Revision: Sat, 04 Feb 2023 12:24:33 GMT

Application Metrics

You can expose some of the application metrics using the prometheus service embedded to the RoadRunner application server.

The component is available by default in the application bundle or via spiral/roadrunner-bridge.

Installation

To enable the component, you just need to add Spiral\RoadRunnerBridge\Bootloader\MetricsBootloader to the bootloader's list.

Configuration

The metrics service does not require configuration in the application. However, you must activate the service in .rr.yaml:

yaml
metrics:
  # prometheus client address (path /metrics added automatically)
  address: localhost:2112

Note
You can view defaults metrics on http://localhost:2112/metrics

Custom Application metrics

You can also publish application-specific metrics. First, you have to register a metric in your configuration file:

yaml
metrics:
  address: localhost:2112
  collect:
    app_metric_counter:
      type: counter
      help: "Application counter."

or declare metrics in PHP code

php
use Spiral\RoadRunner\Metrics\MetricsInterface;
use Spiral\RoadRunner\Metrics\Collector;

class MetricsBootloader extends Bootloader
{
    //...

    public function boot(MetricsInterface $metrics): void
    {
        $metrics->declare(
            'app_metric_counter',
            Collector::counter()->withHelp('Application counter.')
        );
    }
}

Note
Supported types: gauge, counter, summary, histogram.

To populate a metric from the application, use Spiral\RoadRunner\Metrics\MetricsInterface:

php
use Spiral\RoadRunner\Metrics\MetricsInterface; 

// ...

public function index(MetricsInterface $metrics)
{
    $metrics->add('app_metric_counter', 1);
}

You can call MetricsInterface in middleware.

Tagged metrics

You can use tagged (labels) metrics to group values:

yaml
metrics:
  address: localhost:2112
  collect:
    app_type_duration:
      type: histogram
      help: "Application counter."
      labels: [ "type" ]

or declare metrics in PHP code

php
use Spiral\RoadRunner\Metrics\MetricsInterface;
use Spiral\RoadRunner\Metrics\Collector;

class MetricsBootloader extends Bootloader
{
    //...

    public function boot(MetricsInterface $metrics): void
    {
        $metrics->declare(
            'app_metric_counter',
            Collector::counter()->withHelp('Application counter.')->withLabels('type')
        );
    }
}

You should specify values for your labels while pushing the metric:

php
use Spiral\RoadRunner\MetricsInterface; 

// ...

public function index(MetricsInterface $metrics)
{
    $metrics->add('app_type_duration', 0.5, ['some-type']);
}
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