baseten-bdn

Python SDK for working with BDN inside and outside Baseten.

⚠️ SDK may change in incompatible ways between releases until the SDK reaches 1.0.

This package is under initial development. It installs as baseten-bdn and imports as baseten.bdn. The baseten package is a namespace shared with other Baseten SDKs such as baseten and baseten-loops.

Installation

pip install baseten-bdn

Volumes

From any machine with a Baseten API key, baseten.bdn.volumes reads a volume version's manifest or pulls a version into a local directory. The client mints a short-lived token through the Baseten API, resolves the ref, and reads the volume's objects directly from storage with the credentials it is given, verifying every object against its recorded digest.

from baseten.bdn.volumes import VolumeClient

with VolumeClient(api_key="...") as volumes:
    result = volumes.pull("bdn:loops/sampler-abc123:step-100", "./checkpoint")

print(result.version_ref, result.file_count, result.bytes_written)

Refs are bdn:<namespace>/<volume> with an optional :<tag> or @<digest> selector and an optional /path inside the version; VolumeRef parses and renders them. A path on the ref, or include=[...], narrows a pull to those entries without moving them. A pull is staged next to dest_dir and renamed into place once complete, so a failed pull leaves nothing behind; pass overwrite=True to write into an existing directory in place. Pulling is supported on Linux and macOS.

Hot Load

Inside a model pod that is opted in to BDN Hot Load, baseten.bdn.hotload attaches BDN volumes below /bdn/mounts at runtime. An attach returns once the directory is readable.

from baseten.bdn.hotload import HotLoadClient

with HotLoadClient() as hotload:
    adapter = hotload.attach("bdn:adapters/sql-lora@b3:2547…", target="sql-lora")

load_adapter(adapter.path)  # /bdn/mounts/sql-lora

AsyncHotLoadClient offers the same methods as coroutines. Attachments belong to the pod and stay mounted after the client is closed; call detach to free a target name for reuse.

Development

Requires uv.

uv sync
uv run poe lint
uv run poe typecheck
uv run poe test

Run uv run poe format to apply formatting and lint fixes.

License

MIT. See LICENSE.