Prefill the transaction context with the data retrieved from the sentry-trace HTTP header

Author: ste93cry

src/EventListener/TracingRequestListener.php

@@ -9,9 +9,18 @@
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Event\FinishRequestEvent;
 
+/**
+ * This event listener acts on the master requests and starts a transaction
+ * to report performance data to Sentry. It gathers useful data like the
+ * HTTP status code of the response or the name of the route that handles
+ * the request and add them as tags.
+ */
 final class TracingRequestListener extends AbstractTracingRequestListener
 {
     /**
+     * This method is called for each subrequest handled by the framework and
+     * starts a new {@see Transaction}.
+     *
      * @param RequestListenerRequestEvent $event The event
      */
     public function handleKernelRequestEvent(RequestListenerRequestEvent $event): void
@@ -24,7 +33,7 @@ public function handleKernelRequestEvent(RequestListenerRequestEvent $event): vo
         $request = $event->getRequest();
         $requestStartTime = $request->server->get('REQUEST_TIME_FLOAT', microtime(true));
 
-        $context = new TransactionContext();
+        $context = TransactionContext::fromSentryTrace($request->headers->get('sentry-trace', ''));
         $context->setOp('http.server');
         $context->setName(sprintf('%s %s%s%s', $request->getMethod(), $request->getSchemeAndHttpHost(), $request->getBaseUrl(), $request->getPathInfo()));
         $context->setStartTimestamp($requestStartTime);

src/EventListener/TracingSubRequestListener.php

@@ -8,6 +8,10 @@
 use Sentry\Tracing\SpanContext;
 use Symfony\Component\HttpKernel\Event\FinishRequestEvent;
 
+/**
+ * This event listener acts on the sub requests and starts a child span of the
+ * current transaction to gather performance data for each of them.
+ */
 final class TracingSubRequestListener extends AbstractTracingRequestListener
 {
     /**

tests/EventListener/TracingRequestListenerTest.php

@@ -12,7 +12,9 @@
 use Sentry\SentryBundle\EventListener\RequestListenerResponseEvent;
 use Sentry\SentryBundle\EventListener\TracingRequestListener;
 use Sentry\State\HubInterface;
+use Sentry\Tracing\SpanId;
 use Sentry\Tracing\SpanStatus;
+use Sentry\Tracing\TraceId;
 use Sentry\Tracing\Transaction;
 use Sentry\Tracing\TransactionContext;
 use Symfony\Bridge\PhpUnit\ClockMock;
@@ -82,6 +84,35 @@ public function testHandleKernelRequestEvent(Options $options, Request $request,
      */
     public function handleKernelRequestEventDataProvider(): \Generator
     {
+        $transactionContext = new TransactionContext();
+        $transactionContext->setTraceId(new TraceId('566e3688a61d4bc888951642d6f14a19'));
+        $transactionContext->setParentSpanId(new SpanId('566e3688a61d4bc8'));
+        $transactionContext->setParentSampled(true);
+        $transactionContext->setName('GET http://www.example.com/');
+        $transactionContext->setOp('http.server');
+        $transactionContext->setStartTimestamp(1613493597.010275);
+        $transactionContext->setTags([
+            'net.host.port' => '80',
+            'http.method' => 'GET',
+            'http.url' => 'http://www.example.com/',
+            'http.flavor' => '1.1',
+            'route' => '<unknown>',
+            'net.host.name' => 'www.example.com',
+        ]);
+
+        yield 'request.server.sentry-trace EXISTS' => [
+            new Options(['send_default_pii' => false]),
+            Request::create(
+                'http://www.example.com',
+                'GET',
+                [],
+                [],
+                [],
+                ['HTTP_sentry-trace' => '566e3688a61d4bc888951642d6f14a19-566e3688a61d4bc8-1']
+            ),
+            $transactionContext,
+        ];
+
         $transactionContext = new TransactionContext();
         $transactionContext->setName('GET http://www.example.com/');
         $transactionContext->setOp('http.server');