Make ObjectStore backend generic over any obspec store

changes/3698.feature.md

@@ -0,0 +1,8 @@
+`zarr.storage.ObjectStore` now accepts any object implementing the async
+[obspec](https://developmentseed.org/obspec/) protocols, rather than only instances of
+`obstore` store classes. The check is structural, so wrappers around an obstore store
+(a cache, a request logger) can be used directly. Exceptions raised by the underlying
+store are matched by obspec's well-known names, so a store that raises its own
+`NotFoundError`, `NotSupportedError` or `AlreadyExistsError` gets the same handling as
+obstore. The minimum supported `obstore` version is now 0.7.0 and the `remote` extra
+also installs `obspec`.

docs/user-guide/installation.md

@@ -23,7 +23,7 @@ pip install zarr
 There are a number of optional dependency groups you can install for extra functionality.
 These can be installed using `pip install "zarr[<extra>]"`, e.g. `pip install "zarr[gpu]"`
 
-- `remote`: support for reading/writing to remote data stores (fsspec, obstore)
+- `remote`: support for reading/writing to remote data stores (fsspec, obstore, obspec)
 - `gpu`: support for GPUs (cupy)
 - `cli`: support for the `zarr` [command-line interface](cli.md) (typer)
 - `optional`: support for path-like access to local and remote stores (universal-pathlib)

docs/user-guide/storage.md

@@ -193,9 +193,14 @@ print(array)
 
 ### Object Store
 
-[`zarr.storage.ObjectStore`][] stores the contents of the Zarr hierarchy using any ObjectStore
-[storage implementation](https://developmentseed.org/obstore/latest/api/store/), including AWS S3 ([`obstore.store.S3Store`][]), Google Cloud Storage ([`obstore.store.GCSStore`][]), and Azure Blob Storage ([`obstore.store.AzureStore`][]). This store is backed by [obstore](https://developmentseed.org/obstore/latest/), which
-builds on the production quality Rust library [object_store](https://docs.rs/object_store/latest/object_store/).
+[`zarr.storage.ObjectStore`][] stores the contents of the Zarr hierarchy using any object store
+that implements the async [obspec](https://developmentseed.org/obspec/latest/) protocols. The
+[obstore](https://developmentseed.org/obstore/latest/) stores are the usual choice: they cover AWS S3
+([`obstore.store.S3Store`][]), Google Cloud Storage ([`obstore.store.GCSStore`][]) and Azure Blob Storage
+([`obstore.store.AzureStore`][]), and build on the production quality Rust library
+[object_store](https://docs.rs/object_store/latest/object_store/). Because the requirement is structural
+(the store only has to provide the obspec methods, not inherit from anything), middleware that wraps a
+store, such as a cache or a request logger, works just as well.
 
 ```python exec="true" session="storage" source="above" result="ansi"
 from zarr.storage import ObjectStore

pyproject.toml

@@ -76,7 +76,8 @@ keywords = ["Python", "compressed", "ndimensional-arrays", "zarr"]
 # User-facing extras (shipped in package metadata)
 remote = [
     "fsspec>=2023.10.0",
-    "obstore>=0.5.1",
+    "obstore>=0.7.0",
+    "obspec>=0.1.0",
 ]
 gpu = [
     "cupy-cuda12x; sys_platform != 'darwin'",
@@ -124,7 +125,8 @@ test = [
 remote-tests = [
     {include-group = "test"},
     "fsspec>=2023.10.0",
-    "obstore>=0.5.1",
+    "obstore>=0.7.0",
+    "obspec>=0.1.0",
     "botocore",
     "s3fs>=2023.10.0",
     "moto[s3,server]==5.2.3",
@@ -257,6 +259,7 @@ extra-dependencies = [
     'typing_extensions @ git+https://github.com/python/typing_extensions',
     'donfig @ git+https://github.com/pytroll/donfig',
     'obstore @ git+https://github.com/developmentseed/obstore@main#subdirectory=obstore',
+    'obspec @ git+https://github.com/developmentseed/obspec@main',
 ]
 
 [tool.hatch.envs.upstream.env-vars]
@@ -282,7 +285,8 @@ extra-dependencies = [
     'universal_pathlib==0.2.0',
     'typing_extensions==4.14.*',
     'donfig==0.8.*',
-    'obstore==0.5.*',
+    'obstore==0.7.*',
+    'obspec==0.1.*',
     'msgspec==0.19.*',
 ]
 

src/zarr/__init__.py

@@ -79,6 +79,7 @@ def print_packages(packages: list[str]) -> None:
         "gcsfs",
         "universal-pathlib",
         "obstore",
+        "obspec",
     ]
 
     print(f"platform: {platform.platform()}")