Example Prometheus exporter that exports metrics of a Flask application

prometheus_exporter_flask.py

import prometheus_client
import werkzeug.wsgi
import flask
import random
import time
import threading

SERVICE_UPTIME = prometheus_client.Gauge('service_uptime',
                                       'Hold the time elasted since service startup')
RESPONSE_TIME = prometheus_client.Gauge('response_time_last',
                                       'Hold the last request response time')

# Create Flask app
app = flask.Flask(__name__)

@app.route('/')
@RESPONSE_TIME.time()
def hello():
    time.sleep(random.random())
    return "Hello World!"

# Prometheus wsgi middleware to route /metrics requests
app_dispatch = werkzeug.wsgi.DispatcherMiddleware(app, {
  '/metrics': prometheus_client.make_wsgi_app()
})

def update_uptime():
  while True:
    SERVICE_UPTIME.inc(1)
    time.sleep(1)

SERVICE_UPTIME.set(0)
uptime_updater = threading.Thread(target=update_uptime)
uptime_updater.start()