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.. to you under the Apache License, Version 2.0 (the
.. "License"); you may not use this file except in compliance
.. with the License.  You may obtain a copy of the License at

..   http://www.apache.org/licenses/LICENSE-2.0

.. Unless required by applicable law or agreed to in writing,
.. software distributed under the License is distributed on an
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.. KIND, either express or implied.  See the License for the
.. specific language governing permissions and limitations
.. under the License.

.. _filesystem:

.. currentmodule:: pyarrow.fs

Filesystem Interface
====================

PyArrow comes with an abstract filesystem interface, as well as concrete
implementations for various storage types.

The filesystem interface provides input and output streams as well as
directory operations.  A simplified view of the underlying data
storage is exposed.  Data paths are represented as *abstract paths*, which
are ``/``-separated, even on Windows, and shouldn't include special path
components such as ``.`` and ``..``.  Symbolic links, if supported by the
underlying storage, are automatically dereferenced.  Only basic
:class:`metadata <FileStats>` about file entries, such as the file size
and modification time, is made available.

Types
-----

The core interface is represented by the base class :class:`FileSystem`.
Concrete subclasses are available for various kinds of storage:
:class:`local filesystem access <LocalFileSystem>`,
:class:`HDFS <HadoopFileSystem>` and
:class:`Amazon S3-compatible storage <S3FileSystem>`.

Example
-------

Assuming your S3 credentials are correctly configured (for example by setting
the ``AWS_ACCESS_KEY_ID`` and ``AWS_SECRET_ACCESS_KEY`` environment variables),
here is how you can read contents from a S3 bucket::

   >>> from pyarrow import fs
   >>> s3 = fs.S3FileSystem(region='eu-west-3')

   # List all contents in a bucket, recursively
   >>> s3.get_target_stats(fs.FileSelector('my-test-bucket', recursive=True))
   [<FileStats for 'my-test-bucket/File1': type=FileType.File, size=10>,
    <FileStats for 'my-test-bucket/File5': type=FileType.File, size=10>,
    <FileStats for 'my-test-bucket/Dir1': type=FileType.Directory>,
    <FileStats for 'my-test-bucket/Dir2': type=FileType.Directory>,
    <FileStats for 'my-test-bucket/EmptyDir': type=FileType.Directory>,
    <FileStats for 'my-test-bucket/Dir1/File2': type=FileType.File, size=11>,
    <FileStats for 'my-test-bucket/Dir1/Subdir': type=FileType.Directory>,
    <FileStats for 'my-test-bucket/Dir2/Subdir': type=FileType.Directory>,
    <FileStats for 'my-test-bucket/Dir2/Subdir/File3': type=FileType.File, size=10>]

   # Open a file for reading and download its contents
   >>> f = s3.open_input_stream('my-test-bucket/Dir1/File2')
   >>> f.readall()
   b'some data'