57 lines
1.8 KiB
PHP
57 lines
1.8 KiB
PHP
<?php
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declare(strict_types=1);
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namespace OpenTelemetry\API\Metrics;
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/**
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* An observed callback.
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*
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* Callbacks that are bound to an object are automatically detached when the
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* `ObservableCallbackInterface` and the bound object are out of scope.
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* This means that the `ObservableCallbackInterface` can be ignored if the
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* observed callback should be bound to the lifetime of the object.
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* ```php
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* class Example {
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* function __construct(MeterProviderInterface $meterProvider) {
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* $meterProvider->getMeter('example')
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* ->createObservableGauge('random')
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* ->observe(fn(ObserverInterface $observer)
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* => $observer->observe(rand(0, 10)));
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* }
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* }
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* ```
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* Keeping a reference to the `ObservableCallbackInterface` within the bound
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* object to gain a more fine-grained control over the life-time of the callback
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* does not prevent garbage collection (but might require cycle collection).
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*
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* Unbound (static) callbacks must be detached manually using
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* {@link ObservableCallbackInterface::detach()}.
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* ```php
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* class Example {
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* private ObservableCallbackInterface $gauge;
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* function __construct(MeterProviderInterface $meterProvider) {
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* $this->gauge = $meterProvider->getMeter('example')
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* ->createObservableGauge('random')
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* ->observe(static fn(ObserverInterface $observer)
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* => $observer->observe(rand(0, 10)));
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* }
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* function __destruct() {
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* $this->gauge->detach();
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* }
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* }
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* ```
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*
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* @see ObservableCounterInterface::observe()
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* @see ObservableGaugeInterface::observe()
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* @see ObservableUpDownCounterInterface::observe()
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*/
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interface ObservableCallbackInterface
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{
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/**
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* Detaches the associated callback from the instrument.
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*/
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public function detach(): void;
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}
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