import Queue
import db_store
class Error(Exception):
pass
class UnsupportedRecordError(Error):
pass
class RecordProcessor(object):
"""Stores records from a queue into database stores."""
def __init__(self, record_queue, soil_moisture_store, light_store,
humidity_store, temperature_store, watering_event_store):
self._record_queue = record_queue
self._soil_moisture_store = soil_moisture_store
self._light_store = light_store
self._humidity_store = humidity_store
self._temperature_store = temperature_store
self._watering_event_store = watering_event_store
def try_process_next_record(self):
"""Processes the next record from the queue, placing it in a store.
If an item is available in the queue, removes it and places it in the
appropriate store. If no item is in the queue, returns immediately.
Must be called from the same thread from which the database connections
were created.
Returns:
True if it processed a record, False if the queue contained no
records.
Raises:
UnsupportedRecordError if the queue contains an unexpected record
type.
"""
try:
record = self._record_queue.get_nowait()
except Queue.Empty:
return False
if isinstance(record, db_store.SoilMoistureRecord):
self._soil_moisture_store.insert(record)
elif isinstance(record, db_store.LightRecord):
self._light_store.insert(record)
elif isinstance(record, db_store.HumidityRecord):
self._humidity_store.insert(record)
elif isinstance(record, db_store.TemperatureRecord):
self._temperature_store.insert(record)
elif isinstance(record, db_store.WateringEventRecord):
self._watering_event_store.insert(record)
else:
raise UnsupportedRecordError(
'Unrecognized record type: %s' % str(record))
return True
