Re: [Libvirt-cim] Problem of Python dependancies
Daniel Veillard wrote:
Hi,
trying to run the testsuite as checkout from hg today on a Fedora 11
box I got the following error:
[root@paphio cimtest]# CIM_NS=root/virt CIM_USER=root CIM_PASS=xxxxxx
./runtests libvirt-cim -v KVM -i localhost
Starting test suite: libvirt-cim
Traceback (most recent call last):
File "main.py", line 41, in <module>
from XenKvmLib.common_util import create_netpool_conf,
destroy_netpool, \
File "./lib/XenKvmLib/common_util.py", line 29, in <module>
from XenKvmLib.test_xml import *
File "./lib/XenKvmLib/test_xml.py", line 32, in <module>
from xml import xpath
ImportError: cannot import name xpath
This error is caused by a missing PyXML / pyxml package. This is
mentioned as a requirement on our wiki
(http://wiki.libvirt.org/page/Cimtest_setup), but not on our main webpage.
I've been meaning to update the documentation on the webpage for awhile
now. I'll add cimtest instructions to the list of items I need to
update. =)
Looking at suites/libvirt-cim/lib/XenKvmLib/test_xml.py
This file should be removed, as it is obsolete. A few tests still
reference it, but those should be updated as the functionality in
test_xml.py has been replaced by suites/libvirt-cim/lib/XenKvmLib/vxml.py
it seems to try to use the native xml support of Python
from xml import xpath
from xml.dom import minidom, Node
to implement:
------------------------------------------------
def get_value_xpath(xmlStr, xpathStr):
xmldoc = minidom.parseString(xmlStr)
nodes = xpath.Evaluate(xpathStr, xmldoc.documentElement)
if len(nodes) != 1:
raise LookupError('Zero or multiple xpath results found!')
node = nodes[0]
if node.nodeType == Node.ATTRIBUTE_NODE:
return node.value
if node.nodeType == Node.TEXT_NODE:
return node.toxml()
if node.nodeType == Node.ELEMENT_NODE:
ret = ''
for child in node.childNodes:
ret = ret + child.toxml()
return ret
--------------------------------------------------
Then get_value_xpath() is used in the module to poke various values.
First it's not really optimal, the XML should probably be parsed once
but the performance impact is really neglectible :-)
Is there a workaround to have that code run on a standard Fedora 11
setup or did I missed anything ?
I wonder if there are other uses of xml::xpath in the regression
suite. In any case it might be a good idea to use libxml2 bindings
instead since libvirt uses libxml2 it's not likely to be a problem
Would you recommend using libxml2 over using PyXML?
and would avoid this kind of Python XML portability problems. I may
even provide the trivial patch to replace that fragment of code (but
if there is many other use of python xml code in the test suite, that's
a different matter :-)
thanks,
Daniel
--
Kaitlin Rupert
IBM Linux Technology Center
kaitlin(a)linux.vnet.ibm.com