def get_latest(instrument_id, key_id):
"""
Returns the latest entry for a given key on a given instrument
@param instrument_id: Instrument object
@param key_id: Parameter object
"""
# First get it from the cache
try:
last_value = StatusCache.objects.filter(instrument_id=instrument_id,
key_id=key_id).latest('timestamp')
except:
# If that didn't work, get it from the table of values
values = StatusVariable.objects.filter(instrument_id=instrument_id,
key_id=key_id)
# If we don't have any entry yet, just return Non
if len(values)==0:
return None
last_value = values.latest('timestamp')
# Put the latest value in the cache so we don't have to go through this again
cached = StatusCache(instrument_id=last_value.instrument_id,
key_id=last_value.key_id,
value=last_value.value,
timestamp=last_value.timestamp)
cached.save()
return last_value
def store_and_cache(instrument_id, key, value):
"""
Store and cache a DASMON parameter
@param instrument_id: Instrument object
@param key: key string
@param value: value for the given key
"""
try:
key_id = Parameter.objects.get(name=key)
except:
key_id = Parameter(name=key)
key_id.save()
status_entry = StatusVariable(instrument_id=instrument_id,
key_id=key_id,
value=value)
status_entry.save()
# Update the latest value
try:
last_value = StatusCache.objects.filter(instrument_id=instrument_id,
key_id=key_id).latest('timestamp')
last_value.value = value = status_entry.value
last_value.timestamp = status_entry.timestamp
last_value.save()
except:
last_value = StatusCache(instrument_id=instrument_id,
key_id=key_id,
value=status_entry.value,
timestamp=status_entry.timestamp)
last_value.save()
def store_and_cache_(instrument_id, key_id, value, timestamp=None, cache_only=False):
"""
Store and cache a DASMON parameter
@param instrument_id: Instrument object
@param key_id: key Parameter object
@param value: value for the given key
@param cache_only: only update cache
"""
# Do bother with parameter that are not monitored
if key_id.monitored is False:
return
# The longest allowable string is 128 characters
value_string = str(value)
if len(value_string) > 128:
value_string = value_string[:128]
datetime_timestamp = datetime.datetime.fromtimestamp(time.time()).replace(tzinfo=timezone.get_current_timezone())
if cache_only is False:
status_entry = StatusVariable(instrument_id=instrument_id,
key_id=key_id,
value=value_string)
# Force the timestamp value as needed
if timestamp is not None:
try:
datetime_timestamp = datetime.datetime.fromtimestamp(timestamp).replace(tzinfo=timezone.get_current_timezone())
status_entry.timestamp = datetime_timestamp
except:
logging.error("Could not process timestamp [%s]: %s", timestamp, sys.exc_value)
status_entry.save()
datetime_timestamp = status_entry.timestamp
# Update the latest value
try:
last_value = StatusCache.objects.filter(instrument_id=instrument_id,
key_id=key_id).latest('timestamp')
last_value.value = value_string
last_value.timestamp = datetime_timestamp
last_value.save()
except:
last_value = StatusCache(instrument_id=instrument_id,
key_id=key_id,
value=value_string,
timestamp=datetime_timestamp)
last_value.save()
