images: Allow the output format of qemu-img info to be controlled

This will allow for the use of the JSON output format that is easier to
parse within QemuImgInfo and should allow additional information to be
extracted from qemu-img calls in the future.

Change-Id: I0b6d1a98726ffa1ebc78fb3c4563a2e4b40ddeff

1 files changed, 8 insertions, 3 deletions

diff --git a/nova/privsep/qemu.py b/nova/privsep/qemu.py
index 07db81a381..55bdfe2a77 100644
--- a/nova/privsep/qemu.py
+++ b/nova/privsep/qemu.py
@@ -85,17 +85,20 @@ def unprivileged_convert_image(source, dest, in_format, out_format,
 
 
 @nova.privsep.sys_admin_pctxt.entrypoint
-def privileged_qemu_img_info(path, format=None, qemu_version=None):
+def privileged_qemu_img_info(path, format=None, qemu_version=None,
+                             output_format=None):
     """Return an oject containing the parsed output from qemu-img info
 
     This is a privileged call to qemu-img info using the sys_admin_pctxt
     entrypoint allowing host block devices etc to be accessed.
     """
     return unprivileged_qemu_img_info(
-        path, format=format, qemu_version=qemu_version)
+        path, format=format, qemu_version=qemu_version,
+        output_format=output_format)
 
 
-def unprivileged_qemu_img_info(path, format=None, qemu_version=None):
+def unprivileged_qemu_img_info(path, format=None, qemu_version=None,
+                               output_format=None):
     """Return an object containing the parsed output from qemu-img info."""
     try:
         # The following check is about ploop images that reside within
@@ -107,6 +110,8 @@ def unprivileged_qemu_img_info(path, format=None, qemu_version=None):
         cmd = ('env', 'LC_ALL=C', 'LANG=C', 'qemu-img', 'info', path)
         if format is not None:
             cmd = cmd + ('-f', format)
+        if output_format is not None:
+            cmd = cmd + ("--output=%s" % (output_format),)
         # Check to see if the qemu version is >= 2.10 because if so, we need
         # to add the --force-share flag.
         if qemu_version and operator.ge(qemu_version, QEMU_VERSION_REQ_SHARED):