Only start management server once main server is initialized

Closes gh-15378

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/web/server/ManagementContextAutoConfiguration.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -16,9 +16,6 @@
 
 package org.springframework.boot.actuate.autoconfigure.web.server;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-
 import org.springframework.beans.factory.SmartInitializingSingleton;
 import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointProperties;
 import org.springframework.boot.actuate.autoconfigure.web.ManagementContextFactory;
@@ -29,7 +26,7 @@ import org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoCon
 import org.springframework.boot.context.event.ApplicationFailedEvent;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.web.context.ConfigurableWebServerApplicationContext;
-import org.springframework.boot.web.context.WebServerApplicationContext;
+import org.springframework.boot.web.context.WebServerInitializedEvent;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationListener;
@@ -59,9 +56,6 @@ import org.springframework.util.Assert;
 		ManagementServerProperties.class })
 public class ManagementContextAutoConfiguration {
 
-	private static final Log logger = LogFactory
-			.getLog(ManagementContextAutoConfiguration.class);
-
 	@Configuration
 	@ConditionalOnManagementPort(ManagementPortType.SAME)
 	static class SameManagementContextConfiguration
@@ -122,7 +116,7 @@ public class ManagementContextAutoConfiguration {
 	@Configuration
 	@ConditionalOnManagementPort(ManagementPortType.DIFFERENT)
 	static class DifferentManagementContextConfiguration
-			implements SmartInitializingSingleton {
+			implements ApplicationListener<WebServerInitializedEvent> {
 
 		private final ApplicationContext applicationContext;
 
@@ -135,10 +129,8 @@ public class ManagementContextAutoConfiguration {
 		}
 
 		@Override
-		public void afterSingletonsInstantiated() {
-			if (this.applicationContext instanceof WebServerApplicationContext
-					&& ((WebServerApplicationContext) this.applicationContext)
-							.getWebServer() != null) {
+		public void onApplicationEvent(WebServerInitializedEvent event) {
+			if (event.getApplicationContext().equals(this.applicationContext)) {
 				ConfigurableWebServerApplicationContext managementContext = this.managementContextFactory
 						.createManagementContext(this.applicationContext,
 								EnableChildManagementContextConfiguration.class,
@@ -150,11 +142,6 @@ public class ManagementContextAutoConfiguration {
 						managementContext);
 				managementContext.refresh();
 			}
-			else {
-				logger.warn("Could not start embedded management container on "
-						+ "different port (management endpoints are still available "
-						+ "through JMX)");
-			}
 		}
 
 		private void setClassLoaderIfPossible(ConfigurableApplicationContext child) {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/web/server/ManagementContextAutoConfigurationTests.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -15,6 +15,9 @@
  */
 package org.springframework.boot.actuate.autoconfigure.web.server;
 
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
 import org.junit.Rule;
 import org.junit.Test;
 
@@ -33,28 +36,13 @@ import static org.assertj.core.api.Assertions.assertThat;
  * Tests for {@link ManagementContextAutoConfiguration}.
  *
  * @author Madhura Bhave
+ * @author Andy Wilkinson
  */
 public class ManagementContextAutoConfigurationTests {
 
-	private WebApplicationContextRunner contextRunner = new WebApplicationContextRunner()
-			.withConfiguration(
-					AutoConfigurations.of(ManagementContextAutoConfiguration.class,
-							ServletManagementContextAutoConfiguration.class));
-
 	@Rule
 	public OutputCapture output = new OutputCapture();
 
-	@Test
-	public void managementServerPortShouldBeIgnoredForNonEmbeddedServer() {
-		this.contextRunner.withPropertyValues("management.server.port=8081")
-				.run((context) -> {
-					assertThat(context.getStartupFailure()).isNull();
-					assertThat(this.output.toString())
-							.contains("Could not start embedded management container on "
-									+ "different port (management endpoints are still available through JMX)");
-				});
-	}
-
 	@Test
 	public void childManagementContextShouldStartForEmbeddedServer() {
 		WebApplicationContextRunner contextRunner = new WebApplicationContextRunner(
@@ -65,10 +53,19 @@ public class ManagementContextAutoConfigurationTests {
 								ServletManagementContextAutoConfiguration.class,
 								WebEndpointAutoConfiguration.class,
 								EndpointAutoConfiguration.class));
-		contextRunner.withPropertyValues("management.server.port=8081")
-				.run((context) -> assertThat(this.output.toString()).doesNotContain(
-						"Could not start embedded management container on "
-								+ "different port (management endpoints are still available through JMX)"));
+		contextRunner.withPropertyValues("server.port=0", "management.server.port=0").run(
+				(context) -> assertThat(tomcatStartedOccurencesIn(this.output.toString()))
+						.isEqualTo(2));
+
+	}
+
+	private int tomcatStartedOccurencesIn(String output) {
+		int matches = 0;
+		Matcher matcher = Pattern.compile("Tomcat started on port").matcher(output);
+		while (matcher.find()) {
+			matches++;
+		}
+		return matches;
 	}
 
 }