Add an option to log banner rather than printing it to standard out

This commit adds the option to output the banner using the logger
instead of standard out. Rather than taking a boolean
spring.main.show-banner is now configured using an enum. Three values
are supported:

 - LOG: the banner is logged
 - CONSOLE: the banner is printed to standard out (previously true)
 - OFF: the banner is switched off (previously false)

The default behavior remains unchanged; the banner will be printed to
standard out.

Closes gh-4022
See gh-4001

spring-boot-docs/src/main/asciidoc/howto.adoc

@@ -123,7 +123,7 @@ might have.
 [source,properties,indent=0,subs="verbatim,quotes,attributes"]
 ----
 	spring.main.web_environment=false
-	spring.main.show_banner=false
+	spring.main.show_banner=OFF
 ----
 
 and then the Spring Boot banner will not be printed on startup, and the application will
@@ -139,7 +139,7 @@ consider this application
 [source,java,indent=0]
 ----
 	new SpringApplicationBuilder()
-		.showBanner(false)
+		.showBanner(Banner.Mode.OFF)
 		.sources(demo.MyApp.class)
 		.run(args);
 ----
@@ -149,7 +149,7 @@ used with the following configuration:
 [source,properties,indent=0,subs="verbatim,quotes,attributes"]
 ----
 	spring.main.sources=com.acme.Config,com.acme.ExtraConfig
-	spring.main.show-banner=true
+	spring.main.show-banner=CONSOLE
 ----
 
 The actual application will _now_ show the banner (as overridden by configuration) and use

spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -124,7 +124,7 @@ For example:
 [source,java,indent=0]
 ----
 	new SpringApplicationBuilder()
-		.showBanner(false)
+		.showBanner(Banner.Mode.OFF)
 		.sources(Parent.class)
 		.child(Application.class)
 		.run(args);

spring-boot/src/main/java/org/springframework/boot/Banner.java

@@ -25,6 +25,7 @@ import org.springframework.core.env.Environment;
  *
  * @author Phillip Webb
  * @author Michael Stummvoll
+ * @author Jeremy Rickard
  * @since 1.2.0
  */
 public interface Banner {
@@ -37,4 +38,25 @@ public interface Banner {
 	 */
 	void printBanner(Environment environment, Class<?> sourceClass, PrintStream out);
 
+	/**
+	 * An enumeration of possible values for configuring the Banner.
+	 */
+	enum Mode {
+
+		/**
+		 * Disable printing of the banner.
+		 */
+		OFF,
+
+		/**
+		 * Print the banner to System.out.
+		 */
+		CONSOLE,
+
+		/**
+		 * Print the banner to the log file.
+		 */
+		LOG
+	}
+
 }

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

@@ -16,6 +16,8 @@
 
 package org.springframework.boot;
 
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
 import java.lang.reflect.Constructor;
 import java.security.AccessControlException;
 import java.util.ArrayList;
@@ -134,6 +136,7 @@ import org.springframework.web.context.support.StandardServletEnvironment;
  * @author Andy Wilkinson
  * @author Christian Dupuis
  * @author Stephane Nicoll
+ * @author Jeremy Rickard
  * @see #run(Object, String[])
  * @see #run(Object[], String[])
  * @see #SpringApplication(Object...)
@@ -179,7 +182,7 @@ public class SpringApplication {
 
 	private Class<?> mainApplicationClass;
 
-	private boolean showBanner = true;
+	private Banner.Mode showBanner = Banner.Mode.CONSOLE;
 
 	private boolean logStartupInfo = true;
 
@@ -321,7 +324,7 @@ public class SpringApplication {
 			environment = convertToStandardEnvironment(environment);
 		}
 
-		if (this.showBanner) {
+		if (this.showBanner != Banner.Mode.OFF) {
 			printBanner(environment);
 		}
 
@@ -521,27 +524,37 @@ public class SpringApplication {
 	 * banner.location=classpath:banner.txt, banner.charset=UTF-8. If the banner file does
 	 * not exist or cannot be printed, a simple default is created.
 	 * @param environment the environment
-	 * @see #setShowBanner(boolean)
+	 * @see #setShowBanner(org.springframework.boot.Banner.Mode)
 	 */
 	protected void printBanner(Environment environment) {
+
+		Banner selectedBanner = selectBanner(environment);
+
+		if (this.showBanner == Banner.Mode.LOG) {
+			ByteArrayOutputStream baos = new ByteArrayOutputStream();
+			selectedBanner.printBanner(environment, this.mainApplicationClass,
+					new PrintStream(baos));
+			this.log.info(baos.toString());
+		}
+		else {
+			selectedBanner
+					.printBanner(environment, this.mainApplicationClass, System.out);
+		}
+	}
+
+	private Banner selectBanner(Environment environment) {
 		String location = environment.getProperty("banner.location", "banner.txt");
 		ResourceLoader resourceLoader = this.resourceLoader != null ? this.resourceLoader
 				: new DefaultResourceLoader(getClassLoader());
 		Resource resource = resourceLoader.getResource(location);
+
 		if (resource.exists()) {
-			new ResourceBanner(resource).printBanner(environment,
+			return new ResourceBanner(resource);
-					this.mainApplicationClass, System.out);
-			return;
 		}
 		if (this.banner != null) {
-			this.banner.printBanner(environment, this.mainApplicationClass, System.out);
+			return this.banner;
-			return;
 		}
-		printDefaultBanner();
+		return DEFAULT_BANNER;
-	}
-
-	private void printDefaultBanner() {
-		DEFAULT_BANNER.printBanner(null, this.mainApplicationClass, System.out);
 	}
 
 	/**
@@ -840,11 +853,11 @@ public class SpringApplication {
 
 	/**
 	 * Sets if the Spring banner should be displayed when the application runs. Defaults
-	 * to {@code true}.
+	 * to {@code org.springframework.boot.Banner.Mode.CONSOLE}.
-	 * @param showBanner if the banner should be shown
+	 * @param bannerMode if the banner should be shown in log or console, or turned off.
 	 */
-	public void setShowBanner(boolean showBanner) {
+	public void setShowBanner(Banner.Mode bannerMode) {
-		this.showBanner = showBanner;
+		this.showBanner = bannerMode;
 	}
 
 	/**

spring-boot/src/main/java/org/springframework/boot/builder/SpringApplicationBuilder.java

@@ -172,7 +172,7 @@ public class SpringApplicationBuilder {
 		web(false);
 
 		// Probably not interested in multiple banners
-		showBanner(false);
+		showBanner(Banner.Mode.OFF);
 
 		// Make sure sources get copied over
 		this.application.setSources(this.sources);
@@ -311,7 +311,7 @@ public class SpringApplicationBuilder {
 	 * @param showBanner the flag to set. Default true.
 	 * @return the current builder
 	 */
-	public SpringApplicationBuilder showBanner(boolean showBanner) {
+	public SpringApplicationBuilder showBanner(Banner.Mode showBanner) {
 		this.application.setShowBanner(showBanner);
 		return this;
 	}

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

@@ -57,6 +57,14 @@ public class BannerTests {
 		assertThat(this.out.toString(), containsString(":: Spring Boot ::"));
 	}
 
+	@Test
+	public void testDefaultBannerInLog() throws Exception {
+		SpringApplication application = new SpringApplication(Config.class);
+		application.setWebEnvironment(false);
+		this.context = application.run();
+		assertThat(this.out.toString(), containsString(":: Spring Boot ::"));
+	}
+
 	@Test
 	public void testCustomBanner() throws Exception {
 		SpringApplication application = new SpringApplication(Config.class);

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

@@ -76,7 +76,7 @@ public class SimpleMainTests {
 
 	private String[] getArgs(String... args) {
 		List<String> list = new ArrayList<String>(Arrays.asList(
-				"--spring.main.webEnvironment=false", "--spring.main.showBanner=false",
+				"--spring.main.webEnvironment=false", "--spring.main.showBanner=OFF",
 				"--spring.main.registerShutdownHook=false"));
 		if (args.length > 0) {
 			list.add("--spring.main.sources="

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

@@ -82,6 +82,7 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Matchers.anyObject;
+import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
@@ -95,6 +96,7 @@ import static org.mockito.Mockito.verify;
  * @author Andy Wilkinson
  * @author Christian Dupuis
  * @author Stephane Nicoll
+ * @author Jeremy Rickard
  */
 public class SpringApplicationTests {
 
@@ -164,7 +166,7 @@ public class SpringApplicationTests {
 	public void disableBanner() throws Exception {
 		SpringApplication application = spy(new SpringApplication(ExampleConfig.class));
 		application.setWebEnvironment(false);
-		application.setShowBanner(false);
+		application.setShowBanner(Banner.Mode.OFF);
 		this.context = application.run();
 		verify(application, never()).printBanner((Environment) anyObject());
 	}
@@ -173,7 +175,7 @@ public class SpringApplicationTests {
 	public void disableBannerViaProperty() throws Exception {
 		SpringApplication application = spy(new SpringApplication(ExampleConfig.class));
 		application.setWebEnvironment(false);
-		this.context = application.run("--spring.main.show_banner=false");
+		this.context = application.run("--spring.main.show_banner=OFF");
 		verify(application, never()).printBanner((Environment) anyObject());
 	}
 
@@ -213,6 +215,24 @@ public class SpringApplicationTests {
 				containsString("The following profiles are active: myprofile"));
 	}
 
+	@Test
+	public void enableBannerInLogViaProperty() throws Exception {
+		SpringApplication application = spy(new SpringApplication(ExampleConfig.class));
+		application.setWebEnvironment(false);
+		this.context = application.run("--spring.main.show_banner=LOG");
+		verify(application, atLeastOnce()).setShowBanner(Banner.Mode.LOG);
+	}
+
+	@Test
+	public void verifyBannerOutputContainsLogInfo() throws Exception {
+		SpringApplication application = spy(new SpringApplication(ExampleConfig.class));
+		application.setWebEnvironment(false);
+		application.run("--spring.main.show_banner=LOG",
+				"--banner.location=classpath:test-banner.txt");
+		verify(application, atLeastOnce()).setShowBanner(Banner.Mode.LOG);
+		assertThat(this.output.toString(), containsString("o.s.boot.SpringApplication"));
+	}
+
 	@Test
 	public void customId() throws Exception {
 		SpringApplication application = new SpringApplication(ExampleConfig.class);
@@ -545,8 +565,8 @@ public class SpringApplicationTests {
 		TestSpringApplication application = new TestSpringApplication(
 				ExampleConfig.class);
 		application.setWebEnvironment(false);
-		this.context = application.run("--spring.main.show_banner=false");
+		this.context = application.run("--spring.main.show_banner=OFF");
-		assertThat(application.getShowBanner(), is(false));
+		assertThat(application.getShowBanner(), is(Banner.Mode.OFF));
 	}
 
 	@Test
@@ -713,7 +733,7 @@ public class SpringApplicationTests {
 
 		private boolean useMockLoader;
 
-		private boolean showBanner;
+		private Banner.Mode showBanner;
 
 		TestSpringApplication(Object... sources) {
 			super(sources);
@@ -744,12 +764,12 @@ public class SpringApplicationTests {
 		}
 
 		@Override
-		public void setShowBanner(boolean showBanner) {
+		public void setShowBanner(Banner.Mode bannerMode) {
-			super.setShowBanner(showBanner);
+			super.setShowBanner(bannerMode);
-			this.showBanner = showBanner;
+			this.showBanner = bannerMode;
 		}
 
-		public boolean getShowBanner() {
+		public Banner.Mode getShowBanner() {
 			return this.showBanner;
 		}
 

spring-boot/src/test/java/org/springframework/boot/context/config/ConfigFileEnvironmentPostProcessorTests.java

@@ -34,6 +34,7 @@ import org.junit.After;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
+import org.springframework.boot.Banner;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.context.config.ConfigFileEnvironmentPostProcessor.ConfigurationPropertySources;
 import org.springframework.boot.env.EnumerableCompositePropertySource;
@@ -625,17 +626,17 @@ public class ConfigFileEnvironmentPostProcessorTests {
 		this.initializer.postProcessEnvironment(this.environment, this.application);
 		Field field = ReflectionUtils.findField(SpringApplication.class, "showBanner");
 		field.setAccessible(true);
-		assertThat((Boolean) field.get(this.application), equalTo(false));
+		assertThat((Banner.Mode) field.get(this.application), equalTo(Banner.Mode.OFF));
 	}
 
 	@Test
 	public void bindsSystemPropertyToSpringApplication() throws Exception {
 		// gh-951
-		System.setProperty("spring.main.showBanner", "false");
+		System.setProperty("spring.main.showBanner", "OFF");
 		this.initializer.postProcessEnvironment(this.environment, this.application);
 		Field field = ReflectionUtils.findField(SpringApplication.class, "showBanner");
 		field.setAccessible(true);
-		assertThat((Boolean) field.get(this.application), equalTo(false));
+		assertThat((Banner.Mode) field.get(this.application), equalTo(Banner.Mode.OFF));
 	}
 
 	private static Matcher<? super ConfigurableEnvironment> containsPropertySource(

spring-boot/src/test/resources/bindtoapplication.properties

@@ -1 +1 @@
-spring.main.show_banner=false
+spring.main.show_banner=OFF