Manage EmbeddedWebServer in ReactiveWebApplicationContext

This commit adds an `EmbeddedWebServer` instance to the
`ReactiveWebApplicationContext` and ties it to the application
lifecycle.

To launch a reactive web application, two elements are required
from the context:

* a `ReactiveWebServerFactory` to create a server instance
* a `HttpHandler` instance to handle HTTP requests

Closes gh-8337

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/condition/ConditionalOnNotWebApplicationTests.java

@@ -18,12 +18,16 @@ package org.springframework.boot.autoconfigure.condition;
 
 import org.junit.After;
 import org.junit.Test;
+import reactor.core.publisher.Mono;
 
+import org.springframework.boot.autoconfigure.webflux.MockReactiveWebServerFactory;
 import org.springframework.boot.context.embedded.ReactiveWebApplicationContext;
+import org.springframework.boot.context.embedded.ReactiveWebServerFactory;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.mock.web.MockServletContext;
 import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
 
@@ -33,7 +37,7 @@ import static org.assertj.core.api.Assertions.entry;
 /**
  * Tests for {@link ConditionalOnNotWebApplication}.
  *
- * @author Dave Syer$
+ * @author Dave Syer
  * @author Stephane Nicoll
  */
 public class ConditionalOnNotWebApplicationTests {
@@ -61,7 +65,7 @@ public class ConditionalOnNotWebApplicationTests {
 	@Test
 	public void testNotWebApplicationWithReactiveContext() {
 		ReactiveWebApplicationContext ctx = new ReactiveWebApplicationContext();
-		ctx.register(NotWebApplicationConfiguration.class);
+		ctx.register(ReactiveApplicationConfig.class, NotWebApplicationConfiguration.class);
 		ctx.refresh();
 
 		this.context = ctx;
@@ -79,6 +83,20 @@ public class ConditionalOnNotWebApplicationTests {
 				entry("none", "none"));
 	}
 
+	@Configuration
+	protected static class ReactiveApplicationConfig {
+
+		@Bean
+		public ReactiveWebServerFactory reactiveWebServerFactory() {
+			return new MockReactiveWebServerFactory();
+		}
+
+		@Bean
+		public HttpHandler httpHandler() {
+			return (request, response) -> Mono.empty();
+		}
+	}
+
 	@Configuration
 	@ConditionalOnNotWebApplication
 	protected static class NotWebApplicationConfiguration {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/condition/ConditionalOnWebApplicationTests.java

@@ -18,13 +18,17 @@ package org.springframework.boot.autoconfigure.condition;
 
 import org.junit.After;
 import org.junit.Test;
+import reactor.core.publisher.Mono;
 
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
+import org.springframework.boot.autoconfigure.webflux.MockReactiveWebServerFactory;
 import org.springframework.boot.context.embedded.ReactiveWebApplicationContext;
+import org.springframework.boot.context.embedded.ReactiveWebServerFactory;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.mock.web.MockServletContext;
 import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
 
@@ -118,6 +122,15 @@ public class ConditionalOnWebApplicationTests {
 			return "reactive";
 		}
 
+		@Bean
+		public ReactiveWebServerFactory reactiveWebServerFactory() {
+			return new MockReactiveWebServerFactory();
+		}
+
+		@Bean
+		public HttpHandler httpHandler() {
+			return (request, response) -> Mono.empty();
+		}
 	}
 
 }

spring-boot/src/main/java/org/springframework/boot/context/embedded/ReactiveWebApplicationContext.java

@@ -16,13 +16,142 @@
 
 package org.springframework.boot.context.embedded;
 
+import org.springframework.beans.BeansException;
+import org.springframework.context.ApplicationContextException;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.http.server.reactive.HttpHandler;
+import org.springframework.util.StringUtils;
 
 /**
- * A {@link AnnotationConfigApplicationContext} that can be used to bootstrap itself from a contained
- * embedded web server factory bean.
+ * A {@link AnnotationConfigApplicationContext} that can be used to bootstrap
+ * itself from a contained embedded web server factory bean.
+ *
  * @author Brian Clozel
  * @since 2.0.0
  */
 public class ReactiveWebApplicationContext extends AnnotationConfigApplicationContext {
+
+	private volatile EmbeddedWebServer embeddedWebServer;
+
+	public ReactiveWebApplicationContext() {
+		super();
+	}
+
+	public ReactiveWebApplicationContext(Class... annotatedClasses) {
+		super(annotatedClasses);
+	}
+
+	@Override
+	public final void refresh() throws BeansException, IllegalStateException {
+		try {
+			super.refresh();
+		}
+		catch (RuntimeException ex) {
+			stopAndReleaseReactiveWebServer();
+			throw ex;
+		}
+	}
+
+	@Override
+	protected void onRefresh() {
+		super.onRefresh();
+		try {
+			createEmbeddedServletContainer();
+		}
+		catch (Throwable ex) {
+			throw new ApplicationContextException("Unable to start reactive web server", ex);
+		}
+	}
+
+	@Override
+	protected void finishRefresh() {
+		super.finishRefresh();
+		EmbeddedWebServer localServer = startReactiveWebServer();
+		if (localServer != null) {
+			publishEvent(
+					new EmbeddedReactiveWebServerInitializedEvent(localServer, this));
+		}
+	}
+
+	@Override
+	protected void onClose() {
+		super.onClose();
+		stopAndReleaseReactiveWebServer();
+	}
+
+	private void createEmbeddedServletContainer() {
+		EmbeddedWebServer localServer = this.embeddedWebServer;
+		if (localServer == null) {
+			this.embeddedWebServer = getReactiveWebServerFactory()
+					.getReactiveHttpServer(getHttpHandler());
+		}
+		initPropertySources();
+	}
+
+	/**
+	 * Return the {@link ReactiveWebServerFactory} that should be used to create
+	 * the reactive web server. By default this method searches for a suitable bean
+	 * in the context itself.
+	 * @return a {@link ReactiveWebServerFactory} (never {@code null})
+	 */
+	protected ReactiveWebServerFactory getReactiveWebServerFactory() {
+		// Use bean names so that we don't consider the hierarchy
+		String[] beanNames = getBeanFactory()
+				.getBeanNamesForType(ReactiveWebServerFactory.class);
+		if (beanNames.length == 0) {
+			throw new ApplicationContextException(
+					"Unable to start ReactiveWebApplicationContext due to missing "
+							+ "ReactiveWebServerFactory bean.");
+		}
+		if (beanNames.length > 1) {
+			throw new ApplicationContextException(
+					"Unable to start ReactiveWebApplicationContext due to multiple "
+							+ "ReactiveWebServerFactory beans : "
+							+ StringUtils.arrayToCommaDelimitedString(beanNames));
+		}
+		return getBeanFactory().getBean(beanNames[0], ReactiveWebServerFactory.class);
+	}
+
+	/**
+	 * Return the {@link HttpHandler} that should be used to process
+	 * the reactive web server. By default this method searches for a suitable bean
+	 * in the context itself.
+	 * @return a {@link HttpHandler} (never {@code null}
+	 */
+	protected HttpHandler getHttpHandler() {
+		// Use bean names so that we don't consider the hierarchy
+		String[] beanNames = getBeanFactory()
+				.getBeanNamesForType(HttpHandler.class);
+		if (beanNames.length == 0) {
+			throw new ApplicationContextException(
+					"Unable to start ReactiveWebApplicationContext due to missing HttpHandler bean.");
+		}
+		if (beanNames.length > 1) {
+			throw new ApplicationContextException(
+					"Unable to start ReactiveWebApplicationContext due to multiple HttpHandler beans : "
+							+ StringUtils.arrayToCommaDelimitedString(beanNames));
+		}
+		return getBeanFactory().getBean(beanNames[0], HttpHandler.class);
+	}
+
+	private EmbeddedWebServer startReactiveWebServer() {
+		EmbeddedWebServer localServer = this.embeddedWebServer;
+		if (localServer != null) {
+			localServer.start();
+		}
+		return localServer;
+	}
+
+	private void stopAndReleaseReactiveWebServer() {
+		EmbeddedWebServer localServer = this.embeddedWebServer;
+		if (localServer != null) {
+			try {
+				localServer.stop();
+				this.embeddedWebServer = null;
+			}
+			catch (Exception ex) {
+				throw new IllegalStateException(ex);
+			}
+		}
+	}
 }

spring-boot/src/main/java/org/springframework/boot/context/embedded/ServerPortInfoApplicationContextInitializer.java

@@ -29,7 +29,6 @@ import org.springframework.core.env.Environment;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.MutablePropertySources;
 import org.springframework.core.env.PropertySource;
-import org.springframework.util.StringUtils;
 
 /**
  * {@link ApplicationContextInitializer} that sets {@link Environment} properties for the
@@ -54,11 +53,11 @@ public class ServerPortInfoApplicationContextInitializer
 	@Override
 	public void initialize(ConfigurableApplicationContext applicationContext) {
 		applicationContext.addApplicationListener(
-				new ApplicationListener<EmbeddedServletContainerInitializedEvent>() {
+				new ApplicationListener<EmbeddedWebServerInitializedEvent>() {
 
 					@Override
 					public void onApplicationEvent(
-							EmbeddedServletContainerInitializedEvent event) {
+							EmbeddedWebServerInitializedEvent event) {
 						ServerPortInfoApplicationContextInitializer.this
 								.onApplicationEvent(event);
 					}
@@ -66,19 +65,12 @@ public class ServerPortInfoApplicationContextInitializer
 				});
 	}
 
-	protected void onApplicationEvent(EmbeddedServletContainerInitializedEvent event) {
-		String propertyName = getPropertyName(event.getApplicationContext());
+	protected void onApplicationEvent(EmbeddedWebServerInitializedEvent event) {
+		String propertyName =  "local." + event.getServerId() + ".port";
 		setPortProperty(event.getApplicationContext(), propertyName,
 				event.getEmbeddedWebServer().getPort());
 	}
 
-	protected String getPropertyName(EmbeddedWebApplicationContext context) {
-		String name = context.getNamespace();
-		if (StringUtils.isEmpty(name)) {
-			name = "server";
-		}
-		return "local." + name + ".port";
-	}
 
 	private void setPortProperty(ApplicationContext context, String propertyName,
 			int port) {

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

@@ -36,6 +36,7 @@ import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 import org.mockito.ArgumentCaptor;
+import reactor.core.publisher.Mono;
 
 import org.springframework.beans.BeansException;
 import org.springframework.beans.CachedIntrospectionResults;
@@ -44,6 +45,7 @@ import org.springframework.beans.factory.support.BeanNameGenerator;
 import org.springframework.beans.factory.support.DefaultBeanNameGenerator;
 import org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext;
 import org.springframework.boot.context.embedded.ReactiveWebApplicationContext;
+import org.springframework.boot.context.embedded.reactor.ReactorNettyReactiveWebServerFactory;
 import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
 import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
 import org.springframework.boot.context.event.ApplicationPreparedEvent;
@@ -77,6 +79,7 @@ import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.test.context.support.TestPropertySourceUtils;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
@@ -400,7 +403,7 @@ public class SpringApplicationTests {
 
 	@Test
 	public void defaultApplicationContextForReactiveWeb() throws Exception {
-		SpringApplication application = new SpringApplication(ExampleWebConfig.class);
+		SpringApplication application = new SpringApplication(ExampleReactiveWebConfig.class);
 		application.setWebApplicationType(WebApplicationType.REACTIVE);
 		this.context = application.run();
 		assertThat(this.context).isInstanceOf(ReactiveWebApplicationContext.class);
@@ -571,7 +574,7 @@ public class SpringApplicationTests {
 
 	@Test
 	public void loadSources() throws Exception {
-		Object[] sources = { ExampleConfig.class, "a", TestCommandLineRunner.class };
+		Object[] sources = {ExampleConfig.class, "a", TestCommandLineRunner.class};
 		TestSpringApplication application = new TestSpringApplication(sources);
 		application.setWebApplicationType(WebApplicationType.NONE);
 		application.setUseMockLoader(true);
@@ -583,7 +586,7 @@ public class SpringApplicationTests {
 	@Test
 	public void wildcardSources() {
 		Object[] sources = {
-				"classpath:org/springframework/boot/sample-${sample.app.test.prop}.xml" };
+				"classpath:org/springframework/boot/sample-${sample.app.test.prop}.xml"};
 		TestSpringApplication application = new TestSpringApplication(sources);
 		application.setWebApplicationType(WebApplicationType.NONE);
 		this.context = application.run();
@@ -598,7 +601,7 @@ public class SpringApplicationTests {
 	@Test
 	public void runComponents() throws Exception {
 		this.context = SpringApplication.run(
-				new Object[] { ExampleWebConfig.class, Object.class }, new String[0]);
+				new Object[] {ExampleWebConfig.class, Object.class}, new String[0]);
 		assertThat(this.context).isNotNull();
 	}
 
@@ -713,7 +716,7 @@ public class SpringApplicationTests {
 	public void defaultCommandLineArgs() throws Exception {
 		SpringApplication application = new SpringApplication(ExampleConfig.class);
 		application.setDefaultProperties(StringUtils.splitArrayElementsIntoProperties(
-				new String[] { "baz=", "bar=spam" }, "="));
+				new String[] {"baz=", "bar=spam"}, "="));
 		application.setWebApplicationType(WebApplicationType.NONE);
 		this.context = application.run("--bar=foo", "bucket", "crap");
 		assertThat(this.context).isInstanceOf(AnnotationConfigApplicationContext.class);
@@ -864,7 +867,7 @@ public class SpringApplicationTests {
 		assertThat(this.context.getEnvironment().getProperty("foo")).isEqualTo("bar");
 		assertThat(this.context.getEnvironment().getPropertySources().iterator().next()
 				.getName()).isEqualTo(
-						TestPropertySourceUtils.INLINED_PROPERTIES_PROPERTY_SOURCE_NAME);
+				TestPropertySourceUtils.INLINED_PROPERTIES_PROPERTY_SOURCE_NAME);
 	}
 
 	@Test
@@ -877,7 +880,7 @@ public class SpringApplicationTests {
 						FailingConfig.class);
 				application.setWebApplicationType(WebApplicationType.NONE);
 				application.run();
-			};
+			}
 		};
 		thread.start();
 		thread.join(6000);
@@ -1028,6 +1031,22 @@ public class SpringApplicationTests {
 
 	}
 
+	@Configuration
+	static class ExampleReactiveWebConfig {
+
+		@Bean
+		public ReactorNettyReactiveWebServerFactory webServerFactory() {
+			return new ReactorNettyReactiveWebServerFactory(0);
+		}
+
+		@Bean
+		public HttpHandler httpHandler() {
+			return (serverHttpRequest, serverHttpResponse) -> Mono.empty();
+		}
+
+	}
+
+
 	@Configuration
 	static class FailingConfig {