Insert generated image.json into the ostree commit

This is part of coreos/fedora-coreos-tracker#1151

Our generated disk images are largely just a "shell" around the egg
of an ostree commit.  There is almost nothing that lives
in the disk image that isn't in the commit.

(This is especially true now that a preparatory commit previous to
 this moved the *content* of our static `grub.cfg` into `image.json`)

In the original coreos-assembler design I'd tried to cleanly
separate builds of the ostree from disk image builds, but also
support linking them together (with matching version numbers, etc.)
The separate `image.yaml` was part of this.  This...mostly worked.

The goal of this change is that image builds take as input
*just the ostree commit*.  Crucially we would no longer need the config
git repository.  And this in turn unlocks truly better separating
ostree builds from disk image builds in the pipeline *and* supporting
downstream tooling generating disk images from custom containers.

One neat thing here is we will finally fix a longstanding issue
where coreos-assembler fails when just the `image.yaml` changes:
TODO add c-loses for 9-1-2

src/cmd-buildextend-live

@@ -18,7 +18,7 @@ import time
 
 sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
 from cosalib.builds import Builds
-from cosalib.cmdlib import run_verbose, sha256sum_file, generate_image_json
+from cosalib.cmdlib import run_verbose, sha256sum_file, extract_image_json
 from cosalib.cmdlib import import_ostree_commit, get_basearch, ensure_glob
 from cosalib.meta import GenericBuildMeta
 
@@ -46,9 +46,6 @@ if not args.build:
     args.build = builds.get_latest()
 print(f"Targeting build: {args.build}")
 
-image_json = generate_image_json('src/config/image.yaml')
-squashfs_compression = 'lz4' if args.fast else image_json['squashfs-compression']
-
 srcdir_prefix = "src/config/live/"
 
 if not os.path.isdir(srcdir_prefix):
@@ -58,6 +55,13 @@ workdir = os.path.abspath(os.getcwd())
 builddir = builds.get_build_dir(args.build)
 buildmeta_path = os.path.join(builddir, 'meta.json')
 buildmeta = GenericBuildMeta(workdir=workdir, build=args.build)
+repo = os.path.join(workdir, 'tmp/repo')
+
+# Grab the commit hash for this build
+buildmeta_commit = buildmeta['ostree-commit']
+
+image_json = extract_image_json(repo, buildmeta_commit)
+squashfs_compression = 'lz4' if args.fast else image_json['squashfs-compression']
 
 base_name = buildmeta['name']
 if base_name == "rhcos" and args.fast:
@@ -72,10 +76,7 @@ if os.path.exists(build_semaphore):
         f"{build_semaphore} exists: another process is building live")
 
 
-# Grab the commit hash for this build
-buildmeta_commit = buildmeta['ostree-commit']
 
-repo = os.path.join(workdir, 'tmp/repo')
 
 # Don't run if it's already been done, unless forced
 if 'live-iso' in buildmeta['images'] and not args.force:

src/cmd-buildextend-metal

@@ -118,6 +118,9 @@ ostree_repo=${tmprepo}
 # Ensure that we have the cached unpacked commit
 import_ostree_commit_for_build "${build}"
 
+image_json=image.json
+extract_image_json "${tmprepo}" "${commit}" > "${image_json}"
+
 image_format=raw
 if [[ $image_type == qemu ]]; then
     image_format=qcow2

src/cmdlib.sh

@@ -394,6 +394,13 @@ EOF
         done
     fi
 
+    local imagejsondir="${tmp_overridesdir}/imagejson"
+    export ostree_image_json="/usr/share/coreos-assembler/image.json"
+    mkdir -p "${imagejsondir}/usr/share/coreos-assembler/"
+    cp "${image_json}" "${imagejsondir}${ostree_image_json}"
+    commit_overlay cosa-image-json "${imagejsondir}"
+    layers="${layers} cosa-image-json"
+
     local_overrides_lockfile="${tmp_overridesdir}/local-overrides.json"
     if [ -n "${with_cosa_overrides}" ] && [[ -n $(ls "${overridesdir}/rpm/"*.rpm 2> /dev/null) ]]; then
         (cd "${overridesdir}"/rpm && rm -rf .repodata && createrepo_c .)
@@ -874,6 +881,7 @@ builds.bump_timestamp()
 print('Build ${buildid} was inserted ${arch:+for $arch}')")
 }
 
+# Prepare the image.json as part of an ostree image build
 write_image_json() {
     local srcfile=$1; shift
     local outfile=$1; shift
@@ -884,6 +892,19 @@ from cosalib import cmdlib
 cmdlib.write_image_json('${srcfile}', '${outfile}')")
 }
 
+# Fetch the image.json from the ostree commit to stdout.
+# Should be used by disk image builds.
+extract_image_json() {
+    local repo=$1; shift
+    local commit=$1; shift
+    (python3 -c "
+import sys, json
+sys.path.insert(0, '${DIR}')
+from cosalib import cmdlib
+json.dump(sys.stdout, cmdlib.extract_image_json('${repo}', '${commit}'), sort_keys=True)
+")
+}
+
 # Shell wrapper for the Python import_ostree_commit
 import_ostree_commit_for_build() {
     local buildid=$1; shift

src/cosalib/cmdlib.py

@@ -350,10 +350,20 @@ def cmdlib_sh(script):
     '''])
 
 
+# Should be used by disk image builds to extract the image.json from the
+# ostree commit.
+def extract_image_json(repo, commit):
+    out = subprocess.check_output(['ostree', f'--repo={repo}', 'cat', commit, '/usr/share/coreos-assembler/image.json'])
+    return json.loads(out)
+
+
 def generate_image_json(srcfile):
     r = yaml.safe_load(open("/usr/lib/coreos-assembler/image-default.yaml"))
     for k, v in flatten_image_yaml(srcfile).items():
         r[k] = v
+    # Serialize our default GRUB config
+    with open("/usr/lib/coreos-assembler/grub.cfg") as f:
+        r['grub-script'] = f.read()
     return r
 
 

src/cosalib/ova.py

@@ -10,7 +10,7 @@
 sys.path.insert(0, f"{cosa_dir}/cosalib")
 sys.path.insert(0, cosa_dir)
 
-from cosalib.cmdlib import generate_image_json, image_info
+from cosalib.cmdlib import extract_image_json, image_info
 from cosalib.qemuvariants import QemuVariantImage
 
 
@@ -86,7 +86,7 @@ def generate_ovf_parameters(self, vmdk, cpu=2, memory=4096):
         Returns a dictionary with the parameters needed to create an OVF file
         based on the qemu, vmdk, image.yaml, and info from the build metadata
         """
-        image_json = generate_image_json('src/config/image.yaml')
+        image_json = extract_image_json(self._workdir, self.meta['ostree-commit'])
 
         system_type = 'vmx-{}'.format(image_json['vmware-hw-version'])
         os_type = image_json['vmware-os-type']

src/create_disk.sh

@@ -364,7 +364,7 @@ install_grub_cfg() {
     # 0700 to match the RPM permissions which I think are mainly in case someone has
     # manually set a grub password
     mkdir -p -m 0700 $rootfs/boot/grub2
-    cp -v $grub_script $rootfs/boot/grub2/grub.cfg
+    printf "%s" "$grub_script" > $rootfs/boot/grub2/grub.cfg
 }
 
 # Other arch-specific bootloader changes

src/image-default.yaml

@@ -4,7 +4,6 @@ bootfs: "ext4"
 rootfs: "xfs"
 # Add arguments here that will be passed to e.g. mkfs.xfs
 rootfs-args: ""
-grub-script: "/usr/lib/coreos-assembler/grub.cfg"
 
 # Additional default kernel arguments injected into disk images
 extra-kargs: []