oslo.middleware/oslo_middleware/stats.py
Julian Edwards 032addde67 Add new middleware to send API data to statsd
The new StatsMiddleware is a Paste filter that examines the URL path and
request method, and sends a stat count and a timer to a statsd host
whose name is based on the path/method.

If your statsd is configured to send stats to Graphite, you'll end up
with stat names of the form:
timer.<appname>.<METHOD>.<path>.<from>.<url>

Because a dot has special meaning in Graphite, dots in API versions that
appear in the path will be replaced with _, so for example v2.1 becomes v2_1,
and v1.0 becomes v1_0.

Change-Id: Ieaffeded1bf81c0782d88f49b6f5209f11744899
2017-01-04 09:23:57 +10:00

132 lines
4.5 KiB
Python

# Copyright (c) 2016 Cisco Systems
#
# 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.
import logging
import re
import statsd
import webob.dec
from oslo_middleware import base
LOG = logging.getLogger(__name__)
VERSION_REGEX = re.compile("/(v[0-9]{1}\.[0-9]{1})")
UUID_REGEX = re.compile(
'.*(\.[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}).*a',
re.IGNORECASE)
# UUIDs without the - char, used in some places in Nova URLs.
SHORT_UUID_REGEX = re.compile('.*(\.[0-9a-fA-F]{32}).*')
class StatsMiddleware(base.ConfigurableMiddleware):
"""Send stats to statsd based on API requests.
Examines the URL path and request method, and sends a stat count and timer
to a statsd host based on the path/method.
If your statsd is configured to send stats to Graphite, you'll end up with
stat names of the form::
timer.<appname>.<METHOD>.<path>.<from>.<url>
Note that URLs with versions in them (pretty much all of Openstack)
are always processed to replace the dot with _, so for example v2.0
becomes v2_0, and v1.1 becomes v1_1, since a dot '.' has special
meaning in Graphite.
The original StatsD is written in nodejs. If you want a Python
implementation, install Bucky instead as it's a drop-in replacement
(and much nicer IMO).
The Paste config must contain some parameters. Configure a filter like
this::
[filter:stats]
paste.filter_factory = oslo_middleware.stats:StatsMiddleware.factory
name = my_application_name # e.g. 'glance'
stats_host = my_statsd_host.example.com
# Optional args to further process the stat name that's generated:
remove_uuid = True
remove_short_uuid = True
# The above uuid processing is required in, e.g. Nova, if you want to
# collect generic stats rather than one per server instance.
"""
def __init__(self, application, conf):
super(StatsMiddleware, self).__init__(application, conf)
self.application = application
self.stat_name = conf.get('name')
if self.stat_name is None:
raise AttributeError('name must be specified')
self.stats_host = conf.get('stats_host')
if self.stats_host is None:
raise AttributeError('stats_host must be specified')
self.remove_uuid = conf.get('remove_uuid', False)
self.remove_short_uuid = conf.get('remove_short_uuid', False)
self.statsd = statsd.StatsClient(self.stats_host)
@staticmethod
def strip_short_uuid(path):
"""Remove short-form UUID from supplied path.
Only call after replacing slashes with dots in path.
"""
match = SHORT_UUID_REGEX.match(path)
if match is None:
return path
return path.replace(match.group(1), '')
@staticmethod
def strip_uuid(path):
"""Remove normal-form UUID from supplied path.
Only call after replacing slashes with dots in path.
"""
match = UUID_REGEX.match(path)
if match is None:
return path
return path.replace(match.group(1), '')
@staticmethod
def strip_dot_from_version(path):
# Replace vN.N with vNN.
match = VERSION_REGEX.match(path)
if match is None:
return path
return path.replace(match.group(1), match.group(1).replace('.', ''))
@webob.dec.wsgify
def __call__(self, request):
path = request.path
path = self.strip_dot_from_version(path)
# Remove leading slash, if any, so we can be sure of the number
# of dots just below.
path = path.lstrip('/')
stat = "{name}.{method}".format(
name=self.stat_name, method=request.method)
if path != '':
stat += '.' + path.replace('/', '.')
if self.remove_short_uuid:
stat = self.strip_short_uuid(stat)
if self.remove_uuid:
stat = self.strip_uuid(stat)
LOG.debug("Incrementing stat count %s", stat)
with self.statsd.timer(stat):
return request.get_response(self.application)