CMS: Modernizing a CMS Production Code Base

Unified is a tool employed by the CMS offline and computing team to preform checks during the scheduling process of physics workflows on the computing grid available to the CMS group. The whole framework comprising of the WMCore and Unified operates as a finite state machine, starting from requesting a workflow to be scheduled on one of the available nodes. The process includes verifying the credentials of the requester, performing various validity checks on the workflow, scheduling and executing it, and assessing whether the produced results meet a minimum threshold. If the results meet the threshold, the workflow is announced; if not, it is resubmitted as an ACDC workflow. Despite its critical role, Unified was originally written without adhering to coding best practices. It featured several scripts/services comprising of a single, large function handling all tasks, resulting in redundant code and the absence of dedicated classes where necessary. This led to a complex and difficult-to-understand codebase. The task of this project was to refactor these scripts to improve their structure and maintainability.