[Buildroot] [PATCH 7/8] core/show-info: report the ordered list of build steps

[Yann E. MORIN <yann.morin.1998@free.fr>]

Philippe, All,

On 2020-04-11 11:06 -0400, Philippe Proulx spake thusly:
> On Sat, Apr 11, 2020 at 10:19 AM Thomas Petazzoni
> <thomas.petazzoni@bootlin.com> wrote:
[--SNIP--]
> If you tell me that things such build step order and stamp file names do
> not change for many years and as such can be considered as interfaces,
> I'm fine with this.

They are not an interface, definitely not (IMHO). But they are stable
enough that you can build something on them and not expect a breakage
that often.

But an interface? No, we can't commit to that.

> It's always a balance between adding the same logic to all the viewers
> and generating less data.

Since the output of show-info is for machine consumption, and is not
geared at human consuption without first being processed, I don;t see a
problem with generating "more" data.

> My tool could be part of the Buildroot project, but I doubt you'll want
> something that depends on PyQt5 in there.

Not a problem, as it is not a mandatory tool. We already have
utils/brmake that uses unbuffer, which is not available on most distros
by default.

> However, I could certainly
> contribute a Python module which offers utilities over the `show-info`
> output so as to have a versioned, object-oriented API, and then import
> it from an external tool. This way, even if `show-info` changes, the
> Python module can continue to offer the same (non-breaking) interface.

You can't guarantee that either: some keys may disapear, so such a
module could not expose them any more either, so not a stable API.

All you could provide as a stable API, is a way to rerieve basic
information, like the list of packages and such. Or a way to query
keys, which would not provide much more than what 'import json' would.

Regards,
Yann E. MORIN.

> I still think we somewhat need the `build_dir` entry though.
> 
> Phil
> 
> >
> > Best regards,
> >
> > Thomas
> > --
> > Thomas Petazzoni, CTO, Bootlin
> > Embedded Linux and Kernel engineering
> > https://bootlin.com

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