Multi-arch oras artifact pipeline

push.sh

#!/usr/bin/env bash
set -eu -o pipefail

repo="localhost:5000/path/to/thing"
tags="${BUILDKITE_COMMIT:0:7},${BUILDKITE_BRANCH//[^A-Za-z0-9-]/-}"
[[ "$BUILDKITE_BRANCH" == "$BUILDKITE_PIPELINE_DEFAULT_BRANCH" ]] && tags+=",$(cat .release-version),latest"
digests=()

buildkite-agent artifact download "thing-*.tar.gz" .
for artifact in thing-*.tar.gz; do
  platform="${artifact#thing-}"
  platform="${platform%.tar.gz}"
  platform="${platform/-//}"
  digests+=("$(oras push --artifact-platform="$platform" "$repo" "$artifact" --format=go-template="{{.digest}}")")
done

oras manifest index create "$repo:$tags" "${digests[@]}"