Add scripts to generate raw images

See: https://github.com/kairos-io/kairos/issues/377

tools-image/gce.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+# Transform a raw image disk to gce compatible
+RAWIMAGE="$1"
+
+GB=$((1024*1024*1024))
+size=$(qemu-img info -f raw --output json "$RAWIMAGE" | gawk 'match($0, /"virtual-size": ([0-9]+),/, val) {print val[1]}')
+# shellcheck disable=SC2004
+ROUNDED_SIZE=$(echo "$size/$GB+1"|bc)
+echo "Resizing raw image from \"$size\"MB to \"$ROUNDED_SIZE\"GB"
+qemu-img resize -f raw "$RAWIMAGE" "$ROUNDED_SIZE"G
+echo "Compressing raw image $RAWIMAGE to $RAWIMAGE.tar.gz"
+tar -c -z --format=oldgnu -f "$RAWIMAGE".tar.gz $RAWIMAGE
+echo "Restoring size to original raw image"
+qemu-img resize -f raw "$RAWIMAGE" --shrink "$size"
+echo "Done"