feat: use NoopTracerProvider if Sdk is disabled

[GCalmels]

OpenTelemetry already use Sdk::isDisabled() to use NoopTracerProvider if env OTEL_SDK_DISABLED is set to true.
Like this, we can add this env on phpunit.xml file

[cdaguerre]

i don't think it's worth mentioning here

[cdaguerre]

I think this is not the right place to handle it because it will not handle a disabled SDK within Symfony, only for static usage.

Don't you think we should rather adapt the TracerProvider in Symfony itself?
Something by the lines of:

<?php

declare(strict_types=1);

/*
 * This file is part of the worldia/instrumentation-bundle package.
 * (c) Worldia <[email protected]>
 */

namespace Instrumentation\Tracing;

use OpenTelemetry\API\Trace\NoopTracer;
use OpenTelemetry\API\Trace\TracerInterface;
use OpenTelemetry\API\Trace\TracerProviderInterface;
use OpenTelemetry\SDK\Sdk;

class TogglableTracerProvider implements TracerProviderInterface
{
    public function __construct(private TracerProviderInterface $decorated)
    {
    }

    public function getTracer(string $name, string|null $version = null, string|null $schemaUrl = null, iterable $attributes = []): TracerInterface
    {
        if (Sdk::isDisabled()) {
            return new NoopTracer();
        }

        return $this->decorated->getTracer($name, $version, $schemaUrl, $attributes);
    }
}

With :

use Instrumentation\Tracing\TogglableTracerProvider;
use OpenTelemetry\API\Trace\TracerProviderInterface;

return static function (ContainerConfigurator $container) {
    $container->services()
        ->set(TogglableTracerProvider::class)
        ->decorate(TracerProviderInterface::class)
        ->args([
            service('.inner'),
        ])
    ;
};

WDYT?