def getNearestTime(time_query):
"""Given a datetime object, return the nearest time in
the database (in string format), or None if empty."""
# Convert datetime object to string, for lookup in database.
tstamp_query = coils.time2string(time_query)
# Retrieve image timestamps.
try:
tstamp_left = db.session.query(mapping.Image.time).\
filter(mapping.Image.time <= tstamp_query).\
order_by(mapping.Image.time.desc()).limit(1)
tstamp_left = tstamp_left[0].time
delta_left = abs(coils.string2time(tstamp_left) - time_query)
except:
tstamp_left = None
delta_left = dt.timedelta.max
try:
tstamp_right = db.session.query(mapping.Image.time).\
filter(mapping.Image.time >= tstamp_query).\
order_by(mapping.Image.time).limit(1)
tstamp_right = tstamp_right[0].time
delta_right = abs(coils.string2time(tstamp_right) - time_query)
except:
tstamp_right = None
delta_right = dt.timedelta.max
# The nearest value has the smallest delta from the query.
result = tstamp_left if (delta_left < delta_right) else tstamp_right
return result
def doTask(self, tstamp):
"""Write to the database."""
# Add the item.
image = mapping.Image(tstamp)
self._sess.add(image)
# Increment the size.
self._sess.query(mapping.Datum).\
filter(mapping.Datum.name=='size').\
update({'value':mapping.Datum.value+1})
# Update latest timestamp.
self._sess.query(mapping.Datum).\
filter(mapping.Datum.name=='latest_tstamp').\
update({'value': coils.time2string(tstamp)})
# Commit the transaction.
self._sess.commit()
def info():
"""Return system information."""
now = dt.datetime.now()
now = coils.time2string(now)
size = db.session.query(mapping.Datum).\
filter(mapping.Datum.name=='size')[0]
latest_tstamp = db.session.query(mapping.Datum).\
filter(mapping.Datum.name=='latest_tstamp')[0]
latest_url = coils.time2fname(
coils.string2time(
latest_tstamp.value), full=True)
latest_url = 'pics/{}.jpg'.format(latest_url)
load_avg = os.getloadavg()
return flask.jsonify(
server_time=now,
db_size=size.value,
latest_tstamp=latest_tstamp.value,
latest_url=latest_url,
load_avg='{:.2f}, {:.2f}, {:.2f}'.format(*load_avg),
)
def __init__(self, tstamp):
self.value = coils.time2string(tstamp)
