[libvirt] [PATCH v4] virsh: add [--domain DOMAIN] option to domxml-to-native DOMAIN COMMAND

[Dan]

On Wed, Jun 14, 2017 at 08:55:25AM -0400, John Ferlan wrote:
> 
> 
> On 06/02/2017 11:04 AM, Daniel Liu wrote:
> > The option allows someone to run domain-to-native on already existing
> > domain without the need of supplying their XML.  It is basically
> > wrapper around 'virsh dumpxml  | virsh domxml-to-native /dev/stdin'.
> > 
> > Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=835476
> > Signed-off-by: Daniel Liu <srwx4096 at gmail.com>
> > ---
> >  tools/virsh-domain.c | 51 ++++++++++++++++++++++++++++++++++++++-------------
> >  tools/virsh.pod      |  7 ++++---
> >  2 files changed, 42 insertions(+), 16 deletions(-)
> > 
> > diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
> > index ccb514ef9..3496359c5 100644
> > --- a/tools/virsh-domain.c
> > +++ b/tools/virsh-domain.c
> > @@ -9848,9 +9848,13 @@ static const vshCmdOptDef opts_domxmltonative[] = {
> >       .flags = VSH_OFLAG_REQ,
> >       .help = N_("target config data type format")
> >      },
> > +    {.name = "domain",
> > +     .type = VSH_OT_DATA,
> > +     .flags = VSH_OFLAG_REQ_OPT,
> > +     .help = N_("domain name, id or uuid")
> > +    },
> >      {.name = "xml",
> >       .type = VSH_OT_DATA,
> > -     .flags = VSH_OFLAG_REQ,
> >       .help = N_("xml data file to export from")
> >      },
> >      {.name = NULL}
> > @@ -9859,30 +9863,51 @@ static const vshCmdOptDef opts_domxmltonative[] = {
> >  static bool
> >  cmdDomXMLToNative(vshControl *ctl, const vshCmd *cmd)
> >  {
> > -    bool ret = true;
> > +    bool ret = false;
> >      const char *format = NULL;
> > -    const char *xmlFile = NULL;
> > -    char *configData;
> > -    char *xmlData;
> > +    const char *xml = NULL;
> 
> nit: no need to change from xmlFile to xml... The less differences the
> better ;-)
> 
> > +    char *xmlData = NULL;
> > +    char *configData = NULL;
> 
> nit: no need to change order from original, just add ' = NULL' is fine.
> 
> >      unsigned int flags = 0;
> >      virshControlPtr priv = ctl->privData;
> > +    virDomainPtr dom = NULL;
> >  
> >      if (vshCommandOptStringReq(ctl, cmd, "format", &format) < 0 ||
> > -        vshCommandOptStringReq(ctl, cmd, "xml", &xmlFile) < 0)
> > +        vshCommandOptStringReq(ctl, cmd, "xml", &xml) < 0)
> >          return false;
> >  
> > -    if (virFileReadAll(xmlFile, VSH_MAX_XML_FILE, &xmlData) < 0)
> > -        return false;
> > +    VSH_EXCLUSIVE_OPTIONS("domain", "xml");
> >  
> > -    configData = virConnectDomainXMLToNative(priv->conn, format, xmlData, flags);
> > -    if (configData != NULL) {
> > -        vshPrint(ctl, "%s", configData);
> > -        VIR_FREE(configData);
> > +    if (vshCommandOptBool(cmd, "domain") &&
> > +        (!(dom = virshCommandOptDomain(ctl, cmd, NULL))))
> > +            return false;
> > +
> > +    if (dom) {
> > +        xmlData = virDomainGetXMLDesc(dom, flags);
> > +    } else if (xml) {
> > +        if (virFileReadAll(xml, VSH_MAX_XML_FILE, &xmlData) < 0)
> > +            goto cleanup;
> >      } else {
> > -        ret = false;
> > +        vshError(ctl, "%s", _("need either domain or domain XML"));
> > +        goto cleanup;
> > +    }
> > +
> > +    if (!xmlData) {
> > +        vshError(ctl, "%s", _("failed to retrieve XML"));
> > +        goto cleanup;
> >      }
> >  
> > +    if (!(configData = virConnectDomainXMLToNative(priv->conn, format, xmlData, flags))) {
> > +        goto cleanup;
> > +    } else {
> > +        vshPrint(ctl, "%s", configData);
> > +        ret = true;
> > +    }
> > +
> > + cleanup:
> > +    virshDomainFree(dom);
> >      VIR_FREE(xmlData);
> > +    VIR_FREE(configData);
> >      return ret;
> >  }
> >  
> > diff --git a/tools/virsh.pod b/tools/virsh.pod
> > index aee964689..049c2f3c7 100644
> > --- a/tools/virsh.pod
> > +++ b/tools/virsh.pod
> > @@ -1433,10 +1433,11 @@ the I<format> argument must be B<qemu-argv>. For Xen hypervisor, the
> >  I<format> argument may be B<xen-xm>, B<xen-xl>, or B<xen-sxpr>. For
> >  LXC hypervisor, the I<format> argument must be B<lxc-tools>.
> >  
> > -=item B<domxml-to-native> I<format> I<xml>
> > +=item B<domxml-to-native> I<format>
> > +{ I<--domain> I<domain-name-or-id-or-uuid> | [I<--xml>] I<xml> }
> 
> This looks really odd, I think this should be
> 
> { [I<xml> | [I<--domain> I<domain-name-or-id-uuid>] }
> 
> I believe that's the way to describe mutually exclusive options where
> one would be required; otherwise, we have the funky [[ ... ]] which
> indicates mutually exclusive optional arguments. Search on "{ [" in
> virsh.pod for some examples. This seems to be the first case where a
> previously required positional argument can be both a positional and
> optional as long as the alternative means of describing is provided.
> 
> Keeping the I<xml> first at least indicates that it can be used
> *without* the --xml, but is also the "default" when used positionally on
> the command line. If not used positionally, then the --xml would be
> required, e.g. if someone used "virsh domxml-to-native --xml @file
> --format @format".
> 
> Having the [--domain] indicates that in order to use it, it must have
> that --domain argument because "virsh domxml-to-native qemu-argv
> $domainname" would be invalid since the unqualified 2nd argument is
> expected to be an <xml> file.
> 
> Whether any of this is written down anywhere - I'm not sure - it's what
> I've surmised over the few years.
> 
> 
> >  
> > -Convert the file I<xml> in domain XML format to the native guest
> > -configuration format named by I<format>. For QEMU/KVM hypervisor,
> > +Convert the file I<xml> in domain XML format or existing domain to the
> > +native guest configuration format named by I<format>. For QEMU/KVM hypervisor,
> >  the I<format> argument must be B<qemu-argv>. For Xen hypervisor, the
> >  I<format> argument may be B<xen-xm>, B<xen-xl>, or B<xen-sxpr>. For
> >  LXC hypervisor, the I<format> argument must be B<lxc-tools>.
> > 
> 
> Convert the file I<xml> into domain XML format or convert an existing
> I<--domain> to the native guest configuration format named by I<format>.
> The I<xml> and I<--domain> arguments are mutually exclusive.
> 
> John
I found the man page is still missing. Shall I send a patch for the
documentation?

Dan