aivchen/php-prometheus-client

Collect and export PHP App metrics with ease

PHP Prometheus Client

This package provides you an ability to collect and export Prometheus metrics from any modern PHP application.

Why?

• Until now, there was no working Prometheus client for modern PHP
• Framework-agnostic
• Almost zero dependencies
• Won't break your business logic even if something is wrong with Metrics Storage
• Ready to use with static analysis tools (PHPStan, Psalm)

Supported metric types

1. Counter
2. Gauge
3. Histogram

Summary is still in development. What can I do if my client library does not support the metric type I need?

Adapters

• For Laravel: zlodes/prometheus-client-laravel

Installation

composer require zlodes/prometheus-exporter

Class responsibilities

Interface	Description	Default implementation
Registry	To declare a specific metric	ArrayRegistry
Storage	Metrics values storage	InMemoryStorage
Exporter	Output collected metrics	StoredMetricsExporter

Each class should be registered as a service. As a singleton in Laravel or shared service in Symfony.

Simple example

<?php

use Psr\Log\NullLogger;
use Zlodes\PrometheusClient\Collector\CollectorFactory;
use Zlodes\PrometheusClient\Exporter\StoredMetricsExporter;
use Zlodes\PrometheusClient\Metric\Counter;
use Zlodes\PrometheusClient\Metric\Gauge;
use Zlodes\PrometheusClient\Metric\Histogram;
use Zlodes\PrometheusClient\Registry\ArrayRegistry;
use Zlodes\PrometheusClient\Storage\InMemoryStorage;

$registry = new ArrayRegistry();
$storage = new InMemoryStorage();

// Register your metrics
$registry
    ->registerMetric(
        new Gauge('body_temperature', 'Body temperature in Celsius')
    )
    ->registerMetric(
        new Counter('steps', 'Steps count')
    )
    ->registerMetric(
        new Histogram('request_duration', 'Request duration in seconds'),
    );

// Create a Collector factory
$collectorFactory = new CollectorFactory(
    $registry,
    $storage,
    new NullLogger(),
);

// Collect metrics
$bodyTemperatureGauge = $collectorFactory->gauge('body_temperature');

$bodyTemperatureGauge
    ->withLabels(['source' => 'armpit'])
    ->update(36.6);

$bodyTemperatureGauge
    ->withLabels(['source' => 'ass'])
    ->update(37.2);

$collectorFactory
    ->counter('steps')
    ->increment();

$requestTimer = $collectorFactory
    ->histogram('request_duration')
    ->startTimer();

usleep(50_000);

$requestTimer->stop();

// Export metrics
$exporter = new StoredMetricsExporter(
    $registry,
    $storage,
);

foreach ($exporter->export() as $metricOutput) {
    echo $metricOutput . "\n\n";
}

Output example:

# HELP body_temperature Body temperature in Celsius
# TYPE body_temperature gauge
body_temperature{source="armpit"} 36.6
body_temperature{source="ass"} 37.2

# HELP steps Steps count
# TYPE steps counter
steps 1

Testing

Run tests

php ./vendor/bin/phpunit

Creating your own Storage

Keys serialization

There is a Serializer interface (with JSON-based implementation) to simplify work with a key-value storage.

Example can be found in InMemoryStorage.

Storage Testing

There is a simple trait to tests any storage you want. Here is an example:

class InMemoryStorageTest extends TestCase
{
    use StorageTesting;

    private function createStorage(): Storage
    {
        return new InMemoryStorage();
    }
}