Add support for invoking AOT in the Maven Plugin

This commit adds an `aot-generate` goal to the Maven Plugin that
triggers AOT generation on the application. The new goal shares a
number of properties with the existing `run` goal and uses the same
algorithm to detect the main class to use.

Closes spring-projectsgh-30525

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

@@ -34,11 +34,10 @@ dependencies {
 		exclude(group: "javax.inject", module: "javax.inject")
 	}
 
+	implementation("org.springframework:spring-context")
 	implementation(project(":spring-boot-project:spring-boot-tools:spring-boot-buildpack-platform"))
 	implementation(project(":spring-boot-project:spring-boot-tools:spring-boot-loader-tools"))
 
-	intTestImplementation(project(":spring-boot-project:spring-boot-tools:spring-boot-buildpack-platform"))
-	intTestImplementation(project(":spring-boot-project:spring-boot-tools:spring-boot-loader-tools"))
 	intTestImplementation(project(":spring-boot-project:spring-boot-tools:spring-boot-test-support"))
 	intTestImplementation("org.apache.maven.shared:maven-invoker") {
 		exclude(group: "javax.inject", module: "javax.inject")
@@ -53,6 +52,8 @@ dependencies {
 		exclude(group: "javax.inject", module: "javax.inject")
 	}
 
+	mavenRepository(project(path: ":spring-boot-project:spring-boot", configuration: "mavenRepository"))
+
 	runtimeOnly("org.sonatype.plexus:plexus-build-api")
 
 	testImplementation("org.assertj:assertj-core")

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/docs/asciidoc/aot.adoc

@@ -0,0 +1,22 @@
+[[aot]]
+= Optimizing Your Application at Build-Time
+
+Spring AOT inspects an application at build-time and generates an optimized version of it.
+Based on your `@SpringBootApplication`-annotated main class, the AOT engine generates a persistent view of the beans that are going to be contributed at runtime in a way that bean instantiation is as straightforward as possible.
+Additional post-processing of the factory is possible using callbacks.
+For instance, these are used to generate the necessary reflection configuration that GraalVM needs to initialize the context in a native image.
+
+To configure your application to use this feature, add an execution for the `aot-generate` goal, as shown in the following example:
+
+[source,xml,indent=0,subs="verbatim,attributes",tabsize=4]
+----
+include::../maven/aot/pom.xml[tags=aot]
+----
+
+As the `BeanFactory` is fully prepared at build-time, conditions are also evaluated.
+This has an important difference compared to what a regular Spring Boot application does at runtime.
+For instance, if you want to opt-in or opt-out for certain features, you need to configure the environment used at build time to do so.
+The `aot-generate` goal shares a number of properties with the <<run,run goal>> for that reason.
+
+
+include::goals/aot-generate.adoc[leveloffset=+1]

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/docs/asciidoc/index.adoc

@@ -36,6 +36,8 @@ include::packaging-oci-image.adoc[leveloffset=+1]
 
 include::running.adoc[leveloffset=+1]
 
+include::aot.adoc[leveloffset=+1]
+
 include::integration-tests.adoc[leveloffset=+1]
 
 include::build-info.adoc[leveloffset=+1]

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/docs/maven/aot/pom.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project>
+	<modelVersion>4.0.0</modelVersion>
+	<artifactId>aot</artifactId>
+	<build>
+		<plugins>
+			<!-- tag::aot[] -->
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>aot-generate</id>
+						<goals>
+							<goal>aot-generate</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+			<!-- end::aot[] -->
+		</plugins>
+	</build>
+</project>
+
+

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/AotGenerateTests.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2012-2022 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.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.TestTemplate;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for the Maven plugin's AOT support.
+ *
+ * @author Stephane Nicoll
+ */
+@ExtendWith(MavenBuildExtension.class)
+public class AotGenerateTests {
+
+	@TestTemplate
+	void whenAotRunsSourcesAreGenerated(MavenBuild mavenBuild) {
+		mavenBuild.project("aot").goals("package").execute((project) -> {
+			Path aotDirectory = project.toPath().resolve("target/spring-aot/main");
+			assertThat(collectRelativeFileNames(aotDirectory.resolve("sources")))
+					.containsOnly("org/test/SampleApplication__ApplicationContextInitializer.java");
+			assertThat(collectRelativeFileNames(aotDirectory.resolve("resources")))
+					.containsOnly("META-INF/native-image/reflect-config.json");
+		});
+	}
+
+	@TestTemplate
+	void whenAotRunsSourcesAreCompiled(MavenBuild mavenBuild) {
+		mavenBuild.project("aot").goals("package").execute((project) -> {
+			Path classesDirectory = project.toPath().resolve("target/classes");
+			assertThat(collectRelativeFileNames(classesDirectory))
+					.contains("org/test/SampleApplication__ApplicationContextInitializer.class");
+		});
+	}
+
+	@TestTemplate
+	void whenAotRunsResourcesAreCopiedUsingProjectCoordinates(MavenBuild mavenBuild) {
+		mavenBuild.project("aot").goals("package").execute((project) -> {
+			Path classesDirectory = project.toPath().resolve("target/classes/META-INF/native-image");
+			assertThat(collectRelativeFileNames(classesDirectory))
+					.contains("org.springframework.boot.maven.it/aot/reflect-config.json");
+		});
+	}
+
+	Stream<String> collectRelativeFileNames(Path sourceDirectory) {
+		try {
+			return Files.walk(sourceDirectory).filter(Files::isRegularFile)
+					.map((path) -> path.subpath(sourceDirectory.getNameCount(), path.getNameCount()).toString());
+		}
+		catch (IOException ex) {
+			throw new IllegalStateException(ex);
+		}
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/aot/pom.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>aot</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.source>@java.version@</maven.compiler.source>
+		<maven.compiler.target>@java.version@</maven.compiler.target>
+	</properties>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>@project.groupId@</groupId>
+				<artifactId>@project.artifactId@</artifactId>
+				<version>@project.version@</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>aot-generate</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot</artifactId>
+			<version>@project.version@</version>
+		</dependency>
+		<dependency>
+			<groupId>jakarta.servlet</groupId>
+			<artifactId>jakarta.servlet-api</artifactId>
+			<version>@jakarta-servlet.version@</version>
+			<scope>provided</scope>
+		</dependency>
+	</dependencies>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/aot/src/main/java/org/test/SampleApplication.java

@@ -0,0 +1,29 @@
+/*
+ * 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.test;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration(proxyBeanMethods = false)
+public class SampleApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SampleApplication.class, args);
+	}
+
+}

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

@@ -0,0 +1,144 @@
+/*
+ * Copyright 2012-2022 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.io.File;
+import java.io.IOException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.maven.model.Resource;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.shared.artifact.filter.collection.FilterArtifacts;
+
+import org.springframework.boot.loader.tools.FileUtils;
+
+/**
+ * Base class to run a spring application.
+ *
+ * @author Phillip Webb
+ * @author Stephane Nicoll
+ * @author David Liu
+ * @author Daniel Young
+ * @author Dmytro Nosan
+ * @since 6.0.0
+ * @see RunMojo
+ * @see StartMojo
+ */
+public abstract class AbstractApplicationRunMojo extends AbstractRunMojo {
+
+	/**
+	 * Add maven resources to the classpath directly, this allows live in-place editing of
+	 * resources. Duplicate resources are removed from {@code target/classes} to prevent
+	 * them to appear twice if {@code ClassLoader.getResources()} is called. Please
+	 * consider adding {@code spring-boot-devtools} to your project instead as it provides
+	 * this feature and many more.
+	 * @since 1.0.0
+	 */
+	@Parameter(property = "spring-boot.run.addResources", defaultValue = "false")
+	private boolean addResources = false;
+
+	/**
+	 * Path to agent jars. NOTE: a forked process is required to use this feature.
+	 * @since 2.2.0
+	 */
+	@Parameter(property = "spring-boot.run.agents")
+	private File[] agents;
+
+	/**
+	 * Flag to say that the agent requires -noverify.
+	 * @since 1.0.0
+	 */
+	@Parameter(property = "spring-boot.run.noverify")
+	private boolean noverify = false;
+
+	/**
+	 * Flag to include the test classpath when running.
+	 * @since 1.3.0
+	 */
+	@Parameter(property = "spring-boot.run.useTestClasspath", defaultValue = "false")
+	private Boolean useTestClasspath;
+
+	@Override
+	protected void run(File workingDirectory, String startClassName, Map<String, String> environmentVariables)
+			throws MojoExecutionException, MojoFailureException {
+		List<String> args = new ArrayList<>();
+		addAgents(args);
+		addJvmArgs(args);
+		addClasspath(args);
+		args.add(startClassName);
+		addArgs(args);
+		run(workingDirectory, args, environmentVariables);
+	}
+
+	/**
+	 * Run with a forked VM, using the specified command line arguments.
+	 * @param workingDirectory the working directory of the forked JVM
+	 * @param args the arguments (JVM arguments and application arguments)
+	 * @param environmentVariables the environment variables
+	 * @throws MojoExecutionException in case of MOJO execution errors
+	 * @throws MojoFailureException in case of MOJO failures
+	 */
+	protected abstract void run(File workingDirectory, List<String> args, Map<String, String> environmentVariables)
+			throws MojoExecutionException, MojoFailureException;
+
+	@Override
+	protected URL[] getClassPathUrls() throws MojoExecutionException {
+		try {
+			List<URL> urls = new ArrayList<>();
+			addUserDefinedDirectories(urls);
+			addResources(urls);
+			addProjectClasses(urls);
+			FilterArtifacts filters = (this.useTestClasspath ? getFilters() : getFilters(new TestArtifactFilter()));
+			addDependencies(urls, filters);
+			return urls.toArray(new URL[0]);
+		}
+		catch (IOException ex) {
+			throw new MojoExecutionException("Unable to build classpath", ex);
+		}
+	}
+
+	private void addAgents(List<String> args) {
+		if (this.agents != null) {
+			if (getLog().isInfoEnabled()) {
+				getLog().info("Attaching agents: " + Arrays.asList(this.agents));
+			}
+			for (File agent : this.agents) {
+				args.add("-javaagent:" + agent);
+			}
+		}
+		if (this.noverify) {
+			args.add("-noverify");
+		}
+	}
+
+	private void addResources(List<URL> urls) throws IOException {
+		if (this.addResources) {
+			for (Resource resource : this.project.getResources()) {
+				File directory = new File(resource.getDirectory());
+				urls.add(directory.toURI().toURL());
+				FileUtils.removeDuplicatesFromOutputDirectory(this.classesDirectory, directory);
+			}
+		}
+	}
+
+}