https://github.com/spring-projects/spring-modulith/issues/1048

pom.xml

@@ -24,6 +24,7 @@
 		<module>spring-modulith-bom</module>
 		<module>spring-modulith-core</module>
 		<module>spring-modulith-docs</module>
+		<module>spring-modulith-maven-plugin</module>
 		<module>spring-modulith-events</module>
 		<module>spring-modulith-junit</module>
 		<module>spring-modulith-moments</module>

spring-modulith-maven-plugin/pom.xml

@@ -0,0 +1,120 @@
+<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+	<parent>
+		<groupId>org.springframework.modulith</groupId>
+		<artifactId>spring-modulith</artifactId>
+		<version>2.1.0-SNAPSHOT</version>
+		<relativePath>../pom.xml</relativePath>
+	</parent>
+
+	<artifactId>spring-modulith-maven-plugin</artifactId>
+	<packaging>maven-plugin</packaging>
+	<name>Spring Modulith - Maven Plugin</name>
+	<description>Maven plugin and site report support for Spring Modulith documentation.</description>
+
+	<properties>
+		<module.name>spring.modulith.maven.plugin</module.name>
+		<maven.api.version>3.8.6</maven.api.version>
+		<maven.reporting.version>3.1.0</maven.reporting.version>
+		<maven.plugin.tools.version>3.15.2</maven.plugin.tools.version>
+		<plantuml.version>1.2024.8</plantuml.version>
+	</properties>
+
+	<dependencies>
+
+		<dependency>
+			<groupId>${project.groupId}</groupId>
+			<artifactId>spring-modulith-docs</artifactId>
+			<version>${project.version}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>net.sourceforge.plantuml</groupId>
+			<artifactId>plantuml</artifactId>
+			<version>${plantuml.version}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.yaml</groupId>
+			<artifactId>snakeyaml</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.maven</groupId>
+			<artifactId>maven-plugin-api</artifactId>
+			<version>${maven.api.version}</version>
+			<scope>provided</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.maven</groupId>
+			<artifactId>maven-core</artifactId>
+			<version>${maven.api.version}</version>
+			<scope>provided</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.maven</groupId>
+			<artifactId>maven-artifact</artifactId>
+			<version>${maven.api.version}</version>
+			<scope>provided</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.maven.plugin-tools</groupId>
+			<artifactId>maven-plugin-annotations</artifactId>
+			<version>${maven.plugin.tools.version}</version>
+			<scope>provided</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.maven.reporting</groupId>
+			<artifactId>maven-reporting-api</artifactId>
+			<version>${maven.reporting.version}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.maven.reporting</groupId>
+			<artifactId>maven-reporting-impl</artifactId>
+			<version>${maven.reporting.version}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-plugin-plugin</artifactId>
+				<version>${maven.plugin.tools.version}</version>
+				<configuration>
+					<goalPrefix>modulith</goalPrefix>
+				</configuration>
+				<executions>
+					<execution>
+						<id>default-descriptor</id>
+						<goals>
+							<goal>descriptor</goal>
+						</goals>
+					</execution>
+					<execution>
+						<id>help-goal</id>
+						<goals>
+							<goal>helpmojo</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+</project>
+
+
+

spring-modulith-maven-plugin/src/main/java/org/springframework/modulith/maven/DiagramRenderer.java

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2026 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.modulith.maven;
+
+interface DiagramRenderer {
+
+	RenderedDiagram render(String source);
+}
+

spring-modulith-maven-plugin/src/main/java/org/springframework/modulith/maven/ModulithReportMojo.java

@@ -0,0 +1,162 @@
+/*
+ * Copyright 2026 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.modulith.maven;
+
+import java.io.File;
+import java.net.URLClassLoader;
+import java.util.Locale;
+
+import org.apache.maven.doxia.siterenderer.Renderer;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Execute;
+import org.apache.maven.plugins.annotations.LifecyclePhase;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.plugins.annotations.ResolutionScope;
+import org.apache.maven.project.MavenProject;
+import org.apache.maven.reporting.AbstractMavenReport;
+import org.apache.maven.reporting.MavenReportException;
+import org.springframework.modulith.core.ApplicationModules;
+import org.springframework.modulith.docs.Documenter.DiagramOptions.DiagramStyle;
+import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
+
+@Mojo(name = "report", defaultPhase = LifecyclePhase.SITE, threadSafe = true,
+		requiresDependencyResolution = ResolutionScope.RUNTIME)
+@Execute(phase = LifecyclePhase.COMPILE)
+public class ModulithReportMojo extends AbstractMavenReport {
+
+	@Component
+	private Renderer siteRenderer;
+
+	@Parameter(defaultValue = "${project}", required = true, readonly = true)
+	private MavenProject project;
+
+	@Parameter(property = "spring.modulith.report.skip", defaultValue = "false")
+	private boolean skip;
+
+	@Parameter(property = "spring.modulith.report.applicationClassName")
+	private String applicationClassName;
+
+	@Parameter(property = "spring.modulith.report.basePackage")
+	private String basePackage;
+
+	@Parameter(property = "spring.modulith.report.name", defaultValue = "Spring Modulith Report")
+	private String siteReportName;
+
+	@Parameter(property = "spring.modulith.report.description", defaultValue = "Application module dependency diagrams generated from Spring Modulith metadata")
+	private String siteReportDescription;
+
+	@Parameter(property = "spring.modulith.report.outputdir", defaultValue = "modulith")
+	private String siteReportDirectory;
+
+	@Parameter(property = "spring.modulith.report.renderDiagrams", defaultValue = "true")
+	private boolean renderDiagrams;
+
+	@Parameter(property = "spring.modulith.report.diagramStyle", defaultValue = "C4")
+	private DiagramStyle diagramStyle;
+
+	private final ProjectClassLoaderFactory classLoaderFactory = new ProjectClassLoaderFactory();
+	private final ModulithSiteReportGenerator generator = new ModulithSiteReportGenerator(new PlantUmlSvgRenderer());
+
+	@Override
+	public String getOutputName() {
+		return siteReportDirectory + File.separator + "index";
+	}
+
+	@Override
+	public String getName(Locale locale) {
+		return siteReportName;
+	}
+
+	@Override
+	public String getDescription(Locale locale) {
+		return siteReportDescription;
+	}
+
+	@Override
+	protected Renderer getSiteRenderer() {
+		return siteRenderer;
+	}
+
+	@Override
+	protected String getOutputDirectory() {
+		return getReportOutputDirectory().getAbsolutePath();
+	}
+
+	@Override
+	protected MavenProject getProject() {
+		return project;
+	}
+
+	@Override
+	protected void executeReport(Locale locale) throws MavenReportException {
+
+		validateConfiguration();
+
+		try (URLClassLoader classLoader = classLoaderFactory.create(project)) {
+
+			var original = Thread.currentThread().getContextClassLoader();
+
+			try {
+				Thread.currentThread().setContextClassLoader(classLoader);
+
+				var modules = createApplicationModules(classLoader);
+				var outputDirectory = getReportOutputDirectory().toPath().resolve(siteReportDirectory);
+				generator.generate(modules, outputDirectory, diagramStyle, renderDiagrams);
+
+			} finally {
+				Thread.currentThread().setContextClassLoader(original);
+			}
+
+		} catch (Exception ex) {
+			throw new MavenReportException("Failed to generate Spring Modulith site report", ex);
+		}
+	}
+
+	@Override
+	public boolean canGenerateReport() {
+		return !skip;
+	}
+
+	@Override
+	public boolean isExternalReport() {
+		return true;
+	}
+
+	private ApplicationModules createApplicationModules(ClassLoader classLoader) throws ClassNotFoundException {
+
+		if (applicationClassName != null && !applicationClassName.isBlank()) {
+			Class<?> applicationType = ClassUtils.forName(applicationClassName, classLoader);
+			return ApplicationModules.of(applicationType);
+		}
+
+		Assert.hasText(basePackage, "Either applicationClassName or basePackage must be configured!");
+		return ApplicationModules.of(basePackage);
+	}
+
+	private void validateConfiguration() {
+
+		boolean hasApplicationClass = applicationClassName != null && !applicationClassName.isBlank();
+		boolean hasBasePackage = basePackage != null && !basePackage.isBlank();
+
+		if (hasApplicationClass == hasBasePackage) {
+			throw new IllegalArgumentException(
+					"Configure exactly one of spring.modulith.report.applicationClassName or spring.modulith.report.basePackage.");
+		}
+	}
+}
+