cmd-buildextend-metal: some rework of generated config for runvm-osbuild

- Add getconfig() helper functions to reduce boilerplate
- Rename variable for config passed to runvm-osbuild to make it more clear
- Create less files
    - Use variables and pipes instead of creating multiple files
- Limit the config for runvm-osbuild
    - Only pass in the variables that are used there and not the entire image.json

Author: dustymabe

src/cmd-buildextend-metal

@@ -139,24 +139,37 @@ fi
 imgname=${name}-${build}-${image_type}.${basearch}.${image_format}
 imgpath=${PWD}/${imgname}
 
-deploy_via_container=""
-if jq -re '.["deploy-via-container"]' < "${image_json}"; then
-    deploy_via_container="true"
-fi
+# Parse the passed config JSON and extract a mandatory value
+getconfig() {
+    k=$1
+    config=$2
+    jq -re .\""$k"\" < "${config}"
+}
+# Return a configuration value, or default if not set
+getconfig_def() {
+    k=$1
+    shift
+    default=$1
+    config=$2
+    jq -re .\""$k"\"//\""${default}"\" < "${config}"
+}
+
+# Grab a few values from ${image_json}
+deploy_via_container=$(getconfig_def "deploy-via-container" "" "${image_json}")
+extra_kargs="$(python3 -c 'import sys, json; args = json.load(sys.stdin)["extra-kargs"]; print(" ".join(args))' < "${image_json}")"
+
 # OStree container ociarchive file path
 ostree_container="${builddir}/$(meta_key images.ostree.path)"
-container_imgref=$(jq -r '.["container-imgref"]//""' < "${image_json}")
-if [ -z "${container_imgref}" ]; then
-    # If no container_imgref was set let's just set it to some professional
-    # looking default. The name of the ociarchive file should suffice.
-    container_imgref="ostree-image-signed:oci-archive:/$(basename "${ostree_container}")"
-fi
+# If no container_imgref was set let's just set it to some professional
+# looking default. The name of the ociarchive file should suffice.
+container_imgref_default="ostree-image-signed:oci-archive:/$(basename "${ostree_container}")"
+container_imgref=$(getconfig_def "container_imgref" "${container_imgref_default}" "${image_json}")
 
 echo "Estimating disk size..."
 # The additional 35% here is obviously a hack, but we can't easily completely fill the filesystem,
 # and doing so has apparently negative performance implications.
-/usr/lib/coreos-assembler/estimate-commit-disk-size --repo "$ostree_repo" "$commit" --add-percent 35 > "$PWD/tmp/ostree-size.json"
-rootfs_size_mb="$(jq '."estimate-mb".final' "$PWD/tmp/ostree-size.json")"
+ostree_size_json="$(/usr/lib/coreos-assembler/estimate-commit-disk-size --repo "$ostree_repo" "$commit" --add-percent 35)"
+rootfs_size_mb="$(jq '."estimate-mb".final' <<< "${ostree_size_json}")"
 # The minimum size of a disk image we'll need will be the rootfs_size
 # estimate plus the size of the non-root partitions. We'll use this
 # size for the metal images, but for the IaaS/virt image we'll use
@@ -176,14 +189,9 @@ metal_image_size_mb="$(( rootfs_size_mb + nonroot_partition_sizes ))"
 cloud_image_size_mb="$(jq -r ".size*1024" < "${image_json}")"
 echo "Disk sizes: metal: ${metal_image_size_mb}M (estimated), cloud: ${cloud_image_size_mb}M"
 
-set -x
-extra_kargs="$(python3 -c 'import sys, json; args = json.load(sys.stdin)["extra-kargs"]; print(" ".join(args))' < "${image_json}")"
-
 # Generate the JSON describing the disk we want to build
-image_dynamic_yaml="${tmp_builddir}/image-dynamic.yaml"
-image_dynamic_json="${tmp_builddir}/image-dynamic.json"
-image_for_disk_json="${tmp_builddir}/image-for-disk.json"
-cat >"${image_dynamic_yaml}" << EOF
+runvm_osbuild_config_json="${tmp_builddir}/runvm-osbuild-config.json"
+yaml2json /dev/stdin "${runvm_osbuild_config_json}" <<EOF
 container-imgref: "${container_imgref}"
 deploy-via-container: "${deploy_via_container}"
 osname: "${name}"
@@ -197,8 +205,6 @@ cloud-image-size: "${cloud_image_size_mb}"
 # not the last partition on the disk so we need to explicitly size it
 rootfs-size: "${rootfs_size_mb}"
 EOF
-yaml2json "${image_dynamic_yaml}" "${image_dynamic_json}"
-cat "${image_json}" "${image_dynamic_json}" | jq -s add > "${image_for_disk_json}"
 
 # In the jenkins pipelines we build the qemu image first and that operation
 # will do a lot of the same work required for later artifacts (metal, metal4k, etc)
@@ -208,7 +214,7 @@ cat "${image_json}" "${image_dynamic_json}" | jq -s add > "${image_for_disk_json
 # This is OK because we don't checkpoint (cache) any of those stages.
 [ "${image_type}" == "qemu" ] && snapshot="off" || snapshot="on"
 runvm_with_cache_snapshot "$snapshot" -- /usr/lib/coreos-assembler/runvm-osbuild                    \
-            --config "${image_for_disk_json}"                                                       \
+            --config "${runvm_osbuild_config_json}"                                                 \
             --mpp "/usr/lib/coreos-assembler/osbuild-manifests/coreos.osbuild.${basearch}.mpp.yaml" \
             --filepath "${imgpath}"                                                                 \
             --platform "${image_type}"