RE: [yocto] defining standard build targets in layer metadata

> -----Original Message-----
> From: [email protected] <[email protected]> On Behalf Of Alexander Kanavin via lists.yoctoproject.org
> Hello all,
> 
> working on bitbake-setup made me consider that a true end-to-end
> configuration tool should also know what to build, not only what to
> set up.
> 
> Earlier bitbake-setup prototypes allowed defining "oe-targets":[...]
> in its configuration files, but I later on realized this doesn't scale
> and isn't flexible enough, and isn't in the right place to begin with.
> So I took it out in the latest patchset.
> 
> So here's a quick, not-well-thought-out idea:
> 
> BB_TARGETS = "build:'core-image-minimal' test:'-c testmage core-image-minimal' "
> 
> defined somewhere in a layer (e.g. conf/distro/poky.conf or in a fragment).
> 
> And then one would be able to run
> 
> bitbake build
> bitbake test
> bitbake flash
> bitbake deploy
> etc.
> 
> which would standardize not only setting up a build but also running
> it. The particular set of generic target names and their values could
> be defined differently, but the basic idea would be similar.
> 
> Thoughts?

I don't have deep thoughts on implementation details, but I have
experience with optimizing command lines for tools.

I think it's important to have discoverability, and the ability to shorten
argument lists when working with a command line tool.

With my own 'ttc' (target control) tool (similar to labgrid), I support
a 'ttc list' command to show which targets are currently configured in
my lab.  I also have the capability to specify a default target (ie board)
using one of: a setting in a config file, an environment variable (TTC_TARGET),
or a command line option.  So can do stuff like:
export TTC_TARGET=rpi4
ttc kbuild
ttc kinstall
ttc cp some_test target:/usr/local/bin
ttc run /usr/local/bin/some_test

Note that I don't have to specify the target on every command.
ttc also supports a 'ttc setenv <target>' command, that is similar to
oe-init-build-env.  It just creates a new shell with appropriate
environment variables for operating on that target.

I have found these very handy in my own lab.

Separately, I think it would be great if people could use bitbake for deploy
operations.  I'm sure it's possible now with appropriate recipe files, but
I suspect it's not standardized for the Yocto ecosystem.  Maybe it's already
there and I just don't know about it.

Just my 2 cents.
 -- Tim