OnedataRESTFS

OnedataRESTFS is a pure Python library that exposes the Onedata File access and management REST API through the PyFilesystem2 interface, requiring only a minimal set of dependencies.

As a PyFilesystem2 implementation, OnedataRESTFS allows you to work with the Onedata virtual filesystem in the same way as with any other supported filesystem.

Supported Onezone versions: >= 21.02.5.

Supported Oneprovider versions: >= 21.02.5.

High-performance data access alternative

Since OnedataRESTFS performs all filesystem operations using the Onedata REST API, all requests incur latency overhead inherent to HTTPS. For use cases requiring minimal latency (e.g., frequent random access read/write operations), an alternative Python client based on Onedata's native binary communication protocol is available: OnedataFS. However, this library is just a wrapper over low-level functionality implemented in C++ and requires several dependencies to be installed.

The main benefit is that it allows leveraging direct storage access, a.k.a. DirectIO, if the client machine has network access to the storage.

However, if performance is not critical, it's better to use OnedataRESTFS, which is much easier to install, use, and integrate into third-party applications.

Installation

You can install OnedataRESTFS from PyPI as follows:

pip install fs.onedatarestfs

Make sure to install a version not newer than the Onedata Onezone service in your deployment. New versions of this library are published only when some changes are made or a new major Onedata release is published, so there might not be an exact version matching current Onedata release.

Usage

Creating a OnedataRESTFS client instance

To use OnedataRESTFS, you must first create an instance of fs.onedatarestfs.OnedataRESTFS, providing at least two required parameters:

• onedata_onezone_host – Hostname of the Onezone instance to connect to
• onedata_access_token – Onedata access token with Oneprovider REST API privileges (see Access tokens)

from fs.onedatarestfs import OnedataRESTFS
onedata_onezone_host = "..."
onedata_access_token = "..."
odfs = OnedataRESTFS(onedata_onezone_host, onedata_access_token)

Other optional OnedataRESTFS constructor arguments include:

• space – If specified, the client will be limited to a single space
• preferred_oneproviders – By default, OnedataRESTFS will select a Oneprovider for each space automatically. However, a list of preferred Oneprovider hostnames can be provided to prioritize selection based on which Oneproviders support the given space.
• verify_ssl – True by default; can be disabled in development environments
• timeout – Request timeout in seconds (default is 30)

Example operations

The following examples assume that the odfs variable refers to an instance of the OnedataRESTFS class.

List spaces

>>> odfs.listdir('/')
['Space1', 'Space2']

Read and write files

>>> odfs.writetext('/Space1/file.txt', 'TEST')
>>> odfs.readtext('/Space1/file.txt')
'TEST'

Rename a file

>>> odfs.move('/Space1/file.txt', '/Space1/file2.txt')
>>> odfs.listdir('/Space1')
['file2.txt']

For more information on how to use an OnedataRESTFS instance, see the PyFilesystem2 Docs.

Development

Building and running tests

virtualenv -p /usr/bin/python3 venv
. venv/bin/activate

# Install tox
pip install coverage tox

# Run flake8 check
tox -c tox.ini -e flake8

# Run mypy typing check
tox -c tox.ini -e mypy

# Run PyFilesystem test suite
tox -c tox.ini -e fstest

References

• PyFilesystem2
• PyFilesystem2 Docs
• Onedata Homepage
• File access and management REST API
• Onedata access tokens