def getLastValues(self, datasource, datapoint, rra='AVERAGE', ago=300, targets=()):
"""
Get the last value from the specified rrd for each target.
@param datasource: target datasource id
@param datapoint: target datapoint id
@param rra: target RRA
@param ago: how many seconds in the past to read, at maximum
@param targets: iterable of dicts of target configurations, like:
[{'device': {'id': 'localhost',
'name': 'localhost',
'uid': '/zport/dmd/Devices/Server/Linux/devices/localhost',
'uuid': '7e8228b7-a2d6-4dbe-8e35-8b475ad8822e'},
'id': 'eth0',
'name': 'eth0',
'rrdpath': 'Devices/localhost/os/interfaces/eth0',
'uid': '/zport/dmd/Devices/Server/Linux/devices/localhost/os/interfaces/eth0',
'uuid': 'c35cdc58-a630-42be-b2d4-861c5c02362c'}]
@return: 2 item tuple, containing:
a dictionary of {uuid -> last value} for each target element,
a list of tuples of exceptions, messages
"""
valueMap = {}
errors = []
for targetConfig in targets:
try:
valueMap[targetConfig['uuid']] = self.getLastValue(datasource, datapoint, rra, ago, targetConfig)
except StandardError as ex:
msg = "Failure reading configured datapoint %s_%s on target %s" % \
(datasource, datapoint, getTargetId(targetConfig))
errors.append((ex, msg))
return {k: v for k, v in valueMap.items() if v is not None}, errors
def dsTargetKeys(ds):
"""
ds should have two params:
targets: list of targetInfo dicts from targetInfo(target) below.
targetDatapoints: list of tuples of (datasource_id, datapoint_id, RRA)
"""
targetKeys = set()
for target in ds.params.get('targets', []):
targetElementId = getTargetId(target)
for targetDatapoint in ds.params.get('targetDatapoints', []):
targetKeys.add('%s:%s' % (targetElementId, targetDatapoint[0]))
return targetKeys
def getLastValue(self, datasource, datapoint, rra='AVERAGE', ago=300, targetConfig={}):
"""
@param datasource: target datasource id
@param datapoint: target datapoint id
@param rra: target RRA
@param ago: how many seconds in the past to read, at maximum
@param targetConfig: dict of target configuration, like:
{'device': {'id': 'localhost',
'name': 'localhost',
'uid': '/zport/dmd/Devices/Server/Linux/devices/localhost',
'uuid': '7e8228b7-a2d6-4dbe-8e35-8b475ad8822e'},
'id': 'eth0',
'name': 'eth0',
'rrdpath': 'Devices/localhost/os/interfaces/eth0',
'uid': '/zport/dmd/Devices/Server/Linux/devices/localhost/os/interfaces/eth0',
'uuid': 'c35cdc58-a630-42be-b2d4-861c5c02362c'}
@return: last single value from the requested RRD file, or None if not available
"""
targetValue = targetConfig.get(self._targetKey, None)
if not targetValue:
log.warn("No %s present for target %s" % (self._targetKey, getTargetId(targetConfig)))
return None
cachekey = self._getKey(datasource, datapoint, rra, targetValue)
#fetch from the cache if able
if cachekey in self._cache:
log.debug("Using cached value for %s: %s", cachekey, self._cache[cachekey])
return self._cache[cachekey]
readValue = self._readLastValue(targetValue, datasource, datapoint, rra, ago)
if readValue is not None:
self._cache[cachekey] = readValue
return readValue
else:
log.debug("Last value for target %s not present for datapoint %s_%s",
getTargetId(targetConfig), datasource, datapoint)
