def main():
p = Position()
class Vehicle(Base):
__tablename__ = 'vehicles'
id = Column(String, primary_key=True, nullable=False)
carshare_company = Column(String, nullable=False)
name = Column(String)
created = Column(DateTime, default=datetime.datetime.now())
updated = Column(DateTime, default=datetime.datetime.now())
__mapper_args__ = {
'polymorphic_on': carshare_company,
'polymorphic_identity': __tablename__,
'with_polymorphic':'*'
}
@abc.abstractmethod
def set_attributes(self, dict):
''' copy known values from the dict into this object, then update the timestamp
'''
raise NotImplementedError("Please implement this method")
def update_position(self, session, lat, lon, address=None, city=None, state=None, zipcode=None, time_span=144):
''' query the db for a position for this vehicle ... if the vehicle appears to be parked in the
same place as an earlier update, update the
NOTE: the position add/update needs to be committed to the db by the caller of this method
'''
# step 0: cast some variables
pid = str(self.id)
lat = round(lat, 6)
lon = round(lon, 6)
# step 1: get position object from db ...criteria is to find last position
# update within an hour, and the car hasn't moved lat,lon
hours_ago = datetime.datetime.now() - datetime.timedelta(hours=time_span)
p = None
try:
q = session.query(Position).filter(
and_(
Position.vehicle_id == pid,
Position.updated >= hours_ago,
Position.lat == lat,
Position.lon == lon,
)
)
p = q.first()
#import pdb; pdb.set_trace()
except Exception, err:
log.exception('Exception: {0}'.format(err))
# step 2: we didn't find an existing position in the Position history table, so add a new one
try:
if p is None:
p = Position()
p.vehicle_id = pid
p.carshare_co = str(self.carshare_company)
p.set_position(lat, lon, address, city, state, zipcode)
session.add(p)
else:
# step 3: update the position record if need be
p.set_position(lat, lon, address, city, state, zipcode)
except Exception, err:
log.exception('Exception: {0}, committing position to db for vehicle id={1}, lat={2}, lon={3}'.format(err, p.vehicle_id, lat, lon))
session.rollback()