Prometheus (Stats)

• Introduction
• Installing the exporter
• Creating the exporter
• Running Prometheus
• Viewing your metrics
• Project link

Introduction

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.

OpenCensus Node.js has support for this exporter available, distributed through NPM package @opencensus/exporter-prometheus

Installing the exporter

You can install OpenCensus Prometheus Exporter by running these steps:

npm install @opencensus/core
npm install @opencensus/exporter-prometheus

Creating the exporter

To create the exporter, we’ll need to:

• Import and use the Prometheus exporter package
• Define a namespace that will uniquely identify our metrics when viewed on Prometheus
• Expose a port on which we shall run a /metrics endpoint
• With the defined port, we’ll need a Promethus configuration file so that Prometheus can scrape from this endpoint

Now let’s use the Prometheus exporter:

const { globalStats } = require('@opencensus/core');
const { PrometheusStatsExporter } = require('@opencensus/exporter-prometheus');

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

// Pass the created exporter to Stats
globalStats.registerExporter(exporter);

and then for our corresponding prometheus.yaml file:

global:
  scrape_interval: 10s

  external_labels:
    monitor: 'demo'

scrape_configs:
  - job_name: 'demo'

    scrape_interval: 10s

    static_configs:
      - targets: ['localhost:8888']

Running Prometheus

And then run Prometheus with your configuration

prometheus --config.file=prometheus.yaml

Viewing your metrics

Please visit http://localhost:9090

Project link

You can find out more about the Prometheus project at https://prometheus.io/