quicksand-overlay-scaffold

Scaffold a new overlay image package for quicksand.

Overlay packages boot a base VM (default: Ubuntu), run setup commands to install software, and save the result as a compressed overlay. The overlay is bundled into a wheel so users can quicksand install and quicksand run it without rebuilding.

Usage

quicksand-overlay-scaffold my-agent-sandbox

This creates a my-agent-sandbox/ directory with:

my-agent-sandbox/
├── pyproject.toml              # Package metadata and entry points
├── hatch_build.py              # Edit _setup() with your install steps
├── README.md
└── my_agent_sandbox/
    ├── __init__.py             # ImageProvider entry point
    ├── sandbox.py              # Optional Sandbox subclass
    └── images/                 # Built overlay (populated during uv build)

Next Steps

1. Edit hatch_build.py and add your install commands to _setup():

async def _setup(shell: Shell) -> None:
    await shell("apt-get update", timeout=120)
    await shell("apt-get install -y your-packages", timeout=300)
    await shell("pip install your-python-deps", timeout=300)

2. Build the package (boots a VM, runs setup, saves overlay):

uv build --package my-agent-sandbox

3. Test it:

quicksand run my-agent-sandbox

How It Works

During uv build, the hatch_build.py hook:

1. Boots an Ubuntu VM with 4G memory, 4 CPUs, full network, 10G disk
2. Runs your _setup(shell) function inside the VM
3. Saves the VM state as a compressed qcow2 overlay
4. Packages the overlay into a platform-specific wheel

Subsequent builds skip the VM step if images/manifest.json already exists. Delete the images/ directory to force a rebuild.