metrics.py

import time
import sys
import os
from flask import request
import statsd

statsd_host = os.getenv('STATSD_UDP_HOST', 'localhost')
statsd_port = os.getenv('STATSD_UDP_PORT', 8125)

c = statsd.StatsClient(statsd_host, statsd_port, prefix='testapp')

def start_timer():
    request.start_time = time.time()

def stop_timer(response):
    resp_time = time.time() - request.start_time
    sys.stderr.write("Response time: %ssn" % resp_time)
    c.timing('response.latency', float(resp_time))
    return response

def setup_metrics(app):
    app.before_request(start_timer)
    app.after_request(stop_timer)