Re: [PATCH 2/2] daemon: Introduce the possibility for users to register custom XML validator

On Fri, Sep 23, 2022 at 05:42:13PM +0200, Peter Krempa wrote: > Introduce a new config option 'xml_validator' into the daemon config > file which will allow users to make libvirt daemons use a custom XML > validator. > > The rationale is that validators such as 'jing'[1] provide drastically > better error specification when compared to the native libxml2 validator > we use. A drawback though is that jing is written in Java and thus > unusable by libvirt directly and also not a popular package present in > distros. > > For power users and developers it still is worth having this feature to > provide better errors in a native way. I kinda wonder if those users need it integrated in libvirt though, as opposed to just calling jing themselves when needed. It feels like a fairly narrow set of users benefitting here from this change, made even smaller by the fact that those users have to remember to reconfigure libvirt to enable this.

> An example showing the quality of the errors: > > XML used: > > <vcpu placement='static' current='1'>asdf8</vcpu> > > native validator: > error: XML document failed to validate against schema: Unable to validate doc against /home/pipo/libvirt/src/conf/schemas/domain.rng > Extra element vcpu in interleave > Invalid sequence in interleave > Element domain failed to validate content > > jing: > error: XML document failed to validate against schema: Unable to validate doc against /home/pipo/libvirt/src/conf/schemas/domain.rng > /dev/stdin:6:52: error: character content of element "vcpu" invalid; must be an integer No doubt the errors are way better, but a power user can just invoke this script below themselves if they ever want to understand a XML problem better. > > Example script to make this feature work with jing: > > #!/bin/bash > java -jar /home/pipo/git/jing-trang/build/jing.jar $1 /dev/stdin 2>&1 || exit 1 > > [1] https://github.com/relaxng/jing-trang To me this is only compelling if there's an option we can reasonably wire up out of the box.

With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|