snapd package is missing dependency on grub-common for grub-editenv

[Steve Langasek]

'snap prepare-image' requires grub-common to be installed in order for /usr/bin/grub-editenv to be available. Without it, snap prepare image fails as:

$ UBUNTU_IMAGE_SKIP_COPY_UNVERIFIED_MODEL=1 snap prepare-image --channel=edge ./ubuntu_image/tests/data/model.assertion /tmp/unpack
836.00 KB / 836.00 KB [====================================] 100.00 % 2.51 MB/s
2016/09/09 05:29:19.200267 image.go:203: Cannot fetch and check prerequisites for the model assertion, it will not be copied into the image: assertion not found
Fetching pc
836.00 KB / 836.00 KB [====================================] 100.00 % 2.64 MB/s
Fetching ubuntu-core
75.12 MB / 75.12 MB [======================================] 100.00 % 2.21 MB/s
Fetching pc-kernel
110.70 MB / 110.70 MB [====================================] 100.00 % 2.30 MB/s
error: failed to run command "/usr/bin/grub-editenv /tmp/unpack/image/boot/grub/grubenv set snap_kernel=pc-kernel_19.snap": "" (fork/exec /usr/bin/grub-editenv: no such file or directory)
$

No corresponding problem affects uboot, since snapd apparently implements uboot.env environment manipulation directly in go code.

[Oliver Grawert (ogra)]

if such a dep gets added (instaed of doing the same internal handling for grub like we do or uboot), please make sure it is arch specific else we get the grub dependencies installed on arm images

[Oliver Grawert (ogra)]

s/or/for/

[John Lenton (chipaca)]

ogra, what's the equivalent dep for uboot arches?

I'm ignoring the fact that the map between architecture and bootloader
is more flexible than we're pretending in this bug :-)

On 9 September 2016 at 11:33, Oliver Grawert <email address hidden> wrote:
> s/or/for/
>
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> snapd package is missing dependency on grub-common for grub-editenv
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[Oliver Grawert (ogra)]

there is no dep needed for uboot, snapd has uboot.go and AFAIK michael was planning to do the same for grub ...
grub-common is >10MB ... grub-editenv is < 200k of this, currently i'm removing all of grub-common at image build time, only leaving the grub-editenv binary around to not bloat the images with unneeded cruft.

[Michael Vogt (mvo)]

Well, this is slightly tricky. I don't want to make "grub-common" arch specific. This would mean that you can not build i386 images on an arm64 target anymore. So maybe the way forward is the native grubenv code.

[Barry Warsaw (barry)]

Thanks mvo. I've added a bugtask for ubuntu-image and will discuss with Steve.

[Michael Vogt (mvo)]

@Barry I started with native grubenv now https://github.com/snapcore/snapd/compare/master...mvo5:feature/native-grubenv?expand=1