Add new send_response_header option (#17)

* Add new send_response_header option
- configure if the TraceServiceInterface::handleResponse method should be called, to add tracing data to the response object

README.md

@@ -37,7 +37,7 @@ return [
 
 By default, the bundle will use the [W3C TraceContext](https://www.w3.org/TR/trace-context/) standard to receive and pass on the traceId.  
 It's also possible to configure the bundle to setup custom request/response headers and custom ID generators.  
-Read more about the [TraceId configuration](docs/configuration/traceid.md) and [TraceContext configuration](docs/configuration/tracecontext.md) in the /docs pages.
+Read more about all available configuration options on [TraceId configuration](docs/configuration/traceid.md) and [TraceContext configuration](docs/configuration/tracecontext.md) in the /docs pages.
 
 ## How it Works
 
@@ -47,8 +47,8 @@ lets you use trace ID's from somewhere higher up in the stack (like in the web
 server itself).
 
 If no trace ID is found, one is generated by the `TraceIdGeneratorInterface`.
-In tracecontext modus In traceId modus, the IDs are generated according to the TraceContext standard.
-The default generator in traceId modus creates version 4 UUIDs.
+In tracecontext mode In traceId mode, the IDs are generated according to the TraceContext standard.
+The default generator in traceId mode creates version 4 UUIDs.
 
 On the way out, a response header can be set on the response as well using
 the value(s) described above.
@@ -113,7 +113,7 @@ Here's an example of a template.
 By default this bundle will check for services tagged with the `http_client.trace_id` tag and decorate them with the TraceAwareHttpClient.
 When `tagDefaultClient` is enabled the default symfony http client will also be tagged and thus decorated.
 This will add the trace header(s) to all outgoing requests for the tagged clients.
-In traceId modus the header name can be changed with the `header` configuration option.
+In traceId mode the header name can be changed with the `header` configuration option.
 
 ## About us
 

docs/configuration/tracecontext.md

@@ -20,6 +20,9 @@ return static function (SymfonyTraceConfig $config): void {
     // those values are ignored and new trace ID's are generated.
     $config->trustRequestHeader(true);
 
+    // Whether to send the trace details in the response headers. This is turned on by default.
+    $config->sendResponseHeader(true);
+
     // The service key of an object that implements
     // DR\SymfonyTraceBundle\TraceStorageInterface
     // Defaults to TraceStorage::class

docs/configuration/traceid.md

@@ -29,6 +29,9 @@ return static function (SymfonyTraceConfig $config): void {
     // those values are ignored.
     $config->trustRequestHeader(true);
 
+    // Whether to send the trace details in the response headers. This is turned on by default.
+    $config->sendResponseHeader(true);
+
     $config->traceid()
         // The header which the bundle inspects for the incoming trace ID
         // if this is not set an ID will be generated and set at this header

phpstan-baseline.neon

@@ -1,7 +1,7 @@
 parameters:
 	ignoreErrors:
 		-
-			message: "#^Parameter \\#1 \\$mergedConfig \\(array\\{traceMode\\: 'tracecontext'\\|'traceid', traceid\\: array\\{request_header\\: string, response_header\\: string, generator_service\\: string\\|null\\}, trust_request_header\\: bool, storage_service\\: string\\|null, enable_monolog\\: bool, enable_console\\: bool, enable_messenger\\: bool, enable_twig\\: bool, \\.\\.\\.\\}\\) of method DR\\\\SymfonyTraceBundle\\\\DependencyInjection\\\\SymfonyTraceExtension\\:\\:loadInternal\\(\\) should be contravariant with parameter \\$mergedConfig \\(array\\) of method Symfony\\\\Component\\\\HttpKernel\\\\DependencyInjection\\\\ConfigurableExtension\\:\\:loadInternal\\(\\)$#"
+			message: "#^Parameter \\#1 \\$mergedConfig \\(array\\{traceMode\\: 'tracecontext'\\|'traceid', traceid\\: array\\{request_header\\: string, response_header\\: string, generator_service\\: string\\|null\\}, trust_request_header\\: bool, send_response_header\\: bool, storage_service\\: string\\|null, enable_monolog\\: bool, enable_console\\: bool, enable_messenger\\: bool, \\.\\.\\.\\}\\) of method DR\\\\SymfonyTraceBundle\\\\DependencyInjection\\\\SymfonyTraceExtension\\:\\:loadInternal\\(\\) should be contravariant with parameter \\$mergedConfig \\(array\\) of method Symfony\\\\Component\\\\HttpKernel\\\\DependencyInjection\\\\ConfigurableExtension\\:\\:loadInternal\\(\\)$#"
 			count: 1
 			path: src/DependencyInjection/SymfonyTraceExtension.php
 

src/DependencyInjection/Configuration.php

@@ -54,6 +54,10 @@ public function getConfigTreeBuilder(): TreeBuilder
                 ->defaultValue(true)
                 ->info("Whether or not to trust the incoming request's `Trace-Id` header as a real ID")
             ->end()
+            ->booleanNode('send_response_header')
+                ->defaultValue(true)
+                ->info("Whether or not to send a response header with the trace ID. Defaults to true")
+            ->end()
             ->scalarNode('storage_service')
                 ->info('The service name for trace ID storage. Defaults to `TraceStorage`')
             ->end()

src/DependencyInjection/SymfonyTraceExtension.php

@@ -45,6 +45,7 @@ final class SymfonyTraceExtension extends ConfigurableExtension
      *         generator_service: ?string,
      *     },
      *     trust_request_header: bool,
+     *     send_response_header: bool,
      *     storage_service: ?string,
      *     enable_monolog: bool,
      *     enable_console: bool,
@@ -111,6 +112,7 @@ protected function loadInternal(array $mergedConfig, ContainerBuilder $container
             ->setArguments(
                 [
                     $mergedConfig['trust_request_header'],
+                    $mergedConfig['send_response_header'],
                     new Reference($serviceId),
                     new Reference($storeId)
                 ]

src/EventSubscriber/TraceSubscriber.php

@@ -23,6 +23,7 @@ final class TraceSubscriber implements EventSubscriberInterface
      */
     public function __construct(
         private readonly bool                  $trustRequest,
+        private readonly bool                  $sendResponseHeader,
         private readonly TraceServiceInterface $traceService,
         private readonly TraceStorageInterface $traceStorage,
     ) {
@@ -63,6 +64,8 @@ public function onResponse(ResponseEvent $event): void
             return;
         }
 
-        $this->traceService->handleResponse($event->getResponse(), $this->traceStorage->getTrace());
+        if ($this->sendResponseHeader) {
+            $this->traceService->handleResponse($event->getResponse(), $this->traceStorage->getTrace());
+        }
     }
 }

tests/Unit/EventSubscriber/TraceIdSubscriberTest.php → tests/Unit/EventSubscriber/TraceSubscriberTest.php

@@ -20,7 +20,7 @@
 use Symfony\Component\HttpKernel\KernelEvents;
 
 #[CoversClass(TraceSubscriber::class)]
-class TraceIdSubscriberTest extends TestCase
+class TraceSubscriberTest extends TestCase
 {
     private TraceServiceInterface&MockObject $service;
     private TraceStorageInterface&MockOBject $storage;
@@ -34,7 +34,7 @@ protected function setUp(): void
     {
         $this->service   = $this->createMock(TraceServiceInterface::class);
         $this->storage   = $this->createMock(TraceStorageInterface::class);
-        $this->listener  = new TraceSubscriber(true, $this->service, $this->storage);
+        $this->listener  = new TraceSubscriber(true, true, $this->service, $this->storage);
 
         $this->dispatcher = new EventDispatcher();
         $this->dispatcher->addSubscriber($this->listener);
@@ -74,7 +74,7 @@ public function testListenerSetsTheTraceToStorageWhenFoundInRequestHeaders(): vo
     public function testListenerIgnoresIncomingRequestHeadersWhenTrustRequestIsFalse(): void
     {
         $this->dispatcher->removeSubscriber($this->listener);
-        $this->dispatcher->addSubscriber(new TraceSubscriber(false, $this->service, $this->storage));
+        $this->dispatcher->addSubscriber(new TraceSubscriber(false, true, $this->service, $this->storage));
 
         $trace = new TraceContext();
         $this->service->expects(static::never())->method('supports');
@@ -124,4 +124,18 @@ public function testRequestSetsIdOnResponse(): void
             KernelEvents::RESPONSE
         );
     }
+
+    public function testListenerDoesNothingToResponseWithoutMasterRequestWhenSendResponseHeaderIsFalse(): void
+    {
+        $this->dispatcher->removeSubscriber($this->listener);
+        $this->dispatcher->addSubscriber(new TraceSubscriber(false, false, $this->service, $this->storage));
+
+        $this->storage->expects(static::never())->method('getTrace');
+        $this->service->expects(static::never())->method('handleResponse');
+
+        $this->dispatcher->dispatch(
+            new ResponseEvent($this->kernel, $this->request, HttpKernelInterface::MAIN_REQUEST, $this->response),
+            KernelEvents::RESPONSE
+        );
+    }
 }