Celery Tasks don't handle transactions rollback very well

Food for thoughts :

• Get rid of all the pyramid dbsession init in request crap ? like in here : http://www.prschmid.com/2013/04/using-sqlalchemy-with-celery-tasks.html
• use on_failure task method : https://stackoverflow.com/questions/56805430/sqlalchemy-session-cleared-in-celery-job-and-on-success-function