[yocto] Revision file in images

[Marc Ferland]

Anders Darander <anders at chargestorm.se> writes:

> * Marc Ferland <ferlandm at sonatest.com> [121012 17:40]:
>
>> Hi,
>
>> Is a revision file populated in the images produced by the build process?
>> Something listing the revisions of the different layers used. Just like
>> the "OE Build Configuration" summary.
>
> As Saul wrote, I don't know any way of getting this info.
>
>
>> I'd like to easily identify what a target system currently runs.
>
> In my own project, I'm using something like:
>
>
> IMAGE_PREPROCESS_COMMAND += "rootfs_update_timestamp ;\
>              git describe --dirty --long --always
>>${IMAGE_ROOTFS}/etc/build ;\
>              "
>
> This doesn't explicitly put the SHA1's of the included layers into the
> rootfs, but it does put my the most recent tag from my top-layer,
> together with the number of commits after that tag, and an abreviated version
> of the current commits SHA1 into the file /etc/build. This will give me
> all info I need.
>
FYI, I was able to put the SHA1 of each meta data layer by doing:

def print_layers_version(d):
	layertext = "Configured metadata layers:\n%s\n" % '\n'.join(get_layers_branch_rev(d))
	return layertext

IMAGE_PREPROCESS_COMMAND += "echo "${@print_layers_version(d)}" > /
${IMAGE_ROOTFS}/etc/build; "

Marc