Closes the db connection when it's gone because of a long period of inactivity (solves this issue https://code.djangoproject.com/ticket/21597). It forces django to use a new fresh connection.

celery_check_db_connection.py

from django.db import connection
from functools import wraps
def check_db_connection(f):
    @wraps(f)
    def inner(*args, **kargs):
        try:
            connection.connection.ping()
        except:
            connection.close()
        return f(*args, **kargs)
    return inner
    
#usage example:
#   @app.task
#   @check_db_connection
#   def save_contacts(data):
#       (...)