Merge pull request #14173 from nosan:gh-13913

* pr/14173:
  Polish "Limit metrics collection of incoming requests"
  Limit metrics collection of incoming requests

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MetricsProperties.java

@@ -134,6 +134,13 @@ public class MetricsProperties {
 			 */
 			private String requestsMetricName = "http.server.requests";
 
+			/**
+			 * Maximum number of unique URI tag values allowed. After the max number of
+			 * tag values is reached, metrics with additional tag values are denied by
+			 * filter.
+			 */
+			private int maxUriTags = 100;
+
 			public boolean isAutoTimeRequests() {
 				return this.autoTimeRequests;
 			}
@@ -150,6 +157,14 @@ public class MetricsProperties {
 				this.requestsMetricName = requestsMetricName;
 			}
 
+			public int getMaxUriTags() {
+				return this.maxUriTags;
+			}
+
+			public void setMaxUriTags(int maxUriTags) {
+				this.maxUriTags = maxUriTags;
+			}
+
 		}
 
 	}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/OnlyOnceLoggingDenyMeterFilter.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2012-2018 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
+ *
+ *      http://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.metrics;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Supplier;
+
+import io.micrometer.core.instrument.Meter;
+import io.micrometer.core.instrument.config.MeterFilter;
+import io.micrometer.core.instrument.config.MeterFilterReply;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.springframework.util.Assert;
+
+/**
+ * {@link MeterFilter} to log only once a warning message and deny {@link Meter.Id}.
+ *
+ * @author Jon Schneider
+ * @author Dmytro Nosan
+ * @since 2.0.5
+ */
+public final class OnlyOnceLoggingDenyMeterFilter implements MeterFilter {
+
+	private final Logger logger = LoggerFactory
+			.getLogger(OnlyOnceLoggingDenyMeterFilter.class);
+
+	private final AtomicBoolean alreadyWarned = new AtomicBoolean(false);
+
+	private final Supplier<String> message;
+
+	public OnlyOnceLoggingDenyMeterFilter(Supplier<String> message) {
+		Assert.notNull(message, "Message must not be null");
+		this.message = message;
+	}
+
+	@Override
+	public MeterFilterReply accept(Meter.Id id) {
+		if (this.logger.isWarnEnabled()
+				&& this.alreadyWarned.compareAndSet(false, true)) {
+			this.logger.warn(this.message.get());
+		}
+		return MeterFilterReply.DENY;
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/web/client/RestTemplateMetricsAutoConfiguration.java

@@ -16,17 +16,12 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics.web.client;
 
-import java.util.concurrent.atomic.AtomicBoolean;
-
-import io.micrometer.core.instrument.Meter.Id;
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.config.MeterFilter;
-import io.micrometer.core.instrument.config.MeterFilterReply;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties;
+import org.springframework.boot.actuate.autoconfigure.metrics.OnlyOnceLoggingDenyMeterFilter;
 import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration;
 import org.springframework.boot.actuate.metrics.web.client.DefaultRestTemplateExchangeTagsProvider;
 import org.springframework.boot.actuate.metrics.web.client.MetricsRestTemplateCustomizer;
@@ -57,6 +52,12 @@ import org.springframework.web.client.RestTemplate;
 @ConditionalOnBean(MeterRegistry.class)
 public class RestTemplateMetricsAutoConfiguration {
 
+	private final MetricsProperties properties;
+
+	public RestTemplateMetricsAutoConfiguration(MetricsProperties properties) {
+		this.properties = properties;
+	}
+
 	@Bean
 	@ConditionalOnMissingBean(RestTemplateExchangeTagsProvider.class)
 	public DefaultRestTemplateExchangeTagsProvider restTemplateTagConfigurer() {
@@ -66,53 +67,20 @@ public class RestTemplateMetricsAutoConfiguration {
 	@Bean
 	public MetricsRestTemplateCustomizer metricsRestTemplateCustomizer(
 			MeterRegistry meterRegistry,
-			RestTemplateExchangeTagsProvider restTemplateTagConfigurer,
-			MetricsProperties properties) {
+			RestTemplateExchangeTagsProvider restTemplateTagConfigurer) {
 		return new MetricsRestTemplateCustomizer(meterRegistry, restTemplateTagConfigurer,
-				properties.getWeb().getClient().getRequestsMetricName());
+				this.properties.getWeb().getClient().getRequestsMetricName());
 	}
 
 	@Bean
 	@Order(0)
-	public MeterFilter metricsWebClientUriTagFilter(MetricsProperties properties) {
-		String metricName = properties.getWeb().getClient().getRequestsMetricName();
-		MeterFilter denyFilter = new MaximumUriTagsReachedMeterFilter(metricName);
+	public MeterFilter metricsWebClientUriTagFilter() {
+		String metricName = this.properties.getWeb().getClient().getRequestsMetricName();
+		MeterFilter denyFilter = new OnlyOnceLoggingDenyMeterFilter(() -> String
+				.format("Reached the maximum number of URI tags for '%s'. Are you using "
+						+ "'uriVariables' on RestTemplate calls?", metricName));
 		return MeterFilter.maximumAllowableTags(metricName, "uri",
-				properties.getWeb().getClient().getMaxUriTags(), denyFilter);
-	}
-
-	/**
-	 * {@link MeterFilter} to deny further URI tags and log a warning.
-	 */
-	private static class MaximumUriTagsReachedMeterFilter implements MeterFilter {
-
-		private final Logger logger = LoggerFactory
-				.getLogger(MaximumUriTagsReachedMeterFilter.class);
-
-		private final String metricName;
-
-		private final AtomicBoolean alreadyWarned = new AtomicBoolean(false);
-
-		MaximumUriTagsReachedMeterFilter(String metricName) {
-			this.metricName = metricName;
-		}
-
-		@Override
-		public MeterFilterReply accept(Id id) {
-			if (this.alreadyWarned.compareAndSet(false, true)) {
-				logWarning();
-			}
-			return MeterFilterReply.DENY;
-		}
-
-		private void logWarning() {
-			if (this.logger.isWarnEnabled()) {
-				this.logger.warn(
-						"Reached the maximum number of URI tags for '" + this.metricName
-								+ "'. Are you using uriVariables on RestTemplate calls?");
-			}
-		}
-
+				this.properties.getWeb().getClient().getMaxUriTags(), denyFilter);
 	}
 
 }

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

@@ -17,9 +17,11 @@
 package org.springframework.boot.actuate.autoconfigure.metrics.web.reactive;
 
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.config.MeterFilter;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties;
+import org.springframework.boot.actuate.autoconfigure.metrics.OnlyOnceLoggingDenyMeterFilter;
 import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration;
 import org.springframework.boot.actuate.metrics.web.reactive.server.DefaultWebFluxTagsProvider;
 import org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter;
@@ -31,12 +33,14 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.Order;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for instrumentation of Spring
  * WebFlux MVC annotation-based programming model request mappings.
  *
  * @author Jon Schneider
+ * @author Dmytro Nosan
  * @since 2.0.0
  */
 @Configuration
@@ -46,6 +50,12 @@ import org.springframework.context.annotation.Configuration;
 @ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.REACTIVE)
 public class WebFluxMetricsAutoConfiguration {
 
+	private final MetricsProperties properties;
+
+	public WebFluxMetricsAutoConfiguration(MetricsProperties properties) {
+		this.properties = properties;
+	}
+
 	@Bean
 	@ConditionalOnMissingBean(WebFluxTagsProvider.class)
 	public DefaultWebFluxTagsProvider webfluxTagConfigurer() {
@@ -54,9 +64,19 @@ public class WebFluxMetricsAutoConfiguration {
 
 	@Bean
 	public MetricsWebFilter webfluxMetrics(MeterRegistry registry,
-			WebFluxTagsProvider tagConfigurer, MetricsProperties properties) {
+			WebFluxTagsProvider tagConfigurer) {
 		return new MetricsWebFilter(registry, tagConfigurer,
-				properties.getWeb().getServer().getRequestsMetricName());
+				this.properties.getWeb().getServer().getRequestsMetricName());
+	}
+
+	@Bean
+	@Order(0)
+	public MeterFilter metricsHttpServerUriTagFilter() {
+		String metricName = this.properties.getWeb().getServer().getRequestsMetricName();
+		MeterFilter filter = new OnlyOnceLoggingDenyMeterFilter(() -> String
+				.format("Reached the maximum number of URI tags for '%s'.", metricName));
+		return MeterFilter.maximumAllowableTags(metricName, "uri",
+				this.properties.getWeb().getServer().getMaxUriTags(), filter);
 	}
 
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/web/servlet/WebMvcMetricsAutoConfiguration.java

@@ -19,10 +19,12 @@ package org.springframework.boot.actuate.autoconfigure.metrics.web.servlet;
 import javax.servlet.DispatcherType;
 
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.config.MeterFilter;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties.Web.Server;
+import org.springframework.boot.actuate.autoconfigure.metrics.OnlyOnceLoggingDenyMeterFilter;
 import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration;
 import org.springframework.boot.actuate.metrics.web.servlet.DefaultWebMvcTagsProvider;
 import org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter;
@@ -38,6 +40,7 @@ import org.springframework.boot.web.servlet.FilterRegistrationBean;
 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.web.context.WebApplicationContext;
 import org.springframework.web.servlet.DispatcherServlet;
 
@@ -46,6 +49,7 @@ import org.springframework.web.servlet.DispatcherServlet;
  * MVC servlet-based request mappings.
  *
  * @author Jon Schneider
+ * @author Dmytro Nosan
  * @since 2.0.0
  */
 @Configuration
@@ -57,6 +61,12 @@ import org.springframework.web.servlet.DispatcherServlet;
 @EnableConfigurationProperties(MetricsProperties.class)
 public class WebMvcMetricsAutoConfiguration {
 
+	private final MetricsProperties properties;
+
+	public WebMvcMetricsAutoConfiguration(MetricsProperties properties) {
+		this.properties = properties;
+	}
+
 	@Bean
 	@ConditionalOnMissingBean(WebMvcTagsProvider.class)
 	public DefaultWebMvcTagsProvider webMvcTagsProvider() {
@@ -65,9 +75,9 @@ public class WebMvcMetricsAutoConfiguration {
 
 	@Bean
 	public FilterRegistrationBean<WebMvcMetricsFilter> webMvcMetricsFilter(
-			MeterRegistry registry, MetricsProperties properties,
-			WebMvcTagsProvider tagsProvider, WebApplicationContext context) {
-		Server serverProperties = properties.getWeb().getServer();
+			MeterRegistry registry, WebMvcTagsProvider tagsProvider,
+			WebApplicationContext context) {
+		Server serverProperties = this.properties.getWeb().getServer();
 		WebMvcMetricsFilter filter = new WebMvcMetricsFilter(context, registry,
 				tagsProvider, serverProperties.getRequestsMetricName(),
 				serverProperties.isAutoTimeRequests());
@@ -78,4 +88,14 @@ public class WebMvcMetricsAutoConfiguration {
 		return registration;
 	}
 
+	@Bean
+	@Order(0)
+	public MeterFilter metricsHttpServerUriTagFilter() {
+		String metricName = this.properties.getWeb().getServer().getRequestsMetricName();
+		MeterFilter filter = new OnlyOnceLoggingDenyMeterFilter(() -> String
+				.format("Reached the maximum number of URI tags for '%s'.", metricName));
+		return MeterFilter.maximumAllowableTags(metricName, "uri",
+				this.properties.getWeb().getServer().getMaxUriTags(), filter);
+	}
+
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/web/TestController.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012-2018 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
+ *
+ *      http://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.metrics.web;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * Test controller used by metrics tests.
+ *
+ * @author Dmytro Nosan
+ * @author Stephane Nicoll
+ */
+@RestController
+public class TestController {
+
+	@GetMapping("test0")
+	public String test0() {
+		return "test0";
+	}
+
+	@GetMapping("test1")
+	public String test1() {
+		return "test1";
+	}
+
+	@GetMapping("test2")
+	public String test2() {
+		return "test2";
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/web/client/RestTemplateMetricsAutoConfigurationTests.java

@@ -20,11 +20,11 @@ import io.micrometer.core.instrument.MeterRegistry;
 import org.junit.Rule;
 import org.junit.Test;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties;
 import org.springframework.boot.actuate.autoconfigure.metrics.test.MetricsRun;
 import org.springframework.boot.actuate.metrics.web.client.MetricsRestTemplateCustomizer;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration;
+import org.springframework.boot.test.context.assertj.AssertableApplicationContext;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.boot.test.rule.OutputCapture;
 import org.springframework.boot.web.client.RestTemplateBuilder;
@@ -75,26 +75,44 @@ public class RestTemplateMetricsAutoConfigurationTests {
 
 	@Test
 	public void afterMaxUrisReachedFurtherUrisAreDenied() {
-		this.contextRunner.run((context) -> {
-			MetricsProperties properties = context.getBean(MetricsProperties.class);
-			int maxUriTags = properties.getWeb().getClient().getMaxUriTags();
-			MeterRegistry registry = context.getBean(MeterRegistry.class);
-			RestTemplate restTemplate = context.getBean(RestTemplateBuilder.class)
-					.build();
-			MockRestServiceServer server = MockRestServiceServer
-					.createServer(restTemplate);
-			for (int i = 0; i < maxUriTags + 10; i++) {
-				server.expect(requestTo("/test/" + i))
-						.andRespond(withStatus(HttpStatus.OK));
-			}
-			for (int i = 0; i < maxUriTags + 10; i++) {
-				restTemplate.getForObject("/test/" + i, String.class);
-			}
-			assertThat(registry.get("http.client.requests").meters()).hasSize(maxUriTags);
-			assertThat(this.out.toString())
-					.contains("Reached the maximum number of URI tags "
-							+ "for 'http.client.requests'");
-		});
+		this.contextRunner
+				.withPropertyValues("management.metrics.web.client.max-uri-tags=2")
+				.run((context) -> {
+					MeterRegistry registry = getInitializedMeterRegistry(context);
+					assertThat(registry.get("http.client.requests").meters()).hasSize(2);
+					assertThat(this.out.toString()).contains(
+							"Reached the maximum number of URI tags for 'http.client.requests'.");
+					assertThat(this.out.toString()).contains(
+							"Are you using 'uriVariables' on RestTemplate calls?");
+				});
+	}
+
+	@Test
+	public void shouldNotDenyNorLogIfMaxUrisIsNotReached() {
+		this.contextRunner
+				.withPropertyValues("management.metrics.web.client.max-uri-tags=5")
+				.run((context) -> {
+					MeterRegistry registry = getInitializedMeterRegistry(context);
+					assertThat(registry.get("http.client.requests").meters()).hasSize(3);
+					assertThat(this.out.toString()).doesNotContain(
+							"Reached the maximum number of URI tags for 'http.client.requests'.");
+					assertThat(this.out.toString()).doesNotContain(
+							"Are you using 'uriVariables' on RestTemplate calls?");
+				});
+	}
+
+	private MeterRegistry getInitializedMeterRegistry(
+			AssertableApplicationContext context) {
+		MeterRegistry registry = context.getBean(MeterRegistry.class);
+		RestTemplate restTemplate = context.getBean(RestTemplateBuilder.class).build();
+		MockRestServiceServer server = MockRestServiceServer.createServer(restTemplate);
+		for (int i = 0; i < 3; i++) {
+			server.expect(requestTo("/test/" + i)).andRespond(withStatus(HttpStatus.OK));
+		}
+		for (int i = 0; i < 3; i++) {
+			restTemplate.getForObject("/test/" + i, String.class);
+		}
+		return registry;
 	}
 
 	private void validateRestTemplate(RestTemplate restTemplate, MeterRegistry registry) {

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

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2012-2018 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
+ *
+ *      http://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.metrics.web.reactive;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import org.junit.Rule;
+import org.junit.Test;
+
+import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.web.TestController;
+import org.springframework.boot.actuate.metrics.web.reactive.server.DefaultWebFluxTagsProvider;
+import org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter;
+import org.springframework.boot.actuate.metrics.web.reactive.server.WebFluxTagsProvider;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration;
+import org.springframework.boot.test.context.assertj.AssertableReactiveWebApplicationContext;
+import org.springframework.boot.test.context.runner.ReactiveWebApplicationContextRunner;
+import org.springframework.boot.test.rule.OutputCapture;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.web.reactive.server.WebTestClient;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link WebFluxMetricsAutoConfiguration}
+ *
+ * @author Brian Clozel
+ * @author Dmytro Nosan
+ */
+public class WebFluxMetricsAutoConfigurationTests {
+
+	private ReactiveWebApplicationContextRunner contextRunner = new ReactiveWebApplicationContextRunner()
+			.withConfiguration(AutoConfigurations.of(MetricsAutoConfiguration.class,
+					SimpleMetricsExportAutoConfiguration.class,
+					WebFluxMetricsAutoConfiguration.class));
+
+	@Rule
+	public OutputCapture output = new OutputCapture();
+
+	@Test
+	public void shouldProvideWebFluxMetricsBeans() {
+		this.contextRunner.run((context) -> {
+			assertThat(context).getBeans(MetricsWebFilter.class).hasSize(1);
+			assertThat(context).getBeans(DefaultWebFluxTagsProvider.class).hasSize(1);
+		});
+	}
+
+	@Test
+	public void shouldNotOverrideCustomTagsProvider() {
+		this.contextRunner.withUserConfiguration(CustomWebFluxTagsProviderConfig.class)
+				.run((context) -> assertThat(context).getBeans(WebFluxTagsProvider.class)
+						.hasSize(1).containsKey("customWebFluxTagsProvider"));
+	}
+
+	@Test
+	public void afterMaxUrisReachedFurtherUrisAreDenied() {
+		this.contextRunner
+				.withConfiguration(AutoConfigurations.of(WebFluxAutoConfiguration.class))
+				.withUserConfiguration(TestController.class)
+				.withPropertyValues("management.metrics.web.server.max-uri-tags=2")
+				.run((context) -> {
+					MeterRegistry registry = getInitializedMeterRegistry(context);
+					assertThat(registry.get("http.server.requests").meters()).hasSize(2);
+					assertThat(this.output.toString())
+							.contains("Reached the maximum number of URI tags "
+									+ "for 'http.server.requests'");
+				});
+	}
+
+	@Test
+	public void shouldNotDenyNorLogIfMaxUrisIsNotReached() {
+		this.contextRunner
+				.withConfiguration(AutoConfigurations.of(WebFluxAutoConfiguration.class))
+				.withUserConfiguration(TestController.class)
+				.withPropertyValues("management.metrics.web.server.max-uri-tags=5")
+				.run((context) -> {
+					MeterRegistry registry = getInitializedMeterRegistry(context);
+					assertThat(registry.get("http.server.requests").meters()).hasSize(3);
+					assertThat(this.output.toString()).doesNotContain(
+							"Reached the maximum number of URI tags for 'http.server.requests'");
+				});
+	}
+
+	private MeterRegistry getInitializedMeterRegistry(
+			AssertableReactiveWebApplicationContext context) {
+		WebTestClient webTestClient = WebTestClient.bindToApplicationContext(context)
+				.build();
+		for (int i = 0; i < 3; i++) {
+			webTestClient.get().uri("/test" + i).exchange().expectStatus().isOk();
+		}
+		return context.getBean(MeterRegistry.class);
+	}
+
+	@Configuration
+	protected static class CustomWebFluxTagsProviderConfig {
+
+		@Bean
+		public WebFluxTagsProvider customWebFluxTagsProvider() {
+			return mock(WebFluxTagsProvider.class);
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/web/servlet/WebMvcMetricsAutoConfigurationTests.java

@@ -14,37 +14,48 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.actuate.autoconfigure.web.servlet;
+package org.springframework.boot.actuate.autoconfigure.metrics.web.servlet;
 
 import java.util.Collections;
 import java.util.EnumSet;
 
 import javax.servlet.DispatcherType;
+import javax.servlet.Filter;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Tag;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import org.junit.Rule;
 import org.junit.Test;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.web.servlet.WebMvcMetricsAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.web.TestController;
 import org.springframework.boot.actuate.metrics.web.servlet.DefaultWebMvcTagsProvider;
 import org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter;
 import org.springframework.boot.actuate.metrics.web.servlet.WebMvcTagsProvider;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration;
+import org.springframework.boot.test.context.assertj.AssertableWebApplicationContext;
 import org.springframework.boot.test.context.runner.WebApplicationContextRunner;
+import org.springframework.boot.test.rule.OutputCapture;
 import org.springframework.boot.web.servlet.FilterRegistrationBean;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.Ordered;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 
 /**
  * Tests for {@link WebMvcMetricsAutoConfiguration}.
  *
  * @author Andy Wilkinson
+ * @author Dmytro Nosan
  */
 public class WebMvcMetricsAutoConfigurationTests {
 
@@ -52,6 +63,9 @@ public class WebMvcMetricsAutoConfigurationTests {
 			.withConfiguration(
 					AutoConfigurations.of(WebMvcMetricsAutoConfiguration.class));
 
+	@Rule
+	public OutputCapture output = new OutputCapture();
+
 	@Test
 	public void backsOffWhenMeterRegistryIsMissing() {
 		this.contextRunner.run((context) -> assertThat(context)
@@ -92,6 +106,54 @@ public class WebMvcMetricsAutoConfigurationTests {
 				});
 	}
 
+	@Test
+	public void afterMaxUrisReachedFurtherUrisAreDenied() {
+		this.contextRunner
+				.withUserConfiguration(TestController.class,
+						MeterRegistryConfiguration.class)
+				.withConfiguration(AutoConfigurations.of(MetricsAutoConfiguration.class,
+						WebMvcAutoConfiguration.class))
+				.withPropertyValues("management.metrics.web.server.max-uri-tags=2")
+				.run((context) -> {
+					MeterRegistry registry = getInitializedMeterRegistry(context);
+					assertThat(registry.get("http.server.requests").meters()).hasSize(2);
+					assertThat(this.output.toString())
+							.contains("Reached the maximum number of URI tags "
+									+ "for 'http.server.requests'");
+				});
+	}
+
+	@Test
+	public void shouldNotDenyNorLogIfMaxUrisIsNotReached() {
+		this.contextRunner
+				.withUserConfiguration(TestController.class,
+						MeterRegistryConfiguration.class)
+				.withConfiguration(AutoConfigurations.of(MetricsAutoConfiguration.class,
+						WebMvcAutoConfiguration.class))
+				.withPropertyValues("management.metrics.web.server.max-uri-tags=5")
+				.run((context) -> {
+					MeterRegistry registry = getInitializedMeterRegistry(context);
+					assertThat(registry.get("http.server.requests").meters()).hasSize(3);
+					assertThat(this.output.toString())
+							.doesNotContain("Reached the maximum number of URI tags "
+									+ "for 'http.server.requests'");
+				});
+	}
+
+	private MeterRegistry getInitializedMeterRegistry(
+			AssertableWebApplicationContext context) throws Exception {
+		assertThat(context).hasSingleBean(FilterRegistrationBean.class);
+		Filter filter = context.getBean(FilterRegistrationBean.class).getFilter();
+		assertThat(filter).isInstanceOf(WebMvcMetricsFilter.class);
+		MockMvc mockMvc = MockMvcBuilders.webAppContextSetup(context).addFilters(filter)
+				.build();
+		for (int i = 0; i < 3; i++) {
+			mockMvc.perform(MockMvcRequestBuilders.get("/test" + i))
+					.andExpect(status().isOk());
+		}
+		return context.getBean(MeterRegistry.class);
+	}
+
 	@Configuration
 	static class MeterRegistryConfiguration {
 

spring-boot-project/spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -1424,6 +1424,7 @@ content into your application. Rather, pick only the properties that you need.
 	management.metrics.web.client.max-uri-tags=100 # Maximum number of unique URI tag values allowed. After the max number of tag values is reached, metrics with additional tag values are denied by filter.
 	management.metrics.web.client.requests-metric-name=http.client.requests # Name of the metric for sent requests.
 	management.metrics.web.server.auto-time-requests=true # Whether requests handled by Spring MVC or WebFlux should be automatically timed.
+	management.metrics.web.server.max-uri-tags=100 # Maximum number of unique URI tag values allowed. After the max number of tag values is reached, metrics with additional tag values are denied by filter.
 	management.metrics.web.server.requests-metric-name=http.server.requests # Name of the metric for received requests.