def get_sample_with_timestamp(self,
metric,
dimensions=None,
device_name=None,
expire=True):
"""Get (timestamp-epoch-style, value).
"""
# Get the proper dimensions
key = (tuple(sorted(dimensions.items())), device_name)
# Never seen this metric
if metric not in self._sample_store:
raise exceptions.UnknownValue()
# Not enough value to compute rate
elif self.is_counter(metric) and len(
self._sample_store[metric][key]) < 2:
raise exceptions.UnknownValue()
elif self.is_counter(metric) and len(
self._sample_store[metric][key]) >= 2:
res = self._rate(self._sample_store[metric][key][-2],
self._sample_store[metric][key][-1])
if expire:
del self._sample_store[metric][key][:-1]
return res
elif self.is_gauge(metric) and len(
self._sample_store[metric][key]) >= 1:
return self._sample_store[metric][key][-1]
else:
raise exceptions.UnknownValue()
def _rate(cls, sample1, sample2):
"""Simple rate.
"""
try:
rate_interval = sample2[0] - sample1[0]
if rate_interval == 0:
raise exceptions.Infinity()
delta = sample2[1] - sample1[1]
if delta < 0:
raise exceptions.UnknownValue()
return (sample2[0], delta / rate_interval, sample2[2], sample2[3])
except exceptions.Infinity:
raise
except exceptions.UnknownValue:
raise
except Exception as e:
raise exceptions.NaN(e)