[Kimchi-devel] [PATCH] storage volume: fix xml parsing of logical volume format type

[Mark Wu]

On 03/06/2014 12:53 PM, zhshzhou at linux.vnet.ibm.com wrote:
> From: Zhou Zheng Sheng <zhshzhou at linux.vnet.ibm.com>
>
> Not all types of libvirt storage volume provide format information.
> Particularly, the volume in logical pool doesn't have format information
> in the dumped XML description. StorageVolumeModel.lookup assumes there
> is a format tag, but for logical pool volumes it does not exist. So an
> exception is raised when it lookup a logical volume.
>
> To trigger this problem, firstly create a guest using a logical pool. Then
> click the logical pool from the "storage" tab, and it would fail to list
> the volumes.
>
> This patch catches the exception when parsing the format tag, and
> returns an empty string for the format attribute if there is no available
> format information in the XML.
>
> Signed-off-by: Zhou Zheng Sheng <zhshzhou at linux.vnet.ibm.com>
> ---
>   src/kimchi/model/storagevolumes.py | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/src/kimchi/model/storagevolumes.py b/src/kimchi/model/storagevolumes.py
> index 442ff89..6d0e884 100644
> --- a/src/kimchi/model/storagevolumes.py
> +++ b/src/kimchi/model/storagevolumes.py
> @@ -113,7 +113,13 @@ class StorageVolumeModel(object):
>           path = vol.path()
>           info = vol.info()
>           xml = vol.XMLDesc(0)
> -        fmt = xmlutils.xpath_get_text(xml, "/volume/target/format/@type")[0]
> +        try:
> +            fmt = xmlutils.xpath_get_text(
> +                xml, "/volume/target/format/@type")[0]
> +        except IndexError:
> +            # Not all types of libvirt storage can provide volume format
> +            # infomation.
> +            fmt = ''
I think we should return 'raw' instead of an empty string here. I assume 
the reason why libvirt doesn't provide volume format for the volumes in 
logical pool is the volumes in logical pool could not be in any other 
formats except 'raw' without external tool intervene.
>           res = dict(type=VOLUME_TYPE_MAP[info[0]],
>                      capacity=info[1],
>                      allocation=info[2],