Exclude auto-configurations via property

Add `spring.autoconfigure.exclude` to control the list of
auto-configuration classes to exclude via configuration. Merge the
exclusions defined on the `@EnableAutoConfiguration` or
`@SpringBooApplication` if any.

Closes gh-2435

Author: snicoll

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/EnableAutoConfiguration.java

@@ -44,8 +44,9 @@
  * Auto-configuration tries to be as intelligent as possible and will back-away as you
  * define more of your own configuration. You can always manually {@link #exclude()} any
  * configuration that you never want to apply (use {@link #excludeName()} if you don't
- * have access to them). Auto-configuration is always applied after user-defined beans
- * have been registered.
+ * have access to them). You can also exclude them via the
+ * {@code spring.autoconfigure.exclude} property. Auto-configuration is always applied
+ * after user-defined beans have been registered.
  * <p>
  * The package of the class that is annotated with {@code @EnableAutoConfiguration} has
  * specific significance and is often used as a 'default'. For example, it will be used

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/EnableAutoConfigurationImportSelector.java

@@ -19,6 +19,7 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
@@ -29,11 +30,14 @@
 import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.boot.autoconfigure.condition.ConditionEvaluationReport;
+import org.springframework.boot.bind.RelaxedPropertyResolver;
+import org.springframework.context.EnvironmentAware;
 import org.springframework.context.ResourceLoaderAware;
 import org.springframework.context.annotation.DeferredImportSelector;
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.annotation.Order;
+import org.springframework.core.env.Environment;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.core.io.support.SpringFactoriesLoader;
 import org.springframework.core.type.AnnotationMetadata;
@@ -50,10 +54,12 @@
  */
 @Order(Ordered.LOWEST_PRECEDENCE - 1)
 class EnableAutoConfigurationImportSelector implements DeferredImportSelector,
-		BeanClassLoaderAware, ResourceLoaderAware, BeanFactoryAware {
+		BeanClassLoaderAware, ResourceLoaderAware, BeanFactoryAware, EnvironmentAware {
 
 	private ConfigurableListableBeanFactory beanFactory;
 
+	private Environment environment;
+
 	private ClassLoader beanClassLoader;
 
 	private ResourceLoader resourceLoader;
@@ -78,6 +84,7 @@ public String[] selectImports(AnnotationMetadata metadata) {
 			Set<String> excluded = new LinkedHashSet<String>();
 			excluded.addAll(Arrays.asList(attributes.getStringArray("exclude")));
 			excluded.addAll(Arrays.asList(attributes.getStringArray("excludeName")));
+			excluded.addAll(getExcludeAutoConfigurationsProperty());
 			factories.removeAll(excluded);
 			ConditionEvaluationReport.get(this.beanFactory).recordExclusions(excluded);
 			ConditionEvaluationReport.get(this.beanFactory).recordEvaluationCandidates(
@@ -94,6 +101,16 @@ public String[] selectImports(AnnotationMetadata metadata) {
 		}
 	}
 
+	private List<String> getExcludeAutoConfigurationsProperty() {
+		RelaxedPropertyResolver resolver = new RelaxedPropertyResolver(this.environment,
+				"spring.autoconfigure.");
+		String[] value = resolver.getProperty("exclude", String[].class);
+		if (value != null) {
+			return Arrays.asList(value);
+		}
+		return Collections.emptyList();
+	}
+
 	@Override
 	public void setBeanClassLoader(ClassLoader classLoader) {
 		this.beanClassLoader = classLoader;
@@ -110,4 +127,9 @@ public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
 		this.beanFactory = (ConfigurableListableBeanFactory) beanFactory;
 	}
 
+	@Override
+	public void setEnvironment(Environment environment) {
+		this.environment = environment;
+	}
+
 }

spring-boot-autoconfigure/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -29,6 +29,11 @@
     "description": "JMX name of the application admin MBean.",
     "defaultValue": "org.springframework.boot:type=Admin,name=SpringApplication"
   },
+  {
+    "name": "spring.autoconfigure.exclude",
+    "type": "java.lang.Class[]",
+    "description": "Auto-configuration classes to exclude."
+  },
   {
     "name": "spring.batch.job.enabled",
     "type": "java.lang.Boolean",

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/EnableAutoConfigurationImportSelectorTests.java

@@ -18,6 +18,7 @@
 
 import java.util.List;
 
+import org.flywaydb.core.internal.util.StringUtils;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -27,11 +28,13 @@
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.boot.autoconfigure.condition.ConditionEvaluationReport;
 import org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration;
+import org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration;
 import org.springframework.boot.autoconfigure.velocity.VelocityAutoConfiguration;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.io.support.SpringFactoriesLoader;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.mock.env.MockEnvironment;
 
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.containsInAnyOrder;
@@ -54,6 +57,8 @@ public class EnableAutoConfigurationImportSelectorTests {
 
 	private final ConfigurableListableBeanFactory beanFactory = new DefaultListableBeanFactory();
 
+	private final MockEnvironment environment = new MockEnvironment();
+
 	@Mock
 	private AnnotationMetadata annotationMetadata;
 
@@ -63,12 +68,13 @@ public class EnableAutoConfigurationImportSelectorTests {
 	@Before
 	public void configureImportSelector() {
 		this.importSelector.setBeanFactory(this.beanFactory);
+		this.importSelector.setEnvironment(this.environment);
 		this.importSelector.setResourceLoader(new DefaultResourceLoader());
 	}
 
 	@Test
 	public void importsAreSelected() {
-		configureExclusions(new String[0], new String[0]);
+		configureExclusions(new String[0], new String[0], new String[0]);
 		String[] imports = this.importSelector.selectImports(this.annotationMetadata);
 		assertThat(
 				imports.length,
@@ -82,7 +88,7 @@ EnableAutoConfiguration.class, getClass().getClassLoader())
 	@Test
 	public void classExclusionsAreApplied() {
 		configureExclusions(new String[] { FreeMarkerAutoConfiguration.class.getName() },
-				new String[0]);
+				new String[0], new String[0]);
 		String[] imports = this.importSelector.selectImports(this.annotationMetadata);
 		assertThat(imports.length,
 				is(equalTo(getAutoConfigurationClassNames().size() - 1)));
@@ -93,7 +99,7 @@ public void classExclusionsAreApplied() {
 	@Test
 	public void classNamesExclusionsAreApplied() {
 		configureExclusions(new String[0],
-				new String[] { VelocityAutoConfiguration.class.getName() });
+				new String[] { VelocityAutoConfiguration.class.getName() }, new String[0]);
 		String[] imports = this.importSelector.selectImports(this.annotationMetadata);
 		assertThat(imports.length,
 				is(equalTo(getAutoConfigurationClassNames().size() - 1)));
@@ -102,9 +108,22 @@ public void classNamesExclusionsAreApplied() {
 	}
 
 	@Test
-	public void bothExclusionsAreApplied() {
-		configureExclusions(new String[] { VelocityAutoConfiguration.class.getName() },
-				new String[] { FreeMarkerAutoConfiguration.class.getName() });
+	public void propertyExclusionsAreApplied() {
+		configureExclusions(new String[0], new String[0], new String[] {
+				FreeMarkerAutoConfiguration.class.getName()});
+		String[] imports = this.importSelector.selectImports(this.annotationMetadata);
+		assertThat(imports.length,
+				is(equalTo(getAutoConfigurationClassNames().size() - 1)));
+		assertThat(ConditionEvaluationReport.get(this.beanFactory).getExclusions(),
+				contains(FreeMarkerAutoConfiguration.class.getName()));
+	}
+
+	@Test
+	public void severalPropertyExclusionsAreApplied() {
+		configureExclusions(new String[0], new String[0], new String[] {
+				FreeMarkerAutoConfiguration.class.getName(), VelocityAutoConfiguration
+				.class.getName()});
+
 		String[] imports = this.importSelector.selectImports(this.annotationMetadata);
 		assertThat(imports.length,
 				is(equalTo(getAutoConfigurationClassNames().size() - 2)));
@@ -114,7 +133,23 @@ public void bothExclusionsAreApplied() {
 						VelocityAutoConfiguration.class.getName()));
 	}
 
-	private void configureExclusions(String[] classExclusion, String[] nameExclusion) {
+	@Test
+	public void combinedExclusionsAreApplied() {
+		configureExclusions(new String[] { VelocityAutoConfiguration.class.getName() },
+				new String[] { FreeMarkerAutoConfiguration.class.getName() },
+				new String[] { ThymeleafAutoConfiguration.class.getName() });
+		String[] imports = this.importSelector.selectImports(this.annotationMetadata);
+		assertThat(imports.length,
+				is(equalTo(getAutoConfigurationClassNames().size() - 3)));
+		assertThat(
+				ConditionEvaluationReport.get(this.beanFactory).getExclusions(),
+				containsInAnyOrder(FreeMarkerAutoConfiguration.class.getName(),
+						VelocityAutoConfiguration.class.getName(),
+						ThymeleafAutoConfiguration.class.getName()));
+	}
+
+	private void configureExclusions(String[] classExclusion, String[] nameExclusion,
+			String[] propertyExclusion) {
 		given(
 				this.annotationMetadata.getAnnotationAttributes(
 						EnableAutoConfiguration.class.getName(), true)).willReturn(
@@ -123,6 +158,11 @@ private void configureExclusions(String[] classExclusion, String[] nameExclusion
 				classExclusion);
 		given(this.annotationAttributes.getStringArray("excludeName")).willReturn(
 				nameExclusion);
+		if (propertyExclusion.length > 0) {
+			String value = StringUtils.arrayToCommaDelimitedString(propertyExclusion);
+			this.environment.setProperty("spring.autoconfigure.exclude",
+					value);
+		}
 	}
 
 	private List<String> getAutoConfigurationClassNames() {

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -45,6 +45,9 @@ content into your application; rather pick only the properties that you need.
 	spring.main.show-banner=true
 	spring.main....= # see class for all properties
 
+	# AUTO-CONFIGURATION
+	spring.autoconfigure.exclude= # comma-separated list of auto-configuration classes to exclude
+
 	# ADMIN ({sc-spring-boot-autoconfigure}/admin/SpringApplicationAdminJmxAutoConfiguration.{sc-ext}[SpringApplicationAdminJmxAutoConfiguration])
 	spring.application.admin.enabled=false # enable admin features for the application
 	spring.application.admin.jmx-name=org.springframework.boot:type=Admin,name=SpringApplication # JMX name of the application admin MBean

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

@@ -602,7 +602,7 @@ report to the console.
 
 
 
-[[using-boot-disabling-specific-auto-configutation]]
+[[using-boot-disabling-specific-auto-configuration]]
 === Disabling specific auto-configuration
 If you find that specific auto-configure classes are being applied that you don't want,
 you can use the exclude attribute of `@EnableAutoConfiguration` to disable them.
@@ -619,7 +619,12 @@ you can use the exclude attribute of `@EnableAutoConfiguration` to disable them.
 	}
 ----
 
+If the class is not on the classpath, you can use the `excludeName` attribute of
+the annotation and specify the fully qualified name instead. Finally, you can also
+control the list of auto-configuration classes to excludes via the
+`spring.autoconfigure.exclude` property.
 
+TIP: You can define exclusions both at the annotation level and using the property.
 
 [[using-boot-spring-beans-and-dependency-injection]]
 == Spring Beans and dependency injection