Initial tiny attempt at (vectorable) counter metrics

This commit is contained in:
Paul "LeoNerd" Evans 2015-02-24 16:58:26 +00:00
parent e07fc62833
commit e7420a3bef
3 changed files with 115 additions and 0 deletions

54
synapse/metrics/metric.py Normal file
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# -*- coding: utf-8 -*-
# Copyright 2015 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
class CounterMetric(object):
def __init__(self, name, keys=[]):
self.name = name
self.keys = keys # OK not to clone as we never write it
self.counts = {}
# Scalar metrics are never empty
if not len(keys):
self.counts[()] = 0
def inc(self, *values):
if len(values) != len(self.keys):
raise ValueError("Expected as many values to inc() as keys (%d)" %
(len(self.keys))
)
# TODO: should assert that the tag values are all strings
if values not in self.counts:
self.counts[values] = 1
else:
self.counts[values] += 1
def fetch(self):
return dict(self.counts)
def _render_key(self, values):
# TODO: some kind of value escape
return ",".join(["%s=%s" % kv for kv in zip(self.keys, values)])
def render(self):
if not len(self.keys):
return ["%s %d" % (self.name, self.counts[()])]
return ["%s{%s} %d" % (self.name, self._render_key(k), self.counts[k])
for k in sorted(self.counts.keys())]

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# -*- coding: utf-8 -*-
# Copyright 2015 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from tests import unittest
from synapse.metrics.metric import CounterMetric
class CounterMetricTestCase(unittest.TestCase):
def test_scalar(self):
counter = CounterMetric("scalar")
self.assertEquals(counter.render(), [
"scalar 0",
])
counter.inc()
self.assertEquals(counter.render(), [
"scalar 1",
])
counter.inc()
counter.inc()
self.assertEquals(counter.render(), [
"scalar 3"
])
def test_vector(self):
counter = CounterMetric("vector", keys=["method"])
# Empty counter doesn't yet know what values it has
self.assertEquals(counter.render(), [])
counter.inc("GET")
self.assertEquals(counter.render(), [
"vector{method=GET} 1",
])
counter.inc("GET")
counter.inc("PUT")
self.assertEquals(counter.render(), [
"vector{method=GET} 2",
"vector{method=PUT} 1",
])