grub-probe must not be called during image build so grub is diverted. In
multilayer image the chroot is always the tip of the filesystem, so we
divert grub at the beginning of each pass and undivdert it as the end.
For flat images, it's diverted just before building the chroot and
undiverted after.
UbuntuStudio image builds have recently begun failing as a result of adding a
grub theme customization to their flavor, which they then try to apply by
running update-grub from their maintainer scripts. This fails with:
Setting up plymouth-theme-ubuntustudio (0.57) ...
update-alternatives: using /usr/share/plymouth/themes/ubuntustudio-logo/ubuntustudio-logo.plymouth to provide /usr/share/plymouth/themes/default.plymouth (default.plymouth) in auto mode
update-alternatives: using /usr/share/plymouth/themes/ubuntustudio-text/ubuntustudio-text.plymouth to provide /usr/share/plymouth/themes/text.plymouth (text.plymouth) in auto mode
update-initramfs: diverted by livecd-rootfs (will be called later)
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
dpkg: error processing package plymouth-theme-ubuntustudio (--configure):
installed plymouth-theme-ubuntustudio package post-installation script subprocess returned error exit status 1
Packages providing grub themes should be able to call update-grub from their
maintainer scripts, and they should be able to be installed under
livecd-rootfs. It's surprising to me that this hasn't been a problem before
now for any flavors.
We know that grub-probe should not be called as part of an image build, so
just use our standard helper function to divert it before running the chroot
stage and undivert it after.
When the REPO_SNAPSHOT_STAMP variable is set, the auto/build script will attempt
to launch a transparent HTTP proxy on port 8080, and insert an iptables rule to
redirect all outgoing HTTP requests to this proxy.
The proxy, contained in the `magic-proxy` Python script, examines each request
and silently overrides those pointing to InRelease files or files that are
listed in InRelease files. It will instead provide the contents of the requested
file as it was at REPO_SNAPSHOT_STAMP, by downloading the corresponding asset
"by hash".
We don't want to regress the ubuntu desktop traditional image when
livecd-rootfs lands uncordinated with ubuntu-cdimage & debian-cd.
Decoupling enables us to:
- land livecd-rootfs (no change for ubuntu-desktop project,
ubuntu-desktop:ubiquity-ng can be tested once the 2 others branches
lands)
- land ubuntu-cdimage & debian-cd for publishing any arbitrary squashfs
names
- finally, revert that commit and land it in livecd-rootfs to transform
the traditional ubuntu-desktop image to a layered approach.
Fixed prefix for passes to not conflict with global prefix
Set layer to none for layer without language packs
Copy size and manifest to the target directory
Make sure the diff always diffes existing manifests
Default Ubuntu desktop to the layered format
Remove the requirement on setting IMAGEFORMAT to layered to build a
layered image and relies on PASSED instead.
Don't install gpg or gpg-agent when building buildd images for series
earlier than bionic. (In earlier series, those packages didn't exist
and gnupg was build-essential.)