Polish "Add startup time metrics"

See gh-27878

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

@@ -30,7 +30,7 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
 /**
- * {@link EnableAutoConfiguration Auto-configuration} for the {@link StartupTimeMetrics}.
+ * {@link EnableAutoConfiguration Auto-configuration} for startup time metrics.
  *
  * @author Chris Bono
  * @since 2.6.0
@@ -43,7 +43,7 @@ public class StartupTimeMetricsAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	StartupTimeMetrics startupTimeMetrics(MeterRegistry meterRegistry) {
+	public StartupTimeMetrics startupTimeMetrics(MeterRegistry meterRegistry) {
 		return new StartupTimeMetrics(meterRegistry);
 	}
 

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

@@ -17,8 +17,9 @@
 package org.springframework.boot.actuate.autoconfigure.metrics.startup;
 
 import java.time.Duration;
+import java.util.concurrent.TimeUnit;
 
-import io.micrometer.core.instrument.Tags;
+import io.micrometer.core.instrument.TimeGauge;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import org.junit.jupiter.api.Test;
 
@@ -29,15 +30,15 @@ import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.context.event.ApplicationReadyEvent;
 import org.springframework.boot.context.event.ApplicationStartedEvent;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
 
 /**
  * Tests for {@link StartupTimeMetricsAutoConfiguration}.
  *
  * @author Chris Bono
+ * @author Stephane Nicoll
  */
 class StartupTimeMetricsAutoConfigurationTests {
 
@@ -47,14 +48,18 @@ class StartupTimeMetricsAutoConfigurationTests {
 	@Test
 	void startupTimeMetricsAreRecorded() {
 		this.contextRunner.run((context) -> {
-			context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-					context.getSourceApplicationContext(), Duration.ofMillis(2500)));
-			context.publishEvent(new ApplicationReadyEvent(new SpringApplication(), null,
-					context.getSourceApplicationContext(), Duration.ofMillis(3000)));
 			assertThat(context).hasSingleBean(StartupTimeMetrics.class);
 			SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
-			assertThat(registry.find("application.started.time").timeGauge()).isNotNull();
-			assertThat(registry.find("application.ready.time").timeGauge()).isNotNull();
+			context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
+					context.getSourceApplicationContext(), Duration.ofMillis(1500)));
+			TimeGauge startedTimeGage = registry.find("application.started.time").timeGauge();
+			assertThat(startedTimeGage).isNotNull();
+			assertThat(startedTimeGage.value(TimeUnit.MILLISECONDS)).isEqualTo(1500L);
+			context.publishEvent(new ApplicationReadyEvent(new SpringApplication(), null,
+					context.getSourceApplicationContext(), Duration.ofMillis(2000)));
+			TimeGauge readyTimeGage = registry.find("application.ready.time").timeGauge();
+			assertThat(readyTimeGage).isNotNull();
+			assertThat(readyTimeGage.value(TimeUnit.MILLISECONDS)).isEqualTo(2000L);
 		});
 	}
 
@@ -74,19 +79,10 @@ class StartupTimeMetricsAutoConfigurationTests {
 
 	@Test
 	void customStartupTimeMetricsAreRespected() {
-		this.contextRunner.withUserConfiguration(CustomStartupTimeMetricsConfiguration.class)
+		this.contextRunner
+				.withBean("customStartupTimeMetrics", StartupTimeMetrics.class, () -> mock(StartupTimeMetrics.class))
 				.run((context) -> assertThat(context).hasSingleBean(StartupTimeMetrics.class)
-						.hasBean("customStartTimeMetrics"));
-	}
-
-	@Configuration(proxyBeanMethods = false)
-	static class CustomStartupTimeMetricsConfiguration {
-
-		@Bean
-		StartupTimeMetrics customStartTimeMetrics() {
-			return new StartupTimeMetrics(new SimpleMeterRegistry(), Tags.empty(), "myapp.started", "myapp.ready");
-		}
-
+						.hasBean("customStartupTimeMetrics"));
 	}
 
 }

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

@@ -16,8 +16,6 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics.web.jetty;
 
-import java.time.Duration;
-
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Tags;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
@@ -37,6 +35,7 @@ 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.context.AnnotationConfigServletWebServerApplicationContext;
+import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.http.server.reactive.HttpHandler;
@@ -59,8 +58,7 @@ class JettyMetricsAutoConfigurationTests {
 						ServletWebServerFactoryAutoConfiguration.class))
 				.withUserConfiguration(ServletWebServerConfiguration.class, MeterRegistryConfiguration.class)
 				.run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					assertThat(context).hasSingleBean(JettyServerThreadPoolMetricsBinder.class);
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
 					assertThat(registry.find("jetty.threads.config.min").meter()).isNotNull();
@@ -74,8 +72,7 @@ class JettyMetricsAutoConfigurationTests {
 						ReactiveWebServerFactoryAutoConfiguration.class))
 				.withUserConfiguration(ReactiveWebServerConfiguration.class, MeterRegistryConfiguration.class)
 				.run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
 					assertThat(registry.find("jetty.threads.config.min").meter()).isNotNull();
 				});
@@ -96,8 +93,7 @@ class JettyMetricsAutoConfigurationTests {
 						ServletWebServerFactoryAutoConfiguration.class))
 				.withUserConfiguration(ServletWebServerConfiguration.class, MeterRegistryConfiguration.class)
 				.run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					assertThat(context).hasSingleBean(JettyConnectionMetricsBinder.class);
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
 					assertThat(registry.find("jetty.connections.messages.in").meter()).isNotNull();
@@ -111,8 +107,7 @@ class JettyMetricsAutoConfigurationTests {
 						ReactiveWebServerFactoryAutoConfiguration.class))
 				.withUserConfiguration(ReactiveWebServerConfiguration.class, MeterRegistryConfiguration.class)
 				.run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
 					assertThat(registry.find("jetty.connections.messages.in").meter()).isNotNull();
 				});
@@ -126,8 +121,7 @@ class JettyMetricsAutoConfigurationTests {
 				.withUserConfiguration(ServletWebServerConfiguration.class, CustomJettyConnectionMetricsBinder.class,
 						MeterRegistryConfiguration.class)
 				.run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					assertThat(context).hasSingleBean(JettyConnectionMetricsBinder.class)
 							.hasBean("customJettyConnectionMetricsBinder");
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
@@ -145,8 +139,7 @@ class JettyMetricsAutoConfigurationTests {
 				.withPropertyValues("server.ssl.enabled: true", "server.ssl.key-store: src/test/resources/test.jks",
 						"server.ssl.key-store-password: secret", "server.ssl.key-password: password")
 				.run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					assertThat(context).hasSingleBean(JettySslHandshakeMetricsBinder.class);
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
 					assertThat(registry.find("jetty.ssl.handshakes").meter()).isNotNull();
@@ -162,8 +155,7 @@ class JettyMetricsAutoConfigurationTests {
 				.withPropertyValues("server.ssl.enabled: true", "server.ssl.key-store: src/test/resources/test.jks",
 						"server.ssl.key-store-password: secret", "server.ssl.key-password: password")
 				.run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
 					assertThat(registry.find("jetty.ssl.handshakes").meter()).isNotNull();
 				});
@@ -179,8 +171,7 @@ class JettyMetricsAutoConfigurationTests {
 				.withPropertyValues("server.ssl.enabled: true", "server.ssl.key-store: src/test/resources/test.jks",
 						"server.ssl.key-store-password: secret", "server.ssl.key-password: password")
 				.run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					assertThat(context).hasSingleBean(JettySslHandshakeMetricsBinder.class)
 							.hasBean("customJettySslHandshakeMetricsBinder");
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
@@ -215,6 +206,10 @@ class JettyMetricsAutoConfigurationTests {
 				.run((context) -> assertThat(context).doesNotHaveBean(JettySslHandshakeMetricsBinder.class));
 	}
 
+	private ApplicationStartedEvent createApplicationStartedEvent(ConfigurableApplicationContext context) {
+		return new ApplicationStartedEvent(new SpringApplication(), null, context, null);
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class MeterRegistryConfiguration {
 

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

@@ -16,7 +16,6 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics.web.tomcat;
 
-import java.time.Duration;
 import java.util.Collections;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -39,6 +38,7 @@ import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactor
 import org.springframework.boot.web.embedded.tomcat.TomcatWebServer;
 import org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext;
 import org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext;
+import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.http.server.reactive.HttpHandler;
@@ -62,8 +62,7 @@ class TomcatMetricsAutoConfigurationTests {
 						ServletWebServerFactoryAutoConfiguration.class))
 				.withUserConfiguration(ServletWebServerConfiguration.class, MeterRegistryConfiguration.class)
 				.withPropertyValues("server.tomcat.mbeanregistry.enabled=true").run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					assertThat(context).hasSingleBean(TomcatMetricsBinder.class);
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
 					assertThat(registry.find("tomcat.sessions.active.max").meter()).isNotNull();
@@ -79,8 +78,7 @@ class TomcatMetricsAutoConfigurationTests {
 						ReactiveWebServerFactoryAutoConfiguration.class))
 				.withUserConfiguration(ReactiveWebServerConfiguration.class, MeterRegistryConfiguration.class)
 				.withPropertyValues("server.tomcat.mbeanregistry.enabled=true").run((context) -> {
-					context.publishEvent(new ApplicationStartedEvent(new SpringApplication(), null,
-							context.getSourceApplicationContext(), Duration.ZERO));
+					context.publishEvent(createApplicationStartedEvent(context.getSourceApplicationContext()));
 					SimpleMeterRegistry registry = context.getBean(SimpleMeterRegistry.class);
 					assertThat(registry.find("tomcat.sessions.active.max").meter()).isNotNull();
 					assertThat(registry.find("tomcat.threads.current").meter()).isNotNull();
@@ -110,6 +108,10 @@ class TomcatMetricsAutoConfigurationTests {
 						.hasBean("customTomcatMetrics"));
 	}
 
+	private ApplicationStartedEvent createApplicationStartedEvent(ConfigurableApplicationContext context) {
+		return new ApplicationStartedEvent(new SpringApplication(), null, context, null);
+	}
+
 	private void resetTomcatState() {
 		ReflectionTestUtils.setField(Registry.class, "registry", null);
 		AtomicInteger containerCounter = (AtomicInteger) ReflectionTestUtils.getField(TomcatWebServer.class,

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/startup/StartupTimeMetrics.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.actuate.metrics.startup;
 
+import java.time.Duration;
 import java.util.Collections;
 import java.util.concurrent.TimeUnit;
 
@@ -39,6 +40,16 @@ import org.springframework.context.event.SmartApplicationListener;
  */
 public class StartupTimeMetrics implements SmartApplicationListener {
 
+	/**
+	 * The default name to use for the application started time metric.
+	 */
+	public static final String APPLICATION_STARTED_TIME_METRIC_NAME = "application.started.time";
+
+	/**
+	 * The default name to use for the application ready time metric.
+	 */
+	public static final String APPLICATION_READY_TIME_METRIC_NAME = "application.ready.time";
+
 	private final MeterRegistry meterRegistry;
 
 	private final String applicationStartedTimeMetricName;
@@ -47,10 +58,26 @@ public class StartupTimeMetrics implements SmartApplicationListener {
 
 	private final Iterable<Tag> tags;
 
+	/**
+	 * Create a new instance using default metric names.
+	 * @param meterRegistry the registry to use
+	 * @see #APPLICATION_STARTED_TIME_METRIC_NAME
+	 * @see #APPLICATION_READY_TIME_METRIC_NAME
+	 */
 	public StartupTimeMetrics(MeterRegistry meterRegistry) {
-		this(meterRegistry, Collections.emptyList(), "application.started.time", "application.ready.time");
+		this(meterRegistry, Collections.emptyList(), APPLICATION_STARTED_TIME_METRIC_NAME,
+				APPLICATION_READY_TIME_METRIC_NAME);
 	}
 
+	/**
+	 * Create a new instance using the specified options.
+	 * @param meterRegistry the registry to use
+	 * @param tags the tags to associate to application startup metrics
+	 * @param applicationStartedTimeMetricName the name to use for the application started
+	 * time metric
+	 * @param applicationReadyTimeMetricName the name to use for the application ready
+	 * time metric
+	 */
 	public StartupTimeMetrics(MeterRegistry meterRegistry, Iterable<Tag> tags, String applicationStartedTimeMetricName,
 			String applicationReadyTimeMetricName) {
 		this.meterRegistry = meterRegistry;
@@ -76,29 +103,28 @@ public class StartupTimeMetrics implements SmartApplicationListener {
 	}
 
 	private void onApplicationStarted(ApplicationStartedEvent event) {
-		if (event.getStartupTime() == null) {
+		if (event.getStartedTime() == null) {
 			return;
 		}
-		TimeGauge
-				.builder(this.applicationStartedTimeMetricName, () -> event.getStartupTime().toMillis(),
-						TimeUnit.MILLISECONDS)
-				.tags(maybeDcorateTagsWithApplicationInfo(event.getSpringApplication()))
-				.description("Time taken (ms) to start the application").register(this.meterRegistry);
+		registerGauge(this.applicationStartedTimeMetricName, "Time taken (ms) to start the application",
+				event.getStartedTime(), createTagsFrom(event.getSpringApplication()));
 	}
 
 	private void onApplicationReady(ApplicationReadyEvent event) {
-		if (event.getStartupTime() == null) {
+		if (event.getReadyTime() == null) {
 			return;
 		}
-		TimeGauge
-				.builder(this.applicationReadyTimeMetricName, () -> event.getStartupTime().toMillis(),
-						TimeUnit.MILLISECONDS)
-				.tags(maybeDcorateTagsWithApplicationInfo(event.getSpringApplication()))
-				.description("Time taken (ms) for the application to be ready to serve requests")
+		registerGauge(this.applicationReadyTimeMetricName,
+				"Time taken (ms) for the application to be ready to serve requests", event.getReadyTime(),
+				createTagsFrom(event.getSpringApplication()));
+	}
+
+	private void registerGauge(String metricName, String description, Duration time, Iterable<Tag> tags) {
+		TimeGauge.builder(metricName, time::toMillis, TimeUnit.MILLISECONDS).tags(tags).description(description)
 				.register(this.meterRegistry);
 	}
 
-	private Iterable<Tag> maybeDcorateTagsWithApplicationInfo(SpringApplication springApplication) {
+	private Iterable<Tag> createTagsFrom(SpringApplication springApplication) {
 		Class<?> mainClass = springApplication.getMainApplicationClass();
 		if (mainClass == null) {
 			return this.tags;

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/startup/StartupTimeMetricsTests.java

@@ -21,6 +21,7 @@ import java.util.concurrent.TimeUnit;
 
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Tags;
+import io.micrometer.core.instrument.TimeGauge;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -40,44 +41,52 @@ import static org.mockito.Mockito.mock;
  */
 class StartupTimeMetricsTests {
 
-	private static final long APP_STARTED_TIME_MS = 2500;
-
-	private static final long APP_RUNNING_TIME_MS = 2900;
-
 	private MeterRegistry registry;
 
 	private StartupTimeMetrics metrics;
 
 	@BeforeEach
-	void prepareUnit() {
+	void setup() {
 		this.registry = new SimpleMeterRegistry();
 		this.metrics = new StartupTimeMetrics(this.registry);
 	}
 
 	@Test
 	void metricsRecordedWithoutCustomTags() {
-		this.metrics.onApplicationEvent(applicationStartedEvent(APP_STARTED_TIME_MS));
-		this.metrics.onApplicationEvent(applicationReadyEvent(APP_RUNNING_TIME_MS));
-		assertMetricExistsWithValue("application.started.time", APP_STARTED_TIME_MS);
-		assertMetricExistsWithValue("application.ready.time", APP_RUNNING_TIME_MS);
+		this.metrics.onApplicationEvent(applicationStartedEvent(2000L));
+		this.metrics.onApplicationEvent(applicationReadyEvent(2200L));
+		assertMetricExistsWithValue("application.started.time", 2000L);
+		assertMetricExistsWithValue("application.ready.time", 2200L);
 	}
 
 	@Test
 	void metricsRecordedWithCustomTagsAndMetricNames() {
 		Tags tags = Tags.of("foo", "bar");
 		this.metrics = new StartupTimeMetrics(this.registry, tags, "m1", "m2");
-		this.metrics.onApplicationEvent(applicationStartedEvent(APP_STARTED_TIME_MS));
-		this.metrics.onApplicationEvent(applicationReadyEvent(APP_RUNNING_TIME_MS));
-		assertMetricExistsWithCustomTagsAndValue("m1", tags, APP_STARTED_TIME_MS);
-		assertMetricExistsWithCustomTagsAndValue("m2", tags, APP_RUNNING_TIME_MS);
+		this.metrics.onApplicationEvent(applicationStartedEvent(1000L));
+		this.metrics.onApplicationEvent(applicationReadyEvent(1050L));
+		assertMetricExistsWithCustomTagsAndValue("m1", tags, 1000L);
+		assertMetricExistsWithCustomTagsAndValue("m2", tags, 1050L);
+	}
+
+	@Test
+	void metricRecordedWithoutMainAppClassTag() {
+		SpringApplication application = mock(SpringApplication.class);
+		this.metrics.onApplicationEvent(new ApplicationStartedEvent(application, null, null, Duration.ofSeconds(2)));
+		TimeGauge applicationStartedGague = this.registry.find("application.started.time").timeGauge();
+		assertThat(applicationStartedGague).isNotNull();
+		assertThat(applicationStartedGague.getId().getTags()).isEmpty();
 	}
 
 	@Test
-	void metricsRecordedWithoutMainAppClassTagWhenMainAppClassNotAvailable() {
-		this.metrics.onApplicationEvent(applicationStartedEvent(APP_STARTED_TIME_MS));
-		this.metrics.onApplicationEvent(applicationReadyEvent(APP_RUNNING_TIME_MS));
-		assertThat(this.registry.find("application.started.time").timeGauge()).isNotNull();
-		assertThat(this.registry.find("application.ready.time").timeGauge()).isNotNull();
+	void metricRecordedWithoutMainAppClassTagAndAdditionalTags() {
+		SpringApplication application = mock(SpringApplication.class);
+		Tags tags = Tags.of("foo", "bar");
+		this.metrics = new StartupTimeMetrics(this.registry, tags, "started", "ready");
+		this.metrics.onApplicationEvent(new ApplicationReadyEvent(application, null, null, Duration.ofSeconds(2)));
+		TimeGauge applicationReadyGague = this.registry.find("ready").timeGauge();
+		assertThat(applicationReadyGague).isNotNull();
+		assertThat(applicationReadyGague.getId().getTags()).containsExactlyElementsOf(tags);
 	}
 
 	@Test
@@ -102,16 +111,16 @@ class StartupTimeMetricsTests {
 				(startupTimeMs != null) ? Duration.ofMillis(startupTimeMs) : null);
 	}
 
-	private void assertMetricExistsWithValue(String metricName, double expectedValueInMillis) {
+	private void assertMetricExistsWithValue(String metricName, long expectedValueInMillis) {
 		assertMetricExistsWithCustomTagsAndValue(metricName, Tags.empty(), expectedValueInMillis);
 	}
 
 	private void assertMetricExistsWithCustomTagsAndValue(String metricName, Tags expectedCustomTags,
-			double expectedValueInMillis) {
+			Long expectedValueInMillis) {
 		assertThat(this.registry.find(metricName)
 				.tags(Tags.concat(expectedCustomTags, "main-application-class", TestMainApplication.class.getName()))
 				.timeGauge()).isNotNull().extracting((m) -> m.value(TimeUnit.MILLISECONDS))
-						.isEqualTo(expectedValueInMillis);
+						.isEqualTo(expectedValueInMillis.doubleValue());
 	}
 
 	static class TestMainApplication {

spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/restart/RestartApplicationListenerTests.java

@@ -16,7 +16,6 @@
 
 package org.springframework.boot.devtools.restart;
 
-import java.time.Duration;
 import java.util.List;
 
 import org.junit.jupiter.api.AfterEach;
@@ -111,7 +110,7 @@ class RestartApplicationListenerTests {
 			listener.onApplicationEvent(new ApplicationFailedEvent(application, ARGS, context, new RuntimeException()));
 		}
 		else {
-			listener.onApplicationEvent(new ApplicationReadyEvent(application, ARGS, context, Duration.ZERO));
+			listener.onApplicationEvent(new ApplicationReadyEvent(application, ARGS, context, null));
 		}
 	}
 

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

@@ -656,6 +656,17 @@ The following system metrics are provided:
 
 
 
+[[actuator.metrics.supported.application-startup]]
+==== Application Startup Metrics
+Auto-configuration exposes application startup time metrics:
+
+* `application.started.time`: time taken to start the application.
+* `application.ready.time`: time taken for the application to be ready to serve requests.
+
+Metrics are tagged by the fully qualified name of the application class.
+
+
+
 [[actuator.metrics.supported.logger]]
 ==== Logger Metrics
 Auto-configuration enables the event metrics for both Logback and Log4J2.

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

@@ -287,7 +287,7 @@ public class SpringApplication {
 	 */
 	public ConfigurableApplicationContext run(String... args) {
 		StopWatch stopWatch = new StopWatch();
-		stopWatch.start("applicationStarted");
+		stopWatch.start();
 		DefaultBootstrapContext bootstrapContext = createBootstrapContext();
 		ConfigurableApplicationContext context = null;
 		configureHeadlessProperty();
@@ -304,11 +304,12 @@ public class SpringApplication {
 			refreshContext(context);
 			afterRefresh(context, applicationArguments);
 			stopWatch.stop();
-			stopWatch.start("applicationReady");
+			Duration startedTime = Duration.ofMillis(stopWatch.getTotalTimeMillis());
+			stopWatch.start();
 			if (this.logStartupInfo) {
-				new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch);
+				new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), startedTime);
 			}
-			listeners.started(context, Duration.ofMillis(stopWatch.getTotalTimeMillis()));
+			listeners.started(context, startedTime);
 			callRunners(context, applicationArguments);
 		}
 		catch (Throwable ex) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplicationRunListener.java

@@ -83,6 +83,7 @@ public interface SpringApplicationRunListener {
 	 */
 	@Deprecated
 	default void started(ConfigurableApplicationContext context) {
+		started(context, null);
 	}
 
 	/**
@@ -90,11 +91,11 @@ public interface SpringApplicationRunListener {
 	 * {@link CommandLineRunner CommandLineRunners} and {@link ApplicationRunner
 	 * ApplicationRunners} have not been called.
 	 * @param context the application context.
-	 * @param startupTime the time taken to start the application or {@code null} if
+	 * @param startedTime the time taken to start the application or {@code null} if
 	 * unknown
-	 * @since 2.0.0
+	 * @since 2.6.0
 	 */
-	default void started(ConfigurableApplicationContext context, Duration startupTime) {
+	default void started(ConfigurableApplicationContext context, Duration startedTime) {
 		started(context);
 	}
 
@@ -109,6 +110,7 @@ public interface SpringApplicationRunListener {
 	 */
 	@Deprecated
 	default void running(ConfigurableApplicationContext context) {
+		running(context, null);
 	}
 
 	/**
@@ -116,11 +118,11 @@ public interface SpringApplicationRunListener {
 	 * been refreshed and all {@link CommandLineRunner CommandLineRunners} and
 	 * {@link ApplicationRunner ApplicationRunners} have been called.
 	 * @param context the application context.
-	 * @param startupTime the time taken for the application to be ready to service
-	 * requests or {@code null} if unknown
+	 * @param readyTime the time taken for the application to be ready to service requests
+	 * or {@code null} if unknown
 	 * @since 2.6.0
 	 */
-	default void running(ConfigurableApplicationContext context, Duration startupTime) {
+	default void running(ConfigurableApplicationContext context, Duration readyTime) {
 		running(context);
 	}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/StartupInfoLogger.java

@@ -18,6 +18,7 @@ package org.springframework.boot;
 
 import java.lang.management.ManagementFactory;
 import java.net.InetAddress;
+import java.time.Duration;
 import java.util.concurrent.Callable;
 
 import org.apache.commons.logging.Log;
@@ -29,7 +30,6 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.core.log.LogMessage;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
-import org.springframework.util.StopWatch;
 import org.springframework.util.StringUtils;
 
 /**
@@ -56,9 +56,9 @@ class StartupInfoLogger {
 		applicationLog.debug(LogMessage.of(this::getRunningMessage));
 	}
 
-	void logStarted(Log applicationLog, StopWatch stopWatch) {
+	void logStarted(Log applicationLog, Duration startupTime) {
 		if (applicationLog.isInfoEnabled()) {
-			applicationLog.info(getStartedMessage(stopWatch));
+			applicationLog.info(getStartedMessage(startupTime));
 		}
 	}
 
@@ -83,12 +83,12 @@ class StartupInfoLogger {
 		return message;
 	}
 
-	private CharSequence getStartedMessage(StopWatch stopWatch) {
+	private CharSequence getStartedMessage(Duration startupTime) {
 		StringBuilder message = new StringBuilder();
 		message.append("Started ");
 		appendApplicationName(message);
 		message.append(" in ");
-		message.append(stopWatch.getTotalTimeMillis() / 1000.0);
+		message.append(startupTime.toMillis() / 1000.0);
 		message.append(" seconds");
 		try {
 			double uptime = ManagementFactory.getRuntimeMXBean().getUptime() / 1000.0;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/event/ApplicationReadyEvent.java

@@ -37,7 +37,7 @@ public class ApplicationReadyEvent extends SpringApplicationEvent {
 
 	private final ConfigurableApplicationContext context;
 
-	private final Duration startupTime;
+	private final Duration readyTime;
 
 	/**
 	 * Create a new {@link ApplicationReadyEvent} instance.
@@ -47,6 +47,7 @@ public class ApplicationReadyEvent extends SpringApplicationEvent {
 	 * @deprecated since 2.6.0 for removal in 2.8.0 in favor of
 	 * {@link #ApplicationReadyEvent(SpringApplication, String[], ConfigurableApplicationContext, Duration)}
 	 */
+	@Deprecated
 	public ApplicationReadyEvent(SpringApplication application, String[] args, ConfigurableApplicationContext context) {
 		this(application, args, context, null);
 	}
@@ -56,13 +57,14 @@ public class ApplicationReadyEvent extends SpringApplicationEvent {
 	 * @param application the current application
 	 * @param args the arguments the application is running with
 	 * @param context the context that was being created
-	 * @param startupTime the time taken to get the application ready to service requests
+	 * @param readyTime the time taken to get the application ready to service requests
+	 * @since 2.6.0
 	 */
 	public ApplicationReadyEvent(SpringApplication application, String[] args, ConfigurableApplicationContext context,
-			Duration startupTime) {
+			Duration readyTime) {
 		super(application, args);
 		this.context = context;
-		this.startupTime = startupTime;
+		this.readyTime = readyTime;
 	}
 
 	/**
@@ -74,11 +76,12 @@ public class ApplicationReadyEvent extends SpringApplicationEvent {
 	}
 
 	/**
-	 * Return the time taken for the application to be ready to service requests.
-	 * @return the startup time
+	 * Return the time taken for the application to be ready to service requests, or
+	 * {@code null} if unknown.
+	 * @return the time taken to be ready to service requests
 	 */
-	public Duration getStartupTime() {
-		return this.startupTime;
+	public Duration getReadyTime() {
+		return this.readyTime;
 	}
 
 }

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/event/ApplicationStartedEvent.java

@@ -36,7 +36,7 @@ public class ApplicationStartedEvent extends SpringApplicationEvent {
 
 	private final ConfigurableApplicationContext context;
 
-	private final Duration startupTime;
+	private final Duration startedTime;
 
 	/**
 	 * Create a new {@link ApplicationStartedEvent} instance.
@@ -57,13 +57,14 @@ public class ApplicationStartedEvent extends SpringApplicationEvent {
 	 * @param application the current application
 	 * @param args the arguments the application is running with
 	 * @param context the context that was being created
-	 * @param startupTime the time taken to start the application
+	 * @param startedTime the time taken to start the application
+	 * @since 2.6.0
 	 */
 	public ApplicationStartedEvent(SpringApplication application, String[] args, ConfigurableApplicationContext context,
-			Duration startupTime) {
+			Duration startedTime) {
 		super(application, args);
 		this.context = context;
-		this.startupTime = startupTime;
+		this.startedTime = startedTime;
 	}
 
 	/**
@@ -75,11 +76,11 @@ public class ApplicationStartedEvent extends SpringApplicationEvent {
 	}
 
 	/**
-	 * Return the time taken to start the application.
+	 * Return the time taken to start the application, or {@code null} if unknown.
 	 * @return the startup time
 	 */
-	public Duration getStartupTime() {
-		return this.startupTime;
+	public Duration getStartedTime() {
+		return this.startedTime;
 	}
 
 }

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/event/EventPublishingRunListener.java

@@ -104,26 +104,14 @@ public class EventPublishingRunListener implements SpringApplicationRunListener,
 	}
 
 	@Override
-	@Deprecated
-	public void started(ConfigurableApplicationContext context) {
-		started(context, null);
-	}
-
-	@Override
-	public void started(ConfigurableApplicationContext context, Duration startupTime) {
-		context.publishEvent(new ApplicationStartedEvent(this.application, this.args, context, startupTime));
+	public void started(ConfigurableApplicationContext context, Duration startedTime) {
+		context.publishEvent(new ApplicationStartedEvent(this.application, this.args, context, startedTime));
 		AvailabilityChangeEvent.publish(context, LivenessState.CORRECT);
 	}
 
 	@Override
-	@Deprecated
-	public void running(ConfigurableApplicationContext context) {
-		running(context, null);
-	}
-
-	@Override
-	public void running(ConfigurableApplicationContext context, Duration startupTime) {
-		context.publishEvent(new ApplicationReadyEvent(this.application, this.args, context, startupTime));
+	public void running(ConfigurableApplicationContext context, Duration readyTime) {
+		context.publishEvent(new ApplicationReadyEvent(this.application, this.args, context, readyTime));
 		AvailabilityChangeEvent.publish(context, ReadinessState.ACCEPTING_TRAFFIC);
 	}
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java

@@ -88,6 +88,7 @@ import org.springframework.context.annotation.Lazy;
 import org.springframework.context.event.ApplicationEventMulticaster;
 import org.springframework.context.event.ContextRefreshedEvent;
 import org.springframework.context.event.SimpleApplicationEventMulticaster;
+import org.springframework.context.event.SmartApplicationListener;
 import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.context.support.StaticApplicationContext;
 import org.springframework.core.Ordered;
@@ -362,36 +363,18 @@ class SpringApplicationTests {
 	void applicationRunningEventListener() {
 		SpringApplication application = new SpringApplication(ExampleConfig.class);
 		application.setWebApplicationType(WebApplicationType.NONE);
-		final AtomicReference<SpringApplication> reference = new AtomicReference<>();
-		class ApplicationReadyEventListener implements ApplicationListener<ApplicationReadyEvent> {
-
-			@Override
-			public void onApplicationEvent(ApplicationReadyEvent event) {
-				reference.set(event.getSpringApplication());
-			}
-
-		}
-		application.addListeners(new ApplicationReadyEventListener());
+		AtomicReference<ApplicationReadyEvent> reference = setupListener(application, ApplicationReadyEvent.class);
 		this.context = application.run("--foo=bar");
-		assertThat(application).isSameAs(reference.get());
+		assertThat(application).isSameAs(reference.get().getSpringApplication());
 	}
 
 	@Test
 	void contextRefreshedEventListener() {
 		SpringApplication application = new SpringApplication(ExampleConfig.class);
 		application.setWebApplicationType(WebApplicationType.NONE);
-		final AtomicReference<ApplicationContext> reference = new AtomicReference<>();
-		class InitializerListener implements ApplicationListener<ContextRefreshedEvent> {
-
-			@Override
-			public void onApplicationEvent(ContextRefreshedEvent event) {
-				reference.set(event.getApplicationContext());
-			}
-
-		}
-		application.setListeners(Collections.singletonList(new InitializerListener()));
+		AtomicReference<ContextRefreshedEvent> reference = setupListener(application, ContextRefreshedEvent.class);
 		this.context = application.run("--foo=bar");
-		assertThat(this.context).isSameAs(reference.get());
+		assertThat(this.context).isSameAs(reference.get().getApplicationContext());
 		// Custom initializers do not switch off the defaults
 		assertThat(getEnvironment().getProperty("foo")).isEqualTo("bar");
 	}
@@ -419,39 +402,21 @@ class SpringApplicationTests {
 	}
 
 	@Test
-	void applicationStartedEventHasStartupTime() {
+	void applicationStartedEventHasStartedTime() {
 		SpringApplication application = new SpringApplication(ExampleConfig.class);
 		application.setWebApplicationType(WebApplicationType.NONE);
-		final AtomicReference<ApplicationStartedEvent> reference = new AtomicReference<>();
-		class ApplicationStartedEventListener implements ApplicationListener<ApplicationStartedEvent> {
-
-			@Override
-			public void onApplicationEvent(ApplicationStartedEvent event) {
-				reference.set(event);
-			}
-
-		}
-		application.addListeners(new ApplicationStartedEventListener());
+		AtomicReference<ApplicationStartedEvent> reference = setupListener(application, ApplicationStartedEvent.class);
 		this.context = application.run();
-		assertThat(reference.get()).isNotNull().extracting(ApplicationStartedEvent::getStartupTime).isNotNull();
+		assertThat(reference.get()).isNotNull().extracting(ApplicationStartedEvent::getStartedTime).isNotNull();
 	}
 
 	@Test
-	void applicationReadyEventHasStartupTime() {
+	void applicationReadyEventHasReadyTime() {
 		SpringApplication application = new SpringApplication(ExampleConfig.class);
 		application.setWebApplicationType(WebApplicationType.NONE);
-		final AtomicReference<ApplicationReadyEvent> reference = new AtomicReference<>();
-		class ApplicationReadyEventListener implements ApplicationListener<ApplicationReadyEvent> {
-
-			@Override
-			public void onApplicationEvent(ApplicationReadyEvent event) {
-				reference.set(event);
-			}
-
-		}
-		application.addListeners(new ApplicationReadyEventListener());
+		AtomicReference<ApplicationReadyEvent> reference = setupListener(application, ApplicationReadyEvent.class);
 		this.context = application.run();
-		assertThat(reference.get()).isNotNull().extracting(ApplicationReadyEvent::getStartupTime).isNotNull();
+		assertThat(reference.get()).isNotNull().extracting(ApplicationReadyEvent::getReadyTime).isNotNull();
 	}
 
 	@Test
@@ -1287,6 +1252,27 @@ class SpringApplicationTests {
 				&& ((AvailabilityChangeEvent<?>) argument).getState().equals(state);
 	}
 
+	private <T extends ApplicationEvent> AtomicReference<T> setupListener(SpringApplication application,
+			Class<T> targetEventType) {
+		final AtomicReference<T> reference = new AtomicReference<>();
+		class TestEventListener implements SmartApplicationListener {
+
+			@Override
+			@SuppressWarnings("unchecked")
+			public void onApplicationEvent(ApplicationEvent event) {
+				reference.set((T) event);
+			}
+
+			@Override
+			public boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {
+				return targetEventType.isAssignableFrom(eventType);
+			}
+
+		}
+		application.addListeners(new TestEventListener());
+		return reference;
+	}
+
 	private Condition<ConfigurableEnvironment> matchingPropertySource(final Class<?> propertySourceClass,
 			final String name) {
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/StartupInfoLoggerTests.java

@@ -18,6 +18,7 @@ package org.springframework.boot;
 
 import java.net.InetAddress;
 import java.net.UnknownHostException;
+import java.time.Duration;
 
 import org.apache.commons.logging.Log;
 import org.junit.jupiter.api.Test;
@@ -59,7 +60,7 @@ class StartupInfoLoggerTests {
 		stopWatch.start();
 		given(this.log.isInfoEnabled()).willReturn(true);
 		stopWatch.stop();
-		new StartupInfoLogger(getClass()).logStarted(this.log, stopWatch);
+		new StartupInfoLogger(getClass()).logStarted(this.log, Duration.ofMillis(stopWatch.getTotalTimeMillis()));
 		ArgumentCaptor<Object> captor = ArgumentCaptor.forClass(Object.class);
 		verify(this.log).info(captor.capture());
 		assertThat(captor.getValue().toString()).matches("Started " + getClass().getSimpleName()

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/admin/SpringApplicationAdminMXBeanRegistrarTests.java

@@ -17,7 +17,6 @@
 package org.springframework.boot.admin;
 
 import java.lang.management.ManagementFactory;
-import java.time.Duration;
 
 import javax.management.InstanceNotFoundException;
 import javax.management.MBeanServer;
@@ -90,10 +89,9 @@ class SpringApplicationAdminMXBeanRegistrarTests {
 		ConfigurableApplicationContext context = mock(ConfigurableApplicationContext.class);
 		registrar.setApplicationContext(context);
 		registrar.onApplicationReadyEvent(new ApplicationReadyEvent(new SpringApplication(), null,
-				mock(ConfigurableApplicationContext.class), Duration.ZERO));
+				mock(ConfigurableApplicationContext.class), null));
 		assertThat(isApplicationReady(registrar)).isFalse();
-		registrar.onApplicationReadyEvent(
-				new ApplicationReadyEvent(new SpringApplication(), null, context, Duration.ZERO));
+		registrar.onApplicationReadyEvent(new ApplicationReadyEvent(new SpringApplication(), null, context, null));
 		assertThat(isApplicationReady(registrar)).isTrue();
 	}
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/ApplicationPidFileWriterTests.java

@@ -18,7 +18,6 @@ package org.springframework.boot.context;
 
 import java.io.File;
 import java.io.IOException;
-import java.time.Duration;
 import java.util.function.Consumer;
 
 import org.junit.jupiter.api.AfterEach;
@@ -188,7 +187,7 @@ class ApplicationPidFileWriterTests {
 		ConfigurableEnvironment environment = createEnvironment(propName, propValue);
 		ConfigurableApplicationContext context = mock(ConfigurableApplicationContext.class);
 		given(context.getEnvironment()).willReturn(environment);
-		return new ApplicationReadyEvent(new SpringApplication(), new String[] {}, context, Duration.ZERO);
+		return new ApplicationReadyEvent(new SpringApplication(), new String[] {}, context, null);
 	}
 
 	private ConfigurableEnvironment createEnvironment(String propName, String propValue) {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/event/EventPublishingRunListenerTests.java

@@ -16,7 +16,6 @@
 
 package org.springframework.boot.context.event;
 
-import java.time.Duration;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -73,9 +72,9 @@ class EventPublishingRunListenerTests {
 		this.runListener.contextLoaded(context);
 		checkApplicationEvents(ApplicationPreparedEvent.class);
 		context.refresh();
-		this.runListener.started(context, Duration.ZERO);
+		this.runListener.started(context, null);
 		checkApplicationEvents(ApplicationStartedEvent.class, AvailabilityChangeEvent.class);
-		this.runListener.running(context, Duration.ZERO);
+		this.runListener.running(context, null);
 		checkApplicationEvents(ApplicationReadyEvent.class, AvailabilityChangeEvent.class);
 	}