+
+        self.ext_mgr.extensions = {'os-image-create': 'fake'}
+        vol = self._vol_in_request_body(
+            image_id="b0a599e0-41d7-3582-b260-769f443c862a")
+
+        snapshot_id = fake.SNAPSHOT_ID
+        ex = self._expected_vol_from_controller(snapshot_id=snapshot_id)
+        body = {"volume": vol}
+        req = fakes.HTTPRequest.blank('/v3/volumes')
+        req.headers = mv.get_mv_header(mv.SUPPORT_NOVA_IMAGE)
+        req.api_version_request = mv.get_api_version(mv.SUPPORT_NOVA_IMAGE)
+        res_dict = self.controller.create(req, body)
+        self.assertEqual(ex, res_dict)
+        context = req.environ['cinder.context']
+        get_snapshot.assert_called_once_with(self.controller.volume_api,
+                                             context, snapshot_id)
+        kwargs = self._expected_volume_api_create_kwargs(
+            v2_fakes.fake_snapshot(snapshot_id))
+        create.assert_called_once_with(
+            self.controller.volume_api, context,
+            vol['size'], v2_fakes.DEFAULT_VOL_NAME,
+            v2_fakes.DEFAULT_VOL_DESCRIPTION, **kwargs)
+
     def test_volumes_summary_in_unsupport_version(self):
         """Function call to test summary volumes API in unsupported version"""
         req = self._fake_volumes_summary_request(

cinder/tests/unit/image/fake.py

@@ -147,6 +147,24 @@ class _FakeImageService(object):
                                  'auto_disk_config': 'True'},
                   'size': 1234000000}
 
+        image8 = {'id': 'b0a599e0-41d7-3582-b260-769f443c862a',
+                  'name': 'fakeimage8',
+                  'created_at': timestamp,
+                  'updated_at': timestamp,
+                  'deleted_at': None,
+                  'deleted': False,
+                  'status': 'active',
+                  'is_public': False,
+                  'container_format': 'bare',
+                  'disk_format': 'raw',
+                  'properties':
+                  {'block_device_mapping': [
+                      {'boot_index': 0, 'source_type': 'snapshot',
+                       'snapshot_id': fake_constants.SNAPSHOT_ID}],
+                      'ramdisk_id': 'nokernel',
+                      'architecture': 'x86_64',
+                      'auto_disk_config': 'True'}}
+
         self.create(None, image1)
         self.create(None, image2)
         self.create(None, image3)
@@ -154,6 +172,7 @@ class _FakeImageService(object):
         self.create(None, image5)
         self.create(None, image6)
         self.create(None, image7)
+        self.create(None, image8)
         self._imagedata = {}
         self.temp_images = mock.MagicMock()
         super(_FakeImageService, self).__init__()

releasenotes/notes/bug-1560867-support-nova-specific-image-7yt6fd1173c4e3wd.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - Fix the bug that Cinder can't support creating volume
+    from Nova specific image which only includes ``snapshot-id``
+    metadata (Bug #1560867).