[RFC PATCH 1/2] sdk: support creation of container image

[Silvano Cirujano Cuesta <silvano.cirujano-cuesta@siemens.com>]

Extend task "populate_sdk" to support the creation of a container image
containing the SDK.

Signed-off-by: Silvano Cirujano Cuesta <silvano.cirujano-cuesta@siemens.com>
---
 meta/classes/image-sdk-extension.bbclass | 99 ++++++++++++++++++++++--
 1 file changed, 92 insertions(+), 7 deletions(-)

diff --git a/meta/classes/image-sdk-extension.bbclass b/meta/classes/image-sdk-extension.bbclass
index a8c708a..9317256 100644
--- a/meta/classes/image-sdk-extension.bbclass
+++ b/meta/classes/image-sdk-extension.bbclass
@@ -6,10 +6,77 @@
 # This class extends the image.bbclass to supply the creation of a sdk
 
 SDK_INCLUDE_ISAR_APT ?= "0"
+SDK_GENERATE_FORMATS = "${@d.getVar("SDK_FORMATS", "tar")}"
+
+sdk_tar() {
+    # Copy mount_chroot.sh for convenience
+    sudo cp ${SCRIPTSDIR}/mount_chroot.sh ${SDKCHROOT_DIR}
+
+    # Create SDK archive
+    cd -P ${SDKCHROOT_DIR}/..
+    sudo tar --transform="s|^rootfs|sdk-${DISTRO}-${DISTRO_ARCH}|" \
+        -c rootfs | xz -T0 > ${DEPLOY_DIR_IMAGE}/sdk-${DISTRO}-${DISTRO_ARCH}.tar.xz
+}
+
+sdk_container_images() {
+    local cmd="/bin/dash"
+    local empty_tag="empty"
+    local full_tag="latest"
+    local oci_img_dir="${WORKDIR}/oci-image"
+    local sdk_container_formats="$1"
+
+    # prepare OCI container image skeleton
+    sudo umoci init --layout "${oci_img_dir}"
+    sudo umoci new --image "${oci_img_dir}:${empty_tag}"
+    sudo umoci config --image "${oci_img_dir}:${empty_tag}" \
+        --config.cmd="${cmd}"
+    sudo umoci unpack --image "${oci_img_dir}:${empty_tag}" \
+        "${oci_img_dir}_unpacked"
+
+    # add SDK root filesystem as the flesh of the skeleton
+    sudo cp -a "${SDKCHROOT_DIR}"/* "${oci_img_dir}_unpacked/rootfs/"
+
+    # pack container image
+    sudo umoci repack --image "${oci_img_dir}:${full_tag}" \
+        "${oci_img_dir}_unpacked"
+    sudo umoci remove --image "${oci_img_dir}:${empty_tag}"
+    sudo rm -rf "${oci_img_dir}_unpacked"
+
+    # no root needed anymore
+    sudo chown --recursive $(id -u):$(id -g) "${oci_img_dir}"
+
+    # convert the OCI container image to the desired format
+    sdk_id="sdk-${DISTRO}-${DISTRO_ARCH}"
+    image_name="isar-${sdk_id}"
+    image_archive="${DEPLOY_DIR_IMAGE}/${sdk_id}-${sdk_format}.tar"
+    for sdk_format in ${sdk_container_formats} ; do
+        case "${sdk_format}" in
+            "docker-archive" | "oci-archive")
+                if [ "${sdk_format}" = "oci-archive" ] ; then
+                    target="${sdk_format}:${image_archive}:latest"
+                else
+                    target="${sdk_format}:${image_archive}:${image_name}:latest"
+                fi
+                skopeo --insecure-policy copy \
+                    "oci:${oci_img_dir}:${full_tag}" "${target}"
+                xz -T0 "${image_archive}"
+                ;;
+            "oci")
+                tar --create --xz --directory "${oci_img_dir}" \
+                    --file "${image_archive}.xz" .
+                ;;
+            "docker-daemon" | "containers-storage")
+                skopeo --insecure-policy copy \
+                    "oci:${oci_img_dir}:${full_tag}" \
+                    "${sdk_format}:${image_name}:latest"
+                ;;
+        esac
+    done
+}
 
 do_populate_sdk[stamp-extra-info] = "${DISTRO}-${MACHINE}"
 do_populate_sdk[depends] = "sdkchroot:do_build"
-do_populate_sdk[vardeps] += "SDK_INCLUDE_ISAR_APT"
+do_populate_sdk[vardeps] += "SDK_INCLUDE_ISAR_APT SDK_GENERATE_FORMATS"
 do_populate_sdk() {
     if [ "${SDK_INCLUDE_ISAR_APT}" = "1" ]; then
         # Copy isar-apt with deployed Isar packages
@@ -48,12 +115,30 @@ do_populate_sdk() {
         done
     done
 
-    # Copy mount_chroot.sh for convenience
-    sudo cp ${SCRIPTSDIR}/mount_chroot.sh ${SDKCHROOT_DIR}
+    # separate SDK formats: TAR and container formats
+    container_formats=""
+    for sdk_format in ${SDK_GENERATE_FORMATS} ; do
+        case ${sdk_format} in
+            tar)
+                sdk_tar
+                ;;
+            "docker-archive" | "oci" | "oci-archive")
+                container_formats="${container_formats} ${sdk_format}"
+                ;;
+            "docker-daemon" | "containers-storage")
+                if [ -f /.dockerenv ] || [ -f /run/.containerenv ] ; then
+                    die "Adding the SDK container image to a container runtime (${sdk_format}) not supported if running from a container (e.g. 'kas-container')"
+                fi
+                ;;
+            *)
+                die "unsupported SDK format specified: ${sdk_format}"
+                ;;
+        esac
+    done
 
-    # Create SDK archive
-    cd -P ${SDKCHROOT_DIR}/..
-    sudo tar --transform="s|^rootfs|sdk-${DISTRO}-${DISTRO_ARCH}|" \
-        -c rootfs | xz -T0 > ${DEPLOY_DIR_IMAGE}/sdk-${DISTRO}-${DISTRO_ARCH}.tar.xz
+    # generate the SDK in all the desired container formats
+    if [ -n "${container_formats}" ] ; then
+        sdk_container_images "${container_formats}"
+    fi
 }
 addtask populate_sdk after do_rootfs
-- 
2.29.2