On Tue, 14 Sep 2021 17:16:11 +0200 Peter Krempa <pkrempa@redhat.com> wrote:

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 --qmpwrap $VM query-status

is equivalent to

virsh qemu-monitor-command $VM '{"execute":"query-status"}'

and

virsh qemu-monitor-command --qmpwrap $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@redhat.com> ---

I originally called the flag '--qmp' but that could be confusing given that we have '--hmp'. On the other hand it's shorter so I wouldn't mind turning it back to '--qmp'.

I like the idea, as I also find the qemu-monitor-command to be awkward to use. I'm not crazy about the name --qmpwrap, though. I kind of wish we could do something like virsh qemu-monitor-command --cmd command-name --args '{"arg1":true}' but --cmd is already taken as an optional flag for the full json-formatted command. I'm not sure I have any better ideas though. Tangent: Reading the code for this function leads me the surprising discovery that these two commands are actually identical: qemu-monitor-command vm --cmd {\"execute\": \"help\"} qemu-monitor-command vm {\"execute\": --cmd \"help\"} Jonathon

docs/manpages/virsh.rst | 9 ++++++++- tools/virsh-domain.c | 31 ++++++++++++++++++++++++++++--- 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/docs/manpages/virsh.rst b/docs/manpages/virsh.rst index 9561b3f59d..b8cb3cfbc2 100644 --- a/docs/manpages/virsh.rst +++ b/docs/manpages/virsh.rst @@ -7694,7 +7694,8 @@ qemu-monitor-command

::

- qemu-monitor-command domain { [--hmp] | [--pretty] [--return-value] } command... + qemu-monitor-command domain { [--hmp] | [--qmpwrap] [--pretty] + [--return-value] } command...

Send an arbitrary monitor command *command* to domain *domain* through the QEMU monitor. The results of the command will be printed on stdout. @@ -7705,6 +7706,12 @@ 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.

+If *--qmpwrap* is passed the first argument passed as *command* is used as a QMP +command name and appropriately wrapped into a JSON block. Additionally a second +argument passed as *command* is appended as value of the 'arguments' parameter +of the QMP command verbatim. *Note* that in the future automatic formatting +*--qmpwrap* of the arguments might be added, so scripts should format their own JSON. + If *--pretty* is given the QMP reply is pretty-printed.

If *--return-value* is given the 'return' key of the QMP response object is diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c index e5bd1fdd75..ac57196b20 100644 --- a/tools/virsh-domain.c +++ b/tools/virsh-domain.c @@ -9380,6 +9380,10 @@ static const vshCmdOptDef opts_qemu_monitor_command[] = { .type = VSH_OT_BOOL, .help = N_("extract the value of the 'return' key from the returned string") }, + {.name = "qmpwrap", + .type = VSH_OT_BOOL, + .help = N_("wrap the 'cmd' argument in JSON wrapper for QMP") + }, {.name = "cmd", .type = VSH_OT_ARGV, .flags = VSH_OFLAG_REQ, @@ -9405,14 +9409,35 @@ cmdQemuMonitorCommand(vshControl *ctl, const vshCmd *cmd)

VSH_EXCLUSIVE_OPTIONS("hmp", "pretty"); VSH_EXCLUSIVE_OPTIONS("hmp", "return-value"); + VSH_EXCLUSIVE_OPTIONS("hmp", "qmpwrap");

if (!(dom = virshCommandOptDomain(ctl, cmd, NULL))) return false;

- while ((opt = vshCommandOptArgv(ctl, cmd, opt))) - virBufferAsprintf(&buf, "%s ", opt->data); + if (vshCommandOptBool(cmd, "qmpwrap")) { + const char *command = NULL; + const char *arguments = NULL;

- virBufferTrim(&buf, " "); + if ((opt = vshCommandOptArgv(ctl, cmd, opt))) + command = opt->data; + if ((opt = vshCommandOptArgv(ctl, cmd, opt))) + arguments = opt->data; + + if (!command || (arguments && vshCommandOptArgv(ctl, cmd, opt))) { + vshError(ctl, "%s", _("--qmpwrap option requires 1 or 2 arguments")); + return false; + } + + virBufferAsprintf(&buf, "{\"execute\":\"%s\"", command); + if (arguments) + virBufferAsprintf(&buf, ", \"arguments\":%s", arguments); + virBufferAddLit(&buf, "}"); + } else { + while ((opt = vshCommandOptArgv(ctl, cmd, opt))) + virBufferAsprintf(&buf, "%s ", opt->data); + + virBufferTrim(&buf, " "); + }

monitor_cmd = virBufferContentAndReset(&buf);