fix(vrtManager): a volume upload aborts its stream when the volume cannot be made

upload_volume opens the libvirt stream before it creates the volume, but
created the volume outside the block that aborts the stream: a pool that
refused the volume (full, a name taken) left an unfinished stream to be
freed. The creation is now inside that block.

vrtManager/connection.py

@@ -1040,12 +1040,13 @@ class wvmConnect(object):
         stream, which every connection type carries. A failed write leaves
         no volume."""
         stream = self.wvm.newStream(0)
-        vol = pool.createXML(
-            f"<volume><name>{util.xml_escape(name)}</name><capacity>{len(data)}</capacity>"
-            "<target><format type='raw'/></target></volume>",
-            0,
-        )
+        vol = None
         try:
+            vol = pool.createXML(
+                f"<volume><name>{util.xml_escape(name)}</name><capacity>{len(data)}</capacity>"
+                "<target><format type='raw'/></target></volume>",
+                0,
+            )
             vol.upload(stream, 0, len(data), 0)
             stream.sendAll(lambda _stream, size, buffer: buffer.read(size), io.BytesIO(data))
             stream.finish()
@@ -1053,7 +1054,8 @@ class wvmConnect(object):
             # libvirt: a stream that did not finish is aborted before it is freed
             with contextlib.suppress(libvirtError):
                 stream.abort()
-            vol.delete(0)
+            if vol is not None:
+                vol.delete(0)
             raise
         return vol
 

vrtManager/tests/test_cloud_init_seed.py

@@ -81,6 +81,16 @@ class UploadVolumeTestCase(unittest.TestCase):
         conn.wvm.newStream.return_value.abort.assert_called_once_with()
 
 
+    def test_a_volume_that_cannot_be_made_aborts_the_stream(self):
+        conn = wvmConnect.__new__(wvmConnect)
+        conn.wvm = MagicMock()
+        pool = MagicMock()
+        pool.createXML.side_effect = libvirtError("pool is full")
+        with self.assertRaises(libvirtError):
+            conn.upload_volume(pool, "a.iso", b"data")
+        conn.wvm.newStream.return_value.abort.assert_called_once_with()
+
+
 class DeleteWithDisksTestCase(unittest.TestCase):
     def vm(self, seed_in_pool=True):
         from vrtManager.instance import wvmInstance