Allow ANSI output to be configured by properties

Add AnsiOutputApplicationListener which configures AnsiOutput.enabled
based on a `spring.output.ansi.enabled` property.

Fixes gh-1243

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

@@ -711,7 +711,10 @@ messages to the console you can start your application with a `--debug` flag.
 	$ java -jar myapp.jar --debug
 ----
 
-If your terminal supports ANSI, color output will be used to aid readability.
+If your terminal supports ANSI, color output will be used to aid readability. You can set
+`spring.output.ansi.enabled` to a
+{dc-spring-boot}/ansi/AnsiOutput.Enabled.{dc-ext}[supported value] to override the auto
+detection.
 
 
 

spring-boot/src/main/java/org/springframework/boot/ansi/AnsiOutput.java

@@ -48,6 +48,10 @@ public abstract class AnsiOutput {
 		AnsiOutput.enabled = enabled;
 	}
 
+	static Enabled getEnabled() {
+		return AnsiOutput.enabled;
+	}
+
 	/**
 	 * Create a new ANSI string from the specified elements. Any {@link AnsiElement}s will
 	 * be encoded as required.
@@ -121,8 +125,28 @@ public abstract class AnsiOutput {
 		}
 	}
 
+	/**
+	 * Possible values to pass to {@link AnsiOutput#setEnabled}. Determines when to output
+	 * ANSI escape sequences for coloring application output.
+	 */
 	public static enum Enabled {
-		DETECT, ALWAYS, NEVER
+
+		/**
+		 * Try to detect whether ANSI coloring capabilities are available. The default
+		 * value for {@link AnsiOutput}.
+		 */
+		DETECT,
+
+		/**
+		 * Enable ANSI-colored output
+		 */
+		ALWAYS,
+
+		/**
+		 * Disable ANSI-colored output
+		 */
+		NEVER
+
 	};
 
 }

spring-boot/src/main/java/org/springframework/boot/ansi/AnsiOutputApplicationListener.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2012-2014 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.ansi;
+
+import org.springframework.boot.ansi.AnsiOutput.Enabled;
+import org.springframework.boot.bind.RelaxedPropertyResolver;
+import org.springframework.boot.context.config.ConfigFileApplicationListener;
+import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
+import org.springframework.context.ApplicationListener;
+import org.springframework.core.Ordered;
+
+/**
+ * An {@link ApplicationListener} that configures {@link AnsiOutput} depending on the the
+ * value of the property <code>spring.output.ansi.enabled</code>. See
+ * {@link AnsiOutput.Enabled} for valid values.
+ *
+ * @author Raphael von der Grün
+ * @since 1.2.0
+ */
+public class AnsiOutputApplicationListener implements
+		ApplicationListener<ApplicationEnvironmentPreparedEvent>, Ordered {
+
+	@Override
+	public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) {
+		RelaxedPropertyResolver resolver = new RelaxedPropertyResolver(
+				event.getEnvironment(), "spring.output.ansi.");
+		if (resolver.containsProperty("enabled")) {
+			String enabled = resolver.getProperty("enabled");
+			AnsiOutput.setEnabled(Enum.valueOf(Enabled.class, enabled.toUpperCase()));
+		}
+	}
+
+	@Override
+	public int getOrder() {
+		// Apply after the ConfigFileApplicationListener
+		return ConfigFileApplicationListener.DEFAULT_ORDER + 1;
+	}
+
+}

spring-boot/src/main/resources/META-INF/spring.factories

@@ -14,6 +14,7 @@ org.springframework.boot.context.config.DelegatingApplicationContextInitializer
 
 # Application Listeners
 org.springframework.context.ApplicationListener=\
+org.springframework.boot.ansi.AnsiOutputApplicationListener,\
 org.springframework.boot.builder.ParentContextCloserApplicationListener,\
 org.springframework.boot.cloudfoundry.VcapApplicationListener,\
 org.springframework.boot.context.FileEncodingApplicationListener,\
@@ -22,4 +23,3 @@ org.springframework.boot.context.config.DelegatingApplicationListener,\
 org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener,\
 org.springframework.boot.logging.ClasspathLoggingApplicationListener,\
 org.springframework.boot.logging.LoggingApplicationListener
-

spring-boot/src/test/java/org/springframework/boot/ansi/AnsiOutputApplicationListenerTests.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2012-2014 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.ansi;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.ansi.AnsiOutput.Enabled;
+import org.springframework.boot.test.EnvironmentTestUtils;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.StandardEnvironment;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Tests for {@link AnsiOutputApplicationListener}.
+ *
+ * @author Phillip Webb
+ */
+public class AnsiOutputApplicationListenerTests {
+
+	@Before
+	@After
+	public void resetAnsi() {
+		AnsiOutput.setEnabled(Enabled.DETECT);
+	}
+
+	@Test
+	public void enabled() {
+		SpringApplication application = new SpringApplication(Config.class);
+		application.setWebEnvironment(false);
+		Map<String, Object> props = new HashMap<String, Object>();
+		props.put("spring.output.ansi.enabled", "ALWAYS");
+		application.setDefaultProperties(props);
+		application.run();
+		assertThat(AnsiOutput.getEnabled(), equalTo(Enabled.ALWAYS));
+	}
+
+	@Test
+	public void disabled() throws Exception {
+		SpringApplication application = new SpringApplication(Config.class);
+		application.setWebEnvironment(false);
+		Map<String, Object> props = new HashMap<String, Object>();
+		props.put("spring.output.ansi.enabled", "never");
+		application.setDefaultProperties(props);
+		application.run();
+		assertThat(AnsiOutput.getEnabled(), equalTo(Enabled.NEVER));
+	}
+
+	@Test
+	public void disabledViaApplcationProperties() throws Exception {
+		ConfigurableEnvironment environment = new StandardEnvironment();
+		EnvironmentTestUtils.addEnvironment(environment, "spring.config.name:ansi");
+		SpringApplication application = new SpringApplication(Config.class);
+		application.setWebEnvironment(false);
+		application.setEnvironment(environment);
+		application.run();
+		assertThat(AnsiOutput.getEnabled(), equalTo(Enabled.NEVER));
+	}
+
+	@Configuration
+	public static class Config {
+	}
+
+}

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

@@ -0,0 +1 @@
+spring.output.ansi.enabled=never