Rucio Clients

40.1.0 verified Mon Apr 27 auth: no python

Rucio Client Package: Python client library for Rucio, a distributed data management framework used primarily by high-energy physics experiments (e.g., ATLAS, CMS, SKA). Version 40.1.0, monthly release cadence. Supports Python >=3.9.

pip install rucio-clients

Common errors

error ModuleNotFoundError: No module named 'rucio' ↓

cause rucio package (server-side) is not installed; rucio-clients depends on it for library code.

fix

pip install rucio rucio-clients (or just rucio-clients, which pulls rucio as dependency).

error ImportError: cannot import name 'DownloadClient' from 'rucio.client' ↓

cause DownloadClient is in submodule rucio.client.downloadclient, not directly in rucio.client.

fix

Use: from rucio.client.downloadclient import DownloadClient

error FileNotFoundError: [Errno 2] No such file or directory: '""' ↓

cause Missing or empty RUCIO_ACCOUNT or RUCIO_AUTH_TYPE environment variables.

fix

Set required environment variables before instantiating Client(): export RUCIO_ACCOUNT=<username>; export RUCIO_AUTH_TYPE=userpass; export RUCIO_CREDS=<password>

error RucioException: Authentication error ↓

cause Invalid credentials or mismatched auth type.

fix

Check RUCIO_ACCOUNT, RUCIO_AUTH_TYPE, and RUCIO_CREDS (or x509 certificate proxy). For x509, ensure RUCIO_CLIENT_CERT points to valid PEM file.

Warnings

breaking Python 3.9 minimum: rucio-clients 40+ drops support for Python 3.8 and earlier. ↓

fix Upgrade to Python 3.9+ before installing rucio-clients >=40.

gotcha Client authentication requires environment variables (RUCIO_ACCOUNT, RUCIO_AUTH_TYPE, RUCIO_CREDS) or config file; missing them causes silent default fallback to anonymous, often leading to permission errors. ↓

fix Set RUCIO_ACCOUNT and RUCIO_AUTH_TYPE (e.g., 'userpass', 'x509', 'x509_proxy') before creating Client(). Also set RUCIO_CREDS for password or RUCIO_CLIENT_CERT for x509.

deprecated The rucio.client.client.Client class init parameter 'auth_type' is deprecated in favor of environment variable RUCIO_AUTH_TYPE. ↓

fix Set RUCIO_AUTH_TYPE environment variable instead of passing auth_type argument.

Imports

Client
wrong
```
from rucio import Client
```
correct
```
from rucio.client import Client
```
Client lives in rucio.client package; direct import from rucio fails.
DownloadClient
wrong
```
from rucio.downloadclient import DownloadClient
```
correct
```
from rucio.client.downloadclient import DownloadClient
```
DownloadClient is in rucio.client.downloadclient; common mistake to import from rucio.downloadclient.

UploadClient

wrong

from rucio.uploadclient import UploadClient

correct

from rucio.client.uploadclient import UploadClient

Same pattern as DownloadClient.

DidClient
wrong
```
from rucio.client import DIDClient
```
correct
```
from rucio.client.didclient import DIDClient
```
DIDClient is in its own submodule; not directly in rucio.client.

Quickstart

Basic example: initialize Rucio Client with environment-based auth, then download a file.

from rucio.client import Client
from rucio.client.downloadclient import DownloadClient

# Assumes RUCIO_ACCOUNT, RUCIO_AUTH_TYPE env vars set (e.g., userpass, x509)
client = Client()
# Download a dataset
downloader = DownloadClient(client)
dids = [{'scope': 'mock', 'name': 'test.file', 'type': 'FILE', 'base': '/tmp/'}]
downloader.download_dids(dids)