@opentelemetry/exporter-prometheus

What is @opentelemetry/exporter-prometheus?

@opentelemetry/exporter-prometheus is an npm package that allows you to export OpenTelemetry metrics to Prometheus. It provides a way to expose metrics collected by OpenTelemetry to be scraped by a Prometheus server.

What are @opentelemetry/exporter-prometheus's main functionalities?

Setup Prometheus Exporter

This code sets up a Prometheus exporter that starts an HTTP server on port 9464 to expose metrics. It creates a meter provider and a counter metric, which is then incremented by 10.

const { PrometheusExporter } = require('@opentelemetry/exporter-prometheus');
const { MeterProvider } = require('@opentelemetry/sdk-metrics-base');

const exporter = new PrometheusExporter({
  startServer: true,
}, () => {
  console.log('Prometheus scrape endpoint: http://localhost:9464/metrics');
});

const meterProvider = new MeterProvider({
  exporter,
  interval: 1000,
});

const meter = meterProvider.getMeter('example-meter');
const counter = meter.createCounter('example_counter', {
  description: 'An example counter',
});

counter.add(10, { key: 'value' });

Customizing Exporter Options

This code demonstrates how to customize the Prometheus exporter options, such as changing the port and endpoint for the metrics server.

const { PrometheusExporter } = require('@opentelemetry/exporter-prometheus');
const { MeterProvider } = require('@opentelemetry/sdk-metrics-base');

const exporter = new PrometheusExporter({
  port: 8080,
  endpoint: '/custom-metrics',
  startServer: true,
}, () => {
  console.log('Prometheus scrape endpoint: http://localhost:8080/custom-metrics');
});

const meterProvider = new MeterProvider({
  exporter,
  interval: 1000,
});

const meter = meterProvider.getMeter('example-meter');
const counter = meter.createCounter('example_counter', {
  description: 'An example counter',
});

counter.add(10, { key: 'value' });

Other packages similar to @opentelemetry/exporter-prometheus

prom-client

prom-client is a Prometheus client for Node.js that allows you to create and expose metrics to be scraped by a Prometheus server. Unlike @opentelemetry/exporter-prometheus, which integrates with OpenTelemetry, prom-client is a standalone library specifically for Prometheus.

prometheus-api-metrics

prometheus-api-metrics is a middleware for Express.js that automatically collects and exposes metrics for HTTP requests. It is more focused on web server metrics and does not provide the broader OpenTelemetry integration that @opentelemetry/exporter-prometheus offers.

prometheus-gc-stats

prometheus-gc-stats is a library that collects garbage collection metrics from Node.js and exposes them to Prometheus. It is specialized for GC metrics, whereas @opentelemetry/exporter-prometheus can handle a wider range of metrics through OpenTelemetry.

README

OpenTelemetry Prometheus Metric Exporter

Note: This is an experimental package under active development. New releases may include breaking changes.

The OpenTelemetry Prometheus Metrics Exporter allows the user to send collected OpenTelemetry Metrics to Prometheus.

Prometheus is a monitoring system that collects metrics, by scraping exposed endpoints at regular intervals, evaluating rule expressions. It can also trigger alerts if certain conditions are met. For assistance setting up Prometheus, Click here for a guided codelab.

Installation

npm install --save @opentelemetry/sdk-metrics
npm install --save @opentelemetry/exporter-prometheus

Usage

Create & register the exporter on your application.

const { PrometheusExporter } = require('@opentelemetry/exporter-prometheus');
const { MeterProvider }  = require('@opentelemetry/sdk-metrics');

// Add your port and startServer to the Prometheus options
const options = {port: 9464};
const exporter = new PrometheusExporter(options);

// Creates MeterProvider and installs the exporter as a MetricReader
const meterProvider = new MeterProvider();
meterProvider.addMetricReader(exporter);
const meter = meterProvider.getMeter('example-prometheus');

// Now, start recording data
const counter = meter.createCounter('metric_name', {
  description: 'Example of a counter'
});
counter.add(10, { pid: process.pid });

// .. some other work

Viewing your metrics

With the above you should now be able to navigate to the Prometheus UI at: http://localhost:9464/metrics

Useful links

• For more information on OpenTelemetry, visit: https://opentelemetry.io/
• To learn more about Prometheus, visit: https://prometheus.io/
• For more about OpenTelemetry JavaScript: https://github.com/open-telemetry/opentelemetry-js
• For help or feedback on this project, join us in GitHub Discussions

License

Apache 2.0 - See LICENSE for more information.