MetricExporter.php

<?php

declare (strict_types=1);
namespace OpenTelemetry\Contrib\Otlp;

use OpenTelemetry\API\Behavior\LogsMessagesTrait;
use Opentelemetry\Proto\Collector\Metrics\V1\ExportMetricsServiceResponse;
use OpenTelemetry\SDK\Common\Export\TransportInterface;
use OpenTelemetry\SDK\Metrics\AggregationTemporalitySelectorInterface;
use OpenTelemetry\SDK\Metrics\Data\Temporality;
use OpenTelemetry\SDK\Metrics\MetricMetadataInterface;
use OpenTelemetry\SDK\Metrics\PushMetricExporterInterface;
use RuntimeException;
use Throwable;

/**
 * @see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk_exporters/stdout.md#opentelemetry-metrics-exporter---standard-output
 * @see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/protocol/file-exporter.md#json-file-serialization
 * @psalm-import-type SUPPORTED_CONTENT_TYPES from ProtobufSerializer
 */
final class MetricExporter implements PushMetricExporterInterface, AggregationTemporalitySelectorInterface {
    use LogsMessagesTrait;
    private ProtobufSerializer $serializer;
    
    /**
     * @psalm-param TransportInterface<SUPPORTED_CONTENT_TYPES> $transport
     */
    public function __construct(TransportInterface $transport, string|Temporality|null $temporality = null) {
        if (!class_exists('\\Google\\Protobuf\\Api')) {
            throw new RuntimeException('No protobuf implementation found (ext-protobuf or google/protobuf)');
        }
        $this->serializer = ProtobufSerializer::forTransport($this->transport);
    }
    public function temporality(MetricMetadataInterface $metric) : Temporality|string|null {
        return $this->temporality ?? $metric->temporality();
    }
    public function export(iterable $batch) : bool {
        return $this->transport
            ->send($this->serializer
            ->serialize((new MetricConverter($this->serializer))
            ->convert($batch)))
            ->map(function (?string $payload) : bool {
            if ($payload === null) {
                return true;
            }
            $serviceResponse = new ExportMetricsServiceResponse();
            $this->serializer
                ->hydrate($serviceResponse, $payload);
            $partialSuccess = $serviceResponse->getPartialSuccess();
            if ($partialSuccess !== null && $partialSuccess->getRejectedDataPoints()) {
                self::logError('Export partial success', [
                    'rejected_data_points' => $partialSuccess->getRejectedDataPoints(),
                    'error_message' => $partialSuccess->getErrorMessage(),
                ]);
                return false;
            }
            if ($partialSuccess !== null && $partialSuccess->getErrorMessage()) {
                self::logWarning('Export success with warnings/suggestions', [
                    'error_message' => $partialSuccess->getErrorMessage(),
                ]);
            }
            return true;
        })
            ->catch(static function (Throwable $throwable) : bool {
            self::logError('Export failure', [
                'exception' => $throwable,
            ]);
            return false;
        })
            ->await();
    }
    public function shutdown() : bool {
        return $this->transport
            ->shutdown();
    }
    public function forceFlush() : bool {
        return $this->transport
            ->forceFlush();
    }

}