def retrieve_meeting_to_remind(session, offset=30):
""" Retrieve all the meetings for which we have to send a reminder.
:arg session: the database session to use.
:kwarg offset: the frequency at which the cron job is ran in order
to avoid sending twice the same reminder.
"""
today = datetime.utcnow()
meetings = []
for reminder_time in [12, 24, 48, 168]:
# Retrieve meeting planned in less than X hours
new_date = _generate_date_rounded_to_the_hour(today,
reminder_time)
end_date = new_date + timedelta(minutes=offset)
meetings.extend(Meeting.get_meeting_with_reminder(
session, new_date.date(), new_date.time(), end_date.time(),
'H-%s' % reminder_time))
return meetings
