test.prometheus.ts

import { Histogram } from 'prom-client';
import { PrometheusDriver } from 'prometheus-query';

function buildMetricName() {
  return `in_pix_decoded_pix_duration_milliseconds`;
}

function resetHistogram(name: string) {
  const histogram = register.getSingleMetric(name) as Histogram;

  if (!histogram) return;

  histogram.reset();
}

const express = require('express');
const promClient = require('prom-client');

const app = express();
const port = 3000;

// Crie um registro para coletar métricas padrão
const collectDefaultMetrics = promClient.collectDefaultMetrics;
const Registry = promClient.Registry;
const register = new Registry();
collectDefaultMetrics({ register });

// Crie um contador personalizado
const histogram = new promClient.Histogram({
  name: 'in_pix_decoded_pix_duration_milliseconds',
  help: 'Total de duração pix decoded',
  labelNames: ['appName'],
  registers: [register],
});

// Rota principal
app.get('/', async (req, res) => {
  histogram.observe(1);
  histogram.observe(2);
  histogram.observe(3);
  histogram.observe(4);
  histogram.observe(5);

  try {
    const prometheus = new PrometheusDriver({
      endpoint: 'http://localhost:8002/',
    });
    const data = await prometheus.instantQuery(
      'histogram_quantile(0.5, sum(in_pix_decoded_pix_duration_milliseconds_bucket) by (le))',
    );
    console.log(data.result[0].value);
  } catch (err) {
    console.error(err);
  }

  res.send('Olá, Prometheus!');
});

// Endpoint para expor métricas
app.get('/metrics', async (req, res) => {
  res.set('Content-Type', register.contentType);
  res.end(await register.metrics());
});

app.get('/reset', async (req, res) => {
  resetHistogram(buildMetricName());
  res.send('Reset!');
});
app.listen(port, () => {
  console.log(`Aplicação rodando em http://localhost:${port}`);
});