Merge ~seb128/casper:desktop-canary-tweaks into casper:main

[Sebastien Bacher]

The changes have been tested in the canary ppa (without the check on ubuntu-desktop-installer/exit 0, which was added now because we don't want to impact the non canary ISO)

[Michael Hudson-Doyle (mwhudson)]

This all seems OK, although couldn't most of these changes also be done in the live layer at ISO build time? Fine to land like this, I not going to insist on anything.

The -d /root/snap/ubuntu-desktop-installer/ relies on the snaps having been preseeded which is probably always true in practice but isn't quite guaranteed. I'm not sure what would be a better check, we could look for /root/var/lib/snapd/seed/ubuntu*.snap or something but it's probably OK for now.

[Sebastien Bacher (seb128)]

Thanks for the review. It sounded lika a +1 with suggestion for futur improvements so I merged that one for now, which should give us a working canary build without ppa and no regressions on days where there is a casper upload to Ubuntu which we didn't rebase yet.

I've no strong opinion on what's the right place to do the customization, we have a bunch of similar hacks in casper today which is why I added there but we can move things later if wanted

And on the 'check that the image is a canary one' we will check if there is a better way but that should go away anyway once canary becomes the new desktop installer

[Michael Hudson-Doyle (mwhudson)]

That all makes sense to me.

diff --git a/scripts/casper-bottom/61desktop_canary_tweaks b/scripts/casper-bottom/61desktop_canary_tweaks
new file mode 100755
index 0000000..f67b59b
--- /dev/null
+++ b/scripts/casper-bottom/61desktop_canary_tweaks
@@ -0,0 +1,59 @@
+#! /bin/sh
+
+PREREQ=""
+DESCRIPTION="Tweaks for the desktop canary image..."
+
+prereqs()
+{
+       echo "$PREREQ"
+}
+
+case $1 in
+# get pre-requisites
+prereqs)
+       prereqs
+       exit 0
+       ;;
+esac
+
+. /scripts/casper-functions
+
+log_begin_msg "$DESCRIPTION"
+
+if [ ! -d /root/snap/ubuntu-desktop-installer/ ]; then
+    exit 0
+fi
+
+# change settings to have an 'installer only' session by default
+printf "[org.gnome.desktop.a11y]\nalways-show-universal-access-status=true\n" >> /root/usr/share/glib-2.0/schemas/casper.gschema.override
+# we can't unload the dock because the shell would enter the overview on login, https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1788
+printf "[org.gnome.shell.extensions.dash-to-dock:ubuntu]\ndock-fixed=false\nintellihide=false\n" >> /root/usr/share/glib-2.0/schemas/casper.gschema.override
+printf "[org.gnome.shell]\ndisabled-extensions=['[e-mail]']\n" >> /root/usr/share/glib-2.0/schemas/casper.gschema.override
+
+chroot /root glib-compile-schemas /usr/share/glib-2.0/schemas/
+
+# set the right kernel variant
+echo "linux-generic-hwe-22.04" > /run/kernel-meta-package
+
+# start the installer on session start, restore normal session on close
+cat > /root/usr/lib/systemd/user/ubuntu-desktop-installer.service  << EOF
+
+[Unit]
+Description=Ubuntu Desktop Installer
+PartOf=graphical-session.target
+After=graphical-session.target
+
+# Never run in GDM
+Conflicts=[e-mail]
+
+[Service]
+Type=oneshot
+ExecStart=/snap/bin/ubuntu-desktop-installer
+ExecStopPost=sh -c "gsettings set org.gnome.shell.extensions.dash-to-dock dock-fixed true; gsettings set org.gnome.shell.extensions.dash-to-dock intellihide true; gnome-extensions enable [e-mail]"
+Restart=no
+EOF
+
+mkdir /root/etc/systemd/user/graphical-session.target.wants/
+ln -s /root/usr/lib/systemd/user/ubuntu-desktop-installer.service /root/etc/systemd/user/graphical-session.target.wants/
+
+log_end_msg