GH-1338 - Improve bootstrap of ApplicationModulesEndpoint.

We now avoid the eager reference to an ApplicationModulesRuntime instance to avoid it bootstrapping at all, in case the precomputed variant is used.

Author: odrotbohm

spring-modulith-actuator/src/main/java/org/springframework/modulith/actuator/ApplicationModulesEndpoint.java

@@ -19,6 +19,8 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.BeanFactoryInitializer;
+import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
 import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
 import org.springframework.modulith.core.ApplicationModules;
@@ -32,7 +34,7 @@
  * @author Oliver Drotbohm
  */
 @Endpoint(id = "modulith")
-public class ApplicationModulesEndpoint {
+public class ApplicationModulesEndpoint implements BeanFactoryInitializer<ListableBeanFactory> {
 
 	private static final Logger LOGGER = LoggerFactory.getLogger(ApplicationModulesEndpoint.class);
 
@@ -87,4 +89,13 @@ public static ApplicationModulesEndpoint ofApplicationModules(Supplier<Applicati
 	String getApplicationModules() {
 		return structure.obtain();
 	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.BeanFactoryInitializer#initialize(org.springframework.beans.factory.ListableBeanFactory)
+	 */
+	@Override
+	public void initialize(ListableBeanFactory beanFactory) {
+		structure.obtain();
+	}
 }

spring-modulith-actuator/src/main/java/org/springframework/modulith/actuator/autoconfigure/ApplicationModulesEndpointConfiguration.java

@@ -19,6 +19,7 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.context.annotation.Bean;
@@ -44,7 +45,7 @@ class ApplicationModulesEndpointConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	ApplicationModulesEndpoint applicationModulesEndpoint(ApplicationModulesRuntime runtime) {
+	ApplicationModulesEndpoint applicationModulesEndpoint(ObjectProvider<ApplicationModulesRuntime> runtime) {
 
 		if (PRECOMPUTED.exists()) {
 
@@ -54,7 +55,7 @@ ApplicationModulesEndpoint applicationModulesEndpoint(ApplicationModulesRuntime
 			return ApplicationModulesEndpoint.precomputed(fileContent);
 
 		} else {
-			return ApplicationModulesEndpoint.ofApplicationModules(runtime);
+			return ApplicationModulesEndpoint.ofApplicationModules(runtime.getObject());
 		}
 	}
 }