Kevin Wolf <kw...@redhat.com> writes:
> Am 18.06.2019 um 11:01 hat Daniel P. Berrangé geschrieben:
>> On Mon, Jun 17, 2019 at 08:49:03PM +0200, Markus Armbruster wrote:
>> > From: Kevin Wolf <kw...@redhat.com>
>> >
>> > The -mon pretty=on|off switch of the -mon option applies only to QMP
>> > monitors. It's silently ignored for HMP. Deprecate this combination so
>> > that we can make it an error in future versions.
>>
>> No objection to merging this PR as is, but how about we extend the
>> deprecation to QMP too ?
>>
>> I was responsible for adding this option back in 2010 and I don't
>> think I've used it since 2012 when I added pretty printing support
>> to scripts/qmp/qmp-shell. I struggle to imagine good reasons for
>> using QMP directly with pretty printing, as opposed to doing it
>> via qmp-shell or another wrapper tool.
>
> qemu-iotests uses it. It doesn't only make the output (and espeically
> diffs on failure) much more readable, but in fact also avoids very long
> lines in the refernce output that used to break patch emails when we
> didn't use pretty printing yet.
>
> So let's keep it for QMP, please.
Perhaps we can get rid of it if we find a suitable filter.
Hmm, Python comes with one: "python -m json.tool". It expects just one
expression, and fails if anything follows:
$ printf '{"execute": "qmp_capabilities"}\n{"execute": "query-version"}\n'
| socat UNIX:/work/armbru/images/test-qmp STDIO | python3 -m json.tool
Extra data: line 2 column 1 (char 134)
To pretty print a sequence of expressions, you have to wrap a loop
around it:
$ printf '{"execute": "qmp_capabilities"}\n{"execute": "query-version"}\n'
| socat UNIX:/work/armbru/images/test-qmp STDIO | { while read line; do echo
"$line" | python3 -m json.tool; done; }
{
"QMP": {
"version": {
"qemu": {
"micro": 50,
"minor": 0,
"major": 4
},
"package": "v4.0.0-1467-g6385dd6613"
},
"capabilities": [
"oob"
]
}
}
{
"return": {}
}
{
"return": {
"qemu": {
"micro": 50,
"minor": 0,
"major": 4
},
"package": "v4.0.0-1467-g6385dd6613"
}
}
I figure we'd want to loop in Python instead of shell.
My point is: pretty-printing is trivial in Python. The case for
maintaining C code to do it seems weak.
