Add property to specify the order of ServerHttpObservationFilter

The property is named 'management.observations.http.server.filter.order'

Closes gh-35067

Author: mhalbritter

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/observation/ObservationProperties.java

@@ -20,6 +20,7 @@
 import java.util.Map;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.core.Ordered;
 
 /**
  * {@link ConfigurationProperties @ConfigurationProperties} for configuring Micrometer
@@ -96,10 +97,16 @@ public static class Server {
 
 			private final ServerRequests requests = new ServerRequests();
 
+			private final Filter filter = new Filter();
+
 			public ServerRequests getRequests() {
 				return this.requests;
 			}
 
+			public Filter getFilter() {
+				return this.filter;
+			}
+
 			public static class ServerRequests {
 
 				/**
@@ -118,6 +125,23 @@ public void setName(String name) {
 
 			}
 
+			public static class Filter {
+
+				/**
+				 * Order of the filter that creates the observations.
+				 */
+				private int order = Ordered.HIGHEST_PRECEDENCE + 1;
+
+				public int getOrder() {
+					return this.order;
+				}
+
+				public void setOrder(int order) {
+					this.order = order;
+				}
+
+			}
+
 		}
 
 	}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/observation/web/reactive/OrderedServerHttpObservationFilter.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.autoconfigure.observation.web.reactive;
+
+import io.micrometer.observation.ObservationRegistry;
+
+import org.springframework.boot.web.reactive.filter.OrderedWebFilter;
+import org.springframework.core.Ordered;
+import org.springframework.http.server.reactive.observation.ServerRequestObservationConvention;
+import org.springframework.web.filter.reactive.ServerHttpObservationFilter;
+
+/**
+ * {@link ServerHttpObservationFilter} that also implements {@link Ordered}.
+ *
+ * @author Moritz Halbritter
+ */
+class OrderedServerHttpObservationFilter extends ServerHttpObservationFilter implements OrderedWebFilter {
+
+	private final int order;
+
+	OrderedServerHttpObservationFilter(ObservationRegistry observationRegistry,
+			ServerRequestObservationConvention observationConvention, int order) {
+		super(observationRegistry, observationConvention);
+		this.order = order;
+	}
+
+	@Override
+	public int getOrder() {
+		return this.order;
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/observation/web/reactive/WebFluxObservationAutoConfiguration.java

@@ -42,7 +42,6 @@
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
 import org.springframework.http.server.reactive.observation.DefaultServerRequestObservationConvention;
 import org.springframework.http.server.reactive.observation.ServerRequestObservationConvention;
@@ -55,6 +54,7 @@
  * @author Brian Clozel
  * @author Jon Schneider
  * @author Dmytro Nosan
+ * @author Moritz Halbritter
  * @since 3.0.0
  */
 @AutoConfiguration(after = { MetricsAutoConfiguration.class, CompositeMeterRegistryAutoConfiguration.class,
@@ -77,9 +77,8 @@ public WebFluxObservationAutoConfiguration(MetricsProperties metricsProperties,
 	}
 
 	@Bean
-	@ConditionalOnMissingBean
-	@Order(Ordered.HIGHEST_PRECEDENCE + 1)
-	public ServerHttpObservationFilter webfluxObservationFilter(ObservationRegistry registry,
+	@ConditionalOnMissingBean(ServerHttpObservationFilter.class)
+	public OrderedServerHttpObservationFilter webfluxObservationFilter(ObservationRegistry registry,
 			ObjectProvider<ServerRequestObservationConvention> customConvention,
 			ObjectProvider<WebFluxTagsProvider> tagConfigurer,
 			ObjectProvider<WebFluxTagsContributor> contributorsProvider) {
@@ -90,7 +89,8 @@ public ServerHttpObservationFilter webfluxObservationFilter(ObservationRegistry
 		List<WebFluxTagsContributor> tagsContributors = contributorsProvider.orderedStream().toList();
 		ServerRequestObservationConvention convention = createConvention(customConvention.getIfAvailable(), name,
 				tagsProvider, tagsContributors);
-		return new ServerHttpObservationFilter(registry, convention);
+		int order = this.observationProperties.getHttp().getServer().getFilter().getOrder();
+		return new OrderedServerHttpObservationFilter(registry, convention, order);
 	}
 
 	private static ServerRequestObservationConvention createConvention(

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/observation/web/reactive/WebFluxObservationAutoConfigurationTests.java

@@ -57,6 +57,7 @@
  * @author Brian Clozel
  * @author Dmytro Nosan
  * @author Madhura Bhave
+ * @author Moritz Halbritter
  */
 @ExtendWith(OutputCaptureExtension.class)
 @SuppressWarnings("removal")
@@ -169,6 +170,15 @@ void shouldNotDenyNorLogIfMaxUrisIsNotReached(CapturedOutput output) {
 			});
 	}
 
+	@Test
+	void shouldUsePropertyForServerHttpObservationFilterOrder() {
+		this.contextRunner.withPropertyValues("management.observations.http.server.filter.order=1000")
+			.run((context) -> {
+				OrderedServerHttpObservationFilter bean = context.getBean(OrderedServerHttpObservationFilter.class);
+				assertThat(bean.getOrder()).isEqualTo(1000);
+			});
+	}
+
 	private MeterRegistry getInitializedMeterRegistry(AssertableReactiveWebApplicationContext context)
 			throws Exception {
 		return getInitializedMeterRegistry(context, "/test0", "/test1", "/test2");