V3 Specification Implementation(``zarr._storage.v3``)
=====================================================

This module contains the implementation of the `Zarr V3 Specification <https://zarr-specs.readthedocs.io/en/latest/v3/core/v3.0.html>`_.

.. warning::
    Since Zarr Python 2.12 release, this module provides experimental infrastructure for reading and
    writing the upcoming V3 spec of the Zarr format. Users wishing to prepare for the migration can set
    the environment variable ``ZARR_V3_EXPERIMENTAL_API=1`` to begin experimenting, however data
    written with this API should be expected to become stale, as the implementation will still change.

The new ``zarr._store.v3`` package has the necessary classes and functions for evaluating Zarr V3.
Since the design is not finalised, the classes and functions are not automatically imported into
the regular Zarr namespace.

Code snippet for creating Zarr V3 arrays::

	>>> import zarr
	>>> z = zarr.create((10000, 10000),
	>>>		chunks=(100, 100),
	>>>		dtype='f8',
	>>>		compressor='default',
	>>>		path='path-where-you-want-zarr-v3-array',
	>>>		zarr_version=3)

Further, you can use `z.info` to see details about the array you just created::

	>>> z.info
	Name               : path-where-you-want-zarr-v3-array
	Type               : zarr.core.Array
	Data type          : float64
	Shape              : (10000, 10000)
	Chunk shape        : (100, 100)
	Order              : C
	Read-only          : False
	Compressor         : Blosc(cname='lz4', clevel=5, shuffle=SHUFFLE, blocksize=0)
	Store type         : zarr._storage.v3.KVStoreV3
	No. bytes          : 800000000 (762.9M)
	No. bytes stored   : 557
	Storage ratio      : 1436265.7
	Chunks initialized : 0/10000

You can also check ``Store type`` here (which indicates Zarr V3).

.. module:: zarr._storage.v3

.. autoclass:: RmdirV3
.. autoclass:: KVStoreV3
.. autoclass:: FSStoreV3
.. autoclass:: MemoryStoreV3
.. autoclass:: DirectoryStoreV3
.. autoclass:: ZipStoreV3
.. autoclass:: RedisStoreV3
.. autoclass:: MongoDBStoreV3
.. autoclass:: DBMStoreV3
.. autoclass:: LMDBStoreV3
.. autoclass:: SQLiteStoreV3
.. autoclass:: LRUStoreCacheV3
.. autoclass:: ConsolidatedMetadataStoreV3

In v3 `storage transformers <https://zarr-specs.readthedocs.io/en/latest/v3/array-storage-transformers/sharding/v1.0.html>`_
can be set via ``zarr.create(…, storage_transformers=[…])``.
The experimental sharding storage transformer can be tested by setting
the environment variable ``ZARR_V3_SHARDING=1``. Data written with this flag
enabled should be expected to become stale until
`ZEP 2 <https://zarr.dev/zeps/draft/ZEP0002.html>`_ is approved
and fully implemented.

.. module:: zarr._storage.v3_storage_transformers

.. autoclass:: ShardingStorageTransformer

The abstract base class for storage transformers is

.. module:: zarr._storage.store

.. autoclass:: StorageTransformer