Re: [ptxdist] lndir'ing sysroot-target

[Michael Olbrich <m.olbrich@pengutronix.de>]

On Sun, Nov 06, 2011 at 01:37:29AM +0100, Erwin Rol wrote:
> On 5-11-2011 12:23, Michael Olbrich wrote:
> >Hi,
> >
> >On Fri, Nov 04, 2011 at 08:46:41PM +0100, Erwin Rol wrote:
> >>in my search to find a way to split ptxdist into an OS build and
> >>application build process I tried the following.
> >>
> >>1) create and build an ptxdist project with everything the OS needs
> >>like glib, gtk, dbus, cairo, etc.
> >>2) create an ptxdist project with applications. And don't have any
> >>"select"s to OS parts like gtk or cairo in the .in files of the
> >>applications.
> >>3) lndir sysroot-target from the OS build into the sysroot-target of
> >>the application build.
> >>4) build the application images.
> >>
> >>
> >>That way I was able to build my applications apart from the OS, but
> >>still use ptxdist to build.
> >>
> >>Would this be a feature that others are interested in ?
> >>
> >>And any ideas or warnings on what could go wrong ?
> >
> >Something like that already exists. With "build type" == "production" you
> >can put the build in some global location. Then with "use pre-built
> >production release" reuse it and add packages without dependencies on the
> >core system like you suggested.
> >Both sources are then used to create the images. I think it's even possible
> >to combine that with collections.
> >"built on top of another platform" is a variation of this where you use a
> >different local platform in the same BSP build, e.g. a generic ARMv5 core
> >platform + several variants with extra local packages.
> >
> >This works well enough if the base platform is stable. However, because of
> >the missing dependencies you should rebuilt everything when it changes.
> >
> 
> Is that really the same. When I understand you correctly the
> Production build only builds part of the system and the "use
> pre-built" creates the final images out of the two parts.
> 
> That is not the same as generating an OS image that runs and works
> fine. And than use a second ptxdist project to create applications
> that you can be installed on that OS.
> 
> Or did I misunderstand something?

But the only difference is 2 images vs. 1, right? That's not quite that
simple. We can easily add an option to not include the ipkgs from the base
system. However the resulting image needs to be mounted somewhere. To do
this right we would need to strip the mount point from the paths when
creating the image. Otherwise the prefix when building and running wont
match.
The question is why do you want 2 images? Unless you add some ugly hacks
you probably need to add some stuff to /etc anyway (e.g. init scripts).

> PS: is there any documentation on how those mentioned feature should
> work, cause the "Help" in ptxdist isn't really helpful.

Unfortunately not. That would require several pages od documentation and
and nobody is really happy with how these features work anyways...
The main problem is, that I have yet to find two people that agree on how
something like this is supposed to work. And while we could probably
implement a lot of these variations, it would create (or rather already is)
a configuration nightmare that only a few experts can handle.

Michael

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