Re: [nft RFC PATCH] rule: introduce new option to print set elements per line

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Tue, Apr 25, 2017 at 11:35:24AM +0200, Arturo Borrero Gonzalez wrote:
> On 25 April 2017 at 11:22, Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > Hi Arturo,
> >
> > On Fri, Apr 21, 2017 at 12:30:24PM +0200, Arturo Borrero Gonzalez wrote:
> >> Add a new option to nft to print set elements per line instead
> >> of all in a single line.
> >> This is useful when printing a ruleset with very big sets.
> >>
> >> The new option is -t/--elements.
> >>
> >> Annonymous sets/maps/concats are not affected by this. The default
> >> behaviour is not changed.
> >>
> >> Example:
> >>
> >> % nft list ruleset -t -nn
> >> table ip t {
> >>       set s {
> >>               type inet_service
> >>               elements = { 1,
> >>                               2,
> >>                               3,
> >>                               4,
> >>                               12345 }
> >
> > Can we do a more intelligent folding? Via TIOCGWINSZ we can obtain the
> > number of columns so we can try to fit as many elements as possible
> > without wrapping around. Instead of one element per line? I know what
> > I'm asking is harder, but I would like that we explore this path
> > before adding this.
> >
> > And I think we should do this by default, no need for an option.
> > Unless you are a robot, you want an output that you can actually read
> > without lots of lines wrapping around, eg. a very large sets with
> > thousands of elements.
> 
> Ok, by default then.
> 
> Regarding a more intelligent output, the complexity increases quickly,
> since it would require to 'parse' the set before printing it (you
> know, knowing the element printed length, the terminal window size, et
> all). I guess that doing this right may slow down the output a lot,
> similar to what happens in math programs outputs (gnu octave).
> 
> What about an intermediate way?
> 
> if integers, print 4 o 5 per line.
> if maps, contactenations, IPs or strings, print one per line

Give a shot a let's see how this looks like.