[Kimchi-devel] [PATCh V12 4/7] manually manage the metadata element

[Aline Manera]

On 04/29/2014 12:45 PM, shaohef at linux.vnet.ibm.com wrote:
> From: ShaoHe Feng <shaohef at linux.vnet.ibm.com>
>
> virDomain.metadata and virDomain.setMetadata does not work in all livirt
> versions used in the supported distros.
>
> So if libvirt do not support these two API.
>
> let kimchi manually manage the metadata element
>
> Signed-off-by: ShaoHe Feng <shaohef at linux.vnet.ibm.com>
> Signed-off-by: Royce Lv <lvroyce at linux.vnet.ibm.com>
> ---
>   src/kimchi/model/utils.py | 88 ++++++++++++++++++++++++++++++++++++++++-------
>   1 file changed, 75 insertions(+), 13 deletions(-)
>
> diff --git a/src/kimchi/model/utils.py b/src/kimchi/model/utils.py
> index 3aaa956..7845c0d 100644
> --- a/src/kimchi/model/utils.py
> +++ b/src/kimchi/model/utils.py
> @@ -17,10 +17,12 @@
>   # License along with this library; if not, write to the Free Software
>   # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
>
> +import re
>   from kimchi.exception import OperationFailed
> +from kimchi.model.config import CapabilitiesModel
>   import libvirt
>   from lxml import etree
> -from lxml.builder import E
> +from lxml.builder import E, ElementMaker
>
>
>   KIMCHI_META_URL = "https://github.com/kimchi-project/kimchi"
> @@ -37,6 +39,15 @@ def get_vm_name(vm_name, t_name, name_list):
>       raise OperationFailed("KCHUTILS0003E")

>
> +def create_metadata_node(tag):
> +    if CapabilitiesModel().metadata_support:
> +        return E(tag)
> +    else:
> +        EM = ElementMaker(namespace=KIMCHI_META_URL,
> +                          nsmap={KIMCHI_NAMESPACE: KIMCHI_META_URL})
> +        return EM(tag)
> +

This function is only used by _kimchi_set_metadata() so we can move the 
correct code to there.
I will do that before applying so you don't need to resend the patches

> +
>   def get_vm_config_flag(dom, mode="persistent"):
>       # libvirt.VIR_DOMAIN_AFFECT_CURRENT is 0
>       # VIR_DOMAIN_AFFECT_LIVE is 1, VIR_DOMAIN_AFFECT_CONFIG is 2
> @@ -58,6 +69,25 @@ def update_node(root, node):
>       return root
>
>
> +def _kimchi_set_metadata_node(dom, node):
> +    # some other tools will not let libvirt create a persistent
> +    # configuration, raise exception.
> +    if not dom.isPersistent():
> +        msg = 'The VM has not a persistent configuration'
> +        raise OperationFailed("KCHVM0030E",
> +                              {'name': dom.name(), "err": msg})
> +    xml = dom.XMLDesc(libvirt.VIR_DOMAIN_XML_INACTIVE)
> +    root = etree.fromstring(xml)
> +    kimchi = root.find("metadata/{%s}kimchi" % KIMCHI_META_URL)
> +    kimchi = create_metadata_node("kimchi") if kimchi is None else kimchi
> +    update_node(kimchi, node)
> +    metadata = root.find("metadata")
> +    metadata = E.metadata() if metadata is None else metadata
> +    update_node(metadata, kimchi)
> +    update_node(root, metadata)
> +    dom.connect().defineXML(etree.tostring(root))
> +
> +
>   def libvirt_get_kimchi_metadata_node(dom, mode="current"):
>       try:
>           xml = dom.metadata(libvirt.VIR_DOMAIN_METADATA_ELEMENT,
> @@ -69,21 +99,53 @@ def libvirt_get_kimchi_metadata_node(dom, mode="current"):
>
>
>   def set_metadata_node(dom, node, mode="all"):
> -    kimchi = libvirt_get_kimchi_metadata_node(dom, mode)
> -    kimchi = E.kimchi() if kimchi is None else kimchi
> -
> -    update_node(kimchi, node)
> -    kimchi_xml = etree.tostring(kimchi)
> -    # From libvirt doc, Passing None for @metadata says to remove that
> -    # element from the domain XML (passing the empty string leaves the
> -    # element present).  Do not support remove the old metadata.
> -    dom.setMetadata(libvirt.VIR_DOMAIN_METADATA_ELEMENT, kimchi_xml,
> -                    KIMCHI_NAMESPACE, KIMCHI_META_URL,
> -                    flags=get_vm_config_flag(dom, mode))
> +    if CapabilitiesModel().metadata_support:
> +        kimchi = libvirt_get_kimchi_metadata_node(dom, mode)
> +        kimchi = E.kimchi() if kimchi is None else kimchi
> +
> +        update_node(kimchi, node)
> +        kimchi_xml = etree.tostring(kimchi)
> +        # From libvirt doc, Passing None for @metadata says to remove that
> +        # element from the domain XML (passing the empty string leaves the
> +        # element present).  Do not support remove the old metadata.
> +        dom.setMetadata(libvirt.VIR_DOMAIN_METADATA_ELEMENT, kimchi_xml,
> +                        KIMCHI_NAMESPACE, KIMCHI_META_URL,
> +                        flags=get_vm_config_flag(dom, mode))
> +    else:
> +    # FIXME remove this code when all distro libvirt supports metadata element
> +        _kimchi_set_metadata_node(dom, node)
> +
> +
> +def _kimchi_get_metadata_node(dom, tag):
> +    # some other tools will not let libvirt create a persistent
> +    # configuration, just return empty
> +    if not dom.isPersistent():
> +        return None
> +    xml = dom.XMLDesc(libvirt.VIR_DOMAIN_XML_INACTIVE)
> +    root = etree.fromstring(xml)
> +    kimchi = root.find("metadata/{%s}kimchi" % KIMCHI_META_URL)
> +    #remove the "kimchi" prifix of xml
> +    # some developers may do not like to remove prefix by children iteration
> +    # so here, use re to remove the "kimchi" prefix of xml
> +    # and developers please don not define element like this:
> +    #     <foo attr="foo<kimchi:abcd>foo"></foo>
> +    if kimchi is not None:
> +        kimchi_xml = etree.tostring(kimchi)
> +        ns_pattern = re.compile(" xmlns:.*?=((\".*?\")|('.*?'))")
> +        kimchi_xml = ns_pattern.sub("", kimchi_xml)
> +        prefix_pattern = re.compile("(?<=<)[^/]*?:|(?<=</).*?:")
> +        kimchi_xml = prefix_pattern.sub("", kimchi_xml)
> +        return etree.fromstring(kimchi_xml)
> +    return None
>
>
>   def get_metadata_node(dom, tag, mode="current"):
> -    kimchi = libvirt_get_kimchi_metadata_node(dom, mode)
> +    if CapabilitiesModel().metadata_support:
> +        kimchi = libvirt_get_kimchi_metadata_node(dom, mode)
> +    else:
> +    # FIXME remove this code when all distro libvirt supports metadata element
> +        kimchi = _kimchi_get_metadata_node(dom, tag)
> +
>       if kimchi is not None:
>           node = kimchi.find(tag)
>           if node is not None: