Use Micrometer metrics instead of in memory one

spring-cloud-sleuth-core/pom.xml

@@ -24,6 +24,9 @@
 	<packaging>jar</packaging>
 	<name>Spring Cloud Sleuth Core</name>
 	<description>Spring Cloud Sleuth Core</description>
+	<properties>
+		<spring-security-oauth2.version>2.2.0.RELEASE</spring-security-oauth2.version>
+	</properties>
 
 	<parent>
 		<groupId>org.springframework.cloud</groupId>
@@ -131,7 +134,7 @@
 		<dependency>
 			<groupId>org.springframework.security.oauth</groupId>
 			<artifactId>spring-security-oauth2</artifactId>
-			<version>2.2.0.RELEASE</version>
+			<version>${spring-security-oauth2.version}</version>
 			<optional>true</optional>
 		</dependency>
 		<dependency>
@@ -286,20 +289,28 @@
 			<artifactId>brave-instrumentation-grpc</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>io.zipkin.reporter2</groupId>
+			<artifactId>zipkin-reporter-metrics-micrometer</artifactId>
+			<exclusions>
+				<exclusion>
+					<groupId>io.micrometer</groupId>
+					<artifactId>micrometer-core</artifactId>
+				</exclusion>
+			</exclusions>
+		</dependency>
 		<!-- Instrumentation of Lettuce -->
 		<dependency>
 			<groupId>io.lettuce</groupId>
 			<artifactId>lettuce-core</artifactId>
 			<optional>true</optional>
 		</dependency>
-
 		<!-- For Instrumentation of Quartz -->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-quartz</artifactId>
 			<optional>true</optional>
 		</dependency>
-
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-autoconfigure-processor</artifactId>

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/autoconfig/TraceAutoConfiguration.java

@@ -34,15 +34,20 @@
 import brave.propagation.Propagation;
 import brave.propagation.ThreadLocalCurrentTraceContext;
 import brave.sampler.Sampler;
+import io.micrometer.core.instrument.MeterRegistry;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import zipkin2.Span;
 import zipkin2.reporter.InMemoryReporterMetrics;
 import zipkin2.reporter.Reporter;
 import zipkin2.reporter.ReporterMetrics;
+import zipkin2.reporter.metrics.micrometer.MicrometerReporterMetrics;
 
 import org.springframework.beans.factory.annotation.Autowired;
+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.cloud.sleuth.DefaultSpanNamer;
@@ -198,12 +203,6 @@ CurrentTraceContext.Builder sleuthCurrentTraceContextBuilder() {
 		return ThreadLocalCurrentTraceContext.newBuilder();
 	}
 
-	@Bean
-	@ConditionalOnMissingBean
-	ReporterMetrics sleuthReporterMetrics() {
-		return new InMemoryReporterMetrics();
-	}
-
 	@Bean
 	@ConditionalOnMissingBean
 	Reporter<zipkin2.Span> noOpSpanReporter() {
@@ -283,4 +282,40 @@ public String toString() {
 
 	}
 
+	@Configuration
+	@ConditionalOnMissingClass("io.micrometer.core.instrument.MeterRegistry")
+	static class TraceMetricsNoOpConfiguration {
+
+		@Bean
+		@ConditionalOnMissingBean
+		ReporterMetrics sleuthReporterMetrics() {
+			return new InMemoryReporterMetrics();
+		}
+
+	}
+
+	@Configuration
+	@ConditionalOnClass(MeterRegistry.class)
+	static class TraceMetricsMicrometerConfiguration {
+
+		@Configuration
+		@ConditionalOnMissingBean(ReporterMetrics.class)
+		static class NoReporterMetricsConfiguration {
+
+			@Bean
+			@ConditionalOnBean(MeterRegistry.class)
+			ReporterMetrics sleuthMicrometerReporterMetrics(MeterRegistry meterRegistry) {
+				return MicrometerReporterMetrics.create(meterRegistry);
+			}
+
+			@Bean
+			@ConditionalOnMissingBean(MeterRegistry.class)
+			ReporterMetrics sleuthReporterMetrics() {
+				return new InMemoryReporterMetrics();
+			}
+
+		}
+
+	}
+
 }

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/autoconfig/TraceAutoConfigurationTests.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2013-2019 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.cloud.sleuth.autoconfig;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import org.assertj.core.api.BDDAssertions;
+import org.junit.Test;
+import zipkin2.reporter.InMemoryReporterMetrics;
+import zipkin2.reporter.ReporterMetrics;
+import zipkin2.reporter.metrics.micrometer.MicrometerReporterMetrics;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.FilteredClassLoader;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+public class TraceAutoConfigurationTests {
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withConfiguration(AutoConfigurations.of(TraceAutoConfiguration.class));
+
+	@Test
+	public void should_apply_micrometer_reporter_metrics_when_meter_registry_bean_present() {
+		this.contextRunner.withUserConfiguration(WithMeterRegistry.class)
+				.run((context) -> {
+					ReporterMetrics bean = context.getBean(ReporterMetrics.class);
+
+					BDDAssertions.then(bean)
+							.isInstanceOf(MicrometerReporterMetrics.class);
+				});
+	}
+
+	@Test
+	public void should_apply_in_memory_metrics_when_meter_registry_bean_missing() {
+		this.contextRunner.run((context) -> {
+			ReporterMetrics bean = context.getBean(ReporterMetrics.class);
+
+			BDDAssertions.then(bean).isInstanceOf(InMemoryReporterMetrics.class);
+		});
+	}
+
+	@Test
+	public void should_apply_in_memory_metrics_when_meter_registry_class_missing() {
+		this.contextRunner.withClassLoader(new FilteredClassLoader(MeterRegistry.class))
+				.run((context) -> {
+					ReporterMetrics bean = context.getBean(ReporterMetrics.class);
+
+					BDDAssertions.then(bean).isInstanceOf(InMemoryReporterMetrics.class);
+				});
+	}
+
+	@Configuration
+	static class WithMeterRegistry {
+
+		@Bean
+		MeterRegistry meterRegistry() {
+			return new SimpleMeterRegistry();
+		}
+
+	}
+
+}