PropagationGetterInterface.php

<?php

declare (strict_types=1);
namespace OpenTelemetry\Context\Propagation;


/**
 * @see https://github.com/open-telemetry/opentelemetry-specification/blob/v1.6.1/specification/context/api-propagators.md#getter-argument
 */
interface PropagationGetterInterface {
    
    /**
     * Returns the list of all the keys in the carrier.
     *
     * @see https://github.com/open-telemetry/opentelemetry-specification/blob/v1.6.1/specification/context/api-propagators.md#keys
     *
     * @return list<string>
     */
    public function keys($carrier) : array;
    
    /**
     * Gets the value of a given key from a carrier.
     */
    public function get($carrier, string $key) : ?string;

}