From 40d3e193db557330cfc73a69595f0c3e2366df89 Mon Sep 17 00:00:00 2001
From: Daniel Wagner-Hall <dwagnerhall@apple.com>
Date: Tue, 8 Aug 2023 14:20:38 +0100
Subject: [PATCH] Support repotags

---
 oci/private/tarball.sh.tpl | 60 +++++++++++++++++++++++++++++---------
 1 file changed, 46 insertions(+), 14 deletions(-)

diff --git a/oci/private/tarball.sh.tpl b/oci/private/tarball.sh.tpl
index be6f8739..448171a3 100644
--- a/oci/private/tarball.sh.tpl
+++ b/oci/private/tarball.sh.tpl
@@ -16,11 +16,7 @@ cp_f_with_mkdir() {
   cp -f "${SRC}" "${DST}"
 }
 
-# Replace newlines (unix or windows line endings) with % character.
-# We can't pass newlines to yq due to https://github.com/mikefarah/yq/issues/1430 and 
-# we can't update YQ at the moment because structure_test depends on a specific version:
-# see https://github.com/bazel-contrib/rules_oci/issues/212 
-REPOTAGS="$(tr -d '\r' < "${TAGS_FILE}" | tr '\n' '%')"
+REPOTAGS=($(cat "${TAGS_FILE}"))
 
 MANIFESTS_LENGTH=$("${YQ}" eval '.manifests | length' "${INDEX_FILE}")
 if [[ "${MANIFESTS_LENGTH}" != 1 ]]; then
@@ -33,13 +29,6 @@ if [[ "${MEDIA_TYPE}" == "application/vnd.oci.image.index.v1+json" ]]; then
   # Handle multi-architecture image indexes.
   # Ideally the toolchains we rely on would output these for us, but they don't seem to.
 
-  if [[ -n "${REPOTAGS}" ]]; then
-    echo >&2 "OCI image indexes don't support setting repo tags"
-    echo >&2 "Repo tags can only be set for single-architecture docker-packed images"
-    exit 1
-  fi
-
-  cp "${IMAGE_DIR}/index.json" "${STAGING_DIR}/index.json"
   echo -n '{"imageLayoutVersion": "1.0.0"}' > "${STAGING_DIR}/oci-layout"
 
   INDEX_FILE_MANIFEST_DIGEST=$("${YQ}" eval '.manifests[0].digest | sub(":"; "/")' "${INDEX_FILE}" | tr  -d '"')
@@ -62,6 +51,49 @@ if [[ "${MEDIA_TYPE}" == "application/vnd.oci.image.index.v1+json" ]]; then
       cp_f_with_mkdir "${IMAGE_DIR}/blobs/${LAYER_DIGEST}" ${BLOBS_DIR}/${LAYER_DIGEST}
     done
   done
+
+  # Fill in repo tags as per https://github.com/opencontainers/image-spec/issues/796
+  # If there's more than one repo tag, we need to duplicate the manifest entry, so we have one copy per repo tag.
+  MANIFEST_COPIES=".manifests"
+  if [[ "${#REPOTAGS[@]}" -gt 1 ]]; then
+    for i in $(seq 2 "${#REPOTAGS[@]}"); do
+      MANIFEST_COPIES="${MANIFEST_COPIES} + .manifests"
+    done
+  fi
+  # Convert:
+  # {
+  #   "schemaVersion": 2,
+  #   "manifests": [
+  #     {
+  #       "mediaType": "application/vnd.oci.image.index.v1+json",
+  #       "size": 668,
+  #       "digest": "sha256:41981de3b7207f5260fd94fac77272218518d58a6335d843136d88d91341e3d9"
+  #     }
+  #   ]
+  # }
+  # Into:
+  # {
+  #   "schemaVersion": 2,
+  #   "manifests": [
+  #     {
+  #       "mediaType": "application/vnd.oci.image.index.v1+json",
+  #       "size": 668,
+  #       "digest": "sha256:41981de3b7207f5260fd94fac77272218518d58a6335d843136d88d91341e3d9",
+  #       "annotations": {
+  #         "org.opencontainers.image.ref.name": "repo-tag:1"
+  #       }
+  #     },
+  #     {
+  #       "mediaType": "application/vnd.oci.image.index.v1+json",
+  #       "size": 668,
+  #       "digest": "sha256:41981de3b7207f5260fd94fac77272218518d58a6335d843136d88d91341e3d9",
+  #       "annotations": {
+  #         "org.opencontainers.image.ref.name": "repo-tag:2"
+  #       }
+  #     }
+  #   ]
+  # }
+  repo_tags="${REPOTAGS[@]}" "${YQ}" -o json eval "(.manifests = ${MANIFEST_COPIES}) *d {\"manifests\": (env(repo_tags) | split \" \" | map {\"annotations\": {\"org.opencontainers.image.ref.name\": .}})}" "${INDEX_FILE}" > "${STAGING_DIR}/index.json"
 else
   # Assume we're dealing with a single application/vnd.docker.distribution.manifest.list.v2+json manifest.
 
@@ -79,11 +111,11 @@ else
     cp_f_with_mkdir "${IMAGE_DIR}/blobs/${LAYER}" "${BLOBS_DIR}/${LAYER}.tar.gz"
   done
 
-  repo_tags="${REPOTAGS}" \
+  repo_tags="${REPOTAGS[@]}" \
   config="blobs/${CONFIG_DIGEST}" \
   layers="${LAYERS}" \
   "${YQ}" eval \
-          --null-input '.[0] = {"Config": env(config), "RepoTags": "${repo_tags}" | envsubst | split("%") | map(select(. != "")) , "Layers": env(layers) | map( "blobs/" + . + ".tar.gz") }' \
+          --null-input '.[0] = {"Config": env(config), "RepoTags": "${repo_tags}" | envsubst | split(" ") | map(select(. != "")) , "Layers": env(layers) | map( "blobs/" + . + ".tar.gz") }' \
           --output-format json > "${STAGING_DIR}/manifest.json"
 fi