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quay/util/metrics/prometheus.py
Jimmy Zelinskie 4bf4ce33c9 util/metrics: remove metricqueue abstraction
This change replaces the metricqueue library with a native Prometheus
client implementation with the intention to aggregated results with the
Prometheus PushGateway.

This change also adds instrumentation for greenlet context switches.
2019-11-21 12:53:09 -05:00

82 lines
2.2 KiB
Python

import logging
import time
import threading
from flask import g, request
from prometheus_client import push_to_gateway, REGISTRY, Histogram
logger = logging.getLogger(__name__)
request_duration = Histogram('quay_request_duration_seconds',
'seconds taken to process a request',
labelnames=['method', 'endpoint', 'status'],
buckets=[.01, .025, .05, .1, .25, .5, 1.0, 2.5, 5.0])
PROMETHEUS_PUSH_INTERVAL_SECONDS = 30
ONE_DAY_IN_SECONDS = 60 * 60 * 24
class PrometheusPlugin(object):
""" Application plugin for reporting metrics to Prometheus. """
def __init__(self, app=None):
self.app = app
if app is not None:
self.state = self.init_app(app)
else:
self.state = None
def init_app(self, app):
pusher = ThreadPusher(app)
pusher.start()
# register extension with app
app.extensions = getattr(app, 'extensions', {})
app.extensions['prometheus'] = pusher
return pusher
def __getattr__(self, name):
return getattr(self.state, name, None)
class ThreadPusher(threading.Thread):
def __init__(self, app):
super(ThreadPusher, self).__init__()
self.daemon = True
self._app = app
def run(self):
agg_url = self._app.config.get('PROMETHEUS_AGGREGATOR_URL')
while True:
if agg_url is None:
# Practically disable this worker, if there is no aggregator.
time.sleep(ONE_DAY_IN_SECONDS)
continue
time.sleep(PROMETHEUS_PUSH_INTERVAL_SECONDS)
push_to_gateway(agg_url, job=self._app.config.get('PROMETHEUS_NAMESPACE', 'quay'),
registry=REGISTRY)
def timed_blueprint(bp):
"""
Decorates a blueprint to have its request duration tracked by Prometheus.
"""
def _time_before_request():
g._request_start_time = time.time()
bp.before_request(_time_before_request)
def _time_after_request():
def f(r):
start = getattr(g, '_request_start_time', None)
if start is None:
return r
dur = time.time() - start
request_duration.labels(request.method, request.endpoint, r.status_code).observe(dur)
return r
return f
bp.after_request(_time_after_request())
return bp