express-prom-bundle/advanced-example.js

'use strict';

const express = require('express');
const app = express();
const promBundle = require('express-prom-bundle');

const bundle = promBundle({
  buckets: [0.1, 0.4, 0.7],
  includeMethod: true,
  includePath: true,
  customLabels: {year: null},
  transformLabels: labels => Object.assign(labels, {year: new Date().getFullYear()}),
  promClient: {
    collectDefaultMetrics: {
      timeout: 1000
    }
  },
  urlValueParser: {
    minHexLength: 5,
    extraMasks: [
      "^[0-9]+\\.[0-9]+\\.[0-9]+$" // replace dot-separated dates with #val
    ]
  },
  normalizePath: [
    ['^/foo', '/example'] // replace /foo with /example
  ]
});

app.use(bundle);

// native prom-client metric (no prefix)
const c1 = new bundle.promClient.Counter({name: 'c1', help: 'c1 help'});
c1.inc(10);

app.get('/foo/:id', (req, res) => {
  setTimeout(() => {
    res.send('foo response\n');
  }, 500);
});
app.delete('/foo/:id', (req, res) => {
  setTimeout(() => {
    res.send('foo deleted\n');
  }, 300);
});
app.get('/bar', (req, res) => res.send('bar response\n'));

app.listen(3000, () => console.info(  // eslint-disable-line
  'listening on 3000\n'
  + 'test in shell console\n\n'
  + 'curl localhost:3000/foo/1234\n'
  + 'curl localhost:3000/foo/09.08.2018\n'
  + 'curl -X DELETE localhost:3000/foo/5432\n'
  + 'curl localhost:3000/bar\n'
  + 'curl localhost:3000/metrics\n'
));