#!/usr/bin/python
from doppelserver.models import StaticSample, load_session, HourSample
from sqlalchemy import func
import datetime
session = load_session()
def data_for_hour(start):
end = start + datetime.timedelta(hours=1)
# return the average of all data for an hour, starting from start
# note the parentheses around the comparisons in the filter; this is
# required because & binds tighter than comparison!
return session.query(StaticSample.sensor_id, func.avg(StaticSample.data)) \
.filter((StaticSample.time >= start) & (StaticSample.time < end)) \
.group_by(StaticSample.sensor_id).all()
if __name__ == "__main__":
now = datetime.datetime.now()
last_hour = datetime.datetime.now() - datetime.timedelta(hours=1,
minutes=now.minute,
seconds=now.second,
microseconds=now.microsecond)
try:
for (id, datum) in data_for_hour(last_hour):
session.add(HourSample(sensor_id=id, time=last_hour, data=datum))
except IntegrityError:
session.rollback()
