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cern-fts / gfal2-python

python2 and 3 bindings for gfal2
https://dmc-docs.web.cern.ch/dmc-docs/gfal2-python.html
Apache License 2.0
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Gfal2-Python

gfal2-python is a C++ library offering a thin layer of Python wrappers via PyBoost. We recommend installing it via RPMs, but it is also available on PyPI/gfal2-python.

Using the Gfal2 Python Bindings

The Gfal2 Python bindings are intended to be easy to use.

Pre-requisites

Before jumping into usage, ensure you have a proxy certificate available in the default location (/tmp/x509up_u$(id -u)).

Optionally, you may want to install relevant Gfal2 protocol plugins. Our example will use HTTP protocol, so we must ensure we have the Gfal2 HTTP plugin installed:

$ dnf install -y gfal2-plugin-http

Examples

Example of stating a file location: 

import gfal2

ctx = gfal2.creat_context()
ctx.stat("https://eospublic.cern.ch/eos/opstest/dteam/file.test")

Example of copying a file from local to remote:

import gfal2

ctx = gfal2.creat_context()
ctx.filecopy("file:///tmp/file.test", "https://eospublic.cern.ch/eos/opstest/dteam/file.test")
ctx.stat("https://eospublic.cern.ch/eos/opstest/dteam/file.test")

Example of copying the file from remote to local (with custom transfer parameters):

import gfal2

ctx = gfal2.creat_context()
params = ctx.transfer_parameters()
params.set_checksum = ("both", "adler32", None)
params.overwrite = True

ctx.filecopy("https://eospublic.cern.ch/eos/opstest/dteam/file.test", "file:///tmp/file.test")
ctx.checksum("file:///tmp/file.test", "adler32")

Further code examples can be found in the example/python/ source directory.

Installing via Pip

Installing the package via pip install gfal2-python will reproduce the compilation process, hence why you need to make sure you have all the right dependencies. This guide details the steps needed to get all the dependencies, starting from a blank machine.

This guide assumes you have the EPEL repositories installed (epel-release package). In this example, the build platform is Alma9 and we will use v1.12.2, but the same process applies for other versions or build platforms.

# Clone the gfal2-python repository with the desired version (example for v1.12.2)
$ git clone --branch v1.12.2 https://github.com/cern-fts/gfal2-python.git
$ cd gfal2-python/

# Install standard set of build packages
$ ./ci/fedora-packages.sh

# Build the source RPM and install dependencies
$ cd packaging/
$ make srpm
$ dnf builddep -y gfal2-python-*.src.rpm

# Ready to install now from PyPI
$ pip install gfal2-python

Useful links

Enjoy using the Gfal2 Python bindings!