[Buildroot] Project configuration management

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello Mateusz,

On Mon, 4 Apr 2016 15:55:44 +0200, Mateusz S?upny wrote:

> We are using buildroot for building a series of projects. What I feel
> is missing in buildroot is a way to store different configurations in
> scope of a single project. For example, we would like to prepare
> three types of builds, let's name them "Release", that is the basic
> build, "Develop", that is a Release build + dropbear + some other
> utilities, and "Extra", that contains all configuration options from
> Develop + some additional tools (gdb, valgrind, etc.). To achieve
> that, we have to maintain total of (number of projects) x (number of
> build types) different configuration files that are almost identical.
> 
> Can this goal be achieved without using multiple defconfig files that
> share approx 90% of their contents? What would you advise to avoid
> that?
> 
> First solution that comes to my mind is to allow nesting defconfig
> files with some include/source statement, but AFAICS that's not
> supported.
> 
> Please note that we are aware of "layered customizations" concept,
> and we're using it to some degree, but it doesn't solve all the
> issues, e.g. setting toolchain, selecting packages, and setting
> multiple paths to layers itself has to be done in defconfig files
> anyway.

The mechanism we typically advise in such situation is to use defconfig
fragments, and assemble them as needed to create the configuration you
feed into Buildroot. A shell script (or other) can help generating the
configuration fed into Buildroot from the fragments.

I'm Cc'ing Gustavo, who has been using this model for quite some time
for a large project that involves multiple HW platforms, I'm sure he
can give more insights on how to achieve that.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com