Add property to disable Spring Security observations

Setting 'management.observations.spring-security.enabled' installs an
ObservationPredicate, which prevents all observations starting with
'spring.security.' to be created.

Closes gh-34802

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

@@ -40,6 +40,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -82,6 +83,12 @@ public class ObservationAutoConfiguration {
 		return new PropertiesObservationFilter(properties);
 	}
 
+	@Bean
+	@ConditionalOnProperty(name = "management.observations.spring-security.enabled", havingValue = "false")
+	ObservationPredicate springSecurityObservationsDisabler() {
+		return (name, context) -> !name.startsWith("spring.security.");
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	@ConditionalOnClass(MeterRegistry.class)
 	@ConditionalOnMissingClass("io.micrometer.tracing.Tracer")

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -2038,6 +2038,12 @@
         "level": "error"
       }
     },
+    {
+      "name": "management.observations.spring-security.enabled",
+      "description": "Whether to enable observations for Spring Security",
+      "type": "java.lang.Boolean",
+      "defaultValue": true
+    },
     {
       "name": "management.otlp.tracing.compression",
       "defaultValue": "none"

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/observation/ObservationAutoConfigurationTests.java

@@ -291,6 +291,28 @@ class ObservationAutoConfigurationTests {
 		});
 	}
 
+	@Test
+	void shouldNotDisableSpringSecurityObservationsByDefault() {
+		this.contextRunner.run((context) -> {
+			ObservationRegistry observationRegistry = context.getBean(ObservationRegistry.class);
+			Observation.start("spring.security.filterchains", observationRegistry).stop();
+			MeterRegistry meterRegistry = context.getBean(MeterRegistry.class);
+			assertThat(meterRegistry.get("spring.security.filterchains").timer().count()).isOne();
+		});
+	}
+
+	@Test
+	void shouldDisableSpringSecurityObservationsIfPropertyIsSet() {
+		this.contextRunner.withPropertyValues("management.observations.spring-security.enabled=false")
+			.run((context) -> {
+				ObservationRegistry observationRegistry = context.getBean(ObservationRegistry.class);
+				Observation.start("spring.security.filterchains", observationRegistry).stop();
+				MeterRegistry meterRegistry = context.getBean(MeterRegistry.class);
+				assertThatThrownBy(() -> meterRegistry.get("spring.security.filterchains").timer())
+					.isInstanceOf(MeterNotFoundException.class);
+			});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class ObservationPredicates {
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/observability.adoc

@@ -37,4 +37,16 @@ Commons key-values are applied to all observations as low cardinality key-values
 
 The preceding example adds `region` and `stack` key-values to all observations with a value of `us-east-1` and `prod`, respectively.
 
+[[actuator.observability.preventing-observations]]
+=== Preventing Observations
+
+If you'd like to prevent some observations from being reported, you can register beans of type `ObservationPredicate`.
+Observations are only reported if all the `ObservationPredicate` beans return `true` for that observation.
+
+include::code:MyObservationPredicate[]
+
+The preceding example will prevent all observations with a name starting with "denied.prefix.".
+
+TIP: If you want to prevent Spring Security from reporting observations, set the property configprop:management.observations.spring-security.enabled[] to `false`.
+
 The next sections will provide more details about logging, metrics and traces.

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/actuator/observability/preventingobservations/MyObservationPredicate.java

@@ -0,0 +1,32 @@
+/*
+ * 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.docs.actuator.observability.preventingobservations;
+
+import io.micrometer.observation.Observation.Context;
+import io.micrometer.observation.ObservationPredicate;
+
+import org.springframework.stereotype.Component;
+
+@Component
+class MyObservationPredicate implements ObservationPredicate {
+
+	@Override
+	public boolean test(String name, Context context) {
+		return !name.startsWith("denied.prefix.");
+	}
+
+}