store -> readonly

Author: jhamman

docs/guide/storage.rst

@@ -2,7 +2,7 @@ Storage
 =======
 
 Zarr-Python supports multiple storage backends, including: local file systems,
-Zip files, remote stores via ``fspec`` (S3, HTTP, etc.), and in-memory stores. In
+Zip files, remote stores via ``fsspec`` (S3, HTTP, etc.), and in-memory stores. In
 Zarr-Python 3, stores must implement the abstract store API from
 :class:`zarr.abc.store.Store`. 
 
@@ -19,9 +19,9 @@ to Zarr's top level API will result in the store being created automatically.
 .. code-block:: python
 
    >>> import zarr
-   >>> zarr.open("data/foo/bar", mode="r")  # implicitly creates a LocalStore
+   >>> zarr.open("data/foo/bar", mode="r")  # implicitly creates a read-only LocalStore
    <Group file://data/foo/bar>
-   >>> zarr.open("s3://foo/bar", mode="r")  # implicitly creates a RemoteStore
+   >>> zarr.open("s3://foo/bar", mode="r")  # implicitly creates a read-only RemoteStore
    <Group s3://foo/bar>
    >>> data = {}
    >>> zarr.open(data, mode="w")  # implicitly creates a MemoryStore
@@ -43,7 +43,7 @@ filesystem.
 .. code-block:: python
 
    >>> import zarr
-   >>> store = zarr.storage.LocalStore("data/foo/bar", mode="r")
+   >>> store = zarr.storage.LocalStore("data/foo/bar", readonly=True)
    >>> zarr.open(store=store)
    <Group file://data/foo/bar>
 
@@ -72,7 +72,7 @@ that implements the `AbstractFileSystem` API,
 .. code-block:: python
 
    >>> import zarr
-   >>> store = zarr.storage.RemoteStore.from_url("gs://foo/bar", mode="r")
+   >>> store = zarr.storage.RemoteStore.from_url("gs://foo/bar", readonly=True)
    >>> zarr.open(store=store)
    <Array <RemoteStore(GCSFileSystem, foo/bar)> shape=(10, 20) dtype=float32>
 
@@ -86,7 +86,7 @@ Zarr data (metadata and chunks) to a dictionary.
 
    >>> import zarr
    >>> data = {}
-   >>> store = zarr.storage.MemoryStore(data, mode="w")
+   >>> store = zarr.storage.MemoryStore(data)
    >>> zarr.open(store=store, shape=(2, ))
    <Array memory://4943638848 shape=(2,) dtype=float64>
 

src/zarr/abc/store.py

@@ -3,7 +3,7 @@
 from abc import ABC, abstractmethod
 from asyncio import gather
 from itertools import starmap
-from typing import TYPE_CHECKING, Literal, Protocol, runtime_checkable
+from typing import TYPE_CHECKING, Protocol, runtime_checkable
 
 if TYPE_CHECKING:
     from collections.abc import AsyncGenerator, Iterable
@@ -13,24 +13,22 @@
     from zarr.core.buffer import Buffer, BufferPrototype
     from zarr.core.common import BytesLike
 
-__all__ = ["StoreAccessMode", "ByteGetter", "ByteSetter", "Store", "set_or_delete"]
+__all__ = ["ByteGetter", "ByteSetter", "Store", "set_or_delete"]
 
 ByteRangeRequest: TypeAlias = tuple[int | None, int | None]
-StoreAccessMode = Literal["r", "w"]
 
 
 class Store(ABC):
     """
     Abstract base class for Zarr stores.
     """
 
-    _mode: StoreAccessMode
+    _readonly: bool
     _is_open: bool
 
-    def __init__(self, *args: Any, mode: StoreAccessMode = "r", **kwargs: Any) -> None:
+    def __init__(self, *, readonly: bool = False) -> None:
         self._is_open = False
-        assert mode in ("r", "w")
-        self._mode = mode
+        self._readonly = readonly
 
     @classmethod
     async def open(cls, *args: Any, **kwargs: Any) -> Self:
@@ -99,7 +97,7 @@ async def empty(self, prefix: str = "") -> bool:
             True if the store is empty, False otherwise.
         """
 
-        if not prefix.endswith("/"):
+        if prefix and not prefix.endswith("/"):
             prefix += "/"
         async for _ in self.list_prefix(prefix):
             return False
@@ -114,45 +112,15 @@ async def clear(self) -> None:
         async for key in self.list():
             await self.delete(key)
 
-    @abstractmethod
-    def with_mode(self, mode: StoreAccessMode) -> Self:
-        """
-        Return a new store of the same type pointing to the same location with a new mode.
-
-        The returned Store is not automatically opened. Call :meth:`Store.open` before
-        using.
-
-        Parameters
-        ----------
-        mode : StoreAccessMode
-            The new mode to use.
-
-        Returns
-        -------
-        store
-            A new store of the same type with the new mode.
-
-        Examples
-        --------
-        >>> writer = zarr.store.MemoryStore(mode="w")
-        >>> reader = writer.with_mode("r")
-        """
-        ...
-
-    @property
-    def mode(self) -> StoreAccessMode:
-        """Access mode of the store."""
-        return self._mode
-
     @property
     def readonly(self) -> bool:
         """Is the store read-only?"""
-        return self.mode == "r"
+        return self._readonly
 
     def _check_writable(self) -> None:
         """Raise an exception if the store is not writable."""
-        if self.mode != "w":
-            raise ValueError(f"store mode ({self.mode}) does not support writing")
+        if self.readonly:
+            raise ValueError("store was opened in read-only mode and does not support writing")
 
     @abstractmethod
     def __eq__(self, value: object) -> bool:
@@ -347,20 +315,6 @@ async def delete_dir(self, prefix: str) -> None:
         async for key in self.list_prefix(prefix):
             await self.delete(key)
 
-    async def delete_dir(self, prefix: str) -> None:
-        """
-        Remove all keys and prefixes in the store that begin with a given prefix.
-        """
-        if not self.supports_deletes:
-            raise NotImplementedError
-        if not self.supports_listing:
-            raise NotImplementedError
-        self._check_writable()
-        if not prefix.endswith("/"):
-            prefix += "/"
-        async for key in self.list_prefix(prefix):
-            await self.delete(key)
-
     def close(self) -> None:
         """Close the store."""
         self._is_open = False

src/zarr/api/asynchronous.py

@@ -30,8 +30,6 @@
     from collections.abc import Iterable
 
     from zarr.abc.codec import Codec
-    from zarr.abc.store import StoreAccessMode
-    from zarr.core.buffer import NDArrayLike
     from zarr.core.chunk_key_encodings import ChunkKeyEncoding
 
     # TODO: this type could use some more thought
@@ -66,30 +64,9 @@
     "zeros_like",
 ]
 
-# Persistence mode: 'r' means read only (must exist); 'r+' means
-# read/write (must exist); 'a' means read/write (create if doesn't
-# exist); 'w' means create (overwrite if exists); 'w-' means create
-# (fail if exists).
-persistence_to_store_modes: dict[AccessModeLiteral, StoreAccessMode] = {
-    "r": "r",
-    "r+": "w",
-    "a": "w",
-    "w": "w",
-    "w-": "w",
-}
-
-
-def _handle_store_mode(mode: AccessModeLiteral | None) -> StoreAccessMode:
-    if mode is None:
-        return "r"
-    else:
-        return persistence_to_store_modes[mode]
-
 
 def _infer_exists_ok(mode: AccessModeLiteral) -> bool:
-    if mode in ("a", "r+", "w"):
-        return True
-    return False
+    return mode in ("a", "r+", "w")
 
 
 def _get_shape_chunks(a: ArrayLike | Any) -> tuple[ChunkCoords | None, ChunkCoords | None]:
@@ -313,11 +290,7 @@ async def open(
     """
     zarr_format = _handle_zarr_version_or_format(zarr_version=zarr_version, zarr_format=zarr_format)
 
-    store_mode = _handle_store_mode(mode)
-    store_path = await make_store_path(
-        store, mode=store_mode, path=path, storage_options=storage_options
-    )
-    await store_path._init(mode=mode)
+    store_path = await make_store_path(store, mode=mode, path=path, storage_options=storage_options)
 
     # TODO: the mode check below seems wrong!
     if "shape" not in kwargs and mode in {"a", "r", "r+"}:
@@ -427,11 +400,7 @@ async def save_array(
         raise TypeError("arr argument must be numpy or other NDArrayLike array")
 
     mode = kwargs.pop("mode", "a")
-    store_mode = _handle_store_mode(mode)
-    store_path = await make_store_path(
-        store, path=path, mode=store_mode, storage_options=storage_options
-    )
-    await store_path._init(mode=mode)
+    store_path = await make_store_path(store, path=path, mode=mode, storage_options=storage_options)
     if np.isscalar(arr):
         arr = np.array(arr)
     shape = arr.shape
@@ -626,11 +595,7 @@ async def group(
         mode = "w"
     else:
         mode = "r+"
-    store_mode = _handle_store_mode(mode)
-    store_path = await make_store_path(
-        store, path=path, mode=store_mode, storage_options=storage_options
-    )
-    await store_path._init(mode=mode)
+    store_path = await make_store_path(store, path=path, mode=mode, storage_options=storage_options)
 
     if chunk_store is not None:
         warnings.warn("chunk_store is not yet implemented", RuntimeWarning, stacklevel=2)
@@ -743,12 +708,8 @@ async def open_group(
     if chunk_store is not None:
         warnings.warn("chunk_store is not yet implemented", RuntimeWarning, stacklevel=2)
 
-    store_mode = _handle_store_mode(mode)
     exists_ok = _infer_exists_ok(mode)
-    store_path = await make_store_path(
-        store, mode=store_mode, storage_options=storage_options, path=path
-    )
-    await store_path._init(mode=mode)
+    store_path = await make_store_path(store, mode=mode, storage_options=storage_options, path=path)
 
     if attributes is None:
         attributes = {}
@@ -931,11 +892,7 @@ async def create(
     mode = kwargs.pop("mode", None)
     if mode is None:
         mode = "a"
-    store_mode = _handle_store_mode(mode)
-    store_path = await make_store_path(
-        store, path=path, mode=store_mode, storage_options=storage_options
-    )
-    await store_path._init(mode)
+    store_path = await make_store_path(store, path=path, mode=mode, storage_options=storage_options)
     return await AsyncArray.create(
         store_path,
         shape=shape,
@@ -1122,10 +1079,7 @@ async def open_array(
     """
 
     mode = kwargs.pop("mode", None)
-    store_mode = _handle_store_mode(mode)
-    store_path = await make_store_path(
-        store, path=path, mode=store_mode, storage_options=storage_options
-    )
+    store_path = await make_store_path(store, path=path, mode=mode, storage_options=storage_options)
 
     zarr_format = _handle_zarr_version_or_format(zarr_version=zarr_version, zarr_format=zarr_format)