[PATCH v3 1/2] images: add support for container images

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

Add support for creation of container images with the build root
filesystems.

Extend also 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/container-img.bbclass       | 88 ++++++++++++++++++++++++
 meta/classes/image-sdk-extension.bbclass | 51 ++++++++++++--
 meta/classes/image.bbclass               |  1 +
 3 files changed, 133 insertions(+), 7 deletions(-)
 create mode 100644 meta/classes/container-img.bbclass

diff --git a/meta/classes/container-img.bbclass b/meta/classes/container-img.bbclass
new file mode 100644
index 0000000..35c7bbc
--- /dev/null
+++ b/meta/classes/container-img.bbclass
@@ -0,0 +1,88 @@
+# This software is a part of ISAR.
+# Copyright (C) Siemens AG, 2021
+#
+# SPDX-License-Identifier: MIT
+#
+# This class provides the tasks 'containerize_rootfs' and 'containerize_sdk'
+# to create container images containing the target rootfs and the SDK
+# respectively.
+
+CONTAINER_FORMATS ?= "docker-archive"
+
+containerize_rootfs() {
+    local cmd="/bin/dash"
+    local empty_tag="empty"
+    local full_tag="latest"
+    local oci_img_dir="${WORKDIR}/oci-image"
+    local rootfs="$1"
+    local rootfs_id="$2"
+    local container_formats="$3"
+
+    # prepare OCI container image skeleton
+    bbdebug 1 "prepare OCI container image skeleton"
+    rm -rf "${oci_img_dir}"
+    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}" \
+        "${oci_img_dir}_unpacked"
+
+    # add root filesystem as the flesh of the skeleton
+    sudo cp -a "${rootfs}"/* "${oci_img_dir}_unpacked/rootfs/"
+
+    # pack container image
+    bbdebug 1 "pack container image"
+    sudo umoci repack --image "${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) "${oci_img_dir}"
+
+    # convert the OCI container image to the desired format
+    image_name="isar-${rootfs_id}"
+    for image_type in ${CONTAINER_FORMATS} ; do
+        image_archive="${DEPLOY_DIR_IMAGE}/${rootfs_id}-${image_type}.tar"
+        bbdebug 1 "Creating container image type: ${image_type}"
+        case "${image_type}" in
+            "docker-archive" | "oci-archive")
+                if [ "${image_type}" = "oci-archive" ] ; then
+                    target="${image_type}:${image_archive}:latest"
+                else
+                    target="${image_type}:${image_archive}:${image_name}:latest"
+                fi
+                rm -f "${image_archive}" "${image_archive}.xz"
+                bbdebug 2 "Converting OCI image to ${image_type}"
+                skopeo --insecure-policy copy \
+                    "oci:${oci_img_dir}:${full_tag}" "${target}"
+                bbdebug 2 "Compressing image"
+                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}:${full_tag}" \
+                    "${image_type}:${image_name}:latest"
+                ;;
+            *)
+                die "Unsupported format for containerize_rootfs: ${image_type}"
+                ;;
+        esac
+    done
+}
+
+do_container_image[stamp-extra-info] = "${DISTRO}-${MACHINE}"
+do_container_image[vardeps] += "CONTAINER_FORMATS"
+do_container_image(){
+    rootfs_id="${DISTRO}-${DISTRO_ARCH}"
+
+    bbnote "Generate container image in these formats: ${CONTAINER_FORMATS}"
+    containerize_rootfs "${IMAGE_ROOTFS}" "${rootfs_id}" "${CONTAINER_FORMATS}"
+}
+
+addtask container_image before do_image after do_image_tools
diff --git a/meta/classes/image-sdk-extension.bbclass b/meta/classes/image-sdk-extension.bbclass
index a8c708a..63138da 100644
--- a/meta/classes/image-sdk-extension.bbclass
+++ b/meta/classes/image-sdk-extension.bbclass
@@ -6,11 +6,25 @@
 # This class extends the image.bbclass to supply the creation of a sdk
 
 SDK_INCLUDE_ISAR_APT ?= "0"
+SDK_FORMATS ?= "tar-xz"
+
+sdk_tar_xz() {
+    # 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
+    bbnote "SDK rootfs available in ${DEPLOY_DIR_IMAGE}/sdk-${DISTRO}-${DISTRO_ARCH}.tar.xz"
+}
 
 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_FORMATS"
 do_populate_sdk() {
+    local sdk_container_formats=""
+
     if [ "${SDK_INCLUDE_ISAR_APT}" = "1" ]; then
         # Copy isar-apt with deployed Isar packages
         sudo cp -Trpfx ${REPO_ISAR_DIR}/${DISTRO} ${SDKCHROOT_DIR}/isar-apt
@@ -48,12 +62,35 @@ 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
+    for sdk_format in ${SDK_FORMATS} ; do
+        case ${sdk_format} in
+            "tar-xz")
+                sdk_tar_xz
+                ;;
+            "docker-archive" | "oci" | "oci-archive")
+                if [ -z "${sdk_container_formats}" ] ; then
+                    sdk_container_formats="${sdk_format}"
+                else
+                    sdk_container_formats="${sdk_container_formats} ${sdk_format}"
+                fi
+                ;;
+            "docker-daemon" | "containers-storage")
+                if [ -f /.dockerenv ] || [ -f /run/.containerenv ] ; then
+                    die "Adding the SDK container image to a container runtime (${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}-${DISTRO_ARCH}.tar.xz
+    # generate the SDK in all the desired container formats
+    if [ -n "${sdk_container_formats}" ] ; then
+        bbnote "Generating SDK container in ${sdk_container_formats} format"
+        containerize_rootfs "${SDKCHROOT_DIR}" "sdk-${DISTRO}-${DISTRO_ARCH}" "${sdk_container_formats}"
+    fi
 }
+
 addtask populate_sdk after do_rootfs
diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
index eddc444..7fb7b7e 100644
--- a/meta/classes/image.bbclass
+++ b/meta/classes/image.bbclass
@@ -76,6 +76,7 @@ inherit image-tools-extension
 inherit image-postproc-extension
 inherit image-locales-extension
 inherit image-account-extension
+inherit container-img
 
 # Extra space for rootfs in MB
 ROOTFS_EXTRA ?= "64"
-- 
2.30.0