Source code for ursa.store.backends.local

"""Local filesystem backend backed by `obstore.store.LocalStore`.

The configured `root` is combined with `prefix` (if any) and resolved to
an absolute path; `LocalStore` confines all keys under that directory
and creates it on demand.
"""

from __future__ import annotations

from obstore.store import LocalStore

from ursa.store.backends._obstore import ObstoreBackend
from ursa.store.base import ObjectStore
from ursa.store.config import LocalStoreConfig




def build_local_store(cfg: LocalStoreConfig, *, role: str) -> ObjectStore:
    """Construct a Local-filesystem-backed `ObjectStore` for the given role."""
    root = (cfg.root / cfg.prefix).resolve() if cfg.prefix else cfg.root.resolve()
    inner = LocalStore(prefix=root, mkdir=True)
    # obstore's LocalStore does not implement put_opts with attributes
    # or UpdateVersion modes — the wrapper raises typed errors when
    # callers ask for them, rather than letting the obstore exception
    # leak through.
    # The prefix is *already* part of `root` for LocalStore (the obstore
    # handle's prefix is the resolved root). LocalStore returns relative
    # paths from head/list, so we pass `prefix=""` to skip stripping.
    # lancedb's local backend takes a plain absolute path (no scheme).
    # The catalog appends `/catalog` to this root.
    return ObstoreBackend(
        inner,
        role=role,
        backend="local",
        prefix="",
        supports_attributes=False,
        supports_etag_match=False,
        lance_uri=str(root),
        lance_storage_options={},
    )