interface ObservableCallbackInterface

An observed callback.

Callbacks that are bound to an object are automatically detached when the `ObservableCallbackInterface` and the bound object are out of scope. This means that the `ObservableCallbackInterface` can be ignored if the observed callback should be bound to the lifetime of the object. ```php class Example { function __construct(MeterProviderInterface $meterProvider) { $meterProvider->getMeter('example') ->createObservableGauge('random') ->observe(fn(ObserverInterface $observer) => $observer->observe(rand(0, 10))); } } ``` Keeping a reference to the `ObservableCallbackInterface` within the bound object to gain a more fine-grained control over the life-time of the callback does not prevent garbage collection (but might require cycle collection).

Unbound (static) callbacks must be detached manually using {@link ObservableCallbackInterface::detach()}. ```php class Example { private ObservableCallbackInterface $gauge; function __construct(MeterProviderInterface $meterProvider) { $this->gauge = $meterProvider->getMeter('example') ->createObservableGauge('random') ->observe(static fn(ObserverInterface $observer) => $observer->observe(rand(0, 10))); } function __destruct() { $this->gauge->detach(); } } ```

Hierarchy

• interface \OpenTelemetry\API\Metrics\ObservableCallbackInterface

Expanded class hierarchy of ObservableCallbackInterface

All classes that implement ObservableCallbackInterface

See also

ObservableCounterInterface::observe()

ObservableGaugeInterface::observe()

ObservableUpDownCounterInterface::observe()

File

vendor/open-telemetry/api/Metrics/ObservableCallbackInterface.php, line 49

Namespace

interface ObservableCallbackInterface {
    
    /**
     * Detaches the associated callback from the instrument.
     */
    public function detach() : void;

}

Members