Enhance Docker Build Script for Compatibility with Containerd Layer Store

[matifali]

Problem Description

The recent introduction of the containerd layer store in Depot-hosted runners exposed gaps in our understanding and configuration of Docker’s build process. The feature is working as designed, but it conflicts with our existing workflow when handling multi-architecture builds and provenance data.

Specifically:

• Single-architecture images inadvertently include manifest lists with an unexpected "unknown" platform due to Docker's default build provenance metadata.
• The legacy Docker layer store previously stripped this metadata, but the containerd store natively supports manifest lists and does not modify the image format.
• Modifying our scripts is necessary to fully support the containerd layer store while retaining provenance data and enabling multi-architecture builds.

Desired Solution

1. Update build_docker.sh to Use docker buildx:

   • Incorporate docker buildx build to handle multi-platform builds efficiently.
   • Ensure proper handling of provenance metadata and manifest merging when creating multi-arch images.

2. Integrate depot build as an Optional Workflow:

   • Add a flag to toggle between docker buildx and depot build for CI environments.
   • Use depot build for efficient multi-arch builds where possible, falling back to docker buildx for broader compatibility.

3. Enhance CI Workflow:

   • Default to docker buildx for local and dev workflows to avoid additional dependencies.
   • Enable depot build only in CI and set it up dynamically using a GitHub Action.

4. Optimize for Single-Arch Builds:

   • Modify the script to build single-architecture images efficiently (e.g., during dogfood development) while keeping multi-arch workflows intact in CI.

Next Steps

• Update scripts/build_docker.sh to support both docker buildx for local dev and depot build for ci.
• Test single-architecture and multi-architecture builds using both approaches to ensure functionality with the containerd layer store.

References

• Docker Buildx Documentation
• Docker Provenance Metadata
• containerd image store
• Multi-platform builds
• Slack Thread

This issue will help us fully leverage the containerd layer store's benefits while maintaining compatibility and development flexibility.