The offline software framework of the ATLAS experiment (Athena) consists of many small components of various types like Algorithm, Tool or Service. To assemble these components into an executable application for event processing, a dedicated configuration step is necessary. The configuration of a particular job depends on the work-flow (simulation, reconstruction, high-level trigger, overlay, calibration, analysis ...) and the input data (real or simulated data, beam-energy, ...).
The configuration step is done by executing python code. The resulting config-uration depends on optionally pre-set flags as well as meta-data about the data to be processed. For the python configuration code, there is almost no structure enforced, leaving the full power of python to the user.
While this approach did work, it also proved to be error prone and complicated to use. It also leads to jobs containing more components that they actually need. For LHC Run 3 a more robust system is envisioned. It is still based on python but enforces a structure and emphasis modularity. This contribution briefly reports about the configuration system used during LHC Run 1 and Run 2 and details the prototype of an improved system to be used in Run 3 and beyond.
Overview of the high-level trigger electron and photon selection for the ATLAS experiment at the LHC