[libvirt] [PATCH 01/19] virsh: Add QMP command wrapping for 'qemu-monitor-command'

[Eric Blake]

On 12/12/19 11:18 AM, 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.

I'd give an example of the new syntax in the commit message:

virsh qemu-monitor-command domain --qmp COMMAND '{ARGUMENTS...}'

as shorthand for

virsh qemu-monitor-command domain '"execute":"COMMAND", 
"arguments":{ARGUMENTS...}}'

But the sugar is indeed nice (one less layer of {} JSON).

> 
> Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> ---
>   docs/manpages/virsh.rst | 24 +++++++++++++++++-------
>   tools/virsh-domain.c    | 32 +++++++++++++++++++++++++++++---
>   2 files changed, 46 insertions(+), 10 deletions(-)
> 

> -    virBufferTrim(&buf, " ", -1);
> +        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", _("-qmp option requires 1 or 2 arguments"));
> +            return false;

Should we allow concatenation and/or magic behavior based on whether the 
second argument starts with '{'?  For example,

virsh qemu-monitor-command --qmp COMMAND key1=1 'key2="str"'

could be shorthand for

virsh qemu-monitor-command '{"execute":"COMMAND", "arguments":{"key1":1, 
"key2":"str"}}'

But further sugar can be a separate patch, so this one works as-is:
Reviewed-by: Eric Blake <eblake at redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org