Add initial support for preinstallation of snaps in images, and

preinstall pulsemixer in the Ubuntu MATE image.

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (2.469) UNRELEASED; urgency=medium
+
+  * Add initial support for preinstallation of snaps in images, and
+    preinstall pulsemixer in the Ubuntu MATE image.
+
+ -- Steve Langasek <steve.langasek@ubuntu.com>  Fri, 06 Oct 2017 16:23:49 -0700
+
 livecd-rootfs (2.468) artful; urgency=medium
 
   [ Dimitri John Ledkov ]

live-build/auto/build

@@ -27,6 +27,43 @@ fi
 # Setup cleanup function
 Setup_cleanup
 
+preinstall_snaps() {
+	lb chroot_resolv install
+	Chroot chroot sh -c '
+		set -x;
+		cd /var/lib/snapd/seed;
+		SNAPPY_STORE_NO_CDN=1 snap download core'
+	for snap in "$@"; do
+		Chroot chroot sh -c "
+			set -x;
+			cd /var/lib/snapd/seed;
+			SNAPPY_STORE_NO_CDN=1 snap download \"$snap\""
+	done
+	lb chroot_resolv remove
+
+	CORE_SNAP=$(cd chroot/var/lib/snapd/seed; ls -1 core_*.snap)
+
+	cat <<EOF > chroot/var/lib/snapd/seed/seed.yaml
+snaps:
+ - name: core
+   channel: stable
+   file: ${CORE_SNAP}
+EOF
+	for snap in "$@"; do
+		cat <<EOF >> chroot/var/lib/snapd/seed/seed.yaml
+ - name: $snap
+   channel: stable
+EOF
+		echo -n "   file: " >> chroot/var/lib/snapd/seed/seed.yaml
+		(cd chroot/var/lib/snapd/seed; ls -1 "${snap}_*.snap") \
+			>> chroot/var/lib/snapd/seed/seed.yaml
+	done
+
+	mv chroot/var/lib/snapd/seed/*.assert \
+		chroot/var/lib/snapd/seed/assertions/
+	mv chroot/var/lib/snapd/seed/*.snap chroot/var/lib/snapd/seed/snaps/
+}
+
 rm -f binary.success
 (
 	if [ -d config/gnupg ]; then
@@ -322,6 +359,17 @@ deb file:/var/lib/preinstalled-pool/ $LB_DISTRIBUTION $LB_PARENT_ARCHIVE_AREAS
 			;;
 	esac
 
+	# FIXME: this should not be a hard-coded list in this script; this
+	# is an interim solution for 17.10.
+	case $PROJECT:$SUBPROJECT in
+		ubuntu-mate:*)
+			SNAP_LIST=pulsemixer
+			;;
+	esac
+	if [ -n "$SNAP_LIST" ]; then
+		preinstall_snaps $SNAP_LIST
+	fi
+
 	if [ "$PROJECT" = "ubuntu-touch" ] || [ "$PROJECT" = "ubuntu-touch-custom" ]; then
 		if [ "$ARCH" = "armhf" ]; then
 			INFO_DESC="$(lsb_release -d -s)"