Re: [Qemu-devel] [PATCH 1/2] qemu-iotests: add _filter_qmp_events() for filtering out QMP events

[Sascha Silbe <silbe@linux.vnet.ibm.com>]

Dear Max,

Max Reitz <mreitz@redhat.com> writes:

>> +# remove QMP events from output
>> +_filter_qmp_events()
>> +{
>> +    sed -e '/^{\(.*, \)"event": ".*}$/ d'
>> +}
>
> There is a pretty good reason test 067 uses -qmp-pretty (as you yourself
> say, the lines get pretty long otherwise, and if we have any change
> within, the whole line needs to be changed).

Additionally, it's a lot easier to read when indented properly,
especially with the block info containing nested dicts.

> Using the following ugly
> piece of code here instead, we would still be able to use it:
>
> tr '\n' '\t' \
>   | sed -e
> 's/{\s*"timestamp":\s*{[^}]*},\s*"event":[^,}]*\(,\s*"data":\s*{[^}]*}\)\?\s*}\s*//g'
> \
>   | tr '\t' '\n'

Nice trick. Why didn't I come up with it? ;)

It definitely is a bit ugly, though. We can't just drop the entire line
(using "d") as the entire stream now is a single line. Matching
parenthesis pairs is context sensitive, so we can't just use regular
expressions to aggregate results into lines. And before I start
implementing a JSON indenter in awk, I'd rather rewrite the whole test
in Python. So if we stay with the shell test for now, we need something
like your incantation above. It's not perfect, but good enough for now
and I can't think of anything significantly simpler right now either.

Will test your version and send a v2. Thanks for the suggestion!

Sascha
-- 
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