GH-87 - Expose module structure as actuator endpoint.

Introduce Spring Modulith Actuator module to expose the application module structure as Spring Boot actuator. This required a Spring Modulith Runtime module to be extracted from the Spring Modulith Observability one. The former now contains the auto-configured ApplicationRuntime and ApplicationModulesRuntime bean instances to be able to bootstrap a ApplicationModules asynchronously on application startup. The actuator module then contains a Spring Boot @Endpoint implementation consuming the ApplicationModules to render JSON describing the application module structure.

spring-modulith-runtime/src/test/java/org/springframework/modulith/runtime/autoconfigure/SpringBootApplicationRuntimeUnitTests.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 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.modulith.runtime.autoconfigure;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.aop.framework.ProxyFactory;
+import org.springframework.context.ApplicationContext;
+import org.springframework.modulith.runtime.ApplicationRuntime;
+
+/**
+ * Unit tests for {@link SpringBootApplicationRuntime}.
+ *
+ * @author Oliver Drotbohm
+ */
+@ExtendWith(MockitoExtension.class)
+class SpringBootApplicationRuntimeUnitTests {
+
+	@Mock ApplicationContext context;
+
+	@Test // GH-87
+	void extractsUserTypeFromClassBasedProxy() {
+
+		Object proxy = new ProxyFactory(new Sample()).getProxy();
+		ApplicationRuntime runtime = new SpringBootApplicationRuntime(context);
+
+		assertThat(proxy.getClass()).isNotEqualTo(Sample.class);
+		assertThat(runtime.getUserClass(proxy, "sample")).isEqualTo(Sample.class);
+	}
+
+	static class Sample {}
+}

spring-modulith-runtime/src/test/java/org/springframework/modulith/runtime/autoconfigure/SpringModulithRuntimeAutoConfigurationIntegrationTests.java

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+/*
+ * Copyright 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.modulith.runtime.autoconfigure;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.ApplicationContext;
+import org.springframework.modulith.runtime.ApplicationModulesRuntime;
+import org.springframework.modulith.runtime.ApplicationRuntime;
+
+/**
+ * Integration thest for {@link SpringModulithRuntimeAutoConfiguration}.
+ *
+ * @author Oliver Drotbohm
+ */
+@SpringBootTest
+class SpringModulithRuntimeAutoConfigurationIntegrationTests {
+
+	@SpringBootApplication
+	static class SampleApp {}
+
+	@Autowired ApplicationContext context;
+
+	@Test // GH-87
+	void bootstrapRegistersRuntimeInstances() {
+
+		assertThat(context.getBean(ApplicationRuntime.class)).isNotNull();
+		assertThat(context.getBean(ApplicationModulesRuntime.class)).isNotNull();
+	}
+}