Build wkdev-sdk for non-amd64 6architectures.

Podman allows to build multi-architecture OCI images, that combine e.g.
amd64 images + arm64 + ... in one image. Combined with qemu, one can
easily build images for foreign architectures from amd64 hosts.

Use that to extend wkdev-sdk to 'linux/arm/v7', besides the existing
'linux/amd64' support. Extend the GitHub workflow to produce
multi-architecture images. Let's see where this goes :-)

.github/workflows/wkdev-sdk.yml

@@ -36,7 +36,10 @@ jobs:
           remove-haskell: true
           remove-codeql: true
           remove-docker-images: true
-
+
+      - name: Install qemu-user-static
+        run: sudo apt-get -y install qemu-user-static
+
       - name: Install podman
         uses: gacts/install-podman@v1
 

scripts/host-only/wkdev-sdk-bakery

@@ -19,6 +19,7 @@ argsparse_use_option =verbose     "Increase verbosity of this script"
 
 argsparse_use_option =name:       "Name of container image" mandatory default:wkdev-sdk
 argsparse_use_option =mode:       "Operation mode: 'build', 'deploy', or 'export'" mandatory
+argsparse_use_option =platforms:  "Build container for given set of platforms" mandatory default:"linux/arm/v7,linux/amd64"
 argsparse_use_option idle-cores:  "Number of CPU cores to leave idle, when building the image" type:uint default:2
 
 argsparse_usage_description="$(cat <<EOF
@@ -45,6 +46,7 @@ process_command_line_arguments() {
     idle_cores=${program_options["idle-cores"]}
 
     operation_mode="${program_options["mode"]}"
+    platforms="${program_options["platforms"]}"
     [ "${operation_mode}" != 'build' ] && [ "${operation_mode}" != 'deploy' ] && [ "${operation_mode}" != 'export' ] && _abort_ "Unknown operation mode: '${operation_mode}' (valid choices are 'build', 'deploy', or 'export')"
 }
 
@@ -56,7 +58,9 @@ build_image() {
 
     pushd "$(get_image_directory_by_name "${container_image_name}")" &>/dev/null
     timer_start
-    run_podman_silent_unless_verbose build --jobs $(get_number_of_cores_for_build) --tag "$(get_tag_for_build)" . || _abort_ "Container image build failed"
+    run_podman_silent_unless_verbose manifest rm "$(get_tag_for_build)"
+    run_podman_silent_unless_verbose manifest create "$(get_tag_for_manifest creation)" || _abort_ "Container image manifest creation failed"
+    run_podman_silent_unless_verbose build --jobs $(get_number_of_cores_for_build) --platform "${platforms}" --manifest "$(get_tag_for_build)" . || _abort_ "Container image build failed"
     timer_stop
     popd &>/dev/null
 }
@@ -69,7 +73,8 @@ deploy_image() {
 
     local image_directory="$(get_image_directory_by_name "${container_image_name}")"
     pushd "${image_directory}" &>/dev/null || _abort_ "Switching to directory '${image_directory}' failed"
-    run_podman_silent_unless_verbose push "$(get_tag_for_build)" || _abort_ "Pushing to registry failed"
+    run_podman_silent_unless_verbose push "$(get_tag_for_build)" || _abort_ "Pushing image to registry failed"
+    run_podman_silent_unless_verbose manifest push "${container_image_name}:$(get_container_tag)" "docker://$(get_tag_for_build)" || _abort_ "Pushing manifest to registry failed"
     popd &>/dev/null
 }