Script to help create a simple mult-arch artifact

build-mult-arch-artifact.sh

#!/bin/bash

echo 'linux/amd64' > README-linux-amd64.md
echo 'linux/arm64' > README-linux-arm64.md

# Push the artifact for amd64 and get the digest
DIGEST_LINUX_AMD64=$(oras push --oci-layout layout-dir README-linux-amd64.md --format go-template='{{.digest}}')

# Push the artifact for arm64 and get the digest
DIGEST_LINUX_ARM64=$(oras push --oci-layout layout-dir README-linux-arm64.md --format go-template='{{.digest}}')

# Fetch the manifest for amd64
AMD64_MANIFEST=$(oras manifest fetch --oci-layout layout-dir@$DIGEST_LINUX_AMD64 --pretty --descriptor | jq '{
  mediaType: .mediaType,
  size: .size,
  digest: .digest,
  platform: {
    architecture: "amd64",
    os: "linux"
  }
}')

# Fetch the manifest for arm64
ARM64_MANIFEST=$(oras manifest fetch --oci-layout layout-dir@$DIGEST_LINUX_ARM64 --pretty --descriptor | jq '{
  mediaType: .mediaType,
  size: .size,
  digest: .digest,
  platform: {
    architecture: "arm64",
    os: "linux"
  }
}')


IMAGE_INDEX=$(jq -n --argjson amd64 "$AMD64_MANIFEST" --argjson arm64 "$ARM64_MANIFEST" '{
  schemaVersion: 2,
  mediaType: "application/vnd.oci.image.index.v1+json",
  manifests: [$amd64, $arm64]
}')

# Save the image index to a file
echo "$IMAGE_INDEX" > image-index.json

# Push the image index to the registry
oras manifest push --oci-layout ./layout-dir:image-index image-index.json

# View the local manifest
oras manifest get --pretty --oci-layout ./layout-dir:image-index

# push the index and artifacts to the registry
oras cp --from-oci-layout ./layout-dir:image-index localhost:5000/artifact:index --to-plain-http

oras manifest get --plain-http localhost:5000/artifact:index

@theory's script https://gist.github.com/theory/7dc164e5772cae652d838a1c508972ae#file-push_trunk