Call PauseHandler resume from the resume endpoint

docs/modules/ROOT/pages/spring-cloud-commons/application-context-services.adoc

@@ -291,7 +291,7 @@ For a Spring Boot Actuator application, some additional management endpoints are
   To enabled this endpoint you must set `management.endpoint.env.post.enabled=true` and set a regular expression to limit what properties may be set at `management.endpoint.env.post.valid-keys-regex`.
 * `/actuator/refresh` to re-load the bootstrap context and refresh the `@RefreshScope` beans.
 * `/actuator/restart` to close the `ApplicationContext` and restart it (disabled by default).
-* `/actuator/pause` and `/actuator/resume` for calling the `Lifecycle` methods (`stop()` and `start()` on the `ApplicationContext`).
+* `/actuator/pause` and `/actuator/resume` for calling `pause()` and `resume()` on every `PauseHandler` bean. A handler for Spring Integration `Pausable` components is provided.
 
 NOTE: While enabling the `POST` method for `/actuator/env` endpoint can provide flexibility and convenience in managing your application environment variables,
 it's critical to ensure that the endpoint is secured, monitored and valid keys to update are set to prevent potential security risks.

spring-cloud-context/src/main/java/org/springframework/cloud/context/restart/RestartEndpoint.java

@@ -68,6 +68,8 @@ public class RestartEndpoint implements ApplicationListener<ContextRefreshedWith
 
 	private List<PauseHandler> pauseHandlers = Collections.emptyList();
 
+	private volatile boolean paused;
+
 	private long timeout;
 
 	// @ManagedAttribute
@@ -93,12 +95,16 @@ public void onApplicationEvent(ContextRefreshedWithApplicationEvent input) {
 			this.args = this.event.getArgs();
 			this.application = this.event.getSpringApplication();
 			this.application.addInitializers(new PostProcessorInitializer());
-			this.pauseHandlers = this.context.getBeanProvider(PauseHandler.class)
-				.orderedStream()
-				.collect(Collectors.toList());
+			collectPauseHandlers();
 		}
 	}
 
+	private void collectPauseHandlers() {
+		this.pauseHandlers = this.context.getBeanProvider(PauseHandler.class)
+			.orderedStream()
+			.collect(Collectors.toList());
+	}
+
 	@WriteOperation
 	public Object restart() {
 		Thread thread = new Thread(this::safeRestart);
@@ -140,10 +146,14 @@ public synchronized ConfigurableApplicationContext doRestart() {
 			}
 			this.application.setEnvironment(this.context.getEnvironment());
 			close();
+			// The handlers and the paused state belong to the context that was closed
+			this.pauseHandlers = Collections.emptyList();
+			this.paused = false;
 			// If running in a webapp then the context classloader is probably going to
 			// die so we need to revert to a safe place before starting again
 			overrideClassLoaderForRestart();
 			this.context = this.application.run(this.args);
+			collectPauseHandlers();
 		}
 		return this.context;
 	}
@@ -174,6 +184,7 @@ public synchronized void doPause() {
 		for (PauseHandler handler : this.pauseHandlers) {
 			handler.pause();
 		}
+		this.paused = true;
 	}
 
 	// @ManagedOperation
@@ -182,6 +193,7 @@ public synchronized void doResume() {
 			PauseHandler handler = this.pauseHandlers.get(i);
 			handler.resume();
 		}
+		this.paused = false;
 	}
 
 	private void overrideClassLoaderForRestart() {
@@ -235,7 +247,7 @@ public class ResumeEndpoint {
 
 		@WriteOperation
 		public Boolean resume() {
-			if (!isRunning()) {
+			if (RestartEndpoint.this.paused) {
 				doResume();
 				return true;
 			}

spring-cloud-context/src/test/java/org/springframework/cloud/context/restart/RestartIntegrationTests.java

@@ -22,6 +22,7 @@
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
 import static org.assertj.core.api.BDDAssertions.then;
@@ -70,10 +71,75 @@ public void testRestartTwice() {
 		 */
 	}
 
+	@Test
+	public void testResumeAfterPause() {
+		this.context = SpringApplication.run(PauseHandlerConfiguration.class,
+				"--management.endpoint.restart.enabled=true", "--server.port=0",
+				"--management.endpoints.web.exposure.include=restart,pause,resume");
+
+		RestartEndpoint endpoint = this.context.getBean(RestartEndpoint.class);
+		TestPauseHandler handler = this.context.getBean(TestPauseHandler.class);
+
+		then(endpoint.getResumeEndpoint().resume()).isFalse();
+		then(endpoint.getPauseEndpoint().pause()).isTrue();
+		then(handler.paused).isTrue();
+		then(endpoint.getResumeEndpoint().resume()).isTrue();
+		then(handler.paused).isFalse();
+		then(endpoint.getResumeEndpoint().resume()).isFalse();
+	}
+
+	@Test
+	public void testRestartAfterPause() {
+		this.context = SpringApplication.run(PauseHandlerConfiguration.class,
+				"--management.endpoint.restart.enabled=true", "--server.port=0",
+				"--management.endpoints.web.exposure.include=restart,pause,resume");
+
+		RestartEndpoint endpoint = this.context.getBean(RestartEndpoint.class);
+		TestPauseHandler closed = this.context.getBean(TestPauseHandler.class);
+
+		then(endpoint.getPauseEndpoint().pause()).isTrue();
+		this.context = endpoint.doRestart();
+		TestPauseHandler handler = this.context.getBean(TestPauseHandler.class);
+		then(handler).isNotSameAs(closed);
+
+		then(endpoint.getResumeEndpoint().resume()).isFalse();
+		then(endpoint.getPauseEndpoint().pause()).isTrue();
+		then(handler.paused).isTrue();
+		then(endpoint.getResumeEndpoint().resume()).isTrue();
+		then(handler.paused).isFalse();
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	@EnableAutoConfiguration
 	protected static class TestConfiguration {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	@EnableAutoConfiguration
+	protected static class PauseHandlerConfiguration {
+
+		@Bean
+		TestPauseHandler testPauseHandler() {
+			return new TestPauseHandler();
+		}
+
+	}
+
+	static class TestPauseHandler implements PauseHandler {
+
+		boolean paused;
+
+		@Override
+		public void pause() {
+			this.paused = true;
+		}
+
+		@Override
+		public void resume() {
+			this.paused = false;
+		}
+
+	}
+
 }