Re: [PATCH iproute2 net-next 0/3] ss: Allow selection of columns to be displayed

[David Ahern <dsahern@gmail.com>]

On 11/1/18 3:06 PM, Jakub Kicinski wrote:
> On Wed, 31 Oct 2018 20:48:05 -0600, David Ahern wrote:
>>>   spacing with a special character in the format string, that is:
>>>
>>> 	"%S.%Qr.%Qs  %Al:%Pl %Ar:%Pr  %p\n"
>>>
>>>   would mean "align everything to the right, distribute remaining
>>>   whitespace between %S, %Qr and %Qs". But it looks rather complicated
>>>   at a glance.
>>>   
>>
>> My concern here is that once this goes in for 1 command, the others in
>> iproute2 need to follow suit - meaning same syntax style for all
>> commands. Given that I'd prefer we get a reasonable consensus on syntax
>> that will work across commands -- ss, ip, tc. If it is as simple as
>> column names with a fixed order, that is fine but just give proper
>> consideration given the impact.
> 
> FWIW I just started piping iproute2 commands to jq.  Example:
> 
> tc -s -j qdisc show dev em1 | \
> 	jq -r '.[] |  [.kind,.parent,.handle,.offloaded,.bytes,.packets,.drops,.overlimits,.requeues,.backlog,.qlen,.marked] | @tsv'
> 
> JSONification would probably be quite an undertaking for ss :(
> 

Right, that is used in some of the scripts under
tools/testing/selftests. I would put that in the 'heavyweight solution'
category.

A number of key commands offer the capability to control the output via
command line argument (e.g., ps, perf script). Given the amount of data
iproute2 commands throw at a user by default, it would be a good
usability feature to allow a user to customize the output without having
to pipe it into other commands.