Introducing Python as a Supported Language for Accelerator Controls at CERN

In 2019, Python was adopted as an officially supported language for interacting with CERN’s accelerator controls. In practice, this change of status was as much pragmatic as it was progressive - Python has been available as part of the underlying operating system for over a decade and unofficial Python interfaces to controls have existed since at least 2015. So one might ask: what really changed when Python’s adoption became official? This paper will discuss what it takes to officially support Python in a controls environment and will focus on the cultural and technological shifts involved in running Python operationally. It will highlight some of the infrastructure that has been put in place at CERN to facilitate a stable and user-friendly Python platform, as well as some of the key decisions that have led to Python thriving in CERN’s accelerator controls domain. Given its general nature, it is hoped that the approach presented in this paper can serve as a reference for other scientific organisations from a broad range of fields who are considering the adoption of Python in an operational context.