Support seeding of snaps

We run germinate during configure, and read from each resulting <seed>.snaps
file (expanded from STRUCTURE) to find out which snaps to seed. This is written
to config/seeded-snaps, which is read during build to download each one.

live-build/auto/build

@@ -42,7 +42,7 @@ preinstall_snaps() {
 		chroot chroot sh -c "
 			set -x;
 			cd /var/lib/snapd/seed;
-			SNAPPY_STORE_NO_CDN=1 snap download \"$snap\""
+			SNAPPY_STORE_NO_CDN=1 snap download \"${snap%/*}\""
 	done
 	lb chroot_resolv remove
 
@@ -55,12 +55,14 @@ snaps:
    file: ${CORE_SNAP}
 EOF
 	for snap in "$@"; do
+		snap_name=${snap%/*}
 		cat <<EOF >> chroot/var/lib/snapd/seed/seed.yaml
- - name: $snap
+ - name: ${snap_name}
    channel: stable
 EOF
+		case ${snap} in */classic) echo "   classic: true" >> chroot/var/lib/snapd/seed/seed.yaml;; esac
 		echo -n "   file: " >> chroot/var/lib/snapd/seed/seed.yaml
-		(cd chroot/var/lib/snapd/seed; ls -1 ${snap}_*.snap) \
+		(cd chroot/var/lib/snapd/seed; ls -1 ${snap_name}_*.snap) \
 			>> chroot/var/lib/snapd/seed/seed.yaml
 	done
 
@@ -367,40 +369,33 @@ deb file:/var/lib/preinstalled-pool/ $LB_DISTRIBUTION $LB_PARENT_ARCHIVE_AREAS
 		rm chroot/etc/apt/sources.list.preinstall chroot/etc/apt/sources.list.orig
 	fi
 	case $PROJECT:$SUBPROJECT in
-		ubuntu-server:live|ubuntu-mate:*)
-			assertions_dir="chroot/var/lib/snapd/seed/assertions"
-			model_assertion="$assertions_dir/generic-classic.model"
-			account_key_assertion="$assertions_dir/generic.account-key"
-			account_assertion="$assertions_dir/generic.account"
-
-			mkdir -p "$assertions_dir"
-			snap known --remote model series=16 \
-				model=generic-classic brand-id=generic \
-				> "$model_assertion"
-			account_key=$(sed -n -e's/sign-key-sha3-384: //p' \
-				< "$model_assertion")
-
-			snap known --remote account-key \
-				public-key-sha3-384="$account_key" \
-				> "$account_key_assertion"
-			account=$(sed -n -e's/account-id: //p' \
-				< "$account_key_assertion")
-
-			snap known --remote account account-id=generic \
-				> "$account_assertion"
-			;;
-	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
+		*)
+			if [ -e "config/seeded-snaps" ]; then
+				assertions_dir="chroot/var/lib/snapd/seed/assertions"
+				model_assertion="$assertions_dir/generic-classic.model"
+				account_key_assertion="$assertions_dir/generic.account-key"
+				account_assertion="$assertions_dir/generic.account"
+
+				mkdir -p "$assertions_dir"
+				snap known --remote model series=16 \
+					model=generic-classic brand-id=generic \
+					> "$model_assertion"
+				account_key=$(sed -n -e's/sign-key-sha3-384: //p' \
+					< "$model_assertion")
+
+				snap known --remote account-key \
+					public-key-sha3-384="$account_key" \
+					> "$account_key_assertion"
+				account=$(sed -n -e's/account-id: //p' \
+					< "$account_key_assertion")
+
+				snap known --remote account account-id=generic \
+					> "$account_assertion"
+				snap_list=$(cat config/seeded-snaps)
+				preinstall_snaps $snap_list
+			fi
 			;;
 	esac
-	if [ -n "$SNAP_LIST" ]; then
-		preinstall_snaps $SNAP_LIST
-	fi
 
 	if [ "$PROJECT" = "ubuntu-touch" ] || [ "$PROJECT" = "ubuntu-touch-custom" ]; then
 		if [ "$ARCH" = "armhf" ]; then

live-build/auto/config

@@ -254,13 +254,76 @@ if [ "${SUBPROJECT:-}" = minimized ]; then
 	OPTS="${OPTS:+$OPTS }--bootstrap-flavour=minimal --linux-packages=linux-image"
 fi
 
+# cribbed from cdimage, perhaps this should be a small helper script in germinate?
+add_inheritance () {
+	case " $inherit " in
+		*" $1 "*)
+			;;
+		*)
+			inherit="${inherit:+$inherit }$1"
+			;;
+	esac
+}
+
+expand_inheritance () {
+	for seed in $(grep "^$1:" config/germinate-output/structure | cut -d: -f2); do
+		expand_inheritance "$seed"
+	done
+	add_inheritance "$1"
+}
+
+inheritance () {
+	inherit=
+	expand_inheritance "$1"
+	echo "$inherit"
+}
+
+mkdir -p config/germinate-output
+case $PROJECT in
+        kubuntu-active*)
+                SEED=kubuntu-active.$SUITE
+                ;;
+        kubuntu*)
+                SEED=kubuntu.$SUITE
+                ;;
+        xubuntu*)
+                SEED=xubuntu.$SUITE
+                ;;
+        *)
+                SEED=ubuntu.$SUITE
+                ;;
+esac
+
+if ! [ -e config/germinate-output/structure ]; then
+        echo "Running germinate..."
+        (cd config/germinate-output && germinate --no-rdepends --no-installer \
+                -S $SEEDMIRROR -m $MIRROR -d $SUITE -s $SEED \
+                ${COMPONENTS:+-c "$COMPONENTS"} -a $ARCH)
+fi
+
 case $PROJECT in
 	ubuntu|ubuntu-dvd)
 		add_task install minimal standard ubuntu-desktop
 		LIVE_TASK='ubuntu-live'
+		BASE_SEED='desktop'
+		SEEDS_EXPANDED=$(inheritance ${BASE_SEED})
 		case $ARCH in
 			amd64)	add_package live $SIGNED_KERNEL_PACKAGE ;;
 		esac
+		for seed in ${SEEDS_EXPANDED}; do
+			echo "snap: considering ${seed}"
+			file=config/germinate-output/${seed}.snaps
+			[ -e "${file}" ] || continue
+			# extract the first column (snap package name) from germinate's output
+			# translate the human-readable "foo (classic)" into a
+			# more machine readable "foo/classic"
+			seed_snaps=$(sed -rn '1,/-----/d;/-----/,$d; s/(.*) \|.*/\1/; s, \(classic\),/classic,; p' "${file}")
+			for snap in ${seed_snaps}; do
+				echo "snap: found ${snap}"
+				ALL_SNAPS="${ALL_SNAPS:+${ALL_SNAPS} }${snap}"
+			done
+		done
+		echo "${ALL_SNAPS}" > config/seeded-snaps
 		;;
 
 	ubuntu-desktop-next)
@@ -933,51 +996,8 @@ case ${SUBPROJECT:-} in
 	;;
 esac
 
-# cribbed from cdimage, perhaps this should be a small helper script in germinate?
-add_inheritance () {
-	case " $inherit " in
-		*" $1 "*)
-			;;
-		*)
-			inherit="${inherit:+$inherit }$1"
-			;;
-	esac
-}
-
-expand_inheritance () {
-	for seed in $(grep "^$1:" config/germinate-output/structure | cut -d: -f2); do
-		expand_inheritance "$seed"
-	done
-	add_inheritance "$1"
-}
-
-inheritance () {
-	inherit=
-	expand_inheritance "$1"
-	echo "$inherit"
-}
-
 if [ "$PREINSTALLED" = "true" ]; then
 	if [ -n "$PREINSTALL_POOL_SEEDS" ]; then
-		mkdir -p config/germinate-output
-		case $PROJECT in
-			kubuntu-active*)
-				SEED=kubuntu-active.$SUITE
-				;;
-			kubuntu*)
-				SEED=kubuntu.$SUITE
-				;;
-			xubuntu*)
-				SEED=xubuntu.$SUITE
-				;;
-			*)
-				SEED=ubuntu.$SUITE
-				;;
-		esac
-		(cd config/germinate-output && germinate --no-rdepends --no-installer \
-			-S $SEEDMIRROR -m $MIRROR -d $SUITE -s $SEED \
-			${COMPONENTS:+-c "$COMPONENTS"} -a $ARCH)
-
 		UNWANTED_SEEDS="${LIVE_TASK:+$LIVE_TASK }boot installer required"
 		for i in $UNWANTED_SEEDS; do
 			UNWANTED_SEEDS="${UNWANTED_SEEDS:+$UNWANTED_SEEDS }$(inheritance $i)"