glusterfs_native: Unable to delete snapshot

[Ramana Raja]

Run into the following error while trying to delete a snapshot,

CMD "sudo manila-rootwrap /etc/manila/rootwrap.conf gluster --xml snapshot delete 44c78459-d9ff-44a4-9084-877a911034dd" returned: 0 in 0.188s from (pid=16307) execute /usr/lib/python2.7/site-packages/oslo_concurrency/processutils.py:22
ERROR oslo_messaging.rpc.dispatcher
 Exception during message handling: syntax error: line 1, column 0

The partial traceback,

 File "/opt/stack/manila/manila/share/manager.py", line 571, in delete_snapshot
share_server=share_server)
File "/opt/stack/manila/manila/share/drivers/glusterfs_native.py", line 686, in delete_snapshot
outxml = etree.fromstring(out)
File "<string>", line 124, in XML
ParseError: syntax error: line 1, column 0

The variable 'out' which stores the XML output of the Gluster's delete snapshot command, and is parsed later in the code, gets an incorrect value that cannot be parsed. This is because the Gluster CLI runs in the interactive mode even when the stdin is not a terminal.

The faulty code from glusterfs_native driver's delete_snapshot API pasted
below,
<code snippet>
        args = ('--xml', 'snapshot', 'delete', snapshot['id'])
        try:
            out, err = gluster_mgr.gluster_call(*args)
        ...

        outxml = etree.fromstring(out)

</code snippet>

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/172197

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/172197
Committed: https://git.openstack.org/cgit/openstack/manila/commit/?id=6aac2b5693fe319dd31fd166bd78fb759712a5b9
Submitter: Jenkins
Branch: master

commit 6aac2b5693fe319dd31fd166bd78fb759712a5b9
Author: Ramana Raja <email address hidden>
Date: Fri Apr 10 01:38:10 2015 +0530

    glusterfs_native: Fix Gluster command call

    In the delete_snapshot API, the Gluster command issued to delete the
    snapshot ends up being run in the interactive mode of the
    Gluster-CLI. So instead of an XML output, the command results in a
    Gluster-CLI read error. Fix this by forcing the Gluster command to be
    run in the script mode.

    Change-Id: Ic09f59732bf08942a9d216f70f1fc969d9ae0a2d
    Closes-Bug: #1442339