Re: [libvirt] [PATCH v3 1/2] network: Introduce network hooks
On 11.02.2014 10:54, Daniel P. Berrange wrote:
On Mon, Feb 10, 2014 at 07:52:34PM +0100, Michal Privoznik wrote:
> @@ -3583,6 +3639,48 @@ validate:
> }
> }
>
> + /* finally we can call the 'plugged' hook script if any */
> + if (virHookPresent(VIR_HOOK_DRIVER_NETWORK)) {
> + /* the XML construction is a bit complicated here,
> + * as we want to pass both domain XML and network XML */
> + virBuffer buf = VIR_BUFFER_INITIALIZER;
> + char *xml, *net_xml, *dom_xml;
> + int hookret;
> +
> + net_xml = virNetworkDefFormat(netdef, 0);
> + dom_xml = virDomainDefFormat(dom, 0);
> +
> + if (!net_xml || !dom_xml) {
> + VIR_FREE(net_xml);
> + VIR_FREE(dom_xml);
> + goto error;
> + }
> +
> + virBufferAdd(&buf, net_xml, -1);
> + virBufferAdd(&buf, dom_xml, -1);
This isn't very easy for applications to consume. With all the
other things you can just pass stdin straight to your XML
parser and process it. When you concatenate 2 XML docs this
way it becomes much harder, since you have to split the two
docs which means parsing them without an XML parser. Usually
you'd want to place the 2 docs within a parent XML doc so the
overall result is still a single wellformed XML doc.
Okay, but how should the XML look then?
<hookData>
<network/>
<domain/>
</hookData>
I'm basically asking about the root element name. Then, if we do this
for plug & unplug - should we follow the same scheme for network start &
stop? Without the <domain/>. You know, once we require hook script to
take network xml from /hookData/network we can do that for other cases
too, so the XPath to select the network doesn't change. Or is that an
overkill, because the hook script can easily do:
if [ "$2" == "plugged" -o "$2" == "unplugged" ];
then
XPATH="/hookData/network"
else
XPATH="/network"
fi
Michal