[bug#32634] RFC: Process build output

[Ludovic Courtès]

Hello!

Ricardo Wurmus <address@hidden> skribis:

> One thing I don’t like is that I had to set the “print-build-trace?”
> default option to be able to display what build is currently happening.
> Unfortunately, for small derivations this leads to output like this:
>
> Building /gnu/store/2x5xmvimja0pbkvvr8rym91q0249ajiv-fonts-dir.drv - 
> x86_64-linux
> Built /gnu/store/2x5xmvimja0pbkvvr8rym91q0249ajiv-fonts-dir.drv
> Building /gnu/store/diz3pmgrqibvp2pyvgh4wyr4nx5vlx0y-glib-schemas.drv - 
> x86_64-linux
> Built /gnu/store/diz3pmgrqibvp2pyvgh4wyr4nx5vlx0y-glib-schemas.drv
> Building /gnu/store/ss70j6lf8xxiiykdys92iw92khx68ix9-info-dir.drv - 
> x86_64-linux
> Built /gnu/store/ss70j6lf8xxiiykdys92iw92khx68ix9-info-dir.drv
> Building /gnu/store/rh92rslbj4x9abyna6lc11jqifbavx13-librsvg-2.40.20.drv - 
> x86_64-linux
> Built /gnu/store/rh92rslbj4x9abyna6lc11jqifbavx13-librsvg-2.40.20.drv
>
> I would prefer:
>
>     Building /gnu/store/rh92rslbj4x9abyna6lc11jqifbavx13-librsvg-2.40.20.drv 
> … DONE
>
> or similar.
>
> I don’t know about whether the colours are any good; I think the bold
> green is hard to read on a bright terminal, while the black is hard to
> read on a dark terminal.
>
> Lastly: the spinner.  It’s a bit boring, I think.
>
> What do you think?  Is this a step in the right direction?

Surely!  Another thing we could do, instead of writing “Building” lines,
is to display MAX-JOBS status lines that get updated as things go (when
on a TTY).  This is what I had in mind with:

  
https://git.savannah.gnu.org/cgit/guix.git/commit/?h=wip-ui&id=c367549b4779591844cfbf2975301e4d8ae70b92
  https://lists.gnu.org/archive/html/guix-devel/2017-05/msg00516.html

That branch also had changes to print more “build traces” such that we
can distinguish downloads (corresponding to fixed-output derivations)
from other derivations, which has pros and cons.

Thoughts?

Ludo’.