3:34 p.m.
Issuing simple QMP commands is pain as they need to be wrapped by the
JSON wrapper:
{ "execute": "COMMAND" }
and optionally also:
{ "execute": "COMMAND", "arguments":...}
For simple commands without arguments we can add syntax sugar to virsh
which allows simple usage of QMP and additionally prepares also for
passing through of the 'arguments' section:
virsh qemu-monitor-command $VM query-status
is equivalent to
virsh qemu-monitor-command $VM '{"execute":"query-status"}'
and
virsh qemu-monitor-command $VM query-named-block-nodes '{"flat":true}'
or
virsh qemu-monitor-command $VM query-named-block-nodes '"flat":true'
is equivalent to
virsh qemu-monitor-command $VM
'{"execute":"query-named-block-nodes",
"arguments":{"flat":true}}'
Signed-off-by: Peter Krempa <pkrempa(a)redhat.com>
---
v2:
- dropped the '--qmpwrap' option and do wrapping if we don't get a
JSON object instead. Similarly for arguments.
docs/manpages/virsh.rst | 16 ++++++-
tools/virsh-domain.c | 98 ++++++++++++++++++++++++++++++++++++-----
2 files changed, 103 insertions(+), 11 deletions(-)
diff --git a/docs/manpages/virsh.rst b/docs/manpages/virsh.rst
index 350ded2026..b4d31bf884 100644
--- a/docs/manpages/virsh.rst
+++ b/docs/manpages/virsh.rst
@@ -7772,7 +7772,21 @@ If more than one argument is provided for *command*, they are
concatenated with
a space in between before passing the single command to the monitor.
Note that libvirt uses the QMP to talk to qemu so *command* must be valid JSON
-in QMP format to work properly.
+in QMP format to work properly. If *command* is not a JSON object libvirt tries
+to wrap it as a JSON object to provide convenient interface such as the groups
+of commands with identical handling:
+
+::
+
+ # simple command
+ $ virsh qemu-monitor-command VM commandname
+ $ virsh qemu-monitor-command VM
'{"execute":"commandname"}'
+
+ # with arguments
+ $ virsh qemu-monitor-command VM commandname '"arg1":123'
'"arg2":"test"'
+ $ virsh qemu-monitor-command VM commandname
'{"arg1":123,"arg2":"test"}'
+ $ virsh qemu-monitor-command VM '{"execute":"commandname",
"arguments":{"arg1":123,"arg2":"test"}}'
+
If *--pretty* is given the QMP reply is pretty-printed.
diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index 70aa4167c2..659aa1a242 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -9445,6 +9445,84 @@ static const vshCmdOptDef opts_qemu_monitor_command[] = {
{.name = NULL}
};
+
+static char *
+cmdQemuMonitorCommandConcatCmd(vshControl *ctl,
+ const vshCmd *cmd,
+ const vshCmdOpt *opt)
+{
+ g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
+
+ while ((opt = vshCommandOptArgv(ctl, cmd, opt)))
+ virBufferAsprintf(&buf, "%s ", opt->data);
+
+ virBufferTrim(&buf, " ");
+
+ return virBufferContentAndReset(&buf);
+}
+
+
+static char *
+cmdQemuMonitorCommandQMPWrap(vshControl *ctl,
+ const vshCmd *cmd)
+{
+ g_autofree char *fullcmd = cmdQemuMonitorCommandConcatCmd(ctl, cmd, NULL);
+ g_autoptr(virJSONValue) fullcmdjson = virJSONValueFromString(fullcmd);
+ g_autofree char *fullargs = NULL;
+ g_autoptr(virJSONValue) fullargsjson = NULL;
+ const vshCmdOpt *opt = NULL;
+ const char *commandname = NULL;
+ g_autoptr(virJSONValue) command = NULL;
+ g_autoptr(virJSONValue) arguments = NULL;
+
+ /* if we've got a JSON object, pass it through */
+ if (virJSONValueIsObject(fullcmdjson))
+ return g_steal_pointer(&fullcmd);
+
+ /* we try to wrap the command and possible arguments into a JSON object, if
+ * we as fall back we pass through what we've got from the user */
+
+ if ((opt = vshCommandOptArgv(ctl, cmd, opt)))
+ commandname = opt->data;
+
+ /* now we process arguments similarly to how we've dealt with the full command
*/
+ if ((fullargs = cmdQemuMonitorCommandConcatCmd(ctl, cmd, opt)))
+ fullargsjson = virJSONValueFromString(fullargs);
+
+ /* for empty args or a valid JSON object we just use that */
+ if (!fullargs || virJSONValueIsObject(fullargsjson)) {
+ arguments = g_steal_pointer(&fullargsjson);
+ } else {
+ /* for a non-object we try to concatenate individual _ARGV bits into a
+ * JSON object wrapper and try using that */
+ g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
+
+ virBufferAddLit(&buf, "{");
+ /* opt points to the _ARGV option bit containing the command so we'll
+ * iterate through the arguments now */
+ while ((opt = vshCommandOptArgv(ctl, cmd, opt)))
+ virBufferAsprintf(&buf, "%s,", opt->data);
+
+ virBufferTrim(&buf, ",");
+ virBufferAddLit(&buf, "}");
+
+ if (!(arguments = virJSONValueFromString(virBufferCurrentContent(&buf)))) {
+ vshError(ctl, _("failed to wrap arguments '%s' into a QMP
command wrapper"),
+ fullargs);
+ return NULL;
+ }
+ }
+
+ if (virJSONValueObjectCreate(&command,
+ "s:execute", commandname,
+ "A:arguments", &arguments,
+ NULL) < 0)
+ return NULL;
+
+ return virJSONValueToString(command, false);
+}
+
+
static bool
cmdQemuMonitorCommand(vshControl *ctl, const vshCmd *cmd)
{
@@ -9453,8 +9531,6 @@ cmdQemuMonitorCommand(vshControl *ctl, const vshCmd *cmd)
g_autofree char *result = NULL;
g_autoptr(virJSONValue) resultjson = NULL;
unsigned int flags = 0;
- const vshCmdOpt *opt = NULL;
- g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER;
bool pretty = vshCommandOptBool(cmd, "pretty");
bool returnval = vshCommandOptBool(cmd, "return-value");
virJSONValue *formatjson;
@@ -9466,15 +9542,17 @@ cmdQemuMonitorCommand(vshControl *ctl, const vshCmd *cmd)
if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
return false;
- while ((opt = vshCommandOptArgv(ctl, cmd, opt)))
- virBufferAsprintf(&buf, "%s ", opt->data);
-
- virBufferTrim(&buf, " ");
-
- monitor_cmd = virBufferContentAndReset(&buf);
-
- if (vshCommandOptBool(cmd, "hmp"))
+ if (vshCommandOptBool(cmd, "hmp")) {
flags |= VIR_DOMAIN_QEMU_MONITOR_COMMAND_HMP;
+ monitor_cmd = cmdQemuMonitorCommandConcatCmd(ctl, cmd, NULL);
+ } else {
+ monitor_cmd = cmdQemuMonitorCommandQMPWrap(ctl, cmd);
+ }
+
+ if (!monitor_cmd) {
+ vshSaveLibvirtError();
+ return NULL;
+ }
if (virDomainQemuMonitorCommand(dom, monitor_cmd, &result, flags) < 0)
return false;
--
2.31.1