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




On 06/14/2017 09:47 AM, Martin Kletzander wrote:
> 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 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 ;-)
>>
> 
> There was no change, it is an additional variable, the original one is
> below.  The number of differences would be the same, I believe.
> 

If edit the file and change "xml" to "xmlFile" and change the 3 changed
xml variable references things work... Like I said, nit, IDC if it's
changed or not...

>>> +    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)

e.g., s/&xml/&xmlFile

>>>          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) {

e.g.:
else if (xmlFile) {
    if (virFileReadAll(xmlFile,...)

>>> +        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>] }
>>
> 
> Actually, the only thing that Dan can change is the order, but the rest
> should remain.  His version shows that you must supply either --domain
> domain-name-or-id-or-uuid or --xml xml and that in the second case, the
> --xml is optional.
> 
> Your suggested solution, however, mean that you must supply either the
> xml (no mention about the optional --xml) or --domain
> domain-name-or-id-or-uuid or nothing (in a really weird way), as the
> latter option is in square brackets.
> 
> So the only way this could look differently is:
> 
>  { [I<--xml>] I<xml> | I<--domain> I<domain-name-or-id-or-uuid> }
> 

That's fine - I considered this too, but the [I<--xml>] looked strange,
but I see it's technically correct since having the --xml doesn't
necessarily matter and thus enclosed in brackets.

John

>> 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.
>>
> 
> Yes, this sounds better, there is a slight flaw in the original hunk and
> this explains it more nicely.
> 
>> John
>>
>> -- 
>> libvir-list mailing list
>> libvir-list redhat com
>> https://www.redhat.com/mailman/listinfo/libvir-list


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