Add build-image support to the maven plugin

Add a new `build-image` goal to the Maven plugin to allow Docker images
to be create via using the cloud native buildpack.

See gh-19830

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/build.gradle

@@ -15,6 +15,7 @@ configurations {
 
 dependencies {
 	api platform(project(':spring-boot-project:spring-boot-parent'))
+	api project(':spring-boot-project:spring-boot-tools:spring-boot-cloudnativebuildpack')
 
 	compileOnly 'org.apache.maven.plugin-tools:maven-plugin-annotations'
 	compileOnly 'org.sonatype.plexus:plexus-build-api'

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/AbstractPackagerMojo.java

@@ -0,0 +1,199 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.maven;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.function.Supplier;
+
+import org.apache.maven.artifact.Artifact;
+import org.apache.maven.model.Dependency;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.MavenProject;
+import org.apache.maven.project.MavenProjectHelper;
+import org.apache.maven.shared.artifact.filter.collection.ArtifactsFilter;
+import org.apache.maven.shared.artifact.filter.collection.ScopeFilter;
+
+import org.springframework.boot.loader.tools.Layout;
+import org.springframework.boot.loader.tools.LayoutFactory;
+import org.springframework.boot.loader.tools.Layouts.Expanded;
+import org.springframework.boot.loader.tools.Layouts.Jar;
+import org.springframework.boot.loader.tools.Layouts.LayeredJar;
+import org.springframework.boot.loader.tools.Layouts.None;
+import org.springframework.boot.loader.tools.Layouts.War;
+import org.springframework.boot.loader.tools.Libraries;
+import org.springframework.boot.loader.tools.Packager;
+
+/**
+ * Abstract base class for classes that work with an {@link Packager}.
+ *
+ * @author Phillip Webb
+ * @since 2.3.0
+ */
+public abstract class AbstractPackagerMojo extends AbstractDependencyFilterMojo {
+
+	/**
+	 * The Maven project.
+	 * @since 1.0.0
+	 */
+	@Parameter(defaultValue = "${project}", readonly = true, required = true)
+	protected MavenProject project;
+
+	/**
+	 * Maven project helper utils.
+	 * @since 1.0.0
+	 */
+	@Component
+	protected MavenProjectHelper projectHelper;
+
+	/**
+	 * The name of the main class. If not specified the first compiled class found that
+	 * contains a 'main' method will be used.
+	 * @since 1.0.0
+	 */
+	@Parameter
+	private String mainClass;
+
+	/**
+	 * The type of archive (which corresponds to how the dependencies are laid out inside
+	 * it). Possible values are JAR, LAYERED_JAR, WAR, ZIP, DIR, NONE. Defaults to a guess
+	 * based on the archive type.
+	 * @since 1.0.0
+	 */
+	@Parameter(property = "spring-boot.repackage.layout")
+	private LayoutType layout;
+
+	/**
+	 * The layout factory that will be used to create the executable archive if no
+	 * explicit layout is set. Alternative layouts implementations can be provided by 3rd
+	 * parties.
+	 * @since 1.5.0
+	 */
+	@Parameter
+	private LayoutFactory layoutFactory;
+
+	/**
+	 * Exclude Spring Boot devtools from the repackaged archive.
+	 * @since 1.3.0
+	 */
+	@Parameter(property = "spring-boot.repackage.excludeDevtools", defaultValue = "true")
+	private boolean excludeDevtools = true;
+
+	/**
+	 * Include system scoped dependencies.
+	 * @since 1.4.0
+	 */
+	@Parameter(defaultValue = "false")
+	public boolean includeSystemScope;
+
+	/**
+	 * Return a {@link Packager} configured for this MOJO.
+	 * @param <P> the packager type
+	 * @param supplier a packager supplier
+	 * @return a configured packager
+	 */
+	protected <P extends Packager> P getConfiguredPackager(Supplier<P> supplier) {
+		P packager = supplier.get();
+		packager.setLayoutFactory(this.layoutFactory);
+		packager.addMainClassTimeoutWarningListener(new LoggingMainClassTimeoutWarningListener(this::getLog));
+		packager.setMainClass(this.mainClass);
+		if (this.layout != null) {
+			getLog().info("Layout: " + this.layout);
+			packager.setLayout(this.layout.layout());
+		}
+		return packager;
+	}
+
+	/**
+	 * Return {@link Libraries} that the packager can use.
+	 * @param unpacks any libraries that require unpack
+	 * @return the libraries to use
+	 * @throws MojoExecutionException on execution error
+	 */
+	protected final Libraries getLibraries(Collection<Dependency> unpacks) throws MojoExecutionException {
+		Set<Artifact> artifacts = filterDependencies(this.project.getArtifacts(), getFilters(getAdditionalFilters()));
+		Libraries libraries = new ArtifactsLibraries(artifacts, unpacks, getLog());
+		return libraries;
+	}
+
+	private ArtifactsFilter[] getAdditionalFilters() {
+		List<ArtifactsFilter> filters = new ArrayList<>();
+		if (this.excludeDevtools) {
+			Exclude exclude = new Exclude();
+			exclude.setGroupId("org.springframework.boot");
+			exclude.setArtifactId("spring-boot-devtools");
+			ExcludeFilter filter = new ExcludeFilter(exclude);
+			filters.add(filter);
+		}
+		if (!this.includeSystemScope) {
+			filters.add(new ScopeFilter(null, Artifact.SCOPE_SYSTEM));
+		}
+		return filters.toArray(new ArtifactsFilter[0]);
+	}
+
+	/**
+	 * Archive layout types.
+	 */
+	public enum LayoutType {
+
+		/**
+		 * Jar Layout.
+		 */
+		JAR(new Jar()),
+
+		/**
+		 * Layered Jar Layout.
+		 */
+		LAYERED_JAR(new LayeredJar()),
+
+		/**
+		 * War Layout.
+		 */
+		WAR(new War()),
+
+		/**
+		 * Zip Layout.
+		 */
+		ZIP(new Expanded()),
+
+		/**
+		 * Dir Layout.
+		 */
+		DIR(new Expanded()),
+
+		/**
+		 * No Layout.
+		 */
+		NONE(new None());
+
+		private final Layout layout;
+
+		LayoutType(Layout layout) {
+			this.layout = layout;
+		}
+
+		public Layout layout() {
+			return this.layout;
+		}
+
+	}
+
+}