build-image: Store size and checksum in metadata

This will allow us to verify that the downloaded image uncompressed
correctly and to have a proper progress bare even with images of
different sizes.

build-image

@@ -68,6 +68,22 @@ setup_loop() {
     return 0
 }
 
+write_meta() {
+    local out="$1"
+    local image="$2"
+
+    image_sha256sum=$(sha256sum "${image}" | sed 's/\([a-f0-9]\+\) .*/\1/')
+    image_size=$(stat --format='%s' "${image}")
+    echo "Image '${image} has sha256sum ${image_sha256sum}"
+
+    cat <<EOF >> "${out}"
+gitrev: $(git log --format=format:%H -1)
+image:
+  size: ${image_size}
+  sha256sum: ${image_sha256sum}
+EOF
+}
+
 cwd=$(pwd)
 
 distro=${DIST:-buster+ci}
@@ -83,6 +99,7 @@ debootstrap_dist=
 kernel_deb=
 custom_package_opt=
 board_packages=
+meta_yml=files/meta.yml
 
 while getopts ":hb:d:T:B" opt; do
   case ${opt} in
@@ -127,8 +144,7 @@ echo "Installing extra packages ${packages}"
 [ -z "${board_packages}" ] || echo "Installing extra board specific packages ${board_packages}"
 
 mkdir -p tmp/ files/
-echo -n > files/meta.yml
-rm -f "./tmp/${pureos_board}-report.log"
+rm -f "./tmp/${pureos_board}-report.log" "${meta_yml}"
 
 if [ "${build_type}" == "latest" ]; then
     fetch_latest_kernel
@@ -191,7 +207,6 @@ sudo pureos_board="${pureos_board}" \
     ${NULL}
 set +x
 
-echo "gitrev: $(git log --format=format:%H -1)" >> files/meta.yml
 
 if [ "${arch}" == "arm64" ]; then
     if [ ! -f "files/uboot-${uboot_type}/m4.bin" ]; then
@@ -206,6 +221,8 @@ fi
 
 [ -f "./tmp/${pureos_board}-report.log" ] || { echo "No install report found."; exit 1; }
 
+write_meta "${meta_yml}" "${bootimg}"
+
 if [ "${want_qcow2}" == 1 ]; then
     qcow2="$(basename "${bootimg}" .img)".qcow2
     qemu-img convert -f raw -O qcow2 "${bootimg}" "${qcow2}"