Add conditional traceresponse propagation to Symfony auto-instrumentation

src/Instrumentation/Symfony/composer.json

@@ -14,6 +14,9 @@
     "symfony/http-kernel": "*",
     "symfony/http-client-contracts": "*"
   },
+  "suggest": {
+    "open-telemetry/opentelemetry-propagation-traceresponse": "Automatically propagate the context to the client."
+  },
   "require-dev": {
     "friendsofphp/php-cs-fixer": "^3",
     "phan/phan": "^5.0",
@@ -24,7 +27,8 @@
     "open-telemetry/sdk": "^1.0",
     "phpunit/phpunit": "^9.5",
     "vimeo/psalm": "^4.0",
-    "symfony/http-client": "^5.4||^6.0"
+    "symfony/http-client": "^5.4||^6.0",
+    "open-telemetry/opentelemetry-propagation-traceresponse": "*"
   },
   "autoload": {
     "psr-4": {
@@ -38,5 +42,10 @@
     "psr-4": {
       "OpenTelemetry\\Tests\\Instrumentation\\Symfony\\": "tests/"
     }
+  },
+  "config": {
+    "allow-plugins": {
+      "php-http/discovery": false
+    }
   }
 }

src/Instrumentation/Symfony/src/HeadersPropagator.php → src/Instrumentation/Symfony/src/RequestPropagationGetter.php

@@ -11,7 +11,7 @@
 /**
  * @internal
  */
-final class HeadersPropagator implements PropagationGetterInterface
+final class RequestPropagationGetter implements PropagationGetterInterface
 {
     public static function instance(): self
     {

src/Instrumentation/Symfony/src/ResponsePropagationSetter.php

@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Contrib\Instrumentation\Symfony;
+
+use function assert;
+use OpenTelemetry\Context\Propagation\PropagationSetterInterface;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * @internal
+ */
+final class ResponsePropagationSetter implements PropagationSetterInterface
+{
+    public static function instance(): self
+    {
+        static $instance;
+
+        return $instance ??= new self();
+    }
+
+    /** @psalm-suppress InvalidReturnType */
+    public function keys($carrier): array
+    {
+        assert($carrier instanceof Response);
+        /** @psalm-suppress InvalidReturnStatement */
+        return $carrier->headers->keys();
+    }
+
+    public function set(&$carrier, string $key, string $value): void
+    {
+        assert($carrier instanceof Response);
+
+        $carrier->headers->set($key, $value);
+    }
+}

src/Instrumentation/Symfony/src/SymfonyInstrumentation.php

@@ -49,7 +49,7 @@ public static function register(): void
 
                 $parent = Context::getCurrent();
                 if ($request) {
-                    $parent = Globals::propagator()->extract($request, HeadersPropagator::instance());
+                    $parent = Globals::propagator()->extract($request, RequestPropagationGetter::instance());
                     $span = $builder
                         ->setParent($parent)
                         ->setAttribute(TraceAttributes::HTTP_URL, $request->getUri())
@@ -94,19 +94,29 @@ public static function register(): void
                     $span->setStatus(StatusCode::STATUS_ERROR, $exception->getMessage());
                 }
 
-                if ($response) {
-                    if ($response->getStatusCode() >= Response::HTTP_BAD_REQUEST) {
-                        $span->setStatus(StatusCode::STATUS_ERROR);
-                    }
-                    $span->setAttribute(TraceAttributes::HTTP_STATUS_CODE, $response->getStatusCode());
-                    $span->setAttribute(TraceAttributes::HTTP_FLAVOR, $response->getProtocolVersion());
-                    $contentLength = $response->headers->get('Content-Length');
-                    /** @psalm-suppress PossiblyFalseArgument */
-                    if (null === $contentLength && is_string($response->getContent())) {
-                        $contentLength = \strlen($response->getContent());
-                    }
+                if (null === $response) {
+                    $span->end();
+
+                    return;
+                }
+
+                if ($response->getStatusCode() >= Response::HTTP_BAD_REQUEST) {
+                    $span->setStatus(StatusCode::STATUS_ERROR);
+                }
+                $span->setAttribute(TraceAttributes::HTTP_STATUS_CODE, $response->getStatusCode());
+                $span->setAttribute(TraceAttributes::HTTP_FLAVOR, $response->getProtocolVersion());
+                $contentLength = $response->headers->get('Content-Length');
+                /** @psalm-suppress PossiblyFalseArgument */
+                if (null === $contentLength && is_string($response->getContent())) {
+                    $contentLength = \strlen($response->getContent());
+                }
+
+                $span->setAttribute(TraceAttributes::HTTP_RESPONSE_CONTENT_LENGTH, $contentLength);
 
-                    $span->setAttribute(TraceAttributes::HTTP_RESPONSE_CONTENT_LENGTH, $contentLength);
+                // Propagate traceresponse header to response, if TraceResponsePropagator is present
+                if (class_exists('OpenTelemetry\Contrib\Propagation\TraceResponse\TraceResponsePropagator')) {
+                    $prop = new \OpenTelemetry\Contrib\Propagation\TraceResponse\TraceResponsePropagator();
+                    $prop->inject($response, ResponsePropagationSetter::instance(), $scope->context());
                 }
 
                 $span->end();

src/Instrumentation/Symfony/tests/Integration/SymfonyInstrumentationTest.php

@@ -4,6 +4,7 @@
 
 namespace OpenTelemetry\Tests\Instrumentation\Symfony\tests\Integration;
 
+use OpenTelemetry\Contrib\Propagation\TraceResponse\TraceResponsePropagator;
 use OpenTelemetry\SemConv\TraceAttributes;
 use Symfony\Component\EventDispatcher\EventDispatcher;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
@@ -27,7 +28,13 @@ public function test_http_kernel_handle_exception(): void
         });
         $this->assertCount(0, $this->storage);
 
-        $kernel->handle(new Request());
+        $response = $kernel->handle(new Request());
+
+        $this->assertArrayHasKey(
+            TraceResponsePropagator::TRACERESPONSE,
+            $response->headers->all(),
+            'traceresponse header is present if TraceResponsePropagator is present'
+        );
     }
 
     public function test_http_kernel_handle_attributes(): void
@@ -37,7 +44,7 @@ public function test_http_kernel_handle_attributes(): void
         $request = new Request();
         $request->attributes->set('_route', 'test_route');
 
-        $kernel->handle($request);
+        $response = $kernel->handle($request);
 
         $attributes = $this->storage[0]->getAttributes();
         $this->assertCount(1, $this->storage);
@@ -49,6 +56,12 @@ public function test_http_kernel_handle_attributes(): void
         $this->assertEquals(200, $attributes->get(TraceAttributes::HTTP_STATUS_CODE));
         $this->assertEquals('1.0', $attributes->get(TraceAttributes::HTTP_FLAVOR));
         $this->assertEquals(5, $attributes->get(TraceAttributes::HTTP_RESPONSE_CONTENT_LENGTH));
+
+        $this->assertArrayHasKey(
+            TraceResponsePropagator::TRACERESPONSE,
+            $response->headers->all(),
+            'traceresponse header is present if TraceResponsePropagator is present'
+        );
     }
 
     public function test_http_kernel_handle_stream_response(): void
@@ -59,19 +72,31 @@ public function test_http_kernel_handle_stream_response(): void
         }));
         $this->assertCount(0, $this->storage);
 
-        $kernel->handle(new Request());
+        $response = $kernel->handle(new Request());
         $this->assertCount(1, $this->storage);
         $this->assertNull($this->storage[0]->getAttributes()->get(TraceAttributes::HTTP_RESPONSE_CONTENT_LENGTH));
+
+        $this->assertArrayHasKey(
+            TraceResponsePropagator::TRACERESPONSE,
+            $response->headers->all(),
+            'traceresponse header is present if TraceResponsePropagator is present'
+        );
     }
 
     public function test_http_kernel_handle_binary_file_response(): void
     {
         $kernel = $this->getHttpKernel(new EventDispatcher(), fn () => new BinaryFileResponse(__FILE__));
         $this->assertCount(0, $this->storage);
 
-        $kernel->handle(new Request());
+        $response = $kernel->handle(new Request());
         $this->assertCount(1, $this->storage);
         $this->assertNull($this->storage[0]->getAttributes()->get(TraceAttributes::HTTP_RESPONSE_CONTENT_LENGTH));
+
+        $this->assertArrayHasKey(
+            TraceResponsePropagator::TRACERESPONSE,
+            $response->headers->all(),
+            'traceresponse header is present if TraceResponsePropagator is present'
+        );
     }
 
     public function test_http_kernel_handle_with_empty_route(): void
@@ -81,19 +106,31 @@ public function test_http_kernel_handle_with_empty_route(): void
         $request = new Request();
         $request->attributes->set('_route', '');
 
-        $kernel->handle($request, HttpKernelInterface::MAIN_REQUEST, true);
+        $response = $kernel->handle($request, HttpKernelInterface::MAIN_REQUEST, true);
         $this->assertCount(1, $this->storage);
         $this->assertFalse($this->storage[0]->getAttributes()->has(TraceAttributes::HTTP_ROUTE));
+
+        $this->assertArrayHasKey(
+            TraceResponsePropagator::TRACERESPONSE,
+            $response->headers->all(),
+            'traceresponse header is present if TraceResponsePropagator is present'
+        );
     }
 
     public function test_http_kernel_handle_without_route(): void
     {
         $kernel = $this->getHttpKernel(new EventDispatcher());
         $this->assertCount(0, $this->storage);
 
-        $kernel->handle(new Request(), HttpKernelInterface::MAIN_REQUEST, true);
+        $response = $kernel->handle(new Request(), HttpKernelInterface::MAIN_REQUEST, true);
         $this->assertCount(1, $this->storage);
         $this->assertFalse($this->storage[0]->getAttributes()->has(TraceAttributes::HTTP_ROUTE));
+
+        $this->assertArrayHasKey(
+            TraceResponsePropagator::TRACERESPONSE,
+            $response->headers->all(),
+            'traceresponse header is present if TraceResponsePropagator is present'
+        );
     }
 
     private function getHttpKernel(EventDispatcherInterface $eventDispatcher, $controller = null, RequestStack $requestStack = null, array $arguments = []): HttpKernel