libvirt/tools/virsh-backup.c
Daniel P. Berrangé 8603b3d76c tools: add '--xpath EXPRESSION --wrap' args to all dumpxml commands
While you can chain the virsh output up to a later 'xmllint' or 'xpath'
command, integrating it into virsh avoids needs for installing extra
binaries which we've often found to be missing on production installs
of libvirt. It also gives better response if the initial virsh command
hits an error, as you don't get an aborted pipeline.

    $ virsh pool-dumpxml --xpath //permissions default
    <permissions>
      <mode>0711</mode>
      <owner>1000</owner>
      <group>1000</group>
      <label>unconfined_u:object_r:svirt_home_t:s0</label>
    </permissions>

If multiple nodes match, they are emitted individually:

    $ virsh dumpxml --xpath '//devices/*/address[@type="pci"]' --wrap demo
    <address type="pci" domain="0x0000" bus="0x05" slot="0x00" function="0x0"/>
    <address type="pci" domain="0x0000" bus="0x03" slot="0x00" function="0x0"/>
    ...snip...
    <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x0" multifunction="on"/>
    <address type="pci" domain="0x0000" bus="0x07" slot="0x00" function="0x0"/>

but if intending to post-process the output further, the results
can be wrapped in a parent node

    $ virsh dumpxml --xpath '//devices/*/address[@type="pci"]' --wrap demo
    <nodes>
      <address type="pci" domain="0x0000" bus="0x05" slot="0x00" function="0x0"/>
      <address type="pci" domain="0x0000" bus="0x03" slot="0x00" function="0x0"/>
      ...snip...
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x0" multifunction="on"/>
      <address type="pci" domain="0x0000" bus="0x07" slot="0x00" function="0x0"/>
    </nodes>

Fixes https://gitlab.com/libvirt/libvirt/-/issues/244
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2022-06-20 10:40:45 +01:00

167 lines
4.5 KiB
C

/*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include "virsh-backup.h"
#include "virsh-util.h"
#include "internal.h"
#include "virfile.h"
/*
* "backup-begin" command
*/
static const vshCmdInfo info_backup_begin[] = {
{.name = "help",
.data = N_("Start a disk backup of a live domain")
},
{.name = "desc",
.data = N_("Use XML to start a full or incremental disk backup of a live "
"domain, optionally creating a checkpoint")
},
{.name = NULL}
};
static const vshCmdOptDef opts_backup_begin[] = {
VIRSH_COMMON_OPT_DOMAIN_FULL(VIR_CONNECT_LIST_DOMAINS_ACTIVE),
{.name = "backupxml",
.type = VSH_OT_STRING,
.completer = virshCompletePathLocalExisting,
.help = N_("domain backup XML"),
},
{.name = "checkpointxml",
.type = VSH_OT_STRING,
.completer = virshCompletePathLocalExisting,
.help = N_("domain checkpoint XML"),
},
{.name = "reuse-external",
.type = VSH_OT_BOOL,
.help = N_("reuse files provided by caller"),
},
{.name = NULL}
};
static bool
cmdBackupBegin(vshControl *ctl,
const vshCmd *cmd)
{
g_autoptr(virshDomain) dom = NULL;
const char *backup_from = NULL;
g_autofree char *backup_buffer = NULL;
const char *check_from = NULL;
g_autofree char *check_buffer = NULL;
unsigned int flags = 0;
if (vshCommandOptBool(cmd, "reuse-external"))
flags |= VIR_DOMAIN_BACKUP_BEGIN_REUSE_EXTERNAL;
if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
return false;
if (vshCommandOptStringReq(ctl, cmd, "backupxml", &backup_from) < 0)
return false;
if (!backup_from) {
backup_buffer = g_strdup("<domainbackup/>");
} else {
if (virFileReadAll(backup_from, VSH_MAX_XML_FILE, &backup_buffer) < 0) {
vshSaveLibvirtError();
return false;
}
}
if (vshCommandOptStringReq(ctl, cmd, "checkpointxml", &check_from) < 0)
return false;
if (check_from) {
if (virFileReadAll(check_from, VSH_MAX_XML_FILE, &check_buffer) < 0) {
vshSaveLibvirtError();
return false;
}
}
if (virDomainBackupBegin(dom, backup_buffer, check_buffer, flags) < 0)
return false;
vshPrint(ctl, _("Backup started\n"));
return true;
}
/*
* "backup-dumpxml" command
*/
static const vshCmdInfo info_backup_dumpxml[] = {
{.name = "help",
.data = N_("Dump XML for an ongoing domain block backup job")
},
{.name = "desc",
.data = N_("Backup Dump XML")
},
{.name = NULL}
};
static const vshCmdOptDef opts_backup_dumpxml[] = {
VIRSH_COMMON_OPT_DOMAIN_FULL(VIR_CONNECT_LIST_DOMAINS_ACTIVE),
{.name = "xpath",
.type = VSH_OT_STRING,
.completer = virshCompleteEmpty,
.help = N_("xpath expression to filter the XML document")
},
{.name = "wrap",
.type = VSH_OT_BOOL,
.help = N_("wrap xpath results in an common root element"),
},
{.name = NULL}
};
static bool
cmdBackupDumpXML(vshControl *ctl,
const vshCmd *cmd)
{
g_autoptr(virshDomain) dom = NULL;
g_autofree char *xml = NULL;
bool wrap = vshCommandOptBool(cmd, "wrap");
const char *xpath = NULL;
if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
return false;
if (vshCommandOptStringQuiet(ctl, cmd, "xpath", &xpath) < 0)
return false;
if (!(xml = virDomainBackupGetXMLDesc(dom, 0)))
return false;
return virshDumpXML(ctl, xml, "domain-backup", xpath, wrap);
}
const vshCmdDef backupCmds[] = {
{.name = "backup-begin",
.handler = cmdBackupBegin,
.opts = opts_backup_begin,
.info = info_backup_begin,
.flags = 0
},
{.name = "backup-dumpxml",
.handler = cmdBackupDumpXML,
.opts = opts_backup_dumpxml,
.info = info_backup_dumpxml,
.flags = 0
},
{.name = NULL}
};