Raise an exception if qemu-img fails

Raise an exception if the qemu image doesn't
exist or qemu-img fails.

Co-Authored-By: Chuck Short <chuck.short@canonical.com>
Closes-Bug: #1168318
Change-Id: I6b4123590e7d2934de0bc6add900d708d5986039

nova/tests/virt/libvirt/test_driver.py

@@ -10691,7 +10691,7 @@ class LibvirtUtilsTestCase(test.TestCase):
     def test_create_cow_image(self):
         self.mox.StubOutWithMock(os.path, 'exists')
         self.mox.StubOutWithMock(utils, 'execute')
-        rval = ('', '')
+        rval = ('stdout', None)
         os.path.exists('/some/path').AndReturn(True)
         utils.execute('env', 'LC_ALL=C', 'LANG=C',
                       'qemu-img', 'info', '/some/path').AndReturn(rval)

nova/tests/virt/libvirt/test_imagebackend.py

@@ -26,11 +26,13 @@ from oslo.config import cfg
 from nova import context
 from nova import exception
 from nova import keymgr
+from nova.openstack.common import imageutils
 from nova.openstack.common import units
 from nova.openstack.common import uuidutils
 from nova import test
 from nova.tests import fake_processutils
 from nova.tests.virt.libvirt import fake_libvirt_utils
+from nova.virt import images
 from nova.virt.libvirt import imagebackend
 from nova.virt.libvirt import rbd_utils
 
@@ -221,7 +223,9 @@ class RawTestCase(_ImageTestCase, test.NoDBTestCase):
 
         self.mox.VerifyAll()
 
-    def test_create_image_extend(self):
+    @mock.patch.object(images, 'qemu_img_info',
+                       return_value=imageutils.QemuImgInfo())
+    def test_create_image_extend(self, fake_qemu_img_info):
         fn = self.prepare_mocks()
         fn(max_size=self.SIZE, target=self.TEMPLATE_PATH, image_id=None)
         imagebackend.libvirt_utils.copy_image(self.TEMPLATE_PATH, self.PATH)
@@ -252,7 +256,10 @@ class RawTestCase(_ImageTestCase, test.NoDBTestCase):
 
         self.mox.VerifyAll()
 
-    def test_resolve_driver_format(self):
+    @mock.patch.object(images, 'qemu_img_info',
+                       side_effect=exception.InvalidDiskInfo(
+                           reason='invalid path'))
+    def test_resolve_driver_format(self, fake_qemu_img_info):
         image = self.image_class(self.INSTANCE, self.NAME)
         driver_format = image.resolve_driver_format()
         self.assertEqual(driver_format, 'raw')

nova/tests/virt/test_images.py

@@ -12,13 +12,34 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import os
 
+import mock
+
+from nova import exception
+from nova.openstack.common import processutils
 from nova import test
+from nova import utils
 from nova.virt import images
 
 
 class QemuTestCase(test.NoDBTestCase):
     def test_qemu_info_with_bad_path(self):
-        image_info = images.qemu_img_info("/path/that/does/not/exist")
+        self.assertRaises(exception.InvalidDiskInfo,
+                          images.qemu_img_info,
+                          '/path/that/does/not/exist')
+
+    @mock.patch.object(os.path, 'exists', return_value=True)
+    def test_qemu_info_with_errors(self, path_exists):
+        self.assertRaises(processutils.ProcessExecutionError,
+                          images.qemu_img_info,
+                          '/fake/path')
+
+    @mock.patch.object(os.path, 'exists', return_value=True)
+    @mock.patch.object(utils, 'execute',
+                       return_value=('stdout', None))
+    def test_qemu_info_with_no_errors(self, path_exists,
+                                      utils_execute):
+        image_info = images.qemu_img_info('/fake/path')
         self.assertTrue(image_info)
-        self.assertTrue(str(image_info))
+        self.assertTrue(str(image_info))

nova/virt/images.py

@@ -49,10 +49,16 @@ def qemu_img_info(path):
     # TODO(mikal): this code should not be referring to a libvirt specific
     # flag.
     if not os.path.exists(path) and CONF.libvirt.images_type != 'rbd':
-        return imageutils.QemuImgInfo()
+        msg = (_("Path does not exist %(path)s") % {'path': path})
+        raise exception.InvalidDiskInfo(reason=msg)
 
     out, err = utils.execute('env', 'LC_ALL=C', 'LANG=C',
                              'qemu-img', 'info', path)
+    if not out:
+        msg = (_("Failed to run qemu-img info on %(path)s : %(error)s") %
+               {'path': path, 'error': err})
+        raise exception.InvalidDiskInfo(reason=msg)
+
     return imageutils.QemuImgInfo(out)
 
 

nova/virt/libvirt/imagebackend.py

@@ -22,7 +22,7 @@ import six
 
 from nova import exception
 from nova.i18n import _
-from nova.i18n import _LE
+from nova.i18n import _LE, _LI
 from nova import image
 from nova import keymgr
 from nova.openstack.common import excutils
@@ -355,8 +355,15 @@ class Raw(Image):
         self.correct_format()
 
     def _get_driver_format(self):
-        data = images.qemu_img_info(self.path)
-        return data.file_format or 'raw'
+        try:
+            data = images.qemu_img_info(self.path)
+            return data.file_format
+        except exception.InvalidDiskInfo as e:
+            LOG.info(_LI('Failed to get image info from %(path)s, '
+                          'error was %(error)s'),
+                      {'path': self.path,
+                       'error': e})
+            return 'raw'
 
     def _supports_encryption(self):
         # NOTE(dgenin): Kernel, ramdisk and disk.config are fetched using