Add auto-configuration of Jetty Metrics

This is performed by the new JettyMetricsAutoConfiguration, that is
based on the existing TomcatMetricsAutoConfiguration.

Fixes spring-projectsgh-12090

spring-boot-project/spring-boot-actuator-autoconfigure/pom.xml

@@ -188,6 +188,16 @@
 			<artifactId>commons-dbcp2</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.eclipse.jetty</groupId>
+			<artifactId>jetty-server</artifactId>
+			<optional>true</optional>
+		</dependency>
+		<dependency>
+			<groupId>org.eclipse.jetty</groupId>
+			<artifactId>jetty-webapp</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>org.apache.tomcat.embed</groupId>
 			<artifactId>tomcat-embed-core</artifactId>

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

@@ -0,0 +1,85 @@
+/*
+ * 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.jetty;
+
+
+import java.util.Collections;
+
+import io.micrometer.core.instrument.binder.jetty.JettyStatisticsMetrics;
+import org.eclipse.jetty.server.Connector;
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.handler.StatisticsHandler;
+
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
+import org.springframework.boot.web.embedded.jetty.ConfigurableJettyWebServerFactory;
+import org.springframework.boot.web.embedded.jetty.JettyReactiveWebServerFactory;
+import org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory;
+import org.springframework.boot.web.server.WebServerFactoryCustomizer;
+import org.springframework.context.annotation.Bean;
+
+/**
+ * {@link EnableAutoConfiguration Auto-configuration} for {@link JettyStatisticsMetrics}.
+ *
+ * @author Even Holthe
+ * @since 2.1.0
+ */
+@ConditionalOnWebApplication
+@ConditionalOnClass({ JettyStatisticsMetrics.class, Server.class })
+public class JettyMetricsAutoConfiguration {
+	private volatile StatisticsHandler statsHandler;
+
+	@Bean
+	@ConditionalOnMissingBean(JettyStatisticsMetrics.class)
+	public JettyStatisticsMetrics jettyMetrics() {
+		return new JettyStatisticsMetrics(this.statsHandler, Collections.emptyList());
+	}
+
+	@Bean
+	@ConditionalOnWebApplication(type = Type.SERVLET)
+	public WebServerFactoryCustomizer<JettyServletWebServerFactory> serverCapturingServletJettyCustomizer() {
+		return this::statisticsCustomizer;
+	}
+
+	@Bean
+	@ConditionalOnWebApplication(type = Type.REACTIVE)
+	public WebServerFactoryCustomizer<JettyReactiveWebServerFactory> serverCapturingReactiveJettyCustomizer() {
+		return this::statisticsCustomizer;
+	}
+
+	/**
+	 * Add a statistics handler to all Jetty's {@link Connector}s.
+	 *
+	 * @param server An already configured Jetty {@link Server}.
+	 */
+	private void configureStatistics(Server server) {
+		final StatisticsHandler statsHandler = new StatisticsHandler();
+
+		for (Connector connector : server.getConnectors()) {
+			connector.addBean(statsHandler);
+		}
+
+		this.statsHandler = statsHandler;
+	}
+
+	private void statisticsCustomizer(ConfigurableJettyWebServerFactory jettyFactory) {
+		jettyFactory.addServerCustomizers(this::configureStatistics);
+	}
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/web/jetty/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * 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.
+ */
+
+/**
+ * Auto-configuration for Jetty actuator metrics.
+ */
+package org.springframework.boot.actuate.autoconfigure.metrics.web.jetty;

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/resources/META-INF/spring.factories

@@ -55,6 +55,7 @@ org.springframework.boot.actuate.autoconfigure.metrics.web.client.RestTemplateMe
 org.springframework.boot.actuate.autoconfigure.metrics.web.reactive.WebFluxMetricsAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.metrics.web.servlet.WebMvcMetricsAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.metrics.web.tomcat.TomcatMetricsAutoConfiguration,\
+  org.springframework.boot.actuate.autoconfigure.metrics.web.jetty.JettyMetricsAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.mongo.MongoHealthIndicatorAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.neo4j.Neo4jHealthIndicatorAutoConfiguration,\
 org.springframework.boot.actuate.autoconfigure.redis.RedisHealthIndicatorAutoConfiguration,\

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

@@ -0,0 +1,176 @@
+/*
+ * 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.jetty;
+
+import java.util.Collections;
+
+import io.micrometer.core.instrument.binder.MeterBinder;
+import io.micrometer.core.instrument.binder.jetty.JettyStatisticsMetrics;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import org.junit.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryAutoConfiguration;
+import org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration;
+import org.springframework.boot.test.context.runner.ReactiveWebApplicationContextRunner;
+import org.springframework.boot.test.context.runner.WebApplicationContextRunner;
+import org.springframework.boot.web.embedded.jetty.JettyReactiveWebServerFactory;
+import org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory;
+import org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext;
+import org.springframework.boot.web.servlet.ServletContextInitializer;
+import org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.server.reactive.HttpHandler;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link JettyMetricsAutoConfiguration}.
+ *
+ * @author Even Holthe
+ */
+public class JettyMetricsAutoConfigurationTests {
+	@Test
+	public void autoConfiguresJettyStatisticsMetricsWithEmbeddedServletJetty() {
+		new WebApplicationContextRunner(
+				AnnotationConfigServletWebServerApplicationContext::new)
+					.withConfiguration(
+							AutoConfigurations.of(
+								JettyMetricsAutoConfiguration.class,
+								ServletWebServerFactoryAutoConfiguration.class))
+					.withUserConfiguration(JettyMetricsAutoConfigurationTests.ServletWebServerConfiguration.class)
+					.run((context) -> {
+						assertThat(context)
+								.hasSingleBean(JettyStatisticsMetrics.class);
+						SimpleMeterRegistry registry = new SimpleMeterRegistry();
+						context.getBean(JettyStatisticsMetrics.class)
+								.bindTo(registry);
+
+						assertThat(registry.find("jetty.requests").meter())
+								.isNotNull();
+						assertThat(registry.find("jetty.requests.active").gauge())
+								.isNotNull();
+					});
+	}
+
+	@Test
+	public void sessionMetricsAreAvailableWhenEarlyMeterBinderInitializationOccurs() {
+		new WebApplicationContextRunner(
+				AnnotationConfigServletWebServerApplicationContext::new)
+				.withConfiguration(AutoConfigurations.of(
+						JettyMetricsAutoConfiguration.class,
+						ServletWebServerFactoryAutoConfiguration.class))
+				.withUserConfiguration(JettyMetricsAutoConfigurationTests.ServletWebServerConfiguration.class,
+						JettyMetricsAutoConfigurationTests.EarlyMeterBinderInitializationConfiguration.class)
+				.run((context) -> {
+					assertThat(context).hasSingleBean(JettyStatisticsMetrics.class);
+					SimpleMeterRegistry registry = new SimpleMeterRegistry();
+					context.getBean(JettyStatisticsMetrics.class).bindTo(registry);
+
+					assertThat(registry.find("jetty.requests").meter())
+							.isNotNull();
+					assertThat(registry.find("jetty.requests.active").gauge())
+							.isNotNull();
+				});
+	}
+
+	@Test
+	public void autoConfiguresJettyStatisticsMetricsWithEmbeddedReactiveJetty() {
+		new ReactiveWebApplicationContextRunner(
+				AnnotationConfigReactiveWebServerApplicationContext::new)
+					.withConfiguration(AutoConfigurations.of(
+							JettyMetricsAutoConfiguration.class,
+							ReactiveWebServerFactoryAutoConfiguration.class))
+					.withUserConfiguration(JettyMetricsAutoConfigurationTests.ReactiveWebServerConfiguration.class)
+					.run((context) -> {
+						assertThat(context).hasSingleBean(JettyStatisticsMetrics.class);
+						SimpleMeterRegistry registry = new SimpleMeterRegistry();
+						context.getBean(JettyStatisticsMetrics.class).bindTo(registry);
+
+						assertThat(registry.find("jetty.requests").meter())
+								.isNotNull();
+						assertThat(registry.find("jetty.requests.active").gauge())
+								.isNotNull();
+					});
+	}
+
+	@Test
+	public void autoConfiguresJettyStatisticsMetricsWithStandaloneJetty() {
+		new WebApplicationContextRunner()
+				.withConfiguration(
+						AutoConfigurations.of(JettyMetricsAutoConfiguration.class))
+				.run((context) -> assertThat(context).hasSingleBean(JettyMetricsAutoConfiguration.class));
+	}
+
+	@Test
+	public void allowsCustomJettyStatisticsMetricsToBeUsed() {
+		new WebApplicationContextRunner()
+				.withConfiguration(
+						AutoConfigurations.of(JettyMetricsAutoConfiguration.class))
+				.withUserConfiguration(JettyMetricsAutoConfigurationTests.CustomJettyMetrics.class)
+				.run((context) -> assertThat(context).hasSingleBean(JettyStatisticsMetrics.class)
+						.hasBean("customJettyMetrics"));
+	}
+
+	@Configuration
+	static class ServletWebServerConfiguration {
+
+		@Bean
+		public JettyServletWebServerFactory jettyFactory() {
+			return new JettyServletWebServerFactory(0);
+		}
+
+	}
+
+	@Configuration
+	static class ReactiveWebServerConfiguration {
+
+		@Bean
+		public JettyReactiveWebServerFactory tomcatFactory() {
+			return new JettyReactiveWebServerFactory(0);
+		}
+
+		@Bean
+		public HttpHandler httpHandler() {
+			return mock(HttpHandler.class);
+		}
+
+	}
+
+	@Configuration
+	static class CustomJettyMetrics {
+
+		@Bean
+		public JettyStatisticsMetrics customJettyMetrics() {
+			return new JettyStatisticsMetrics(null, Collections.emptyList());
+		}
+
+	}
+
+	@Configuration
+	static class EarlyMeterBinderInitializationConfiguration {
+
+		@Bean
+		public ServletContextInitializer earlyInitializer(ApplicationContext context) {
+			return (servletContext) -> context.getBeansOfType(MeterBinder.class);
+		}
+
+	}
+}