calculate_macobac crashes if remote server is not accessible

Summary

During the integration testing with Workload (DIRAC), the downloading of the Keeling Curve data failed, raising a ConnectionError and a subsequent job crash.

Apparently, the problem is intermittent (an issue on a Keeling Curve server side). In this case, the workflow should gracefully exit.

Steps to reproduce

Attempt to run macobac computation while the remote server is not accessible.

What is the expected correct behavior?

The application shall exit gracefully with a predefined exit code.

Relevant logs and/or screenshots

See the log here: https://gitlab.cta-observatory.org/cta-computing/dpps/CTADIRAC/uploads/e80cf7cc7e306f7354f01d514e7fd3a0/calibpipe_Log.txt

Environment

• Version used:
• Operation System: