Optimize Alpine packaging workflow

scripts/apk/runtime-test.sh

@@ -10,6 +10,7 @@ arch="${ALPINE_ARCH:-x86_64}"
 platform="${ALPINE_TEST_PLATFORM:-linux/amd64}"
 repo_dir="${repo_root}/packages/${repo_name}/${arch}"
 runtime_mode="${ALPINE_RUNTIME_TEST_MODE:-auto}"
+runtime_image="${ALPINE_RUNTIME_TEST_IMAGE:-alpine-apk-runtime-test:${alpine_version}}"
 
 validate_repo() {
   if [[ ! -d "${repo_dir}" ]]; then
@@ -66,10 +67,9 @@ run_hook_docker() {
     -e "PACKAGE_NAME=${package_name}" \
     -v "${repo_root}:/work:ro" \
     -v "${repo_root}/packages/${repo_name}:/repo:ro" \
-    "alpine:${alpine_version}" \
+    "${runtime_image}" \
     sh -lc '
       set -e
-      apk add --no-cache bash openrc >/dev/null
       cp "/repo/${ALPINE_ARCH}"/*.rsa.pub /etc/apk/keys/
       printf "%s\n" /repo >> /etc/apk/repositories
       apk update
@@ -79,6 +79,15 @@ run_hook_docker() {
     '
 }
 
+build_runtime_image() {
+  docker build \
+    --platform "${platform}" \
+    --build-arg "ALPINE_VERSION=${alpine_version}" \
+    -f "${repo_root}/scripts/apk/runtime-test.Dockerfile" \
+    -t "${runtime_image}" \
+    "${repo_root}"
+}
+
 validate_repo
 
 case "${runtime_mode}" in
@@ -99,6 +108,8 @@ esac
 
 if [[ "${runtime_mode}" == "direct" ]]; then
   prepare_direct_runtime
+else
+  build_runtime_image
 fi
 
 while IFS= read -r package_dir; do