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kishannsanganikishannsangani
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Added B3MultiPropagater (#680)
* Added B3MultiPropagater * Added static self and removed case insensitive getter function * Added unit tests for B3MultiPropagator class * Refactored B3MultiPropagator and added tests in B3MultiPropagatorTest * Added description for B3MultiPropagator
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Diff for: ‎src/API/Trace/Propagation/B3MultiPropagator.php

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<?php
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declare(strict_types=1);
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namespace OpenTelemetry\API\Trace\Propagation;
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use OpenTelemetry\API\Trace\AbstractSpan;
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use OpenTelemetry\API\Trace\SpanContext;
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use OpenTelemetry\API\Trace\SpanContextInterface;
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use OpenTelemetry\Context\Context;
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use OpenTelemetry\Context\Propagation\ArrayAccessGetterSetter;
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use OpenTelemetry\Context\Propagation\PropagationGetterInterface;
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use OpenTelemetry\Context\Propagation\PropagationSetterInterface;
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use OpenTelemetry\Context\Propagation\TextMapPropagatorInterface;
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/**
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* B3Multi is a propagator that supports the specification for the header
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* "b3" used for trace context propagation across service boundaries.
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* (https://github.com/openzipkin/b3-propagation)
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*/
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final class B3MultiPropagator implements TextMapPropagatorInterface
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{
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/**
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* The X-B3-TraceId header is required and is encoded as 32 or 16 lower-hex characters.
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* For example, a 128-bit TraceId header might look like: X-B3-TraceId: 463ac35c9f6413ad48485a3953bb6124 .
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* Unless propagating only the Sampling State, the X-B3-TraceId header is required.
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*
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* @see https://github.com/openzipkin/b3-propagation#traceid-1
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*/
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public const TRACE_ID = 'X-B3-TraceId';
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/**
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* The X-B3-SpanId header is required and is encoded as 16 lower-hex characters.
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* For example, a SpanId header might look like: X-B3-SpanId: a2fb4a1d1a96d312 .
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* Unless propagating only the Sampling State, the X-B3-SpanId header is required.
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*
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* @see https://github.com/openzipkin/b3-propagation#spanid-1
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*/
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public const SPAN_ID = 'X-B3-SpanId';
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/**
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* The X-B3-ParentSpanId header must be present on a child span and absent on the root span.
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* It is encoded as 16 lower-hex characters.
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* For example, a ParentSpanId header might look like: X-B3-ParentSpanId: 0020000000000001
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*
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* @see https://github.com/openzipkin/b3-propagation#parentspanid-1
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*/
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public const PARENT_SPAN_ID = 'X-B3-ParentSpanId';
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/**
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* An accept sampling decision is encoded as X-B3-Sampled: 1 and a deny as X-B3-Sampled: 0.
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* Absent means defer the decision to the receiver of this header.
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* For example, a Sampled header might look like: X-B3-Sampled: 1
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*
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* Note: Before this specification was written, some tracers propagated X-B3-Sampled as true or false as opposed to 1 or 0.
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* While you shouldn't encode X-B3-Sampled as true or false, a lenient implementation may accept them.
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*
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* @see https://github.com/openzipkin/b3-propagation#sampling-state-1
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*/
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public const SAMPLED = 'X-B3-Sampled';
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/**
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* Debug is encoded as X-B3-Flags: 1.
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* Absent or any other value can be ignored.
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* Debug implies an accept decision, so don't also send the X-B3-Sampled header.
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*
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* @see https://github.com/openzipkin/b3-propagation#debug-flag
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*/
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public const DEBUG_FLAG = 'X-B3-Flags';
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private const IS_SAMPLED = '1';
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private const IS_NOT_SAMPLED = '0';
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public const FIELDS = [
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self::TRACE_ID,
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self::SPAN_ID,
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self::PARENT_SPAN_ID,
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self::SAMPLED,
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self::DEBUG_FLAG,
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];
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private static ?self $instance = null;
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public static function getInstance(): self
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{
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if (null === self::$instance) {
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self::$instance = new self();
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}
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return self::$instance;
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}
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/** {@inheritdoc} */
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public function fields(): array
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{
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return self::FIELDS;
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}
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/** {@inheritdoc} */
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public function inject(&$carrier, PropagationSetterInterface $setter = null, Context $context = null): void
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{
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$setter = $setter ?? ArrayAccessGetterSetter::getInstance();
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$context = $context ?? Context::getCurrent();
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$spanContext = AbstractSpan::fromContext($context)->getContext();
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if (!$spanContext->isValid()) {
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return;
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}
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$setter->set($carrier, self::TRACE_ID, $spanContext->getTraceId());
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$setter->set($carrier, self::SPAN_ID, $spanContext->getSpanId());
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$setter->set($carrier, self::SAMPLED, $spanContext->isSampled() ? self::IS_SAMPLED : self::IS_NOT_SAMPLED);
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}
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public function extract($carrier, PropagationGetterInterface $getter = null, Context $context = null): Context
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{
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$getter = $getter ?? ArrayAccessGetterSetter::getInstance();
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$context = $context ?? Context::getCurrent();
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$spanContext = self::extractImpl($carrier, $getter);
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if (!$spanContext->isValid()) {
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return $context;
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}
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return $context->withContextValue(AbstractSpan::wrap($spanContext));
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}
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private static function getSampledValue($carrier, PropagationGetterInterface $getter): ?int
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{
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$value = $getter->get($carrier, self::SAMPLED);
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if ($value === null) {
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return null;
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}
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if ($value === '0' || $value === '1') {
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return (int) $value;
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}
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if (strtolower($value) === 'true') {
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return 1;
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}
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if (strtolower($value) === 'false') {
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return 0;
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}
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return null;
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}
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private static function extractImpl($carrier, PropagationGetterInterface $getter): SpanContextInterface
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{
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$traceId = $getter->get($carrier, self::TRACE_ID);
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$spanId = $getter->get($carrier, self::SPAN_ID);
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$sampled = self::getSampledValue($carrier, $getter);
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if ($traceId === null || $spanId === null) {
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return SpanContext::getInvalid();
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}
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// Validates the traceId, spanId and sampled
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// Returns an invalid spanContext if any of the checks fail
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if (!SpanContext::isValidTraceId($traceId) || !SpanContext::isValidSpanId($spanId)) {
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return SpanContext::getInvalid();
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}
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$isSampled = ($sampled === SpanContext::SAMPLED_FLAG);
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// Only traceparent header is extracted. No tracestate.
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return SpanContext::createFromRemoteParent(
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$traceId,
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$spanId,
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$isSampled ? SpanContextInterface::TRACE_FLAG_SAMPLED : SpanContextInterface::TRACE_FLAG_DEFAULT
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);
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}
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}

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