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

Martin Kletzander mkletzan at redhat.com
Wed Jun 14 13:47:02 UTC 2017


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 ;-)
>

There was no change, it is an additional variable, the original one is
below.  The number of differences would be the same, I believe.

>> +    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>] }
>

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> }

>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 at redhat.com
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