Re: Navigating the layer labyrinth

Joshua Lock <joshua.g.lock@...>

On 12/10/17 10:34, Bernd wrote:
I am a new user for a few weeks now, trying to make a customized image
for a toradex colibri-vf module, so far I have succeeded in the
following disciplines:
* adding the 3rd party layers that I need
* making my own layers
* using a .bbappend to patch the device tree
* using a .bbappend to workaround a bug(?) in one of the freescale layers
* writing my own recipe to install a python script
* writing recipes for pulling additional python packages with pypi and
* writing my own image recipe
* making it boot and run on the target platform
During this learning experience I have made the following observations
of circumstances that made it especially hard for me to get things
done, I'm not yet really sure if this is a documentation issue or if
it is really a missing feature but I feel I could have had a much
*much* easier time learning and understanding the concepts and
relationships and the inner workings of existing layers upon which I
want to build my system if the following things were possible (and/or
if they are already possible they should be documented in the very
first chapter of the documentation):
* Finding the *file path* of an existing recipe (or append file or
class) *by its name* and also all existing .bbappends for it, i
imagine something simple like bitbake --show-paths foo-bar would
output me the small list of absolute paths of recipe files by the name
foo-bar and all matching .bbappend files in the order in which they
would be applied, it would show me only this small list of paths and
not dump 100kb of unrelated information along with it. This would be
incredibly helpful when I need to inspect an existing recipe in order
to understand how I can bbappend it or even just to see and understand
what it actually does.
bitbake-layers supports at least some of this functionality:

$ bitbake-layers -h
NOTE: Starting bitbake server...
usage: bitbake-layers [-d] [-q] [-F] [--color COLOR] [-h] <subcommand> ...

BitBake layers utility

optional arguments:
-d, --debug Enable debug output
-q, --quiet Print only errors
-F, --force Force add without recipe parse verification
--color COLOR Colorize output (where COLOR is auto, always, never)
-h, --help show this help message and exit

add-layer Add a layer to bblayers.conf.
remove-layer Remove a layer from bblayers.conf.
flatten flatten layer configuration into a separate output
layerindex-fetch Fetches a layer from a layer index along with its
dependent layers, and adds them to conf/bblayers.conf.
Find layer dependencies from layer index.
show-layers show current configured layers.
show-overlayed list overlayed recipes (where the same recipe exists
in another layer)
show-recipes list available recipes, showing the layer they are
provided by
show-appends list bbappend files and recipe files they apply to
show-cross-depends Show dependencies between recipes that cross layer
create-layer Create a basic layer

Use bitbake-layers <subcommand> --help to get help on a specific command



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