docs/manpages/virsh.rst | 9 ++++++++- tools/virsh-domain.c | 31 ++++++++++++++++++++++++++++--- 2 files changed, 36 insertions(+), 4 deletions(-)
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'.
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);
--
2.31.1
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); >
On Tue, Sep 14, 2021 at 05:16:11PM +0200, Peter Krempa 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'. How about just following a DWIM approach and not adding any flag These two cases are trivially distinguished: virsh qemu-monitor-command $VM '{"execute":"query-named-block-nodes", "arguments":{"flat":true}}' virsh qemu-monitor-command $VM query-named-block-nodes '{"flat":true}' because the second doesn't start with a '{' Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
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