Collect and display build information

This commit updates the Maven plugin to generate a
`META-INF/boot/build.properties` file with various build-specific
settings (group, artifact, name, version and build time). Additionally,
the plugin can be configured to write an arbitrary number of additional
properties.

A new `BuildProperties` bean is automatically exposed when such a file is
present. If that bean is present, an `InfoContributor` is automatically
created to expose that information under the `build` key.

As for the git contributor, it is possible to only display the core
settings or everything using the `management.info.build.mode` property.

See gh-2559

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/info/ProjectInfoAutoConfiguration.java

@@ -22,9 +22,11 @@ import java.util.Properties;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnResource;
 import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
 import org.springframework.boot.bind.RelaxedPropertyResolver;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.info.BuildProperties;
 import org.springframework.boot.info.GitProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ConditionContext;
@@ -60,6 +62,13 @@ public class ProjectInfoAutoConfiguration {
 		return new GitProperties(loadFrom(this.properties.getGit().getLocation(), "git"));
 	}
 
+	@ConditionalOnResource(resources = "${spring.info.build.location:classpath:META-INF/boot/build.properties}")
+	@ConditionalOnMissingBean
+	@Bean
+	public BuildProperties buildProperties() throws Exception {
+		return new BuildProperties(loadFrom(this.properties.getBuild().getLocation(), "build"));
+	}
+
 	protected Properties loadFrom(Resource location, String prefix) throws IOException {
 		String p = prefix.endsWith(".") ? prefix : prefix + ".";
 		Properties source = PropertiesLoaderUtils.loadProperties(location);
@@ -72,7 +81,6 @@ public class ProjectInfoAutoConfiguration {
 		return target;
 	}
 
-
 	static class GitResourceAvailableCondition extends SpringBootCondition {
 
 		private final ResourceLoader defaultResourceLoader = new DefaultResourceLoader();

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/info/ProjectInfoProperties.java

@@ -19,6 +19,7 @@ package org.springframework.boot.autoconfigure.info;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 
 /**
@@ -30,8 +31,14 @@ import org.springframework.core.io.Resource;
 @ConfigurationProperties("spring.info")
 public class ProjectInfoProperties {
 
+	private final Build build = new Build();
+
 	private final Git git = new Git();
 
+	public Build getBuild() {
+		return this.build;
+	}
+
 	public Git getGit() {
 		return this.git;
 	}
@@ -46,13 +53,34 @@ public class ProjectInfoProperties {
 		getGit().setLocation(defaultGitLocation);
 	}
 
+
+	/**
+	 * Build specific info properties.
+	 */
+	public static class Build {
+
+		/**
+		 * Location of the generated build.properties file.
+		 */
+		private Resource location = new ClassPathResource("META-INF/boot/build.properties");
+
+		public Resource getLocation() {
+			return this.location;
+		}
+
+		public void setLocation(Resource location) {
+			this.location = location;
+		}
+
+	}
+
 	/**
 	 * Git specific info properties.
 	 */
 	public static class Git {
 
 		/**
-		 * Location of the generated git info properties file.
+		 * Location of the generated git.properties file.
 		 */
 		private Resource location;
 

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/info/ProjectInfoAutoConfigurationTests.java

@@ -23,6 +23,7 @@ import org.junit.After;
 import org.junit.Test;
 
 import org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration;
+import org.springframework.boot.info.BuildProperties;
 import org.springframework.boot.info.GitProperties;
 import org.springframework.boot.test.EnvironmentTestUtils;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
@@ -82,12 +83,48 @@ public class ProjectInfoAutoConfigurationTests {
 
 	@Test
 	public void gitPropertiesFallbackWithGitPropertiesBean() {
-		load(CustomGitPropertiesConfiguration.class,
+		load(CustomInfoPropertiesConfiguration.class,
 				"spring.info.git.location=classpath:/org/springframework/boot/autoconfigure/info/git.properties");
 		GitProperties gitProperties = this.context.getBean(GitProperties.class);
 		assertThat(gitProperties).isSameAs(this.context.getBean("customGitProperties"));
 	}
 
+	@Test
+	public void buildPropertiesDefaultLocation() {
+		load();
+		BuildProperties buildProperties = this.context.getBean(BuildProperties.class);
+		assertThat(buildProperties.getGroup()).isEqualTo("com.example");
+		assertThat(buildProperties.getArtifact()).isEqualTo("demo");
+		assertThat(buildProperties.getName()).isEqualTo("Demo Project");
+		assertThat(buildProperties.getVersion()).isEqualTo("0.0.1-SNAPSHOT");
+		assertThat(buildProperties.getTime().getTime()).isEqualTo(1457100965000L);
+	}
+
+	@Test
+	public void buildPropertiesCustomLocation() {
+		load("spring.info.build.location=classpath:/org/springframework/boot/autoconfigure/info/build.properties");
+		BuildProperties buildProperties = this.context.getBean(BuildProperties.class);
+		assertThat(buildProperties.getGroup()).isEqualTo("com.example.acme");
+		assertThat(buildProperties.getArtifact()).isEqualTo("acme");
+		assertThat(buildProperties.getName()).isEqualTo("acme");
+		assertThat(buildProperties.getVersion()).isEqualTo("1.0.1-SNAPSHOT");
+		assertThat(buildProperties.getTime().getTime()).isEqualTo(1457088120000L);
+	}
+
+	@Test
+	public void buildPropertiesCustomInvalidLocation() {
+		load("spring.info.build.location=classpath:/org/acme/no-build.properties");
+		Map<String, BuildProperties> beans = this.context.getBeansOfType(BuildProperties.class);
+		assertThat(beans).hasSize(0);
+	}
+
+	@Test
+	public void buildPropertiesFallbackWithBuildInfoBean() {
+		load(CustomInfoPropertiesConfiguration.class);
+		BuildProperties buildProperties = this.context.getBean(BuildProperties.class);
+		assertThat(buildProperties).isSameAs(this.context.getBean("customBuildProperties"));
+	}
+
 	private void load(String... environment) {
 		load(null, environment);
 	}
@@ -105,13 +142,18 @@ public class ProjectInfoAutoConfigurationTests {
 	}
 
 	@Configuration
-	static class CustomGitPropertiesConfiguration {
+	static class CustomInfoPropertiesConfiguration {
 
 		@Bean
 		public GitProperties customGitProperties() {
 			return new GitProperties(new Properties());
 		}
 
+		@Bean
+		public BuildProperties customBuildProperties() {
+			return new BuildProperties(new Properties());
+		}
+
 	}
 
 }

spring-boot-autoconfigure/src/test/resources/META-INF/boot/build.properties

@@ -0,0 +1,5 @@
+build.group=com.example
+build.artifact=demo
+build.name=Demo Project
+build.version=0.0.1-SNAPSHOT
+build.time=2016-03-04T15\:16\:05+0100

spring-boot-autoconfigure/src/test/resources/org/springframework/boot/autoconfigure/info/build.properties

@@ -0,0 +1,5 @@
+build.group=com.example.acme
+build.artifact=acme
+build.name=acme
+build.version=1.0.1-SNAPSHOT
+build.time=2016-03-04T11:42:00+0100