71 lines
2.3 KiB
PHP
71 lines
2.3 KiB
PHP
|
<?php
|
||
|
|
|
||
|
|
declare(strict_types=1);
|
||
|
|
|
||
|
|
namespace OpenTelemetry\SDK\Trace\Sampler;
|
||
|
|
|
||
|
|
use InvalidArgumentException;
|
||
|
|
use OpenTelemetry\Context\ContextInterface;
|
||
|
|
use OpenTelemetry\SDK\Common\Attribute\AttributesInterface;
|
||
|
|
use OpenTelemetry\SDK\Trace\SamplerInterface;
|
||
|
|
use OpenTelemetry\SDK\Trace\SamplingResult;
|
||
|
|
use OpenTelemetry\SDK\Trace\Span;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This implementation of the SamplerInterface records with given probability.
|
||
|
|
* Example:
|
||
|
|
* ```
|
||
|
|
* use OpenTelemetry\API\Trace\TraceIdRatioBasedSampler;
|
||
|
|
* $sampler = new TraceIdRatioBasedSampler(0.01);
|
||
|
|
* ```
|
||
|
|
*/
|
||
|
|
class TraceIdRatioBasedSampler implements SamplerInterface
|
||
|
|
{
|
||
|
|
private float $probability;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* TraceIdRatioBasedSampler constructor.
|
||
|
|
* @param float $probability Probability float value between 0.0 and 1.0.
|
||
|
|
*/
|
||
|
|
public function __construct(float $probability)
|
||
|
|
{
|
||
|
|
if ($probability < 0.0 || $probability > 1.0) {
|
||
|
|
throw new InvalidArgumentException('probability should be be between 0.0 and 1.0.');
|
||
|
|
}
|
||
|
|
$this->probability = $probability;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns `SamplingResult` based on probability. Respects the parent `SampleFlag`
|
||
|
|
* {@inheritdoc}
|
||
|
|
*/
|
||
|
|
public function shouldSample(
|
||
|
|
ContextInterface $parentContext,
|
||
|
|
string $traceId,
|
||
|
|
string $spanName,
|
||
|
|
int $spanKind,
|
||
|
|
AttributesInterface $attributes,
|
||
|
|
array $links
|
||
|
|
): SamplingResult {
|
||
|
|
// TODO: Add config to adjust which spans get sampled (only default from specification is implemented)
|
||
|
|
$parentSpan = Span::fromContext($parentContext);
|
||
|
|
$parentSpanContext = $parentSpan->getContext();
|
||
|
|
$traceState = $parentSpanContext->getTraceState();
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Since php can only store up to 63 bit positive integers
|
||
|
|
*/
|
||
|
|
$traceIdLimit = (1 << 60) - 1;
|
||
|
|
$lowerOrderBytes = hexdec(substr($traceId, strlen($traceId) - 15, 15));
|
||
|
|
$traceIdCondition = $lowerOrderBytes < round($this->probability * $traceIdLimit);
|
||
|
|
$decision = $traceIdCondition ? SamplingResult::RECORD_AND_SAMPLE : SamplingResult::DROP;
|
||
|
|
|
||
|
|
return new SamplingResult($decision, [], $traceState);
|
||
|
|
}
|
||
|
|
|
||
|
|
public function getDescription(): string
|
||
|
|
{
|
||
|
|
return sprintf('%s{%.6F}', 'TraceIdRatioBasedSampler', $this->probability);
|
||
|
|
}
|
||
|
|
}
|