blob: c11a90d5d7ad88f79dc115313bd30aa81e955225 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
|
<?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);
}
}
|
