Prometheus exporter for your own metrics

This package is a Symfony bundle for exporting metrics to Prometheus. Create your own MetricGenerator services to generate values on-demand en expose them under the /metrics endpoint.

It does not expose any metric, you have to code your own.

Usage

Require the package

composer require prismamedia/metrics

# config/bundles.php
return [
    // ...
    PrismaMedia\Metrics\Bundle\PrismaMediaMetricsBundle::class => ['all' => true],
    // ...
];

Import routing file

# config/routes.yaml
metrics:
    resource: '@PrismaMediaMetricsBundle/Resources/config/routes.xml'

Implement your own metric generator

Your metrics are generated on demand by a class implementing

The best practice is to create a distinct classes for distinct metric names. Each class can returns several values with distinct labels.

In the following example, we expose a metric named app_article_total labelled with each status. In Prometheus (& Grafana), the values can be added in order to get the overall total.

<?php
# src/Metrics/ArticleCountMetric.php

namespace App\Metrics;

use Doctrine\DBAL\Connection;
use PrismaMedia\Metrics\Metric;
use PrismaMedia\Metrics\MetricGenerator;

class ArticleCountMetric implements MetricGenerator
{
    private $connection;
    public function __construct(Connection $connection)
    {
        $this->connection = $connection;
    }

    public function getMetrics(): \Traversable
    {
        // SELECT a.status, COUNT(*) as total FROM article GROUP BY a.status
        $qbd = $this->connection->createQueryBuilder();
        $qbd->select('a.status, COUNT(*) as total')
            ->from('article', 'a')
            ->groupBy('a.status');

        foreach ($qbd->execute()->fetchAll() as $row) {
            // app_article_total{status=<status>} <total>
            yield new Metric('app_article_total', (int) $row['total'], [
                'status' => $row['status'],
            ]);
        }
    }
}

Declare the service in Symfony with the tag prisma_media.metric.

# config/services.yaml
services:
    App\Metrics\:
        resource: '../src/Metrics'
        tags: ['prisma_media.metric']

The /metrics endpoint will return something like this:

# curl https://localhost:8080/metrics
app_article_total{status=published} 230
app_article_total{status=review} 2
app_article_total{status=draft} 5

ck-developer/metrics

Prometheus exporter for your own metrics

Usage

Implement your own metric generator