Extract ABSStore to zarr._storage.absstore

First step towards being able to assign CODEOWNERS
to simplify maintenance. This does not yet attempt
the rename to zarr.storage.absstore in order lower
conflicts with open PRs. Imports should remain un-
changed for the moment.

see: zarr-developers#764

Author: joshmoore

zarr/_storage/__init__.py

@@ -0,0 +1,199 @@
+"""This module contains storage classes related to Azure Blob Storage (ABS)"""
+
+import warnings
+from collections.abc import MutableMapping
+from zarr.util import normalize_storage_path
+
+__doctest_requires__ = {
+    ('ABSStore', 'ABSStore.*'): ['azure.storage.blob'],
+}
+
+
+class ABSStore(MutableMapping):
+    """Storage class using Azure Blob Storage (ABS).
+
+    Parameters
+    ----------
+    container : string
+        The name of the ABS container to use.
+        .. deprecated::
+           Use ``client`` instead.
+    prefix : string
+        Location of the "directory" to use as the root of the storage hierarchy
+        within the container.
+    account_name : string
+        The Azure blob storage account name.
+        .. deprecated:: 2.8.3
+           Use ``client`` instead.
+    account_key : string
+        The Azure blob storage account access key.
+        .. deprecated:: 2.8.3
+           Use ``client`` instead.
+    blob_service_kwargs : dictionary
+        Extra arguments to be passed into the azure blob client, for e.g. when
+        using the emulator, pass in blob_service_kwargs={'is_emulated': True}.
+        .. deprecated:: 2.8.3
+           Use ``client`` instead.
+    dimension_separator : {'.', '/'}, optional
+        Separator placed between the dimensions of a chunk.
+    client : azure.storage.blob.ContainerClient, optional
+        And ``azure.storage.blob.ContainerClient`` to connect with. See
+        `here <https://docs.microsoft.com/en-us/python/api/azure-storage-blob/azure.storage.blob.containerclient?view=azure-python>`_  # noqa
+        for more.
+
+        .. versionadded:: 2.8.3
+
+    Notes
+    -----
+    In order to use this store, you must install the Microsoft Azure Storage SDK for Python,
+    ``azure-storage-blob>=12.5.0``.
+    """
+
+    def __init__(self, container=None, prefix='', account_name=None, account_key=None,
+                 blob_service_kwargs=None, dimension_separator=None,
+                 client=None,
+                 ):
+        self._dimension_separator = dimension_separator
+        self.prefix = normalize_storage_path(prefix)
+        if client is None:
+            # deprecated option, try to construct the client for them
+            msg = (
+                "Providing 'container', 'account_name', 'account_key', and 'blob_service_kwargs'"
+                "is deprecated. Provide and instance of 'azure.storage.blob.ContainerClient' "
+                "'client' instead."
+            )
+            warnings.warn(msg, FutureWarning, stacklevel=2)
+            from azure.storage.blob import ContainerClient
+            blob_service_kwargs = blob_service_kwargs or {}
+            client = ContainerClient(
+                "https://{}.blob.core.windows.net/".format(account_name), container,
+                credential=account_key, **blob_service_kwargs
+                )
+
+        self.client = client
+        self._container = container
+        self._account_name = account_name
+        self._account_key = account_key
+
+    def _warn_deprecated(self, property_):
+        msg = ("The {} property is deprecated and will be removed in a future "
+               "version. Get the property from 'ABSStore.client' instead.")
+        warnings.warn(msg.format(property_), FutureWarning, stacklevel=3)
+
+    @property
+    def container(self):
+        self._warn_deprecated("container")
+        return self._container
+
+    @property
+    def account_name(self):
+        self._warn_deprecated("account_name")
+        return self._account_name
+
+    @property
+    def account_key(self):
+        self._warn_deprecated("account_key")
+        return self._account_key
+
+    def _append_path_to_prefix(self, path):
+        if self.prefix == '':
+            return normalize_storage_path(path)
+        else:
+            return '/'.join([self.prefix, normalize_storage_path(path)])
+
+    @staticmethod
+    def _strip_prefix_from_path(path, prefix):
+        # normalized things will not have any leading or trailing slashes
+        path_norm = normalize_storage_path(path)
+        prefix_norm = normalize_storage_path(prefix)
+        if prefix:
+            return path_norm[(len(prefix_norm)+1):]
+        else:
+            return path_norm
+
+    def __getitem__(self, key):
+        from azure.core.exceptions import ResourceNotFoundError
+        blob_name = self._append_path_to_prefix(key)
+        try:
+            return self.client.download_blob(blob_name).readall()
+        except ResourceNotFoundError:
+            raise KeyError('Blob %s not found' % blob_name)
+
+    def __setitem__(self, key, value):
+        value = ensure_bytes(value)
+        blob_name = self._append_path_to_prefix(key)
+        self.client.upload_blob(blob_name, value, overwrite=True)
+
+    def __delitem__(self, key):
+        from azure.core.exceptions import ResourceNotFoundError
+        try:
+            self.client.delete_blob(self._append_path_to_prefix(key))
+        except ResourceNotFoundError:
+            raise KeyError('Blob %s not found' % key)
+
+    def __eq__(self, other):
+        return (
+            isinstance(other, ABSStore) and
+            self.client == other.client and
+            self.prefix == other.prefix
+        )
+
+    def keys(self):
+        return list(self.__iter__())
+
+    def __iter__(self):
+        if self.prefix:
+            list_blobs_prefix = self.prefix + '/'
+        else:
+            list_blobs_prefix = None
+        for blob in self.client.list_blobs(list_blobs_prefix):
+            yield self._strip_prefix_from_path(blob.name, self.prefix)
+
+    def __len__(self):
+        return len(self.keys())
+
+    def __contains__(self, key):
+        blob_name = self._append_path_to_prefix(key)
+        return self.client.get_blob_client(blob_name).exists()
+
+    def listdir(self, path=None):
+        dir_path = normalize_storage_path(self._append_path_to_prefix(path))
+        if dir_path:
+            dir_path += '/'
+        items = [
+            self._strip_prefix_from_path(blob.name, dir_path)
+            for blob in self.client.walk_blobs(name_starts_with=dir_path, delimiter='/')
+        ]
+        return items
+
+    def rmdir(self, path=None):
+        dir_path = normalize_storage_path(self._append_path_to_prefix(path))
+        if dir_path:
+            dir_path += '/'
+        for blob in self.client.list_blobs(name_starts_with=dir_path):
+            self.client.delete_blob(blob)
+
+    def getsize(self, path=None):
+        store_path = normalize_storage_path(path)
+        fs_path = self._append_path_to_prefix(store_path)
+        if fs_path:
+            blob_client = self.client.get_blob_client(fs_path)
+        else:
+            blob_client = None
+
+        if blob_client and blob_client.exists():
+            return blob_client.get_blob_properties().size
+        else:
+            size = 0
+            if fs_path == '':
+                fs_path = None
+            elif not fs_path.endswith('/'):
+                fs_path += '/'
+            for blob in self.client.walk_blobs(name_starts_with=fs_path, delimiter='/'):
+                blob_client = self.client.get_blob_client(blob)
+                if blob_client.exists():
+                    size += blob_client.get_blob_properties().size
+            return size
+
+    def clear(self):
+        self.rmdir()