fix: Move Trace-Propagation to Terminate Event (#88)

contributors: @L3tum, @MollocH

.gitattributes

@@ -0,0 +1 @@
+* text eol=lf

EventListener/FinishRootSpanSubscriber.php

@@ -27,6 +27,7 @@ public static function getSubscribedEvents(): array
     {
         return [
             'kernel.finish_request' => ['onFinishRequest', -16],
+            'kernel.terminate' => ['onTerminate', -16],
         ];
     }
 
@@ -44,6 +45,21 @@ public function onFinishRequest(KernelEvent $event): void
         }
 
         $this->tracing->finishActiveSpan();
+    }
+
+    public function onTerminate(KernelEvent $event): void
+    {
+        # TODO: when Symfony 4.4 is unmaintained (November 2023), remove outer if-block in favor of isMainRequest()
+        if (method_exists($event, 'isMainRequest')) {
+            if (!$event->isMainRequest()) {
+                return;
+            }
+        } elseif (method_exists($event, 'isMasterRequest')) {
+            if (!$event->isMasterRequest()) {
+                return;
+            }
+        }
+
         $this->persistence->flush();
     }
 }

Tests/EventListener/FinishRootSpanSubscriberTest.php

@@ -37,6 +37,7 @@ public function setUp(): void
     public function testGetSubscribedEvents(): void
     {
         self::assertArrayHasKey('kernel.finish_request', $this->subject::getSubscribedEvents());
+        self::assertArrayHasKey('kernel.terminate', $this->subject::getSubscribedEvents());
     }
 
     public function testOnFinishRequestIsMainRequest(): void
@@ -45,7 +46,7 @@ public function testOnFinishRequestIsMainRequest(): void
         $event = new KernelEvent($this->kernel->reveal(), $this->request->reveal(), HttpKernelInterface::MASTER_REQUEST);
 
         $this->tracing->finishActiveSpan()->shouldBeCalledOnce();
-        $this->persistence->flush()->shouldBeCalledOnce();
+        $this->persistence->flush()->shouldNotBeCalled();
 
         $this->subject->onFinishRequest($event);
     }
@@ -59,4 +60,26 @@ public function testOnFinishRequestIsNotMainRequest(): void
 
         $this->subject->onFinishRequest($event);
     }
+
+    public function testOnTerminateIsMainRequest(): void
+    {
+        # TODO: when Symfony 4.4 is unmaintained (November 2023), replace HttpKernelInterface::MASTER_REQUEST with HttpKernelInterface::MAIN_REQUEST
+        $event = new KernelEvent($this->kernel->reveal(), $this->request->reveal(), HttpKernelInterface::MASTER_REQUEST);
+
+        $this->tracing->finishActiveSpan()->shouldNotBeCalled();
+        $this->persistence->flush()->shouldBeCalledOnce();
+
+        $this->subject->onTerminate($event);
+    }
+
+    public function testOnTerminateIsNotMainRequest(): void
+    {
+        # TODO: when Symfony 4.4 is unmaintained (November 2023), replace HttpKernelInterface::MASTER_REQUEST with HttpKernelInterface::MAIN_REQUEST
+        $event = new KernelEvent($this->kernel->reveal(), $this->request->reveal(), HttpKernelInterface::SUB_REQUEST);
+
+        $this->tracing->finishActiveSpan()->shouldNotBeCalled();
+        $this->persistence->flush()->shouldNotBeCalled();
+
+        $this->subject->onTerminate($event);
+    }
 }