Add support for creating layered war files with Gradle

See gh-22195

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/BootWar.java

@@ -22,6 +22,7 @@ import java.util.function.Function;
 
 import org.gradle.api.Action;
 import org.gradle.api.Project;
+import org.gradle.api.artifacts.ResolvableDependencies;
 import org.gradle.api.file.CopySpec;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.file.FileCopyDetails;
@@ -30,6 +31,8 @@ import org.gradle.api.internal.file.copy.CopyAction;
 import org.gradle.api.provider.Property;
 import org.gradle.api.specs.Spec;
 import org.gradle.api.tasks.Classpath;
+import org.gradle.api.tasks.Internal;
+import org.gradle.api.tasks.Nested;
 import org.gradle.api.tasks.Optional;
 import org.gradle.api.tasks.bundling.War;
 
@@ -50,12 +53,18 @@ public class BootWar extends War implements BootArchive {
 
 	private static final String LIB_DIRECTORY = "WEB-INF/lib/";
 
+	private static final String LAYERS_INDEX = "WEB-INF/layers.idx";
+
 	private final BootArchiveSupport support;
 
 	private final Property<String> mainClass;
 
 	private FileCollection providedClasspath;
 
+	private final ResolvedDependencies resolvedDependencies = new ResolvedDependencies();
+
+	private LayeredSpec layered = new LayeredSpec();
+
 	/**
 	 * Creates a new {@code BootWar} task.
 	 */
@@ -65,6 +74,14 @@ public class BootWar extends War implements BootArchive {
 		getWebInf().into("lib-provided", fromCallTo(this::getProvidedLibFiles));
 		this.support.moveModuleInfoToRoot(getRootSpec());
 		getRootSpec().eachFile(this.support::excludeNonZipLibraryFiles);
+		getProject().getConfigurations().all((configuration) -> {
+			ResolvableDependencies incoming = configuration.getIncoming();
+			incoming.afterResolve((resolvableDependencies) -> {
+				if (resolvableDependencies == incoming) {
+					this.resolvedDependencies.processConfiguration(configuration);
+				}
+			});
+		});
 	}
 
 	private Object getProvidedLibFiles() {
@@ -74,12 +91,21 @@ public class BootWar extends War implements BootArchive {
 	@Override
 	public void copy() {
 		this.support.configureManifest(getManifest(), getMainClass().get(), CLASSES_DIRECTORY, LIB_DIRECTORY, null,
-				null);
+				(isLayeredDisabled()) ? null : LAYERS_INDEX);
 		super.copy();
 	}
 
+	private boolean isLayeredDisabled() {
+		return this.layered != null && !this.layered.isEnabled();
+	}
+
 	@Override
 	protected CopyAction createCopyAction() {
+		if (!isLayeredDisabled()) {
+			LayerResolver layerResolver = new LayerResolver(this.resolvedDependencies, this.layered, this::isLibrary);
+			String layerToolsLocation = this.layered.isIncludeLayerTools() ? LIB_DIRECTORY : null;
+			return this.support.createCopyAction(this, layerResolver, layerToolsLocation);
+		}
 		return this.support.createCopyAction(this);
 	}
 
@@ -181,6 +207,25 @@ public class BootWar extends War implements BootArchive {
 		return isLibrary(details) ? ZipCompression.STORED : ZipCompression.DEFLATED;
 	}
 
+	/**
+	 * Returns the spec that describes the layers in a layered jar.
+	 * @return the spec for the layers
+	 * @since 2.5.0
+	 */
+	@Nested
+	public LayeredSpec getLayered() {
+		return this.layered;
+	}
+
+	/**
+	 * Configures the war's layering using the given {@code action}.
+	 * @param action the action to apply
+	 * @since 2.5.0
+	 */
+	public void layered(Action<LayeredSpec> action) {
+		action.execute(this.layered);
+	}
+
 	/**
 	 * Return if the {@link FileCopyDetails} are for a library. By default any file in
 	 * {@code WEB-INF/lib} or {@code WEB-INF/lib-provided} is considered to be a library.
@@ -201,6 +246,11 @@ public class BootWar extends War implements BootArchive {
 		return launchScript;
 	}
 
+	@Internal
+	ResolvedDependencies getResolvedDependencies() {
+		return this.resolvedDependencies;
+	}
+
 	/**
 	 * Syntactic sugar that makes {@link CopySpec#into} calls a little easier to read.
 	 * @param <T> the result type

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/LayeredSpec.java

@@ -41,7 +41,7 @@ import org.springframework.boot.loader.tools.layer.LibraryContentFilter;
 import org.springframework.util.Assert;
 
 /**
- * Encapsulates the configuration for a layered jar.
+ * Encapsulates the configuration for a layered archive.
  *
  * @author Madhura Bhave
  * @author Scott Frederick
@@ -65,7 +65,7 @@ public class LayeredSpec {
 
 	/**
 	 * Returns whether the layer tools should be included as a dependency in the layered
-	 * jar.
+	 * archive.
 	 * @return whether the layer tools should be included
 	 */
 	@Input
@@ -74,7 +74,8 @@ public class LayeredSpec {
 	}
 
 	/**
-	 * Sets whether the layer tools should be included as a dependency in the layered jar.
+	 * Sets whether the layer tools should be included as a dependency in the layered
+	 * archive.
 	 * @param includeLayerTools {@code true} if the layer tools should be included,
 	 * otherwise {@code false}
 	 */
@@ -83,7 +84,7 @@ public class LayeredSpec {
 	}
 
 	/**
-	 * Returns whether the layers.idx should be included in the jar.
+	 * Returns whether the layers.idx should be included in the archive.
 	 * @return whether the layers.idx should be included
 	 */
 	@Input
@@ -92,8 +93,8 @@ public class LayeredSpec {
 	}
 
 	/**
-	 * Sets whether the layers.idx should be included in the jar.
-	 * @param enabled {@code true} layers.idx should be included in the jar, otherwise
+	 * Sets whether the layers.idx should be included in the archive.
+	 * @param enabled {@code true} layers.idx should be included in the archive, otherwise
 	 * {@code false}
 	 */
 	public void setEnabled(boolean enabled) {
@@ -171,7 +172,8 @@ public class LayeredSpec {
 	}
 
 	/**
-	 * Returns the order of the layers in the jar from least to most frequently changing.
+	 * Returns the order of the layers in the archive from least to most frequently
+	 * changing.
 	 * @return the layer order
 	 */
 	@Input
@@ -180,7 +182,7 @@ public class LayeredSpec {
 	}
 
 	/**
-	 * Sets to order of the layers in the jar from least to most frequently changing.
+	 * Sets the order of the layers in the archive from least to most frequently changing.
 	 * @param layerOrder the layer order
 	 */
 	public void setLayerOrder(String... layerOrder) {
@@ -188,7 +190,7 @@ public class LayeredSpec {
 	}
 
 	/**
-	 * Sets to order of the layers in the jar from least to most frequently changing.
+	 * Sets the order of the layers in the archive from least to most frequently changing.
 	 * @param layerOrder the layer order
 	 */
 	public void setLayerOrder(List<String> layerOrder) {

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests.java

@@ -16,10 +16,14 @@
 
 package org.springframework.boot.gradle.tasks.bundling;
 
+import java.util.Arrays;
+import java.util.Set;
+import java.util.TreeSet;
+
 import org.springframework.boot.gradle.junit.GradleCompatibility;
 
 /**
- * Integration tests for {@link BootJar}.
+ * Integration tests for {@link BootWar}.
  *
  * @author Andy Wilkinson
  */
@@ -27,7 +31,14 @@ import org.springframework.boot.gradle.junit.GradleCompatibility;
 class BootWarIntegrationTests extends AbstractBootArchiveIntegrationTests {
 
 	BootWarIntegrationTests() {
-		super("bootWar", "WEB-INF/lib/", "WEB-INF/classes/");
+		super("bootWar", "WEB-INF/lib/", "WEB-INF/classes/", "WEB-INF/");
+	}
+
+	@Override
+	String[] getExpectedApplicationLayerContents(String... additionalFiles) {
+		Set<String> contents = new TreeSet<>(Arrays.asList(additionalFiles));
+		contents.addAll(Arrays.asList("WEB-INF/layers.idx", "META-INF/"));
+		return contents.toArray(new String[0]);
 	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootWarTests.java

@@ -20,6 +20,8 @@ import java.io.File;
 import java.io.IOException;
 import java.util.jar.JarFile;
 
+import org.gradle.api.Action;
+import org.gradle.api.artifacts.Configuration;
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -32,7 +34,8 @@ import static org.assertj.core.api.Assertions.assertThat;
 class BootWarTests extends AbstractBootArchiveTests<BootWar> {
 
 	BootWarTests() {
-		super(BootWar.class, "org.springframework.boot.loader.WarLauncher", "WEB-INF/lib/", "WEB-INF/classes/");
+		super(BootWar.class, "org.springframework.boot.loader.WarLauncher", "WEB-INF/lib/", "WEB-INF/classes/",
+				"WEB-INF/");
 	}
 
 	@Test
@@ -111,4 +114,19 @@ class BootWarTests extends AbstractBootArchiveTests<BootWar> {
 		getTask().copy();
 	}
 
+	@Override
+	void populateResolvedDependencies(Configuration configuration) {
+		getTask().getResolvedDependencies().processConfiguration(configuration);
+	}
+
+	@Override
+	void applyLayered(Action<LayeredSpec> action) {
+		getTask().layered(action);
+	}
+
+	@Override
+	boolean archiveHasClasspathIndex() {
+		return false;
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootJarIntegrationTests-implicitLayers.gradle

@@ -16,6 +16,7 @@ dependencies {
 	implementation("com.example:library:1.0-SNAPSHOT")
 	implementation("org.apache.commons:commons-lang3:3.9")
 	implementation("org.springframework:spring-core:5.2.5.RELEASE")
+	implementation("org.springframework.boot:spring-boot-starter-logging:2.2.0.RELEASE")
 }
 
 task listLayers(type: JavaExec) {

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-customLayers.gradle

+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+	id 'war'
+}
+
+bootWar {
+	mainClass = 'com.example.Application'
+	layered {
+		application {
+			intoLayer("static") {
+				include "META-INF/resources/**", "resources/**", "static/**", "public/**"
+			}
+			intoLayer("app")
+		}
+		dependencies {
+			intoLayer("snapshot-dependencies") {
+				include "*:*:*SNAPSHOT"
+			}
+			intoLayer("commons-dependencies") {
+				include "org.apache.commons:*"
+			}
+			intoLayer("dependencies")
+		}
+		layerOrder = ["dependencies", "commons-dependencies", "snapshot-dependencies", "static", "app"]
+	}
+}
+
+repositories {
+	mavenCentral()
+	maven { url "file:repository" }
+}
+
+dependencies {
+	implementation("com.example:library:1.0-SNAPSHOT")
+	implementation("org.apache.commons:commons-lang3:3.9")
+	implementation("org.springframework:spring-core:5.2.5.RELEASE")
+}
+
+task listLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "list"
+}
+
+task extractLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "extract"
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-developmentOnlyDependenciesAreNotIncludedInTheArchiveByDefault.gradle

@@ -16,3 +16,9 @@ dependencies {
 	developmentOnly("commons-io:commons-io:2.6")
 	implementation("commons-io:commons-io:2.6")
 }
+
+bootWar {
+	layered {
+		enabled = false
+	}
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-developmentOnlyDependenciesCanBeIncludedInTheArchive.gradle

@@ -19,3 +19,9 @@ dependencies {
 bootWar {
 	classpath configurations.developmentOnly
 }
+
+bootWar {
+	layered {
+		enabled = false
+	}
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-implicitLayers.gradle

+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+	id 'war'
+}
+
+bootWar {
+	mainClass = 'com.example.Application'
+}
+
+repositories {
+	mavenCentral()
+	maven { url "file:repository" }
+}
+
+dependencies {
+	implementation("com.example:library:1.0-SNAPSHOT")
+	implementation("org.apache.commons:commons-lang3:3.9")
+	implementation("org.springframework:spring-core:5.2.5.RELEASE")
+	implementation("org.springframework.boot:spring-boot-starter-logging:2.2.0.RELEASE")
+}
+
+task listLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "list"
+}
+
+task extractLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "extract"
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-jarTypeFilteringIsApplied.gradle

@@ -17,3 +17,9 @@ dependencies {
 	implementation(name: "standard")
 	implementation(name: "starter")
 }
+
+bootWar {
+	layered {
+		enabled = false
+	}
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-layersWithCustomSourceSet.gradle

+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+	id 'war'
+}
+
+sourceSets {
+	custom
+}
+
+bootWar {
+	mainClass = 'com.example.Application'
+}
+
+repositories {
+	mavenCentral()
+	maven { url "file:repository" }
+}
+
+dependencies {
+	implementation("com.example:library:1.0-SNAPSHOT")
+	implementation("org.apache.commons:commons-lang3:3.9")
+	implementation("org.springframework:spring-core:5.2.5.RELEASE")
+}
+
+task listLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "list"
+}
+
+task extractLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "extract"
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-multiModuleCustomLayers.gradle

+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+	id 'war'
+}
+
+subprojects {
+	apply plugin: 'java'
+	group = 'org.example.projects'
+	version = '1.2.3'
+}
+
+bootWar {
+	mainClass = 'com.example.Application'
+	layered {
+		application {
+			intoLayer("static") {
+				include "META-INF/resources/**", "resources/**", "static/**", "public/**"
+			}
+			intoLayer("app")
+		}
+		dependencies {
+			intoLayer("snapshot-dependencies") {
+				include "*:*:*SNAPSHOT"
+				excludeProjectDependencies()
+			}
+			intoLayer("subproject-dependencies") {
+				includeProjectDependencies()
+			}
+			intoLayer("commons-dependencies") {
+				include "org.apache.commons:*"
+			}
+			intoLayer("dependencies")
+		}
+		layerOrder = ["dependencies", "commons-dependencies", "snapshot-dependencies", "subproject-dependencies", "static", "app"]
+	}
+}
+
+repositories {
+	mavenCentral()
+	maven { url "file:repository" }
+}
+
+dependencies {
+	implementation(project(':alpha'))
+	implementation(project(':bravo'))
+	implementation("com.example:library:1.0-SNAPSHOT")
+	implementation("org.apache.commons:commons-lang3:3.9")
+	implementation("org.springframework:spring-core:5.2.5.RELEASE")
+}
+
+task listLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "list"
+}
+
+task extractLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "extract"
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-multiModuleImplicitLayers.gradle

+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+	id 'war'
+}
+
+subprojects {
+	apply plugin: 'java'
+	group = 'org.example.projects'
+	version = '1.2.3'
+}
+
+bootWar {
+	mainClass = 'com.example.Application'
+}
+
+repositories {
+	mavenCentral()
+	maven { url "file:repository" }
+}
+
+dependencies {
+	implementation(project(':alpha'))
+	implementation(project(':bravo'))
+	implementation("com.example:library:1.0-SNAPSHOT")
+	implementation("org.apache.commons:commons-lang3:3.9")
+	implementation("org.springframework:spring-core:5.2.5.RELEASE")
+}
+
+task listLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "list"
+}
+
+task extractLayers(type: JavaExec) {
+	classpath = bootWar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "extract"
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-notUpToDateWhenBuiltWithLayerToolsAndThenWithoutLayerTools.gradle

+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+	id 'war'
+}
+
+bootWar {
+	mainClass = 'com.example.Application'
+	layered {
+		{layerTools}
+	}
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-notUpToDateWhenBuiltWithoutLayersAndThenWithLayers.gradle

+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+	id 'war'
+}
+
+bootWar {
+	mainClass = 'com.example.Application'
+	layered {
+		{layerEnablement}
+	}
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-upToDateWhenBuiltWithDefaultLayeredAndThenWithExplicitLayered.gradle

+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+	id 'war'
+}
+
+bootWar {
+	mainClass = 'com.example.Application'
+	{layered}
+}