<?php

namespace ProcessMaker\Services;

use Exception;

use ProcessMaker\Facades\Metrics;

use Prometheus\CollectorRegistry;

use Prometheus\Counter;

use Prometheus\Gauge;

use Prometheus\Histogram;

use Prometheus\RenderTextFormat;

use Prometheus\Storage\Redis;

use RuntimeException;

class MetricsService

{

/**

* The CollectorRegistry instance used by the MetricsService.

*

* @var CollectorRegistry

*/

private $collectionRegistry;

/**

* The namespace used by the MetricsService.

*

* @var string

*/

private $namespace;

/**

* Initializes the MetricsService with a CollectorRegistry using the provided storage adapter.

*

* @param mixed $adapter The storage adapter to use (e.g., Redis).

*/

public function __construct(private $adapter = null)

{

$this->namespace = config('app.prometheus_namespace', 'app');

try {

// Set up Redis as the adapter if none is provided

if ($adapter === null) {

$adapter = Redis::fromExistingConnection(app('redis')->client());

}

$this->collectionRegistry = new CollectorRegistry($adapter);

} catch (Exception $e) {

throw new RuntimeException('Error initializing the metrics adapter: ' . $e->getMessage());

}

}

/**

* Get the collection registry.

*

* @return CollectorRegistry The collection registry instance.

*/

public function getCollectionRegistry(): CollectorRegistry

{

return $this->collectionRegistry;

}

/**

* Registers or retrieves a counter metric.

*

* @param string $name The name of the counter.

* @param string|null $help The help text of the counter.

* @param array $labels The labels of the counter.

* @return Counter The registered or retrieved counter.

*/

public function counter(string $name, string $help = null, array $labels = []): Counter

{

$help = $help ?? $name;

return $this->collectionRegistry->getOrRegisterCounter(

$this->namespace,

$name,

$help,

$labels

);

}

/**

* Registers or retrieves a gauge metric.

*

* @param string $name The name of the gauge.

* @param string|null $help The help text of the gauge.

* @param array $labels The labels of the gauge.

* @return Gauge The registered or retrieved gauge.

*/

public function gauge(string $name, string $help = null, array $labels = []): Gauge

{

$help = $help ?? $name;

return $this->collectionRegistry->getOrRegisterGauge(

$this->namespace,

$name,

$help,

$labels

);

}

/**

* Registers or retrieves a histogram metric.

*

* @param string $name The name of the histogram.

* @param string|null $help The help text of the histogram.

* @param array $labels The labels of the histogram.

* @param array $buckets The buckets of the histogram.

* @return Histogram The registered or retrieved histogram.

*/

public function histogram(string $name, string $help = null, array $labels = [], array $buckets = [0.1, 1, 5, 10]): Histogram

{

$help = $help ?? $name;

return $this->collectionRegistry->getOrRegisterHistogram(

$this->namespace,

$name,

$help,

$labels,

$buckets

);

}

/**

* Sets a gauge metric to a specific value.

*

* @param string $name The name of the gauge.

* @param float $value The value to set the gauge to.

* @param array $labelValues The values of the labels for the gauge.

*/

public function setGauge(string $name, float $value, array $labelValues = []): void

{

$gauge = $this->collectionRegistry->getGauge($this->namespace, $name);

$gauge->set($value, $labelValues);

}

/**

* Renders the metrics in the Prometheus text format.

*

* @return string The rendered metrics.

*/

public function renderMetrics(): string

{

$renderer = new RenderTextFormat();

$metrics = $this->collectionRegistry->getMetricFamilySamples();

return $renderer->render($metrics);

}

/**

* Increments a counter metric by 1.

*

* @param string $name The name of the counter.

* @param string|null $help The help text of the counter.

* @param array $labels The labels of the counter.

*

* @return void

*/

public function counterInc(string $name, string $help = null, array $labels = []): void

{

// Add system labels

$labels = $this->addSystemLabels($labels);

$labelKeys = array_keys($labels);

Metrics::counter($name, $help, $labelKeys)->inc($labels);

}

/**

* Histogram observation.

*

* @param string $name The name of the histogram.

* @param string|null $help The help text of the histogram.

* @param array $labels The labels of the histogram.

* @param array $buckets The buckets of the histogram.

* @param float $executionTime The execution

*

* @return void

*/

public function histogramObserve(string $name, string $help = null, array $labels = [], array $buckets = [0.1, 1, 5, 10], float $executionTime = 0): void

{

// Add system labels

$labels = $this->addSystemLabels($labels);

$labelKeys = array_keys($labels);

Metrics::histogram(

$name,

$help,

$labelKeys,

$buckets

)->observe(

$executionTime,

$labels

);

}

/**

* Add system labels to the provided labels.

*

* @param array $labels The labels to add system labels to.

*

* @return array The keys of the labels.

*/

public function addSystemLabels(array $labels)

{

// Add system labels

$labels['app_version'] = $this->getApplicationVersion();

$labels['app_name'] = config('app.name');

$labels['app_custom_label'] = config('app.prometheus_custom_label');

return $labels;

}

public function clearMetrics(): void

{

$this->collectionRegistry->wipeStorage();

}

/**

* Gets the version of the application.

*

* @return string The version of the application.

*/

private function getApplicationVersion()

{

$root = base_path('composer.json');

$composer_json_path = json_decode(file_get_contents($root));

return $composer_json_path->version ?? '4.0.0';

}

}