Add an image-default.yaml, pass JSON to create_disk.sh

The way we parse an `image.yaml` and then convert it
into arguments for `create_disk.sh` is unwieldy.

Instead, convert `image.yaml` into JSON, inheriting default values
from a separate `image-default.yaml` we ship.  Then pass
that JSON to `create_disk.sh`.

This only converts the `rootfs` argument, but if people
are OK with this I can go ahead and convert everything
else - getting us to where the only argument to `create_disk.sh`
is a JSON file that's already been pre-validated.

src/cmd-buildextend-metal

@@ -151,15 +151,19 @@ if [ "${image_type}" = dasd ] || [ "${image_type}" = metal4k ]; then
     ignition_platform_id=metal
 fi
 
+yaml2json() {
+    python3 -c 'import sys, json, yaml; json.dump(yaml.safe_load(sys.stdin), sys.stdout)' < "$1" > "$2"
+}
+
+# Convert the image.yaml to JSON so that it can be more easily parsed
+# by the shell script in create_disk.sh.
+yaml2json "$configdir/image.yaml" image-config.json
+yaml2json "/usr/lib/coreos-assembler/image-default.yaml" image-default.json
+cat image-default.json image-config.json | jq -s add > image.json
+
 # bootfs
 bootfs_type="$(python3 -c 'import sys, yaml; print(yaml.safe_load(sys.stdin).get("bootfs", "ext4"))' < "$configdir/image.yaml")"
-
-# First parse the old luks_rootfs flag (a custom "stringified bool")
-rootfs_type="$(python3 -c 'import sys, yaml; lf=yaml.safe_load(sys.stdin).get("luks_rootfs", ""); print("luks" if lf.lower() in ("yes", "true") else "")' < "$configdir/image.yaml")"
-if [ -z "${rootfs_type}" ]; then
-    # Now the newer rootfs flag
-    rootfs_type="$(python3 -c 'import sys, yaml; print(yaml.safe_load(sys.stdin).get("rootfs", "xfs"))' < "$configdir/image.yaml")"
-fi
+rootfs_type=$(jq -re .rootfs < image.json)
 
 # fs-verity requires block size = page size. We need to take that into account
 # in the disk size estimation due to higher fragmentation on larger blocks.
@@ -253,6 +257,7 @@ target_drive=("-drive" "if=none,id=target,format=${image_format},file=${path}.tm
 
 runvm "${target_drive[@]}" -- \
         /usr/lib/coreos-assembler/create_disk.sh \
+            --config "$(pwd)"/image.json \
             --buildid "${build}" \
             --imgid "${img}" \
             --grub-script /usr/lib/coreos-assembler/grub.cfg \
@@ -262,7 +267,6 @@ runvm "${target_drive[@]}" -- \
             --ostree-remote "${ostree_remote}" \
             --ostree-repo "${ostree_repo}" \
             --rootfs-size "${rootfs_size}" \
-            --rootfs "${rootfs_type}" \
             "${disk_args[@]}"
 /usr/lib/coreos-assembler/finalize-artifact "${path}.tmp" "${path}"
 

src/create_disk.sh

@@ -37,25 +37,25 @@ Options:
     --ostree-repo: location of the ostree repo
     --rootfs-size: Create the root filesystem with specified size
     --boot-verity: Provide this to enable ext4 fs-verity for /boot
-    --rootfs: xfs|ext4verity|luks
     --no-x86-bios-partition: don't create a BIOS partition on x86_64
 
 You probably don't want to run this script by hand. This script is
 run as part of 'coreos-assembler build'.
 EOC
 }
 
+config=
 disk=
 rootfs_size="0"
 boot_verity=0
-rootfs_type="xfs"
 x86_bios_partition=1
 extrakargs=""
 
 while [ $# -gt 0 ];
 do
     flag="${1}"; shift;
     case "${flag}" in
+        --config)                config="${1}"; shift;;
         --disk)                  disk="${1}"; shift;;
         --buildid)               buildid="${1}"; shift;;
         --imgid)                 imgid="${1}"; shift;;
@@ -68,7 +68,6 @@ do
         --ostree-repo)           ostree="${1}"; shift;;
         --rootfs-size)           rootfs_size="${1}"; shift;;
         --boot-verity)           boot_verity=1;;
-        --rootfs)                rootfs_type="${1}" shift;;
         --no-x86-bios-partition) x86_bios_partition=0;;
          *) echo "${flag} is not understood."; usage; exit 10;;
      esac;
@@ -84,6 +83,7 @@ arch="$(uname -m)"
 
 disk=$(realpath /dev/disk/by-id/virtio-target)
 
+config="${config:?--config must be defined}"
 buildid="${buildid:?--buildid must be defined}"
 imgid="${imgid:?--imgid must be defined}"
 ostree="${ostree:?--ostree-repo must be defined}"
@@ -92,6 +92,17 @@ remote_name="${remote_name:?--ostree-remote must be defined}"
 grub_script="${grub_script:?--grub-script must be defined}"
 os_name="${os_name:?--os_name must be defined}"
 
+getconfig() {
+    k=$1
+    jq -re .$k < ${config}
+}
+
+# First parse the old luks_rootfs flag (a custom "stringified bool")
+if test "$(getconfig luks_rootfs)" = "yes"; then
+    rootfs_type=luks
+else
+    rootfs_type=$(getconfig rootfs)
+fi
 case "${rootfs_type}" in
     xfs|ext4verity|luks|btrfs) ;;
     *) echo "Invalid rootfs type: ${rootfs_type}" 1>&2; exit 1;;

src/image-default.yaml

@@ -0,0 +1,2 @@
+# This file contains defaults for image.yaml that is used by create_disk.sh
+rootfs: "xfs"