object-store-based Store implementation

.pre-commit-config.yaml

@@ -9,9 +9,9 @@ repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
     rev: v0.7.3
     hooks:
-    - id: ruff
-      args: ["--fix", "--show-fixes"]
-    - id: ruff-format
+      - id: ruff
+        args: ["--fix", "--show-fixes"]
+      - id: ruff-format
   - repo: https://github.com/codespell-project/codespell
     rev: v2.3.0
     hooks:
@@ -20,7 +20,7 @@ repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v5.0.0
     hooks:
-    - id: check-yaml
+      - id: check-yaml
   - repo: https://github.com/pre-commit/mirrors-mypy
     rev: v1.13.0
     hooks:
@@ -35,6 +35,7 @@ repos:
           - numpy
           - typing_extensions
           - universal-pathlib
+          - obstore==0.3.0-beta.8
           # Tests
           - pytest
   - repo: https://github.com/scientific-python/cookie

pyproject.toml

@@ -70,6 +70,7 @@ test = [
     "mypy",
     "hypothesis",
     "universal-pathlib",
+    "obstore==0.3.0b9",
 ]
 
 jupyter = [

src/zarr/storage/object_store.py

@@ -0,0 +1,319 @@
+from __future__ import annotations
+
+import asyncio
+from collections import defaultdict
+from collections.abc import Iterable
+from typing import TYPE_CHECKING, Any, TypedDict
+
+import obstore as obs
+
+from zarr.abc.store import ByteRangeRequest, Store
+from zarr.core.buffer import Buffer
+from zarr.core.buffer.core import BufferPrototype
+
+if TYPE_CHECKING:
+    from collections.abc import AsyncGenerator, Coroutine, Iterable
+    from typing import Any
+
+    from obstore import ListStream, ObjectMeta, OffsetRange, SuffixRange
+    from obstore.store import ObjectStore as _ObjectStore
+
+    from zarr.core.buffer import Buffer, BufferPrototype
+    from zarr.core.common import BytesLike
+
+
+class ObjectStore(Store):
+    """A Zarr store that uses obstore for fast read/write from AWS, GCP, and Azure.
+
+    Parameters
+    ----------
+    store : obstore.store.ObjectStore
+        An obstore store instance that is set up with the proper credentials.
+    """
+
+    store: _ObjectStore
+    """The underlying obstore instance."""
+
+    def __eq__(self, value: object) -> bool:
+        if not isinstance(value, ObjectStore):
+            return False
+
+        return bool(self.store.__eq__(value.store))
+
+    def __init__(self, store: _ObjectStore, *, read_only: bool = False) -> None:
+        if not isinstance(
+            store,
+            (
+                obs.store.AzureStore,
+                obs.store.GCSStore,
+                obs.store.HTTPStore,
+                obs.store.S3Store,
+                obs.store.LocalStore,
+                obs.store.MemoryStore,
+            ),
+        ):
+            raise TypeError(f"expected ObjectStore class, got {store!r}")
+        self.store = store
+        super().__init__(read_only=read_only)
+
+    def __str__(self) -> str:
+        return f"object://{self.store}"
+
+    def __repr__(self) -> str:
+        return f"ObjectStore({self})"
+
+    async def get(
+        self, key: str, prototype: BufferPrototype, byte_range: ByteRangeRequest | None = None
+    ) -> Buffer:
+        if byte_range is None:
+            resp = await obs.get_async(self.store, key)
+            return prototype.buffer.from_bytes(await resp.bytes_async())
+
+        start, end = byte_range
+        if start is not None and end is not None:
+            resp = await obs.get_range_async(self.store, key, start=start, end=end)
+            return prototype.buffer.from_bytes(memoryview(resp))
+        elif start is not None:
+            if start >= 0:
+                # Offset request
+                resp = await obs.get_async(self.store, key, options={"range": {"offset": start}})
+            else:
+                resp = await obs.get_async(self.store, key, options={"range": {"suffix": start}})
+
+            return prototype.buffer.from_bytes(await resp.bytes_async())
+        else:
+            raise ValueError(f"Unexpected input to `get`: {start=}, {end=}")
+
+    async def get_partial_values(
+        self,
+        prototype: BufferPrototype,
+        key_ranges: Iterable[tuple[str, ByteRangeRequest]],
+    ) -> list[Buffer | None]:
+        return await _get_partial_values(self.store, prototype=prototype, key_ranges=key_ranges)
+
+    async def exists(self, key: str) -> bool:
+        try:
+            await obs.head_async(self.store, key)
+        except FileNotFoundError:
+            return False
+        else:
+            return True
+
+    @property
+    def supports_writes(self) -> bool:
+        return True
+
+    async def set(self, key: str, value: Buffer) -> None:
+        buf = value.to_bytes()
+        await obs.put_async(self.store, key, buf)
+
+    async def set_if_not_exists(self, key: str, value: Buffer) -> None:
+        buf = value.to_bytes()
+        await obs.put_async(self.store, key, buf, mode="create")
+
+    @property
+    def supports_deletes(self) -> bool:
+        return True
+
+    async def delete(self, key: str) -> None:
+        await obs.delete_async(self.store, key)
+
+    @property
+    def supports_partial_writes(self) -> bool:
+        return False
+
+    async def set_partial_values(
+        self, key_start_values: Iterable[tuple[str, int, BytesLike]]
+    ) -> None:
+        raise NotImplementedError
+
+    @property
+    def supports_listing(self) -> bool:
+        return True
+
+    def list(self) -> AsyncGenerator[str, None]:
+        objects: ListStream[list[ObjectMeta]] = obs.list(self.store)
+        return _transform_list(objects)
+
+    def list_prefix(self, prefix: str) -> AsyncGenerator[str, None]:
+        objects: ListStream[list[ObjectMeta]] = obs.list(self.store, prefix=prefix)
+        return _transform_list(objects)
+
+    def list_dir(self, prefix: str) -> AsyncGenerator[str, None]:
+        objects: ListStream[list[ObjectMeta]] = obs.list(self.store, prefix=prefix)
+        return _transform_list_dir(objects, prefix)
+
+
+async def _transform_list(
+    list_stream: AsyncGenerator[list[ObjectMeta], None],
+) -> AsyncGenerator[str, None]:
+    async for batch in list_stream:
+        for item in batch:
+            yield item["path"]
+
+
+async def _transform_list_dir(
+    list_stream: AsyncGenerator[list[ObjectMeta], None], prefix: str
+) -> AsyncGenerator[str, None]:
+    # We assume that the underlying object-store implementation correctly handles the
+    # prefix, so we don't double-check that the returned results actually start with the
+    # given prefix.
+    prefix_len = len(prefix)
+    async for batch in list_stream:
+        for item in batch:
+            # Yield this item if "/" does not exist after the prefix.
+            if "/" not in item["path"][prefix_len:]:
+                yield item["path"]
+
+
+class _BoundedRequest(TypedDict):
+    """Range request with a known start and end byte.
+
+    These requests can be multiplexed natively on the Rust side with
+    `obstore.get_ranges_async`.
+    """
+
+    original_request_index: int
+    """The positional index in the original key_ranges input"""
+
+    start: int
+    """Start byte offset."""
+
+    end: int
+    """End byte offset."""
+
+
+class _OtherRequest(TypedDict):
+    """Offset or suffix range requests.
+
+    These requests cannot be concurrent on the Rust side, and each need their own call
+    to `obstore.get_async`, passing in the `range` parameter.
+    """
+
+    original_request_index: int
+    """The positional index in the original key_ranges input"""
+
+    path: str
+    """The path to request from."""
+
+    range: OffsetRange | SuffixRange
+    """The range request type."""
+
+
+class _Response(TypedDict):
+    """A response buffer associated with the original index that it should be restored to."""
+
+    original_request_index: int
+    """The positional index in the original key_ranges input"""
+
+    buffer: Buffer
+    """The buffer returned from obstore's range request."""
+
+
+async def _make_bounded_requests(
+    store: obs.store.ObjectStore,
+    path: str,
+    requests: list[_BoundedRequest],
+    prototype: BufferPrototype,
+) -> list[_Response]:
+    """Make all bounded requests for a specific file.
+
+    `obstore.get_ranges_async` allows for making concurrent requests for multiple ranges
+    within a single file, and will e.g. merge concurrent requests. This only uses one
+    single Python coroutine.
+    """
+
+    starts = [r["start"] for r in requests]
+    ends = [r["end"] for r in requests]
+    responses = await obs.get_ranges_async(store, path=path, starts=starts, ends=ends)
+
+    buffer_responses: list[_Response] = []
+    for request, response in zip(requests, responses, strict=True):
+        buffer_responses.append(
+            {
+                "original_request_index": request["original_request_index"],
+                "buffer": prototype.buffer.from_bytes(memoryview(response)),
+            }
+        )
+
+    return buffer_responses
+
+
+async def _make_other_request(
+    store: obs.store.ObjectStore,
+    request: _OtherRequest,
+    prototype: BufferPrototype,
+) -> list[_Response]:
+    """Make suffix or offset requests.
+
+    We return a `list[_Response]` for symmetry with `_make_bounded_requests` so that all
+    futures can be gathered together.
+    """
+    resp = await obs.get_async(store, request["path"], options={"range": request["range"]})
+    buffer = await resp.bytes_async()
+    return [
+        {
+            "original_request_index": request["original_request_index"],
+            "buffer": prototype.buffer.from_bytes(buffer),
+        }
+    ]
+
+
+async def _get_partial_values(
+    store: obs.store.ObjectStore,
+    prototype: BufferPrototype,
+    key_ranges: Iterable[tuple[str, ByteRangeRequest]],
+) -> list[Buffer | None]:
+    """Make multiple range requests.
+
+    ObjectStore has a `get_ranges` method that will additionally merge nearby ranges,
+    but it's _per_ file. So we need to split these key_ranges into **per-file** key
+    ranges, and then reassemble the results in the original order.
+
+    We separate into different requests:
+
+    - One call to `obstore.get_ranges_async` **per target file**
+    - One call to `obstore.get_async` for each other request.
+    """
+    key_ranges = list(key_ranges)
+    per_file_bounded_requests: dict[str, list[_BoundedRequest]] = defaultdict(list)
+    other_requests: list[_OtherRequest] = []
+
+    for idx, (path, (start, end)) in enumerate(key_ranges):
+        if start is None:
+            raise ValueError("Cannot pass `None` for the start of the range request.")
+
+        if end is not None:
+            # This is a bounded request with known start and end byte.
+            per_file_bounded_requests[path].append(
+                {"original_request_index": idx, "start": start, "end": end}
+            )
+        elif start < 0:
+            # Suffix request from the end
+            other_requests.append(
+                {"original_request_index": idx, "path": path, "range": {"suffix": abs(start)}}
+            )
+        elif start >= 0:
+            # Offset request to the end
+            other_requests.append(
+                {"original_request_index": idx, "path": path, "range": {"offset": start}}
+            )
+        else:
+            raise ValueError(f"Unsupported range input: {start=}, {end=}")
+
+    futs: list[Coroutine[Any, Any, list[_Response]]] = []
+    for path, bounded_ranges in per_file_bounded_requests.items():
+        futs.append(_make_bounded_requests(store, path, bounded_ranges, prototype))
+
+    for request in other_requests:
+        futs.append(_make_other_request(store, request, prototype))  # noqa: PERF401
+
+    buffers: list[Buffer | None] = [None] * len(key_ranges)
+
+    # TODO: this gather a list of list of Response; not sure if there's a way to
+    # unpack these lists inside of an `asyncio.gather`?
+    for responses in await asyncio.gather(*futs):
+        for resp in responses:
+            buffers[resp["original_request_index"]] = resp["buffer"]
+
+    return buffers

tests/test_store/test_object.py

@@ -0,0 +1,22 @@
+# ruff: noqa: E402
+import pytest
+
+obstore = pytest.importorskip("obstore")
+
+from zarr.core.buffer import cpu
+from zarr.storage.object_store import ObjectStore
+from zarr.testing.store import StoreTests
+
+
+class TestObjectStore(StoreTests[ObjectStore, cpu.Buffer]):
+    store_cls = ObjectStore
+    buffer_cls = cpu.Buffer
+
+    @pytest.fixture
+    def store_kwargs(self, tmpdir) -> dict[str, str | bool]:
+        store = obstore.store.LocalStore(prefix=tmpdir)
+        return {"store": store, "read_only": False}
+
+    @pytest.fixture
+    def store(self, store_kwargs: dict[str, str | bool]) -> ObjectStore:
+        return self.store_cls(**store_kwargs)