Use Observation infrastructure for instrumenting WebClient

As of spring-projects/spring-framework#28341, `WebClient` is
instrumented directly for `Observation`.
This commit removes the custom `ExchangeFilterFunction` that previously
instrumented the client for metrics.

As a result, the relevant tag providers are now deprecated and adapted
as `ObservationConvention` for the time being.

Closes gh-32518

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

@@ -149,16 +149,6 @@ public class MetricsProperties {
 				 */
 				private String metricName = "http.client.requests";
 
-				/**
-				 * Auto-timed request settings.
-				 */
-				@NestedConfigurationProperty
-				private final AutoTimeProperties autotime = new AutoTimeProperties();
-
-				public AutoTimeProperties getAutotime() {
-					return this.autotime;
-				}
-
 				@DeprecatedConfigurationProperty(replacement = "management.observations.http.client.requests.name")
 				public String getMetricName() {
 					return this.metricName;

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

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2012-2022 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.metrics.web.client;
+
+import io.micrometer.common.KeyValues;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.observation.Observation;
+
+import org.springframework.boot.actuate.metrics.web.reactive.client.WebClientExchangeTagsProvider;
+import org.springframework.web.reactive.function.client.ClientObservationContext;
+import org.springframework.web.reactive.function.client.ClientObservationConvention;
+import org.springframework.web.reactive.function.client.ClientRequest;
+import org.springframework.web.reactive.function.client.WebClient;
+
+/**
+ * Adapter class that applies {@link WebClientExchangeTagsProvider} tags as a
+ * {@link ClientObservationConvention}.
+ *
+ * @author Brian Clozel
+ */
+@SuppressWarnings("deprecation")
+class ClientObservationConventionAdapter implements ClientObservationConvention {
+
+	private static final String URI_TEMPLATE_ATTRIBUTE = WebClient.class.getName() + ".uriTemplate";
+
+	private final String metricName;
+
+	private final WebClientExchangeTagsProvider tagsProvider;
+
+	ClientObservationConventionAdapter(String metricName, WebClientExchangeTagsProvider tagsProvider) {
+		this.metricName = metricName;
+		this.tagsProvider = tagsProvider;
+	}
+
+	@Override
+	public boolean supportsContext(Observation.Context context) {
+		return context instanceof ClientObservationContext;
+	}
+
+	@Override
+	public KeyValues getLowCardinalityKeyValues(ClientObservationContext context) {
+		KeyValues keyValues = KeyValues.empty();
+		mutateClientRequest(context);
+		Iterable<Tag> tags = this.tagsProvider.tags(context.getCarrier(), context.getResponse(),
+				context.getError().orElse(null));
+		for (Tag tag : tags) {
+			keyValues = keyValues.and(tag.getKey(), tag.getValue());
+		}
+		return keyValues;
+	}
+
+	/*
+	 * {@link WebClientExchangeTagsProvider} relies on a request attribute to get the URI
+	 * template, we need to adapt to that.
+	 */
+	private static void mutateClientRequest(ClientObservationContext context) {
+		ClientRequest clientRequest = ClientRequest.from(context.getCarrier())
+				.attribute(URI_TEMPLATE_ATTRIBUTE, context.getUriTemplate()).build();
+		context.setCarrier(clientRequest);
+	}
+
+	@Override
+	public KeyValues getHighCardinalityKeyValues(ClientObservationContext context) {
+		return KeyValues.empty();
+	}
+
+	@Override
+	public String getName() {
+		return this.metricName;
+	}
+
+}

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

@@ -18,6 +18,8 @@ package org.springframework.boot.actuate.autoconfigure.metrics.web.client;
 
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.config.MeterFilter;
+import io.micrometer.observation.Observation;
+import io.micrometer.observation.ObservationRegistry;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.CompositeMeterRegistryAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties;
@@ -30,33 +32,43 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 import org.springframework.core.annotation.Order;
 
 /**
- * {@link EnableAutoConfiguration Auto-configuration} for HTTP client-related metrics.
+ * {@link EnableAutoConfiguration Auto-configuration} for HTTP client-related
+ * observations.
  *
  * @author Jon Schneider
  * @author Phillip Webb
  * @author Stephane Nicoll
  * @author Raheela Aslam
- * @since 2.1.0
+ * @author Brian Clozel
+ * @since 3.0.0
  */
 @AutoConfiguration(after = { ObservationAutoConfiguration.class, CompositeMeterRegistryAutoConfiguration.class,
 		RestTemplateAutoConfiguration.class, WebClientAutoConfiguration.class })
-@ConditionalOnClass(MeterRegistry.class)
-@ConditionalOnBean(MeterRegistry.class)
-@Import({ RestTemplateObservationConfiguration.class, WebClientMetricsConfiguration.class })
-public class HttpClientMetricsAutoConfiguration {
+@ConditionalOnClass(Observation.class)
+@ConditionalOnBean(ObservationRegistry.class)
+@Import({ RestTemplateObservationConfiguration.class, WebClientObservationConfiguration.class })
+public class HttpClientObservationsAutoConfiguration {
+
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnClass(MeterRegistry.class)
+	@ConditionalOnBean(MeterRegistry.class)
+	class MeterFilterConfiguration {
+
+		@Bean
+		@Order(0)
+		MeterFilter metricsHttpClientUriTagFilter(MetricsProperties properties) {
+			String metricName = properties.getWeb().getClient().getRequest().getMetricName();
+			MeterFilter denyFilter = new OnlyOnceLoggingDenyMeterFilter(() -> String.format(
+					"Reached the maximum number of URI tags for '%s'. Are you using 'uriVariables'?", metricName));
+			return MeterFilter.maximumAllowableTags(metricName, "uri", properties.getWeb().getClient().getMaxUriTags(),
+					denyFilter);
+		}
 
-	@Bean
-	@Order(0)
-	public MeterFilter metricsHttpClientUriTagFilter(MetricsProperties properties) {
-		String metricName = properties.getWeb().getClient().getRequest().getMetricName();
-		MeterFilter denyFilter = new OnlyOnceLoggingDenyMeterFilter(() -> String
-				.format("Reached the maximum number of URI tags for '%s'. Are you using 'uriVariables'?", metricName));
-		return MeterFilter.maximumAllowableTags(metricName, "uri", properties.getWeb().getClient().getMaxUriTags(),
-				denyFilter);
 	}
 
 }

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

@@ -16,7 +16,6 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics.web.client;
 
-import io.micrometer.observation.Observation;
 import io.micrometer.observation.ObservationRegistry;
 
 import org.springframework.beans.factory.ObjectProvider;
@@ -39,8 +38,8 @@ import org.springframework.web.client.RestTemplate;
  * @author Brian Clozel
  */
 @Configuration(proxyBeanMethods = false)
-@ConditionalOnClass({ RestTemplate.class, Observation.class })
-@ConditionalOnBean({ RestTemplateBuilder.class, ObservationRegistry.class })
+@ConditionalOnClass(RestTemplate.class)
+@ConditionalOnBean(RestTemplateBuilder.class)
 @SuppressWarnings("deprecation")
 class RestTemplateObservationConfiguration {
 

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

@@ -16,41 +16,42 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics.web.client;
 
-import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.observation.ObservationRegistry;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties;
-import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties.Web.Client.ClientRequest;
-import org.springframework.boot.actuate.metrics.web.reactive.client.DefaultWebClientExchangeTagsProvider;
-import org.springframework.boot.actuate.metrics.web.reactive.client.MetricsWebClientCustomizer;
+import org.springframework.boot.actuate.autoconfigure.observation.ObservationProperties;
+import org.springframework.boot.actuate.metrics.web.reactive.client.ObservationWebClientCustomizer;
 import org.springframework.boot.actuate.metrics.web.reactive.client.WebClientExchangeTagsProvider;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.web.reactive.function.client.ClientObservationConvention;
+import org.springframework.web.reactive.function.client.DefaultClientObservationConvention;
 import org.springframework.web.reactive.function.client.WebClient;
 
 /**
  * Configure the instrumentation of {@link WebClient}.
  *
  * @author Brian Clozel
- * @author Stephane Nicoll
  */
 @Configuration(proxyBeanMethods = false)
 @ConditionalOnClass(WebClient.class)
-class WebClientMetricsConfiguration {
+@SuppressWarnings("deprecation")
+class WebClientObservationConfiguration {
 
 	@Bean
-	@ConditionalOnMissingBean
-	WebClientExchangeTagsProvider defaultWebClientExchangeTagsProvider() {
-		return new DefaultWebClientExchangeTagsProvider();
-	}
-
-	@Bean
-	MetricsWebClientCustomizer metricsWebClientCustomizer(MeterRegistry meterRegistry,
-			WebClientExchangeTagsProvider tagsProvider, MetricsProperties properties) {
-		ClientRequest request = properties.getWeb().getClient().getRequest();
-		return new MetricsWebClientCustomizer(meterRegistry, tagsProvider, request.getMetricName(),
-				request.getAutotime());
+	ObservationWebClientCustomizer metricsWebClientCustomizer(ObservationRegistry observationRegistry,
+			ObservationProperties observationProperties,
+			ObjectProvider<WebClientExchangeTagsProvider> optionalTagsProvider, MetricsProperties metricsProperties) {
+		String metricName = metricsProperties.getWeb().getClient().getRequest().getMetricName();
+		String observationName = observationProperties.getHttp().getClient().getRequests().getName();
+		String name = (observationName != null) ? observationName : metricName;
+		WebClientExchangeTagsProvider tagsProvider = optionalTagsProvider.getIfAvailable();
+		ClientObservationConvention observationConvention = (tagsProvider != null)
+				? new ClientObservationConventionAdapter(name, tagsProvider)
+				: new DefaultClientObservationConvention(name);
+		return new ObservationWebClientCustomizer(observationRegistry, observationConvention);
 	}
 
 }

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

@@ -1905,16 +1905,28 @@
     {
       "name": "management.metrics.web.client.request.autotime.enabled",
       "description": "Whether to automatically time web client requests.",
-      "defaultValue": true
+      "defaultValue": true,
+      "deprecation": {
+        "level": "error",
+        "reason": "Should be applied at the ObservationRegistry level."
+      }
     },
     {
       "name": "management.metrics.web.client.request.autotime.percentiles",
-      "description": "Computed non-aggregable percentiles to publish."
+      "description": "Computed non-aggregable percentiles to publish.",
+      "deprecation": {
+        "level": "error",
+        "reason": "Should be applied at the ObservationRegistry level."
+      }
     },
     {
       "name": "management.metrics.web.client.request.autotime.percentiles-histogram",
       "description": "Whether percentile histograms should be published.",
-      "defaultValue": false
+      "defaultValue": false,
+      "deprecation": {
+        "level": "error",
+        "reason": "Should be applied at the ObservationRegistry level."
+      }
     },
     {
       "name": "management.metrics.web.client.requests-metric-name",

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

@@ -77,7 +77,7 @@ org.springframework.boot.actuate.autoconfigure.metrics.r2dbc.ConnectionPoolMetri
 org.springframework.boot.actuate.autoconfigure.metrics.redis.LettuceMetricsAutoConfiguration
 org.springframework.boot.actuate.autoconfigure.metrics.startup.StartupTimeMetricsListenerAutoConfiguration
 org.springframework.boot.actuate.autoconfigure.metrics.task.TaskExecutorMetricsAutoConfiguration
-org.springframework.boot.actuate.autoconfigure.metrics.web.client.HttpClientMetricsAutoConfiguration
+org.springframework.boot.actuate.autoconfigure.metrics.web.client.HttpClientObservationsAutoConfiguration
 org.springframework.boot.actuate.autoconfigure.metrics.web.jetty.JettyMetricsAutoConfiguration
 org.springframework.boot.actuate.autoconfigure.metrics.web.reactive.WebFluxMetricsAutoConfiguration
 org.springframework.boot.actuate.autoconfigure.metrics.web.servlet.WebMvcMetricsAutoConfiguration

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

@@ -41,7 +41,7 @@ import org.springframework.boot.actuate.autoconfigure.metrics.amqp.RabbitMetrics
 import org.springframework.boot.actuate.autoconfigure.metrics.cache.CacheMetricsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.jdbc.DataSourcePoolMetricsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.orm.jpa.HibernateMetricsAutoConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.web.client.HttpClientMetricsAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.web.client.HttpClientObservationsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.web.reactive.WebFluxMetricsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.web.servlet.WebMvcMetricsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.observation.ObservationAutoConfiguration;
@@ -140,7 +140,7 @@ class MetricsIntegrationTests {
 			JvmMetricsAutoConfiguration.class, LogbackMetricsAutoConfiguration.class,
 			SystemMetricsAutoConfiguration.class, RabbitMetricsAutoConfiguration.class,
 			CacheMetricsAutoConfiguration.class, DataSourcePoolMetricsAutoConfiguration.class,
-			HibernateMetricsAutoConfiguration.class, HttpClientMetricsAutoConfiguration.class,
+			HibernateMetricsAutoConfiguration.class, HttpClientObservationsAutoConfiguration.class,
 			WebFluxMetricsAutoConfiguration.class, WebMvcMetricsAutoConfiguration.class, JacksonAutoConfiguration.class,
 			HttpMessageConvertersAutoConfiguration.class, RestTemplateAutoConfiguration.class,
 			WebMvcAutoConfiguration.class, DispatcherServletAutoConfiguration.class,

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

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2012-2022 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.metrics.web.client;
+
+import java.net.URI;
+
+import io.micrometer.common.KeyValue;
+import io.micrometer.observation.Observation;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.actuate.metrics.web.reactive.client.DefaultWebClientExchangeTagsProvider;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.reactive.function.client.ClientObservationContext;
+import org.springframework.web.reactive.function.client.ClientRequest;
+import org.springframework.web.reactive.function.client.ClientResponse;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link ClientObservationConventionAdapter}.
+ *
+ * @author Brian Clozel
+ */
+@SuppressWarnings("deprecation")
+class ClientObservationConventionAdapterTests {
+
+	private static final String TEST_METRIC_NAME = "test.metric.name";
+
+	private ClientObservationConventionAdapter convention = new ClientObservationConventionAdapter(TEST_METRIC_NAME,
+			new DefaultWebClientExchangeTagsProvider());
+
+	private ClientRequest request = ClientRequest.create(HttpMethod.GET, URI.create("/resource/test")).build();
+
+	private ClientResponse response = ClientResponse.create(HttpStatus.OK).body("foo").build();
+
+	private ClientObservationContext context;
+
+	@BeforeEach
+	void setup() {
+		this.context = new ClientObservationContext();
+		this.context.setCarrier(this.request);
+		this.context.setResponse(this.response);
+		this.context.setUriTemplate("/resource/{name}");
+	}
+
+	@Test
+	void shouldUseConfiguredName() {
+		assertThat(this.convention.getName()).isEqualTo(TEST_METRIC_NAME);
+	}
+
+	@Test
+	void shouldOnlySupportClientHttpObservationContext() {
+		assertThat(this.convention.supportsContext(this.context)).isTrue();
+		assertThat(this.convention.supportsContext(new OtherContext())).isFalse();
+	}
+
+	@Test
+	void shouldPushTagsAsLowCardinalityKeyValues() {
+		assertThat(this.convention.getLowCardinalityKeyValues(this.context)).contains(KeyValue.of("status", "200"),
+				KeyValue.of("outcome", "SUCCESS"), KeyValue.of("uri", "/resource/{name}"),
+				KeyValue.of("method", "GET"));
+	}
+
+	@Test
+	void shouldNotPushAnyHighCardinalityKeyValue() {
+		assertThat(this.convention.getHighCardinalityKeyValues(this.context)).isEmpty();
+	}
+
+	static class OtherContext extends Observation.Context {
+
+	}
+
+}

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

@@ -60,7 +60,7 @@ class RestTemplateObservationConfigurationTests {
 	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner().with(MetricsRun.simple())
 			.withBean(ObservationRegistry.class, TestObservationRegistry::create)
 			.withConfiguration(AutoConfigurations.of(ObservationAutoConfiguration.class,
-					RestTemplateAutoConfiguration.class, HttpClientMetricsAutoConfiguration.class));
+					RestTemplateAutoConfiguration.class, HttpClientObservationsAutoConfiguration.class));
 
 	@Test
 	void contributesCustomizerBean() {
@@ -139,7 +139,7 @@ class RestTemplateObservationConfigurationTests {
 	@Test
 	void backsOffWhenRestTemplateBuilderIsMissing() {
 		new ApplicationContextRunner().with(MetricsRun.simple())
-				.withConfiguration(AutoConfigurations.of(HttpClientMetricsAutoConfiguration.class))
+				.withConfiguration(AutoConfigurations.of(HttpClientObservationsAutoConfiguration.class))
 				.run((context) -> assertThat(context).doesNotHaveBean(DefaultRestTemplateExchangeTagsProvider.class)
 						.doesNotHaveBean(ObservationRestTemplateCustomizer.class));
 	}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -18,15 +18,17 @@ package org.springframework.boot.actuate.autoconfigure.metrics.web.client;
 
 import java.time.Duration;
 
-import io.micrometer.core.instrument.MeterRegistry;
-import io.micrometer.core.instrument.Timer;
-import io.micrometer.core.instrument.distribution.HistogramSnapshot;
+import io.micrometer.observation.ObservationRegistry;
+import io.micrometer.observation.tck.TestObservationRegistry;
+import io.micrometer.observation.tck.TestObservationRegistryAssert;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import reactor.core.publisher.Mono;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.test.MetricsRun;
 import org.springframework.boot.actuate.autoconfigure.observation.ObservationAutoConfiguration;
+import org.springframework.boot.actuate.metrics.web.reactive.client.DefaultWebClientExchangeTagsProvider;
+import org.springframework.boot.actuate.metrics.web.reactive.client.ObservationWebClientCustomizer;
 import org.springframework.boot.actuate.metrics.web.reactive.client.WebClientExchangeTagsProvider;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration;
@@ -47,22 +49,30 @@ import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
 
 /**
- * Tests for {@link WebClientMetricsConfiguration}
+ * Tests for {@link WebClientObservationConfiguration}
  *
  * @author Brian Clozel
  * @author Stephane Nicoll
  */
 @ExtendWith(OutputCaptureExtension.class)
-class WebClientMetricsConfigurationTests {
+@SuppressWarnings("deprecation")
+class WebClientObservationConfigurationTests {
 
 	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner().with(MetricsRun.simple())
+			.withBean(ObservationRegistry.class, TestObservationRegistry::create)
 			.withConfiguration(AutoConfigurations.of(ObservationAutoConfiguration.class,
-					WebClientAutoConfiguration.class, HttpClientMetricsAutoConfiguration.class));
+					WebClientAutoConfiguration.class, HttpClientObservationsAutoConfiguration.class));
+
+	@Test
+	void contributesCustomizerBean() {
+		this.contextRunner.run((context) -> assertThat(context).hasSingleBean(ObservationWebClientCustomizer.class)
+				.doesNotHaveBean(DefaultWebClientExchangeTagsProvider.class));
+	}
 
 	@Test
 	void webClientCreatedWithBuilderIsInstrumented() {
 		this.contextRunner.run((context) -> {
-			MeterRegistry registry = context.getBean(MeterRegistry.class);
+			TestObservationRegistry registry = context.getBean(TestObservationRegistry.class);
 			WebClient.Builder builder = context.getBean(WebClient.Builder.class);
 			validateWebClient(builder, registry);
 		});
@@ -77,8 +87,9 @@ class WebClientMetricsConfigurationTests {
 	@Test
 	void afterMaxUrisReachedFurtherUrisAreDenied(CapturedOutput output) {
 		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);
+			TestObservationRegistry registry = getInitializedRegistry(context);
+			// TODO check size is 2
+			TestObservationRegistryAssert.assertThat(registry).hasObservationWithNameEqualTo("http.client.requests");
 			assertThat(output).contains("Reached the maximum number of URI tags for 'http.client.requests'.")
 					.contains("Are you using 'uriVariables'?");
 		});
@@ -87,30 +98,17 @@ class WebClientMetricsConfigurationTests {
 	@Test
 	void shouldNotDenyNorLogIfMaxUrisIsNotReached(CapturedOutput output) {
 		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);
+			TestObservationRegistry registry = getInitializedRegistry(context);
+			// TODO check size is 3
+			TestObservationRegistryAssert.assertThat(registry).hasObservationWithNameEqualTo("http.client.requests");
 			assertThat(output).doesNotContain("Reached the maximum number of URI tags for 'http.client.requests'.")
 					.doesNotContain("Are you using 'uriVariables'?");
 		});
 	}
 
-	@Test
-	void autoTimeRequestsCanBeConfigured() {
-		this.contextRunner.withPropertyValues("management.metrics.web.client.request.autotime.enabled=true",
-				"management.metrics.web.client.request.autotime.percentiles=0.5,0.7",
-				"management.metrics.web.client.request.autotime.percentiles-histogram=true").run((context) -> {
-					MeterRegistry registry = getInitializedMeterRegistry(context);
-					Timer timer = registry.get("http.client.requests").timer();
-					HistogramSnapshot snapshot = timer.takeSnapshot();
-					assertThat(snapshot.percentileValues()).hasSize(2);
-					assertThat(snapshot.percentileValues()[0].percentile()).isEqualTo(0.5);
-					assertThat(snapshot.percentileValues()[1].percentile()).isEqualTo(0.7);
-				});
-	}
-
-	private MeterRegistry getInitializedMeterRegistry(AssertableApplicationContext context) {
+	private TestObservationRegistry getInitializedRegistry(AssertableApplicationContext context) {
 		WebClient webClient = mockWebClient(context.getBean(WebClient.Builder.class));
-		MeterRegistry registry = context.getBean(MeterRegistry.class);
+		TestObservationRegistry registry = context.getBean(TestObservationRegistry.class);
 		for (int i = 0; i < 3; i++) {
 			webClient.get().uri("https://example.org/projects/" + i).retrieve().toBodilessEntity()
 					.block(Duration.ofSeconds(30));
@@ -118,12 +116,13 @@ class WebClientMetricsConfigurationTests {
 		return registry;
 	}
 
-	private void validateWebClient(WebClient.Builder builder, MeterRegistry registry) {
+	private void validateWebClient(WebClient.Builder builder, TestObservationRegistry registry) {
 		WebClient webClient = mockWebClient(builder);
-		assertThat(registry.find("http.client.requests").meter()).isNull();
+		TestObservationRegistryAssert.assertThat(registry).doesNotHaveAnyObservation();
 		webClient.get().uri("https://example.org/projects/{project}", "spring-boot").retrieve().toBodilessEntity()
 				.block(Duration.ofSeconds(30));
-		assertThat(registry.find("http.client.requests").tags("uri", "/projects/{project}").meter()).isNotNull();
+		TestObservationRegistryAssert.assertThat(registry).hasObservationWithNameEqualTo("http.client.requests").that()
+				.hasLowCardinalityKeyValue("uri", "https://example.org/projects/{project}");
 	}
 
 	private WebClient mockWebClient(WebClient.Builder builder) {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinAutoConfigurationIntegrationTests.java

@@ -21,7 +21,7 @@ import zipkin2.reporter.urlconnection.URLConnectionSender;
 
 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.client.HttpClientMetricsAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.web.client.HttpClientObservationsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.observation.ObservationAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.tracing.BraveAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.tracing.MicrometerTracingAutoConfiguration;
@@ -64,7 +64,7 @@ class ZipkinAutoConfigurationIntegrationTests {
 		return runner
 				.withConfiguration(AutoConfigurations.of(MicrometerTracingAutoConfiguration.class,
 						ObservationAutoConfiguration.class, BraveAutoConfiguration.class, ZipkinAutoConfiguration.class,
-						HttpClientMetricsAutoConfiguration.class, MetricsAutoConfiguration.class,
+						HttpClientObservationsAutoConfiguration.class, MetricsAutoConfiguration.class,
 						SimpleMetricsExportAutoConfiguration.class))
 				.withClassLoader(new FilteredClassLoader(URLConnectionSender.class));
 	}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -29,7 +29,10 @@ import org.springframework.web.reactive.function.client.ClientResponse;
  * @author Brian Clozel
  * @author Nishant Raut
  * @since 2.1.0
+ * @deprecated since 3.0.0 for removal in 3.2.0 in favor of
+ * {@link org.springframework.web.reactive.function.client.DefaultClientObservationConvention}
  */
+@Deprecated
 public class DefaultWebClientExchangeTagsProvider implements WebClientExchangeTagsProvider {
 
 	@Override

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

@@ -1,60 +0,0 @@
-/*
- * Copyright 2012-2020 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.metrics.web.reactive.client;
-
-import io.micrometer.core.instrument.MeterRegistry;
-
-import org.springframework.boot.actuate.metrics.AutoTimer;
-import org.springframework.boot.web.reactive.function.client.WebClientCustomizer;
-import org.springframework.web.reactive.function.client.WebClient;
-
-/**
- * {@link WebClientCustomizer} that configures the {@link WebClient} to record request
- * metrics.
- *
- * @author Brian Clozel
- * @since 2.1.0
- */
-public class MetricsWebClientCustomizer implements WebClientCustomizer {
-
-	private final MetricsWebClientFilterFunction filterFunction;
-
-	/**
-	 * Create a new {@code MetricsWebClientFilterFunction} that will record metrics using
-	 * the given {@code meterRegistry} with tags provided by the given
-	 * {@code tagProvider}.
-	 * @param meterRegistry the meter registry
-	 * @param tagProvider the tag provider
-	 * @param metricName the name of the recorded metric
-	 * @param autoTimer the auto-timers to apply or {@code null} to disable auto-timing
-	 * @since 2.2.0
-	 */
-	public MetricsWebClientCustomizer(MeterRegistry meterRegistry, WebClientExchangeTagsProvider tagProvider,
-			String metricName, AutoTimer autoTimer) {
-		this.filterFunction = new MetricsWebClientFilterFunction(meterRegistry, tagProvider, metricName, autoTimer);
-	}
-
-	@Override
-	public void customize(WebClient.Builder webClientBuilder) {
-		webClientBuilder.filters((filterFunctions) -> {
-			if (!filterFunctions.contains(this.filterFunction)) {
-				filterFunctions.add(0, this.filterFunction);
-			}
-		});
-	}
-
-}

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

@@ -1,120 +0,0 @@
-/*
- * Copyright 2012-2022 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.metrics.web.reactive.client;
-
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicBoolean;
-
-import io.micrometer.core.instrument.MeterRegistry;
-import io.micrometer.core.instrument.Tag;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import reactor.core.publisher.Mono;
-import reactor.core.publisher.SignalType;
-import reactor.util.context.Context;
-import reactor.util.context.ContextView;
-
-import org.springframework.boot.actuate.metrics.AutoTimer;
-import org.springframework.web.reactive.function.client.ClientRequest;
-import org.springframework.web.reactive.function.client.ClientResponse;
-import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
-import org.springframework.web.reactive.function.client.ExchangeFunction;
-
-/**
- * {@link ExchangeFilterFunction} applied via a {@link MetricsWebClientCustomizer} to
- * record metrics.
- *
- * @author Brian Clozel
- * @author Tadaya Tsuyukubo
- * @author Scott Frederick
- * @since 2.1.0
- */
-public class MetricsWebClientFilterFunction implements ExchangeFilterFunction {
-
-	private static final String METRICS_WEBCLIENT_START_TIME = MetricsWebClientFilterFunction.class.getName()
-			+ ".START_TIME";
-
-	private static final Log logger = LogFactory.getLog(MetricsWebClientFilterFunction.class);
-
-	private final MeterRegistry meterRegistry;
-
-	private final WebClientExchangeTagsProvider tagProvider;
-
-	private final String metricName;
-
-	private final AutoTimer autoTimer;
-
-	/**
-	 * Create a new {@code MetricsWebClientFilterFunction}.
-	 * @param meterRegistry the registry to which metrics are recorded
-	 * @param tagProvider provider for metrics tags
-	 * @param metricName name of the metric to record
-	 * @param autoTimer the auto-timer configuration or {@code null} to disable
-	 * @since 2.2.0
-	 */
-	public MetricsWebClientFilterFunction(MeterRegistry meterRegistry, WebClientExchangeTagsProvider tagProvider,
-			String metricName, AutoTimer autoTimer) {
-		this.meterRegistry = meterRegistry;
-		this.tagProvider = tagProvider;
-		this.metricName = metricName;
-		this.autoTimer = (autoTimer != null) ? autoTimer : AutoTimer.DISABLED;
-	}
-
-	@Override
-	public Mono<ClientResponse> filter(ClientRequest request, ExchangeFunction next) {
-		if (!this.autoTimer.isEnabled()) {
-			return next.exchange(request);
-		}
-		return next.exchange(request).as((responseMono) -> instrumentResponse(request, responseMono))
-				.contextWrite(this::putStartTime);
-	}
-
-	private Mono<ClientResponse> instrumentResponse(ClientRequest request, Mono<ClientResponse> responseMono) {
-		final AtomicBoolean responseReceived = new AtomicBoolean();
-		return Mono.deferContextual((ctx) -> responseMono.doOnEach((signal) -> {
-			if (signal.isOnNext() || signal.isOnError()) {
-				responseReceived.set(true);
-				recordTimer(request, signal.get(), signal.getThrowable(), getStartTime(ctx));
-			}
-		}).doFinally((signalType) -> {
-			if (!responseReceived.get() && SignalType.CANCEL.equals(signalType)) {
-				recordTimer(request, null, null, getStartTime(ctx));
-			}
-		}));
-	}
-
-	private void recordTimer(ClientRequest request, ClientResponse response, Throwable error, Long startTime) {
-		try {
-			Iterable<Tag> tags = this.tagProvider.tags(request, response, error);
-			this.autoTimer.builder(this.metricName).tags(tags).description("Timer of WebClient operation")
-					.register(this.meterRegistry).record(System.nanoTime() - startTime, TimeUnit.NANOSECONDS);
-		}
-		catch (Exception ex) {
-			logger.warn("Failed to record timer metrics", ex);
-			// Allow request-response exchange to continue, unaffected by metrics problem
-		}
-	}
-
-	private Long getStartTime(ContextView context) {
-		return context.get(METRICS_WEBCLIENT_START_TIME);
-	}
-
-	private Context putStartTime(Context context) {
-		return context.put(METRICS_WEBCLIENT_START_TIME, System.nanoTime());
-	}
-
-}

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

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2012-2022 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.metrics.web.reactive.client;
+
+import io.micrometer.observation.ObservationRegistry;
+
+import org.springframework.boot.web.reactive.function.client.WebClientCustomizer;
+import org.springframework.web.reactive.function.client.ClientObservationConvention;
+import org.springframework.web.reactive.function.client.WebClient;
+
+/**
+ * {@link WebClientCustomizer} that configures the {@link WebClient} to record request
+ * observations.
+ *
+ * @author Brian Clozel
+ * @since 3.0.0
+ */
+public class ObservationWebClientCustomizer implements WebClientCustomizer {
+
+	private final ObservationRegistry observationRegistry;
+
+	private final ClientObservationConvention observationConvention;
+
+	/**
+	 * Create a new {@code ObservationWebClientCustomizer} that will configure the
+	 * {@code Observation} setup on the client.
+	 * @param observationRegistry the registry to publish observations to
+	 * @param observationConvention the convention to use to populate observations
+	 */
+	public ObservationWebClientCustomizer(ObservationRegistry observationRegistry,
+			ClientObservationConvention observationConvention) {
+		this.observationRegistry = observationRegistry;
+		this.observationConvention = observationConvention;
+	}
+
+	@Override
+	public void customize(WebClient.Builder webClientBuilder) {
+		webClientBuilder.observationRegistry(this.observationRegistry)
+				.observationConvention(this.observationConvention);
+	}
+
+}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -27,8 +27,11 @@ import org.springframework.web.reactive.function.client.ClientResponse;
  *
  * @author Brian Clozel
  * @since 2.1.0
+ * @deprecated since 3.0.0 for removal in 3.2.0 in favor of
+ * {@link org.springframework.web.reactive.function.client.ClientObservationConvention}
  */
 @FunctionalInterface
+@Deprecated
 public interface WebClientExchangeTagsProvider {
 
 	/**

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

@@ -39,6 +39,7 @@ import static org.mockito.Mockito.mock;
  * @author Brian Clozel
  * @author Nishant Raut
  */
+@SuppressWarnings("deprecation")
 class DefaultWebClientExchangeTagsProviderTests {
 
 	private static final String URI_TEMPLATE_ATTRIBUTE = WebClient.class.getName() + ".uriTemplate";

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

@@ -1,64 +0,0 @@
-/*
- * Copyright 2012-2021 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.metrics.web.reactive.client;
-
-import io.micrometer.core.instrument.MeterRegistry;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-
-import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
-import org.springframework.web.reactive.function.client.WebClient;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.mockito.Mockito.mock;
-
-/**
- * Tests for {@link MetricsWebClientCustomizer}
- *
- * @author Brian Clozel
- */
-class MetricsWebClientCustomizerTests {
-
-	private MetricsWebClientCustomizer customizer;
-
-	private WebClient.Builder clientBuilder;
-
-	@BeforeEach
-	void setup() {
-		this.customizer = new MetricsWebClientCustomizer(mock(MeterRegistry.class),
-				mock(WebClientExchangeTagsProvider.class), "test", null);
-		this.clientBuilder = WebClient.builder();
-	}
-
-	@Test
-	void customizeShouldAddFilterFunction() {
-		this.clientBuilder.filter(mock(ExchangeFilterFunction.class));
-		this.customizer.customize(this.clientBuilder);
-		this.clientBuilder.filters(
-				(filters) -> assertThat(filters).hasSize(2).first().isInstanceOf(MetricsWebClientFilterFunction.class));
-	}
-
-	@Test
-	void customizeShouldNotAddDuplicateFilterFunction() {
-		this.customizer.customize(this.clientBuilder);
-		this.clientBuilder.filters((filters) -> assertThat(filters).hasSize(1));
-		this.customizer.customize(this.clientBuilder);
-		this.clientBuilder.filters(
-				(filters) -> assertThat(filters).singleElement().isInstanceOf(MetricsWebClientFilterFunction.class));
-	}
-
-}

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

@@ -1,194 +0,0 @@
-/*
- * Copyright 2012-2022 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.metrics.web.reactive.client;
-
-import java.io.IOException;
-import java.net.URI;
-import java.time.Duration;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicBoolean;
-
-import io.micrometer.core.instrument.MeterRegistry;
-import io.micrometer.core.instrument.MockClock;
-import io.micrometer.core.instrument.Tag;
-import io.micrometer.core.instrument.Timer;
-import io.micrometer.core.instrument.search.MeterNotFoundException;
-import io.micrometer.core.instrument.simple.SimpleConfig;
-import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-import reactor.core.publisher.Mono;
-import reactor.test.StepVerifier;
-
-import org.springframework.boot.actuate.metrics.AutoTimer;
-import org.springframework.http.HttpMethod;
-import org.springframework.http.HttpStatus;
-import org.springframework.web.reactive.function.client.ClientRequest;
-import org.springframework.web.reactive.function.client.ClientResponse;
-import org.springframework.web.reactive.function.client.ExchangeFunction;
-import org.springframework.web.reactive.function.client.WebClient;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.mockito.BDDMockito.given;
-import static org.mockito.Mockito.mock;
-
-/**
- * Tests for {@link MetricsWebClientFilterFunction}
- *
- * @author Brian Clozel
- * @author Scott Frederick
- */
-class MetricsWebClientFilterFunctionTests {
-
-	private static final String URI_TEMPLATE_ATTRIBUTE = WebClient.class.getName() + ".uriTemplate";
-
-	private MeterRegistry registry;
-
-	private MetricsWebClientFilterFunction filterFunction;
-
-	private final FaultyTagsProvider tagsProvider = new FaultyTagsProvider();
-
-	private ClientResponse response;
-
-	private ExchangeFunction exchange;
-
-	@BeforeEach
-	void setup() {
-		this.registry = new SimpleMeterRegistry(SimpleConfig.DEFAULT, new MockClock());
-		this.filterFunction = new MetricsWebClientFilterFunction(this.registry, this.tagsProvider,
-				"http.client.requests", AutoTimer.ENABLED);
-		this.response = mock(ClientResponse.class);
-		this.exchange = (r) -> Mono.just(this.response);
-	}
-
-	@Test
-	void filterShouldRecordTimer() {
-		ClientRequest request = ClientRequest
-				.create(HttpMethod.GET, URI.create("https://example.com/projects/spring-boot")).build();
-		given(this.response.statusCode()).willReturn(HttpStatus.OK);
-		this.filterFunction.filter(request, this.exchange).block(Duration.ofSeconds(5));
-		assertThat(this.registry.get("http.client.requests")
-				.tags("method", "GET", "uri", "/projects/spring-boot", "status", "200").timer().count()).isEqualTo(1);
-	}
-
-	@Test
-	void filterWhenUriTemplatePresentShouldRecordTimer() {
-		ClientRequest request = ClientRequest
-				.create(HttpMethod.GET, URI.create("https://example.com/projects/spring-boot"))
-				.attribute(URI_TEMPLATE_ATTRIBUTE, "/projects/{project}").build();
-		given(this.response.statusCode()).willReturn(HttpStatus.OK);
-		this.filterFunction.filter(request, this.exchange).block(Duration.ofSeconds(5));
-		assertThat(this.registry.get("http.client.requests")
-				.tags("method", "GET", "uri", "/projects/{project}", "status", "200").timer().count()).isEqualTo(1);
-	}
-
-	@Test
-	void filterWhenIoExceptionThrownShouldRecordTimer() {
-		ClientRequest request = ClientRequest
-				.create(HttpMethod.GET, URI.create("https://example.com/projects/spring-boot")).build();
-		ExchangeFunction errorExchange = (r) -> Mono.error(new IOException());
-		this.filterFunction.filter(request, errorExchange).onErrorResume(IOException.class, (t) -> Mono.empty())
-				.block(Duration.ofSeconds(5));
-		assertThat(this.registry.get("http.client.requests")
-				.tags("method", "GET", "uri", "/projects/spring-boot", "status", "IO_ERROR").timer().count())
-						.isEqualTo(1);
-	}
-
-	@Test
-	void filterWhenExceptionThrownShouldRecordTimer() {
-		ClientRequest request = ClientRequest
-				.create(HttpMethod.GET, URI.create("https://example.com/projects/spring-boot")).build();
-		ExchangeFunction exchange = (r) -> Mono.error(new IllegalArgumentException());
-		this.filterFunction.filter(request, exchange).onErrorResume(IllegalArgumentException.class, (t) -> Mono.empty())
-				.block(Duration.ofSeconds(5));
-		assertThat(this.registry.get("http.client.requests")
-				.tags("method", "GET", "uri", "/projects/spring-boot", "status", "CLIENT_ERROR").timer().count())
-						.isEqualTo(1);
-	}
-
-	@Test
-	void filterWhenCancelThrownShouldRecordTimer() {
-		ClientRequest request = ClientRequest
-				.create(HttpMethod.GET, URI.create("https://example.com/projects/spring-boot")).build();
-		given(this.response.statusCode()).willReturn(HttpStatus.OK);
-		Mono<ClientResponse> filter = this.filterFunction.filter(request, this.exchange);
-		StepVerifier.create(filter).thenCancel().verify(Duration.ofSeconds(5));
-		assertThat(this.registry.get("http.client.requests")
-				.tags("method", "GET", "uri", "/projects/spring-boot", "status", "CLIENT_ERROR").timer().count())
-						.isEqualTo(1);
-		assertThatThrownBy(() -> this.registry.get("http.client.requests")
-				.tags("method", "GET", "uri", "/projects/spring-boot", "status", "200").timer())
-						.isInstanceOf(MeterNotFoundException.class);
-	}
-
-	@Test
-	void filterWhenCancelAfterResponseThrownShouldNotRecordTimer() {
-		ClientRequest request = ClientRequest
-				.create(HttpMethod.GET, URI.create("https://example.com/projects/spring-boot")).build();
-		given(this.response.statusCode()).willReturn(HttpStatus.OK);
-		Mono<ClientResponse> filter = this.filterFunction.filter(request, this.exchange);
-		StepVerifier.create(filter).expectNextCount(1).thenCancel().verify(Duration.ofSeconds(5));
-		assertThat(this.registry.get("http.client.requests")
-				.tags("method", "GET", "uri", "/projects/spring-boot", "status", "200").timer().count()).isEqualTo(1);
-		assertThatThrownBy(() -> this.registry.get("http.client.requests")
-				.tags("method", "GET", "uri", "/projects/spring-boot", "status", "CLIENT_ERROR").timer())
-						.isInstanceOf(MeterNotFoundException.class);
-	}
-
-	@Test
-	void filterWhenExceptionAndRetryShouldNotAccumulateRecordTime() {
-		ClientRequest request = ClientRequest
-				.create(HttpMethod.GET, URI.create("https://example.com/projects/spring-boot")).build();
-		ExchangeFunction exchange = (r) -> Mono.error(new IllegalArgumentException())
-				.delaySubscription(Duration.ofMillis(1000)).cast(ClientResponse.class);
-		this.filterFunction.filter(request, exchange).retry(1)
-				.onErrorResume(IllegalArgumentException.class, (t) -> Mono.empty()).block(Duration.ofSeconds(5));
-		Timer timer = this.registry.get("http.client.requests")
-				.tags("method", "GET", "uri", "/projects/spring-boot", "status", "CLIENT_ERROR").timer();
-		assertThat(timer.count()).isEqualTo(2);
-		assertThat(timer.max(TimeUnit.MILLISECONDS)).isLessThan(2000);
-	}
-
-	@Test
-	void whenMetricsRecordingFailsThenFilteringSucceeds() {
-		ClientRequest request = ClientRequest
-				.create(HttpMethod.GET, URI.create("https://example.com/projects/spring-boot")).build();
-		given(this.response.statusCode()).willReturn(HttpStatus.OK);
-		this.tagsProvider.failOnce();
-		this.filterFunction.filter(request, this.exchange).block(Duration.ofSeconds(5));
-	}
-
-	static class FaultyTagsProvider extends DefaultWebClientExchangeTagsProvider {
-
-		private final AtomicBoolean fail = new AtomicBoolean(false);
-
-		@Override
-		public Iterable<Tag> tags(ClientRequest request, ClientResponse response, Throwable throwable) {
-			if (this.fail.compareAndSet(true, false)) {
-				throw new RuntimeException();
-			}
-			return super.tags(request, response, throwable);
-		}
-
-		void failOnce() {
-			this.fail.set(true);
-		}
-
-	}
-
-}

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

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2012-2022 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.metrics.web.reactive.client;
+
+import io.micrometer.observation.ObservationConvention;
+import io.micrometer.observation.ObservationRegistry;
+import io.micrometer.observation.tck.TestObservationRegistry;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.test.util.ReflectionTestUtils;
+import org.springframework.web.reactive.function.client.ClientObservationConvention;
+import org.springframework.web.reactive.function.client.DefaultClientObservationConvention;
+import org.springframework.web.reactive.function.client.WebClient;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link ObservationWebClientCustomizer}
+ *
+ * @author Brian Clozel
+ */
+@SuppressWarnings("deprecation")
+class ObservationWebClientCustomizerTests {
+
+	private static final String TEST_METRIC_NAME = "http.test.metric.name";
+
+	private TestObservationRegistry observationRegistry = TestObservationRegistry.create();
+
+	private ClientObservationConvention observationConvention = new DefaultClientObservationConvention(
+			TEST_METRIC_NAME);
+
+	private ObservationWebClientCustomizer customizer = new ObservationWebClientCustomizer(this.observationRegistry,
+			this.observationConvention);
+
+	private WebClient.Builder clientBuilder = WebClient.builder();
+
+	@Test
+	void shouldCustomizeObservationConfiguration() {
+		this.customizer.customize(this.clientBuilder);
+		assertThat((ObservationRegistry) ReflectionTestUtils.getField(this.clientBuilder, "observationRegistry"))
+				.isEqualTo(this.observationRegistry);
+		assertThat((ObservationConvention<?>) ReflectionTestUtils.getField(this.clientBuilder, "observationConvention"))
+				.isInstanceOf(DefaultClientObservationConvention.class).extracting("name").isEqualTo(TEST_METRIC_NAME);
+	}
+
+}