Create a flag for force_to_raw for images

 * Allows for deployers to use compressed images if they prefer
 * Flag defaults to current behavior
 * Fixes bug 932180
 * Re-enables fetch_to_raw which was being skipped
 * Removes obsolete and broken method from libvirt
 * Checksumming will be re-enabled in a later patch

Change-Id: I40c33cfd3997cae8d127fa45f8cf0aa071418170

nova/tests/test_libvirt.py

@@ -1975,14 +1975,14 @@ def fake_statvfs(path):
         self.assertEquals(4096000, fs_info['used'])
 
     def test_fetch_image(self):
-        self.mox.StubOutWithMock(images, 'fetch')
+        self.mox.StubOutWithMock(images, 'fetch_to_raw')
 
         context = 'opaque context'
         target = '/tmp/targetfile'
         image_id = '4'
         user_id = 'fake'
         project_id = 'fake'
-        images.fetch(context, image_id, target, user_id, project_id)
+        images.fetch_to_raw(context, image_id, target, user_id, project_id)
 
         self.mox.ReplayAll()
         libvirt_utils.fetch_image(context, target, image_id,

nova/virt/images.py

@@ -27,12 +27,22 @@
 from nova import flags
 import nova.image
 from nova import log as logging
+from nova.openstack.common import cfg
 from nova import utils
 
 
 FLAGS = flags.FLAGS
 LOG = logging.getLogger(__name__)
 
+image_opts = [
+    cfg.BoolOpt('force_raw_images',
+                default=True,
+                help='Force backing images to raw format'),
+]
+
+FLAGS = flags.FLAGS
+FLAGS.register_opts(image_opts)
+
 
 def fetch(context, image_href, path, _user_id, _project_id):
     # TODO(vish): Improve context handling and add owner and auth data
@@ -72,20 +82,20 @@ def _qemu_img_info(path):
 
     data = _qemu_img_info(path_tmp)
 
-    fmt = data.get("file format", None)
+    fmt = data.get("file format")
     if fmt is None:
         os.unlink(path_tmp)
         raise exception.ImageUnacceptable(
             reason=_("'qemu-img info' parsing failed."), image_id=image_href)
 
-    if fmt != "raw":
-        staged = "%s.converted" % path
-        if "backing file" in data:
-            backing_file = data['backing file']
-            os.unlink(path_tmp)
-            raise exception.ImageUnacceptable(image_id=image_href,
-                reason=_("fmt=%(fmt)s backed by: %(backing_file)s") % locals())
+    if "backing file" in data:
+        backing_file = data['backing file']
+        os.unlink(path_tmp)
+        raise exception.ImageUnacceptable(image_id=image_href,
+            reason=_("fmt=%(fmt)s backed by: %(backing_file)s") % locals())
 
+    if fmt != "raw" and FLAGS.force_raw_images:
+        staged = "%s.converted" % path
         LOG.debug("%s was %s, converting to raw" % (image_href, fmt))
         out, err = utils.execute('qemu-img', 'convert', '-O', 'raw',
                                  path_tmp, staged)

nova/virt/libvirt/connection.py

@@ -933,21 +933,6 @@ def call_if_not_exists(base, fn, *args, **kwargs):
                 if size:
                     disk.extend(target, size)
 
-    @staticmethod
-    def _fetch_image(context, target, image_id, user_id, project_id):
-        """Grab image to raw format"""
-        images.fetch_to_raw(context, image_id, target, user_id, project_id)
-
-        if FLAGS.checksum_base_images:
-            f = open(target, 'r')
-            checksum = utils.hash_file(f)
-            f.close()
-
-            checksum_fname = '%s.sha1' % target
-            fd = os.open(checksum_filename, os.O_WRONLY, mode=0444)
-            os.write(fd, checksum)
-            os.close(fd)
-
     @staticmethod
     def _create_local(target, local_size, unit='G', fs_format=None):
         """Create a blank image of specified size"""
@@ -1912,7 +1897,7 @@ def pre_block_migration(self, ctxt, instance_ref, disk_info_json):
                 cached_file = info['backing_file'].split('_')[0]
 
                 if not os.path.exists(backing_file):
-                    self._cache_image(fn=self._fetch_image,
+                    self._cache_image(fn=libvirt_utils.fetch_image,
                         context=ctxt,
                         target=info['path'],
                         fname=cached_file,

nova/virt/libvirt/utils.py

@@ -21,13 +21,11 @@
 
 import os
 import random
-import shutil
 
 from nova import exception
 from nova import flags
 from nova.openstack.common import cfg
 from nova import utils
-from nova.virt.disk import api as disk
 from nova.virt import images
 
 
@@ -258,4 +256,4 @@ def get_fs_info(path):
 
 def fetch_image(context, target, image_id, user_id, project_id):
     """Grab image"""
-    images.fetch(context, image_id, target, user_id, project_id)
+    images.fetch_to_raw(context, image_id, target, user_id, project_id)