Remove ServerWebExchange dependency in ServerRequestObservationContext

Avoiding cycle between http.server and web.server packages.

See gh-30013

Author: jhoeller

spring-web/src/main/java/org/springframework/http/server/reactive/observation/ServerRequestObservationContext.java

@@ -25,11 +25,12 @@
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.http.server.reactive.ServerHttpResponse;
 import org.springframework.lang.Nullable;
-import org.springframework.web.server.ServerWebExchange;
 
 /**
  * Context that holds information for metadata collection regarding
- * {@link ServerHttpObservationDocumentation#HTTP_REACTIVE_SERVER_REQUESTS reactive HTTP requests} observations.
+ * {@link ServerHttpObservationDocumentation#HTTP_REACTIVE_SERVER_REQUESTS reactive HTTP requests}
+ * observations.
+ *
  * <p>This context also extends {@link RequestReplyReceiverContext} for propagating
  * tracing information during HTTP request processing.
  *
@@ -39,10 +40,11 @@
 public class ServerRequestObservationContext extends RequestReplyReceiverContext<ServerHttpRequest, ServerHttpResponse> {
 
 	/**
-	 * Name of the request attribute holding the {@link ServerRequestObservationContext context} for the current observation.
+	 * Name of the request attribute holding the {@link ServerRequestObservationContext context}
+	 * for the current observation.
 	 * @since 6.1
 	 */
-	public static final String CURRENT_OBSERVATION_CONTEXT_ATTRIBUTE = ServerRequestObservationContext.class.getName() + ".context";
+	public static final String CURRENT_OBSERVATION_CONTEXT_ATTRIBUTE = ServerRequestObservationContext.class.getName();
 
 
 	private final Map<String, Object> attributes;
@@ -53,7 +55,15 @@ public class ServerRequestObservationContext extends RequestReplyReceiverContext
 	private boolean connectionAborted;
 
 
-	public ServerRequestObservationContext(ServerHttpRequest request, ServerHttpResponse response, Map<String, Object> attributes) {
+	/**
+	 * Create a new {@code ServerRequestObservationContext} instance.
+	 * @param request the current request
+	 * @param response the current response
+	 * @param attributes the current attributes
+	 */
+	public ServerRequestObservationContext(
+			ServerHttpRequest request, ServerHttpResponse response, Map<String, Object> attributes) {
+
 		super((req, key) -> req.getHeaders().getFirst(key));
 		setCarrier(request);
 		setResponse(response);
@@ -89,8 +99,8 @@ public void setPathPattern(@Nullable String pathPattern) {
 	}
 
 	/**
-	 * Whether the current connection was aborted by the client, resulting
-	 * in a {@link reactor.core.publisher.SignalType#CANCEL cancel signal} on the reactive chain,
+	 * Whether the current connection was aborted by the client, resulting in a
+	 * {@link reactor.core.publisher.SignalType#CANCEL cancel signal} on the reactive chain,
 	 * or an {@code AbortedException} when reading the request.
 	 * @return if the connection has been aborted
 	 */
@@ -99,8 +109,8 @@ public boolean isConnectionAborted() {
 	}
 
 	/**
-	 * Set whether the current connection was aborted by the client, resulting
-	 * in a {@link reactor.core.publisher.SignalType#CANCEL cancel signal} on the reactive chain,
+	 * Set whether the current connection was aborted by the client, resulting in a
+	 * {@link reactor.core.publisher.SignalType#CANCEL cancel signal} on the reactive chain,
 	 * or an {@code AbortedException} when reading the request.
 	 * @param connectionAborted if the connection has been aborted
 	 */
@@ -110,13 +120,15 @@ public void setConnectionAborted(boolean connectionAborted) {
 
 
 	/**
-	 * Get the current {@link ServerRequestObservationContext observation context} from the given exchange, if available.
-	 * @param exchange the current exchange
+	 * Get the current {@link ServerRequestObservationContext observation context}
+	 * from the given attributes, if available.
+	 * @param attributes the current exchange attributes
 	 * @return the current observation context
 	 * @since 6.1
 	 */
-	public static Optional<ServerRequestObservationContext> findCurrent(ServerWebExchange exchange) {
-		return Optional.ofNullable(exchange.getAttribute(CURRENT_OBSERVATION_CONTEXT_ATTRIBUTE));
+	public static Optional<ServerRequestObservationContext> findCurrent(Map<String, Object> attributes) {
+		return Optional.ofNullable(
+				(ServerRequestObservationContext) attributes.get(CURRENT_OBSERVATION_CONTEXT_ATTRIBUTE));
 	}
 
 }

spring-web/src/main/java/org/springframework/web/server/adapter/HttpWebHandlerAdapter.java

@@ -296,9 +296,10 @@ public Mono<Void> handle(ServerHttpRequest request, ServerHttpResponse response)
 				exchange.getLogPrefix() + formatRequest(exchange.getRequest()) +
 						(traceOn ? ", headers=" + formatHeaders(exchange.getRequest().getHeaders()) : ""));
 
-		ServerRequestObservationContext observationContext = new ServerRequestObservationContext(exchange.getRequest(),
-				exchange.getResponse(), exchange.getAttributes());
-		exchange.getAttributes().put(ServerRequestObservationContext.CURRENT_OBSERVATION_CONTEXT_ATTRIBUTE, observationContext);
+		ServerRequestObservationContext observationContext = new ServerRequestObservationContext(
+				exchange.getRequest(), exchange.getResponse(), exchange.getAttributes());
+		exchange.getAttributes().put(
+				ServerRequestObservationContext.CURRENT_OBSERVATION_CONTEXT_ATTRIBUTE, observationContext);
 
 		return getDelegate().handle(exchange)
 				.transformDeferred(call -> transform(exchange, observationContext, call))

spring-web/src/test/java/org/springframework/web/server/adapter/HttpWebHandlerAdapterObservabilityTests.java

@@ -51,6 +51,7 @@ class HttpWebHandlerAdapterObservabilityTests {
 
 	private final MockServerHttpResponse response = new MockServerHttpResponse();
 
+
 	@Test
 	void handlerShouldSetObservationContextOnExchange() {
 		HttpStatusSuccessStubWebHandler targetHandler = new HttpStatusSuccessStubWebHandler(HttpStatus.OK);
@@ -97,6 +98,7 @@ private TestObservationRegistryAssert.TestObservationRegistryAssertReturningObse
 				.hasObservationWithNameEqualTo("http.server.requests").that();
 	}
 
+
 	private static class HttpStatusSuccessStubWebHandler implements WebHandler {
 
 		private final HttpStatus responseStatus;
@@ -109,12 +111,13 @@ public HttpStatusSuccessStubWebHandler(HttpStatus responseStatus) {
 
 		@Override
 		public Mono<Void> handle(ServerWebExchange exchange) {
-			this.observationContext = ServerRequestObservationContext.findCurrent(exchange);
+			this.observationContext = ServerRequestObservationContext.findCurrent(exchange.getAttributes());
 			exchange.getResponse().setStatusCode(this.responseStatus);
 			return Mono.empty();
 		}
 	}
 
+
 	private static class ReactorContextWebHandler implements WebHandler {
 
 		ContextView contextView;
@@ -129,6 +132,7 @@ public Mono<Void> handle(ServerWebExchange exchange) {
 		}
 	}
 
+
 	private static class ThrowingExceptionWebHandler implements WebHandler {
 
 		private final Throwable exception;
@@ -141,11 +145,12 @@ private ThrowingExceptionWebHandler(Throwable exception) {
 
 		@Override
 		public Mono<Void> handle(ServerWebExchange exchange) {
-			this.observationContext = ServerRequestObservationContext.findCurrent(exchange);
+			this.observationContext = ServerRequestObservationContext.findCurrent(exchange.getAttributes());
 			return Mono.error(this.exception);
 		}
 	}
 
+
 	private static class BadRequestExceptionHandler implements WebExceptionHandler {
 
 		@Override

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/support/RouterFunctionMapping.java

@@ -174,7 +174,7 @@ private void setAttributes(
 			org.springframework.web.filter.reactive.ServerHttpObservationFilter
 					.findObservationContext(serverRequest.exchange())
 					.ifPresent(context -> context.setPathPattern(matchingPattern.toString()));
-			ServerRequestObservationContext.findCurrent(serverRequest.exchange())
+			ServerRequestObservationContext.findCurrent(serverRequest.exchange().getAttributes())
 					.ifPresent(context -> context.setPathPattern(matchingPattern.toString()));
 		}
 		Map<String, String> uriVariables =

spring-webflux/src/main/java/org/springframework/web/reactive/handler/AbstractUrlHandlerMapping.java

@@ -170,7 +170,7 @@ protected Object lookupHandler(PathContainer lookupPath, ServerWebExchange excha
 		org.springframework.web.filter.reactive.ServerHttpObservationFilter
 				.findObservationContext(exchange)
 				.ifPresent(context -> context.setPathPattern(pattern.toString()));
-		ServerRequestObservationContext.findCurrent(exchange)
+		ServerRequestObservationContext.findCurrent(exchange.getAttributes())
 				.ifPresent(context -> context.setPathPattern(pattern.toString()));
 		exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, pathWithinMapping);
 		exchange.getAttributes().put(URI_TEMPLATE_VARIABLES_ATTRIBUTE, matchInfo.getUriVariables());

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/RequestMappingInfoHandlerMapping.java

@@ -145,7 +145,7 @@ protected void handleMatch(RequestMappingInfo info, HandlerMethod handlerMethod,
 		org.springframework.web.filter.reactive.ServerHttpObservationFilter
 				.findObservationContext(exchange)
 				.ifPresent(context -> context.setPathPattern(bestPattern.toString()));
-		ServerRequestObservationContext.findCurrent(exchange)
+		ServerRequestObservationContext.findCurrent(exchange.getAttributes())
 				.ifPresent(context -> context.setPathPattern(bestPattern.toString()));
 		exchange.getAttributes().put(URI_TEMPLATE_VARIABLES_ATTRIBUTE, uriVariables);
 		exchange.getAttributes().put(MATRIX_VARIABLES_ATTRIBUTE, matrixVariables);

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/support/RouterFunctionMappingTests.java

@@ -137,7 +137,7 @@ void mappedRequestShouldHoldAttributes() {
 		assertThat(matchingPattern.getPatternString()).isEqualTo("/match");
 		assertThat(org.springframework.web.filter.reactive.ServerHttpObservationFilter.findObservationContext(exchange))
 				.hasValueSatisfying(context -> assertThat(context.getPathPattern()).isEqualTo(matchingPattern.getPatternString()));
-		assertThat(ServerRequestObservationContext.findCurrent(exchange))
+		assertThat(ServerRequestObservationContext.findCurrent(exchange.getAttributes()))
 				.hasValueSatisfying(context -> assertThat(context.getPathPattern()).isEqualTo(matchingPattern.getPatternString()));
 
 		ServerRequest serverRequest = exchange.getAttribute(RouterFunctions.REQUEST_ATTRIBUTE);